1

CONTENTS

1. Introduction 2

2. Review of Literature 3

3. Anatomy & development of the maxilla & palate. 34

4. Anatomy, Physiology of the Velopharynx 46

and Speech

5. Management of palato-maxillary defects.

i) Multidisciplinary approach. 65

ii) Psychological considerations. 75

iii) Materials used in the management. 86

iv) Prosthetic management of soft & hard palate 100

defects in general.

v) Prosthetic management of hard palate defects. 107

vi) Prosthetic management of soft palate defects. 178

vii) Prosthetic management of Cleft lip and palate. 200

6. Discussion 226

7. Conclusion 230

8. Bibliography 231

2

Maxillofacial Prosthetics is the art and science of anatomic,

functional or cosmetic reconstruction by means of non living substitutes of

those regions in the maxilla, mandible, face and even other body parts that

are missing or defective because of surgical intervention, trauma,

pathology or developmental or congenital malformation.

It is considered a sub speciality of Prosthodontics, as many phases

of Maxillofacial Prosthetics are merely logical extensions of

Prosthodontics. The intimate relationship between the two becomes even

more obvious when it is noted that the basic techniques and materials

used are similar if not identical.

Success in Maxillofacial Prosthetics as in Prosthodontics depends

on full cognizance of the principles that underlie facial harmony, colour

matching, anchorage and retention, weight bearing and leverage, durability

and strength of materials used, tissue compatibility and tolerance.

This dissertation attempts to emphasize these principles while

reviewing the rehabilitation of maxillary and palatal defects.

3

The MaxiIlofacial Prosthodontist normally provides appliances and

devices to restore esthetics and function to the patient who cannot be

restored to normal appearance or function by means of plastic

reconstruction. Despite, remarkable advances in surgical management of

oral and facial defects, many such defects especially those involving the

eyes and ears, cannot be satisfactorily repaired by surgery alone. Further,

the increased lifespan of individuals and the growing demand for health

care services puts additional obligations on the maxillofacial

prosthodontist.

Patients with palatal defects labor under handicaps, which cannot

be fully appreciated by those with normal palates. The prosthetic or

non-surgical method of cleft-palate or acquired defects of palate correction

comprises of essentially two forms of appliances i.e. the obturator and the

artificial velum.

The term obturator is taken from the Latin 'obturare' meaning to

stop up. It is an appliance, which corrects any opening of the hard or soft

palate or of both. Early literature states that obturators and prosthesis for

oral deformities were amongst the earliest appliances in the mouth, and

consisted of wads of fabrics, wax, metal, leather and wood.

The following review surveys the literature and attempts to relate this

information to problems encountered in the successful rehabilitation of

patients with maxillofacial defects in the hard and soft palate.

4

Ambrose Pare28 (1510-90) was one of the first of these operators to

furnish description of an obturator. Pare introduced the term 'bec-de-lievre'

(harelip), merely using obturators for closing palatal defects. Obturators

designed by him, had their own means of retention. The first obturator

designed by him, consisted of a small sponge, which would swell by

moisture distilled from the brain and puffed to fill the cavity of the palate so

that the plate could not fall down. A second type of obturator described by

him contained a turnbuckle which could be rotated some 90º by forceps for

retention.

Pierre Fauchard28 (1678-1761) described ingenious obturators that

composed of a stalk, terminating in a screw with wings covered by sponge

to aid in retention.

Fig.1: Mechanical devices that Pare used to close perforation of the palate. (a)- A dry sponge attached to prongs that swell up and provide retention. (b)- A turnbuckle type of arrangement used for retention.

Fig. 2: Fauchard’s designs for palatal obturators. (a) Wings are in the shape of propellers, which can be folded during

insertion and spread out after insertion with special key. (b) Retaining feature is butterfly shaped. (c) An obturator made in 1900 inspired by Fauchard.

5

Stearn 134 (1841) was the first to introduce speech aid prosthesis

Rowell, Hullihen and Sversen84 introduced Velum to obturators. Velum

is an obturator prosthesis designed to close a defect in soft palate.

Suerson 84,104 (1867) suggested the rigid fixed obturator using a wire loop

posterior extension shaped by use of warm gutta percha.

Kingsley28,84 (1880) described artificial appliances for the restoration of

congenital as well as acquired defects of the maxillofacial region with soft

vulcanizable rubber. The Kingsley velum consists of two flaps joined

throughout the midline. The lower flap, the one that completes the palatal

dome, extends from the apex of the fissure posteriorly as far as the bases

of the uvulae. This flap overlaps the soft parts to prevent it being pushed

through the cleft. The other flap is also triangular with its posterior border

curved and thinned to featheredge to prevent irritation of the posterior

pharyngeal wall when it comes in contact.

Fig. 3: Suerson type obturator for cleft palate.

Fig. 4: Kingsley Velum

6

Kelsey-Fry5 (1927) stressed the very great need of the close cooperation

between the surgeon and the dental prosthetist and the importance of pre-

operative consultation to decide, as exactly as possible, the amount of

tissue to be removed, which teeth (if any) to preserve and so forth.

Pitchler5 (1929) discussed a vulcanite appliance used after maxillary

resection, which was made in two parts. The upper hollow portion filling the

space created by surgery and fitting lid like into the lower portion or

denture to which it is fastened, when in position by a lateral hook.

Kazanjian5 (1931) described an ingenious arrangement for hinging the

anterior extension of the prosthesis so that the appliance could be more

easily introduced, and after placement the anterior attachment would be

swung back into position where it could be fastened or clipped in place.

Schalit A.136 (1946) first described meatus obturator for cleft palate.

Gaylord James50 (1951) reviewed the Fitz-Gibbon technique for

rehabilitation of the cleft palate patient, which includes an all-metal

obturator in gold. He also mentioned the Fitz-Gibbon classification of cleft

palate patients

Appleman RM5 (1951) described the prosthetic repair of defects of the

maxilla due to surgery. He mentions the technique of making impressions.

The preliminary impression is made in impression compound, which is

withdrawn before it sets completely. This is allowed to harden outside the

mouth, scraped and then an irreversible hydrocolloid final impression is

made with this tray.

The prosthesis in edentulous maxillectomy case is made in a way

that first, the bulb is prepared over which another impression is made and

then the record base fabricated to fuse with bulb, over which the records

are made and then the obturator is made. He also described the use of a

soft plasticizing acrylic material in the denture on the buccal side of

remaining teeth for retention in partially dentulous cases where the

remaining teeth are not healthy enough to withstand loads of metal

retainers.

Olinger NA95 (1952) reviewed cleft palate rehabilitation and described the

technique for fabricating an artificial velum attached by a pin lock hinge to

the palatal plate and also replacing the vomer by a vertical flange

intranasally.

7

Torn DB 139(1952) has described speech and partial denture prosthetics

and emphasized the need for speech therapy following both surgical and

prosthetic correction.

Martin BC and Trabue JC90 (1952) emphasized the treatment to be

individualized for each patient and the advantage of using a team

approach of a surgeon, orthodontist, prosthodontist and speech therapist.

Lazzari JB 73 (1952) described prosthetic closure of a traumatic palatal

perforation and recommended that the opening in the palate be packed

within 2 mm of the palatal surface of the opening as it appears on the cast.

No relief is provided in and about the opening. The restoration is fabricated

in gold like a regular cast partial denture.

Ackerman A.J1 (1955) advocated obturator prosthesis for situations in

which the hard palate has been removed completely together with some

portions of the soft palate. The prosthesis was based upon extension into

the nasal cavity to achieve retention. The posterior extension of the

prosthesis was made to rest on the floor of the nasal cavity at the rim of

the defect and the anterior extension was in the region of nasal spine. The

anterior extension of the prosthesis was made movable using a wire insert

to facilitate retraction and extension of the prosthesis.

Nififfer T. J. & Shipron T.J. 92(1957) described a technique for fabricating

the hollow bulb obturator. They lined the defect with two thickness of wax

and adapted a paper clip so that a loop extends down into the cavity, while

the ends of the wire rest on the keyed artificial stone. The paper clip lined

cavity is then poured in stone. The paper clip attached stone assembly is

used for making hollow bulb by forming the interface between two sections

of the flasks during packing.

Gibbons and Bloomer 51(1958). They first described the palatal lift

prosthesis as a management technique for velopharyngeal incompetence.

They designed a supportive type of prosthetic speech aid elevating the soft

palate as a means of decreasing the lumen of the palatopharyngeal valve

in speech. The basic speech aid prosthesis consisted of the retentive

portion of cast metal frame with wrought wire retainers clasping teeth and

a metal extension with plastic for elevating the soft palate. According to

them, the degree of elevation and retraction of the palate accomplished by

the supporting prosthesis presents an adjustment to several requirements.

q A reduction in palatopharyngeal lumen needed to decrease

hypernasality and increase oral pressure for consonant articulation.

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q The preservation of an airway to provide for comfortable nasal

breathing.

q The avoidance of undue stress upon the supporting teeth as the

appliance resists the natural elasticity and weight of the palate in

elevation.

Sharry J.J 124(1958) commented that meatus obturator first described by

Schialit (1946) resulted in remarkable improvement of speech in cleft

palate patients. He stated that since, it does not depend upon palatal

muscle movements to be effective, it is not affected by their anatomic

limitations. It is based upon the presumption that complete occlusion of the

oropharynx from the nasopharynx is not necessary for good speech by

cleft palate persons.

Rather, it is believed that partial occlusion of the nasal cavity results in a

marked diminution or complete elimination of the nasality in the speech of

cleft palate patients.

He also stated that the medial wall of the prosthesis along the

midline of the palate should extend only as high as remaining hard palate,

because the medial wall of the defect covered by a very thin layer of

mucosa would be easily irritated by a large prosthesis.

Ali Aram and Subtently 6(1959) studied normal subjects, and concluded

that the pharyngeal section must be properly designed at the desired level.

They found that position and movement of soft palate, in relation to the

pharynx changes with age.

At birth and shortly thereafter, the soft palate at rest is roughly

parallel to the roof of the pharynx so that the upper nasopharynx is only a

narrow slot. Essentially, a superior-inferior movement of the soft palate

accomplishes closure of the velopharyngeal mechanism. As growth occurs

in the pharyngeal area and the adenoid tissue regress, the movement of

the soft palate takes the characteristic anteroposterior elevation

demonstrated by most adults.

Velopharyngeal closure is slightly below the level of the palatal

plane upto 8 years of age, and is consistently above the level of the palatal

plane thereafter. At one time, it was believed that Passavant’s pad

identified the vertical locale of the nasopharyngeal portion of the

prosthesis. However, the variable occurrence and location of Passavant's

pad usurped its employment as a reliable landmark. Currently, the bulge of

9

the anterior tubercle of the atlas is used for bulk orientation, keeping in

mind that the area of pharyngeal constriction may occur above this locale.

Aram & Subtenly acknowledged the existence of individual

asymmetries in pharyngeal junction which makes it necessary to modify

the shape and placement of the pharyngeal section, and concluded that

the dentist should design a bulb that is minimal in size, so as to relieve

muscular strain and torque on the prosthesis while contacting both lateral

and posterior pharyngeal walls. They studied the speech of 23 adult and

adolescent cleft palate speakers with obturator prosthesis. They reported a

wide variation in obturator position and size. The position of the obturator

varied from 20mm below the palatal plane to 6mm above the plane. The

vertical extension varied from 11 to 35mm. The best speech results were

obtained with higher placement of the obturator. Where deficiencies were

noted clinically regarding tissue approximation, the lateral dimension was

most commonly found to be deficient in extension.

Miglani and Drane 87(1959) believed in the presence of teeth on the non-

surgical side as a prerequisite for an immediate obturator. They also

believed in the importance of fabricating temporary obturator about 10

days postoperatively.

Adisman IK. 2(1962) described the fabrication of removable partial

dentures for patients with acquired defects of the maxilla and mandible. He

stated that the fundamental objective is the restoration of function and the

preservation of the remaining teeth and tissues while treating these

patients. Regardless of the fact, whether, the appliance is transitional or

temporary in nature, fundamental principles of partial denture designs

should be followed.

He advocated sectional type final impression to ensure accurate

duplication of anatomic undercuts in the nasal cavity or hard palate to be

assembled out of the mouth in proper position. He also advocated

utilization of retentive devices for removable partial denture obturators like

the internal clip attachment, circumferential, Roach and Jackson Grip

Clasps and precision attachments whenever and wherever possible. He

believed that to decrease the weight of prosthesis, obturator should be

hollow. He stated that for defects in the hard palate it is sufficient to cover

the defect and create a seal by engaging a minimal amount of the

periphery of the undercut surface of the defect. Unlike, the hard palate

10

defects, opening in soft palate may require more extensive coverage area

to create an efficient seal.

Robinson J. E. 118(1963) described a surgical prosthetic appliance for

patients undergoing surgical removal of the maxilla and floor of the orbit. It

consisted of an acrylic resin template with spring wire attachment on the

defect side that would project near the infra-orbital rim over the enucleated

eye to be fastened, to the forehead for retention. According to him, such a

surgical prosthesis will add to the success of both the operative

procedures and the rehabilitation of the patient.

Bulbulian AH 28(1965) in his excellent review on the evolution of

maxillofacial prosthetics mentioned the landmark contributions of the

pioneers in this field.

Payne A.G.L., Welton W.G. 105(1965) described an inflatable obturator

design using a mechanism similar to the air valve of a tyre.

Warren D.W. 146(1965) discussed the physiologic approach to cleft palate

prosthesis and emphasized the use of pressure-flow technique in the

prosthetic management. The technique provides a means for estimating

muscle valving against the speech aid as well as relating changes in the

velar structure to associated changes in speech.

Roberts 29(1965) described fabrication of closed hollow bulb prosthesis

utilizing modeling compound for filling the defect area, which is later

removed and closed by acrylic lid. He advocated that the occlusion should

be as balanced as possible, with freedom of lateral movements without

lateral interferences, He stated that in cases where retention is less,

mechanical means of retention should be utilized using springs and

swivels. The action of spring is to produce forces, which will press the

upper denture upward and backwards and the lower denture downwards

and forwards. However lateral movements are restricted. The springs are

attached to the denture in the premolar region by swivels.

A.C. Roberts also advocated split model method for hollow bulb

obturator in cases when casts have deep undercuts. The model is fret

sawed through a depth of about 1/8 inch from the base, the saw cut

extending through the cavity. The model is then fractured through the

remaining 1/8 inch. This aids in reassembling and location. This method

also allows the extension into the cavity to be tried in, and alterations made

before finishing the obturator.

11

Roberts described obturator prosthesis for congenital defects of soft palate

as movable and stationary velum prosthesis The movable velum

prosthesis is one in which the velum prosthesis is under the control of the

muscles of soft palate and this type of appliance responds to the delicate

movements of the muscles. Such an appliance is attached to the main

appliance that is the retentive appliance by a hinge mechanism.

The stationary velum prosthesis is a projection from the posterior

end of the denture into the pharyngeal space and is so shaped that the

muscles are always in contact with the lateral and posterior surfaces of the

appliances in their various movements. C. B. Thompson described velum

obturator in which the velum is made hollow and consisted of two parts i.e.

the main velum, which is hollowed out and a lid, which is sealed with cold

cure acrylic. Roberts also described stationary velum appliances with

some degree of movement. The degree of movement depending on the

texture and resilience of the material used. Latex velum are used which

are attached by means of tags of stainless steel wire to the flat retention

plate forming an extension into the cleft.

Mazaheri and Millard 29(1965) attempted to correlate voice quality with

location and dimension of the pharyngeal bulb. This result showed that

optimal bulb position varied with each individual patient. Voice quality was

judged as best when the bulb was positioned in the area of greatest lateral

and posterior pharyngeal wall activity.

They tested three positions with interchangeable obturators - High

(above the posterior pharyngeal wall activity), medium (at the pharyngeal

wall activity), low (below the pharyngeal wall activity). Each obturator was

adjusted for 5 weeks before speech recordings were made. Their

investigations disclosed that the middle position resulted in the best

speech for most patients. The inferior superior dimension of the original

median obturator for these patients varied from 13 to 19mm with a mean

value of 13.09 mm. Each obturator could be reduced 3mm in superior and

inferior extension without any effect on speech.

Boucher Louis J.21 (1966) presented a technique in which he used silastic

foam for fabrication of the obturator. The obturator prosthesis was attached

to the maxillary denture by magnets. The magnets were placed as far

12

laterally and posterior in the denture as possible to obtain maximum

amount of retention available.

Ampil and Ellinger 4(1967) described fabrication of hollow silicone

obturator bulb attached to acrylic resin base as temporary prosthesis for

maxillectomy patients. According to them, the primary advantages, of

using a hollow silicone obturator bulbs in temporary restoration are: -

a) It permits the placement of the pliable bulb into greater undercuts areas

of the defects, thus, providing better mechanical retention and seal.

b) The inherent rubber like qualities of the material tends to resist sliding

and skidding of the restoration.

Zarb G. A. 155(1967) stated that if the pterygoid hamulus is removed during

the maxillectomy procedure, the attachment and/or function of tensor veli

palatini, buccinator and superior constrictor muscles could be

compromised resulting in the medial collapse of the disto-lateral position of

the defect. If this situation is anticipated, the cast should be reduced 2 to

3mm medially before fabricating the prosthesis. Zarb, also believed that an

immediate temporary obturator is almost always indicated as well as

feasible in a maxillary resection. Such a prosthesis enhances healing,

function, esthetics and, mental well-being of our patients. He advocated

temporary obturation, with a resilient material, which not only protects the

tissues but also retains the prosthesis.

Lang B.R. 71(1967) presented a modification in the construction of a

speech aid restoration by extending its application to cleft palate patients.

He fabricated speech aid appliance with beaver’s tail shaped extension,

which was at the level of the medial spine of the atlas. This extension was

initially developed in soft modeling compound and later refined in wax. The

posterior extension was finally replaced by clear acrylic resin. Lang stated

that palatal lift prosthesis is a speech aid and not a means of speech

correction. Complete success can be realized with these appliances when

the prosthesis is used in conjunction with a programme of speech therapy.

Brown Kenneth E 23(1968) stated that in cases with maxillectomy defects

where tissues have been protectively conditioned by surgical

reconstructive graft, the peripheral contours of obturator prosthesis might

be developed to create a buttress like action against them. To obtain

maximum lateral retentiveness, the buttressing effect of the obturator's

lateral border should be placed as high and as far away possible from the

rotation axis as possible. The contouring should never impinge upon any

13

delicate unprotected structures or be of such dimensions that it would not

harmonize with the dictates of the path of insertion.

Beder O 11(1968) described the emergency temporary obturator.

ElMahdy A.S. 45(1969) advocated a simple and accurate method based on

the use of two flasks with interchangeable parts for fabrication of a closed

hollow bulb obturator.

Brown Kenneth E. 24(1969) described a technique for fabricating hollow

bulb obturator by processing the defect and the maxillary portion of the

prosthesis separately by using two interchangeable flasks. The two

separate sections are, then joined later on, with cold cure acrylic resin.

Riley Cordell 116(1970) presented a technique for modifying patients’

existing dentures into temporary obturators following maxillectomy by

utilizing an intermediate soft denture reline material. After the bulb is traced

from the lateral posterior corner to the anterior midline, the lateral height of

the bulb should be increased to a point well above the juncture of the skin

graft and the buccal oral mucosa. The weight of the bulb is lowered by

scooping out a portion of set material with a scalpel in the centre and is left

open superiorly.

Browne Kenneth E. 25(1970) described certain clinical considerations to

improve obturator treatment. He believed that irradiated tissues should be

spared of undue stress and in instances of high radiation dosages,

prosthodontic treatment may not be considered. He stated whatever tissue

remained following surgery should be used judiciously for support and

stability. Scar formed along the surgical margin should be utilized for

retention. He advocated monoplane occlusion in conjunction with reduced

tooth size to minimize masticatory stresses and laterally generated forces.

He emphasized that sound prosthodontic principles should be utilized in

treating these patients so, that a concept of not mere survival from disease

alone, but a return to a normal functioning life is achieved.

Kloeffler 69 (1970) in his report on maxillary orthopedics in cleft palate

treatment described the approach of McNeil of early maxillary orthopedics

to expand the maxillary arch by using 4 to 12 graded restorations to create

slow expansion. After proper expansion of the maxillary segments (which

required 40 days), the floating premaxilla was retruded by the use of head

cap and either elastic or adhesive tape and the lip closed at 6 months. This

early treatment merits delayed surgical closure as it aligns the segment

better prior to surgery.

14

Marshall R. C. et al 79(1971) studied the effect of palatal lift prosthesis

upon the speech intelligibility of a dysarthric patient. He stated that

dysarthric patients can improve their speech intelligibility with palatal lift

prosthesis and that the effects of prosthesis upon a patient’s speech might

be more adequately determined after the individual has used the device for

a considerable period of time. They noticed that palatal lift prosthesis in

addition to speech intelligibility reflected improvement in resonance and.

articulation skills.

Chalian V. A and Barnett M.U. 30(1972) described a technique for

fabricating a one-piece hollow obturator using autopolymerizing acrylic

resin shim, for decreasing its weight and making it light. Heat cure acrylic

is then flowed around the shim so that the shim becomes an integral part

of the bulb.

Hahn George W. 54(1972) described the fabrication of silicone bulb

prosthesis for obturating the defect following maxillectomy. He advocated

the fabrication of prosthesis in two parts. Initially, silicone bulb obturator

prosthesis is fabricated followed by the fabrication of a denture to fit the

remaining part of the maxillary arch and the bulb. An acrylic insert is

incorporated in the denture for retention.

The technique had following advantages

a) It allows the patient to wear and insert the bulb without wearing his

dentures.

b) It allows utilization of more undercuts for retention because of the

flexibility of silicone bulb

c) The insert holds the denture more securely in place than the usual

obturator.

d) Seals off the surgical defect lightly with very little discomfort.

e) Lighter and more comfortable to the patients.

Toremalm N. G. 138(1972) described a simple and inexpensive technique

for fabrication of temporary obturator. He used silicone rubber (dimethyI

polysilicone) for making the obturator prosthesis. The cast of the defect is

used as a model for mixing silicone-rubber substances; the foam

component and the catalyst. The porous surface of sponge is

compressible. Elastic obturator is painted with silicone rubber to make it

water proof.

Adisman KI, Laney WR 3(1972) summarized the minimum acceptable

laboratory procedures for maxillofacial prosthodontics and for the intraoral

15

obturator prosthesis they mention that the palatopharyngeal extension

section should be designed by the dentist to have either of the following:

cast metal connector, acrylic resin connector, cast metal connector or

wrought wire connector embedded in acrylic resin, retention loops for nasal

and pharyngeal sections, uvula ring extensions, rigid and non rigid

connectors for the palatal lift prosthesis.

They added that the nasal and pharyngeal extensions from the

parent prosthesis (designed by the dentist) could be – solid acrylic or

silicone extension, hollow acrylic or silicone extensions, which may be rigid

or flexible. These procedures would include the following minimum

procedures in the laboratory – management of impressions, management

of casts, wax up (and spacers if required) of the two component system,

flasking and investment, processing and assembly of components,

finishing & polishing and testing the efficiency of the seal of hollow

extension prosthesis.

Chierici and Lawson 32 (1973) in their work on clinical speech

considerations in prosthodontics describe the seven dimensions basic to

speech – respiration, phonation, resonation, articulation, audition,

neurologic integration and emotional behaviour.

Buckner Horst 27(1974) described a technique for fabrication of a denture

with hollow bulb obturator and lid utilizing permanent soft acrylic lining by

investing, packing and heat curing in one process. The technique is of

great advantage as soft acrylic resin is used to engage undercuts in the

cavity, leading to increased retention. Also the prosthesis is lightweight as

the thickness of the shell, and the lid can be determined and controlled in

every phase of the procedure

Ohyama et al 93(1975) presented a technique to construct a hollow

extension obturator comprised of two materials. An inner hard acrylic resin

hollow core is used to reduce the weight and provide dimensional accuracy

while an outer layer of soft silicone enhances retention and tissue

tolerance.

Tautin & Shaaf 29(1975) presented a novel approach to obturator

construction, by utilizing a superiorly based defect (facial defect) for

gaining access to the oral defect in patients with trismus. Such a

fabrication was termed by them as superiorly based obturator wherein the

maxillary defect is approached from the top rather than from below.

16

Immekus & Aramany 57(1975) described the use of Andrew’s Bridge for

cleft palate patients as this system permits the replacement of lost teeth as

well as supportive structures necessary for proper esthetics.

Parel & Drane 99 (1975) described the prosthetic support of the visual

apparatus after maxillectomy and orbital floor resection. There are three

options: - one-section prosthesis (hollow or solid), two-section prosthesis

with flexible antral extension and two-section prosthesis with solid antral

extension. Solid one- section prosthesis is easy to insert and maintain, but

it transmits jaw movements to the eye. Two-section prostheses do not

transmit this but they are difficult to insert and maintain. Hence, the

surgical reconstruction of the orbital floor should be treatment of choice

followed by prosthetic treatment.

Mazaheri M and Mazaheri EH 85(1976) enlisted various prosthodontic

aspects of palatal elevation and palatopharyngeal stimulation –

q Elevation, of the soft palate should he gradual to avoid placing

pressure upon the teeth retaining the prosthesis and to reduce

mucosal irritation.

q Prosthesis stimulation should be initiated as soon as palatal paralysis

is noted to prevent disuse atrophy.

q The palatal lift prosthesis may be used as a temporary or definitive

treatment for palatal in competency. When, adequate elevation of the

soft palate has been achieved, the prosthesis may be discarded;

otherwise the patient could wear the prosthesis as a permanent

supportive device.

q The construction of tile combined palatal lift / pharyngeal section

prosthesis includes the gradual palatal elevation and moulding of the

pharyngeal section to reduce the gag reflexes and to increase

palatopharyngeal muscle adaptation to the prosthesis.

q Speech and myofunctional therapy should be instituted in conjunction

with prosthetic treatment.

q The palatal lift and combination prosthesis are made effective for

patients with less severe neurologic impairment and speech

articulatory problems.

q The palatal lift prosthesis is more effective for those patients with

palatal incompetency, who have no involvement of the other oro-

pharyngeal muscles. The combination type of prosthesis is more

17

effective for patients with palatopharyngeal insufficiency without

marked speech articulatory disorders.

Matalon V.and La Feunte H 82(1976) outlined a simplified technique for

processing a hollow obturator using sugar to occupy space during

processing. The sugar was then removed leaving the interior of the

prosthesis hollow. The hole created from removing sugar is later sealed by

autopolymerizing resin.

Robert H. Wood and William Carl 151(1977) described a technique for

fabrication of hollow silicone obturator attached to a hollow dental

prosthesis, by utilizing flexible impression trays for making impression of

the defect. William Carl also described fabrication of immediate surgical

and transitional silicone obturator prosthesis for patients undergoing

maxillectomy. He stated that temporary stage should be maintained till the

healing is complete and is usually 3 to 6 months before definitive obturator

prosthesis can be constructed.

Dalston 39(1977) described the speech pathologist’s view in the

prosthodontic management of cleft palate patient. The use of an obturator

as a training prosthesis to increase muscle activity during speech,

occasionally to the extent that the use of prosthesis can be discontinued

has been documented. However, surgery is a better option according to

the author.

Aaron Schneider 122(1978) described a technique for fabrication of hollow

bulb obturator utilizing double investment procedure and ice.

Desjardins RP 40(1978) stated that the defect of a partially edentulous

maxilla may need only coverage and sealing without maximal superior

penetration. However, the completely edentulous maxilla requires maximal

penetration and intimate contact of the obturator and extension of the

prosthesis to the surrounding surfaces of the defect for retention, stability

and support. He stated that for partially edentulous arch with maxillary

defects, the placement of retentive clasps as near to, and as far from the

defect as possible, is an excellent principle of design. He believed that the

occlusal plane or the artificial teeth for the prosthesis with the jaw having

the defect should be favoured.

The mandibular dentition should be restored as ideally as possible

to minimize or eliminate occlusal imbalances for the maxillary prosthesis,

restoring a maxillary defect. He further stated that the stability of the

maxillary prosthesis would be enhanced if the forces of occlusion in

18

mastication would direct the prosthesis upward inward and posteriorly in

bilateral simultaneous posterior teeth contact. To prevent annoyance from

mucous drainage in the well fitting maxillary obturator prosthesis, Kenneth

Adisman added that providing a groove or trench on the superior surface

of obturator extension inclined downward towards the nasopharynx would

aid in the passage of mucous and nasal fluid posteriorly. Sometimes, an

auxiliary escape channel may be indicated to prevent the accumulation of

nasal mucous secretions.

Aramany 7 (1978) gave the basic principles of obturator design for partially

edentulous maxillectomy patients. He classified these defects into 6

categories depending on the frequency of defects occurring in a population

of 123 patients.

Aramany 8 (1978) described the system of forces acting on obturators for

the partially edentulous maxillectomy patient and gave guidelines for

designing the prosthesis according to the type of defect present.

Parr 102(1979) described fabrication of combination obturator having rigid

and a flexible component. He said that rigid component should be used in

defects where there is no undercuts to provide retention or where retention

is gained from a flexible soft tissue scar band. The rigid extension is

usually made hollow; to decrease the weight and the border of the

extension is usually placed as high as possible to resist downward

displacement. The flexible component or obturator is used in defects with

hard or soft tissues undercut, also it may be allowed to extend superiorly to

contact with the tissues to gain, additional support and stability for the

prosthesis. The combination appliance thus presents a design of an

obturator prosthesis, which takes maximum advantage of the patients

remaining anatomy.

Koray Oral et al 96(1979) described the construction of buccal flange

obturator in which the obturator does not have a closed hollow section.

Instead of the prosthesis projecting into the defect as a hollow section, the

anterior, posterior and lateral flanges of the obturator are extended into the

defect. He later studied the efficacy of buccal flange obturator in partial

maxillectomy patients in comparison with hollow obturator and with no

obturator to evaluate speech intelligibility.

They converted the buccal flange obturator into hollow obturator by

the addition of a lid made of autopolymerizing acrylic resin just prior to

speech evaluation. They concluded that in both live and tape-recorded

19

speech evaluation, the buccal flange obturator produced speech, which

was significantly superior to speech with no obturator. The hollow obturator

also produced speech significantly superior to speech with no obturator.

The buccal flange obturator showed a statistically, significant

superiority as compared to the hollow obturator. Clinically the buccal flange

obturator proved superior to the hollow obturator in simplicity, speed of

fabrication, ease of cleaning, reduced weight retention and hygiene.

Lavelle W. E. & Hardy72 (1979) stated that for optimal results with palatal

lift prosthesis, the patients should have some pharyngeal wall movement.

It is also desirable for the palatal, pharyngeal, and glossopharyngeal

muscles to have relatively low muscle tone or be hypotonic. If these

muscles are hypertonic, severe pain in the lateral pharyngeal area

particularly during swallowing may occur. It is also desirable to have

adequate palatal tissue to permit a drape of palatal projection around the

borders of the palatal projection of the prosthesis to create a seat between

the acrylic resin and the pharyngeal walls. The optimal result criteria

include:

q Complete palatopharyngeal closure during speech

q Oro-nasal coupling during nasal speech production and for nasal

respiration

q No prosthetic interference to oral articulation

q Acceptable oral and pharyngeal comfort

Rahn et al 113 (1979) discussed prosthodontic principles in surgical

planning for maxillary and mandibular resection patients and gave the

following guidelines.

q As much of the soft palate as possible should be preserved which

helps in posterior seal and definite limits for posterior extension of

obturator. The presence of soft plate also allows the extension of

prosthesis posteriorly over the anterior border to increase retention

especially in patients with posterior and lateral wall defects.

q The vomer and inferior conchae should be removed from the

margins or if present, should be relieved in the prosthesis as these

structures cannot tolerate and resist superior movement of

prosthesis.

q Excision of dentulous maxilla should be done in middle of the

socket of most anterior tooth to be removed and not immediately

adjacent to the preserved tooth.

20

q Fibrous attachments in the labial sulcus, particularly at the medial

margin of the maxillary resection should be avoided, as these

attachments cause limitation in extension of prosthesis.

q Maxillary tuberosities should be left intact as far as possible as they

provide stability and support

q Placement of skin grafts to be encouraged as they allow patient to

tolerate the prosthesis. Also the mucodermal scar band contracts to

form a continuous scar band in the lateral margin of the maxillary

defect. This band provides a narrowing of the defect and a relative

undercut superior to the band, thus allowing the obturator to extend

more superiorly and laterally to obtain retention.

Zaki Hussein S. 154(1980) described a method for adding a bypass to an

edentulous obturator to prevent nasal emission of fluids. The prosthesis

consists of a hollow bulb obturator with a tube through its lateral wall,

which opens onto the posterior superior aspect of the obturator at one end

and into the premolar region orally.

Pomerantz & Zimmerman 111(1982) described the use of two non-parallel

canine abutments for a tissue bar overdenture obturator by joining the two

abutments by TMS pin system

Benington & Clifford 14 (1982) discussed a way of making impressions to

record the natural undercuts with silicone impression material to overcome

the difficulty of directing the flow of material anteriorly over the palatal

shelves. They described the use of a special tray with a hole prepared in

the palate of the impression tray through which the impression material is

injected with a syringe.

Shifman A. 126(1983) described a technique to construct an open obturator

against a removable silicone core to facilitate processing, recovery and

polishing of the obturator that is open superiorly.

Taicher et al 133(1983) described fabrication of polydimethyl siloxane

acrylic resin obturator. Besides having usual advantages of silicone,

polydimethyl siloxane resin obturator in addition, has excellent dimensional

stability, is well tolerated, non-toxic and non-carcinogenic. Also, it has

greater tear resistance, is more translucent without pigments. It has

controlled stiffness when prosthesis with less flexibility is required and has

higher density than most silicones. They advocated that such prostheses

are useful in patients with severe trismus and unyielding tissue because of

its flexibility and superior tolerance by intraoral and nasal tissues.

21

Ramsey WO 114(1983) presented terminology pertaining to various

aspects of palatal lift prosthesis. He agreed with the use of term lamina or

velar lamina for that portion or, a prosthesis that underlies, elevates and

supports the neurologically impaired velum. He described that a lamina

consists of a base that underlies the anterior one third of the velum, middle

or midsection and a vertex that underlies a variable portion of the terminal

one third of the velum. The outline form of the lamina could be more

appropriately described as oblong - ovate or obovate than compared to

spatulate, beaver tail etc.

The margin of the lamina in contact with the posterior pharyngeal

wall if blunt, should be best described as truncate and if notched to

accommodate motor muscle must be called emarginated. Anterior

posterior configuration of the velum could be either flat or arcuate in

accordance with the anterior posterior curvature of a normal velum in

moderate elevation. Lastly, he described the mode of attachment of velum

to the maxillary denture base as fixed, adjustable, rigid or semi rigid.

Taylor TD, Desjardins RP 136(1983) reviewed the meatus type obturator

and stated that this type of obturator is best indicated for treatment of

edentulous or partially edentulous with acquired soft palate defects where

the retention and stability of the prosthesis are difficult to achieve.

King & Martin 67 (1983) studied cast circumferential and wire clasps for

obturator retention. Light wire means non-cast type wire clasp. Wires used

are platinum- gold- palladium wire, Co-Cr-Ni alloy wire; orthodontic S.S.

wires are also used. Generally 18 or 19 gauge wires are used. Wire clasps

are used for surgical or interim obturators, as they can be readily adapted

to teeth and incorporated in all acrylic prosthesis.

They found as per earlier studies that lingual retention was more

effective than buccal retention. When support approached a straight line

both buccal and lingual retention was required and if anterior ridge and

teeth present indirect retention and bracing of the lingual plate with buccal

retention was most effective.

J. D. Browning et al 26(1984) described fabrication of a hollow obturator

using fluid resin. The technique allows for precise control of the thickness

of, the resin for minimum weight but with, sufficient thickness to allow for

adjustment if necessary.

22

Coffey 33 (1984) discussed obturation of congenital and acquired intraoral

anatomic defects with inflatable latex balloon attached to tissue side of the

rigid prosthesis.

Kouyoumdjian & Chalian 70(1984) described a technique for fabrication

of an interim obturator with duplication of the recently removed teeth and

palate by using a vacuformed matrix of the preoperative cast. This

duplication aids the patient as it provides an environment for the tongue

similar to the preoperative one and simplifies deglutition and speech.

Phankosol et al 106(1985) presented fabrication of closed hollow

obturators with removable lid made up of mouth guard material, which is

vacuum formed. Removable lid obturators, combine the benefits of both

closed and open obturators. The removable lid permits cleaning of the

inner hollow surface by the patient and also makes the obturator light.

Also, the lid is easy to replace at a follow up visit once or twice a year.

Moore et al 91(1985) compared the rigid and flexible obturation of surgical

cleft of the soft palate using PERCI and listener judgement and found that

the rigid obturator had the best fit with the pharyngeal complex (0.5 square

cm area) and sounded the best to trained listeners. Thus, rigid or

conventional obturation is better than an obturation technique that

introduces varying degrees of flexibility.

Beery et al 12(1985) reviewed the role of oral endoscopy in prosthetic

management of the soft palate defect since its introduction by Taub

in1966. They stated that it should be used to diagnose the deficit in the

closure and also to assess the effectiveness of the prosthesis.

Reisberg and Smith 115(1985) described an objective aerodynamic

assessment of speech aid prosthesis to provide information about

palatopharyngeal function to guide in the modification of the prosthesis to

provide adequate palatopharyngeal function for speech.

Palmer & Coffey 25 (1985) described the technique of fabrication of a

hollow bulb without the use of water or pressure, which when used

requires opening the bulb, draining the water and resealing.

Disantis 43 (1985) discussed a technique using vacuformed resin for

fabrication of an immediate surgical obturator, which saves a lot of time.

Jacob et al 59 (1985) described a technique for converting a surgical

obturator into an interim obturator by using intermediate soft denture liner.

The method allows the immediate soft denture lining material to function as

23

an impression material or to become an integral part of the interim

prosthesis.

Schwartzman et al 123 (1985) studied the occlusal force transfer by

removable partial denture designs in radical maxillectomy. They furthered

the study carried out by Fiebiger et al (1975), which was inconclusive.

They found that physiologic adjustment of the framework greatly reduced

the stresses transmitted, highest stresses transferred in the premolar

region for all designs.

Lingual retainers produced more stresses than buccal retainers. In

the anterior region and I-bar clasp with cingulum rest was the best

combination for axial force transmission. From the perspective of the

equitability of stress transfer, the tested designs from best to worst were

the infra-bulge I-bar retainer (either buccal or lingual retention), light wire

circumferential retainer with buccal retention, circumferential cast buccal

retention and swing lock system.

Minsley G E et al 88(1986) gave a technique for the fabrication of closed

hollow obturator prosthesis. The technique allows for control of wall

thickness of the obturator extension thereby minimizing the weight of the

prosthesis. The lid placed over the open palatal portion of the obturator is

ultimately sealed with an additional layer of heat-cured acrylic resin. In

addition, the junction between the lid and the palatal portion is remotely

located in relation to the lid thus minimizing micro leakage.

Parel et al 100 (1986) discussed the intra oral applications of

osseointegration in maxillofacial prosthodontics especially in highly

compromised patients for whom previous conventional treatment is

marginally successful or limited from inception.

Yuuji Sato et al 120(1987) described palatal Iift prosthesis for edentulous

patients. The prosthesis consisted of a movable palatopharyngeal section

that elevates the soft palate by the force of orthodontic wire. The

prosthesis improved both speech and swallowing. Orthodontic wire used

were Ni-Ti, which shows a unique stress-strain curve.

Groetesma W.R. 52(1987) reviewed the role of maxillofacial prosthesis as

a speech rehabilitation aid and its use in patients with velopharyngeal

inadequacy, glossectomy and maxillectomy patients.

Karnell et al 66(1987) described the use of nasoendoscopy. The flexible

fibreoptic endoscope inserted nasally provides a clear view of the

velopharyngeal port during speech without limiting movement of the oral

24

structures during speech production and should be used along with oral

videoendoscopy especially in patients with complex etiology and patients

with poor maxillary dentition as minimal bulk of prosthesis is required for

retention and stability and videoendoscopy aids in developing the obturator

with minimal bulk and optimal result.

Spratley M. et al 132(1988) suggested a new design for palatal lift

appliances in patients with neurogenic velopharyngeal incompetence

utilizing a hinged posterior extension. Their design utilized initially a rigid

hinge but this was difficult to adjust and had limited mobility. Subsequently

they utilized single wire spring hinge using 0.6mm initially, which was later

changed to 0.5mm twin wire, which allowed easy adjustments to achieve

optimal elevation and some degree of lateral movement.

The material of choice for fabrication of extension was high molecular

mass copolymer vinyl mouth guard material. A wire grid constructed by

bending and spot welding 0.6mm stainless steel wire was used as a base

for the copolymer- extension. Such hinged appliance was found adequate

to support the palate whilst remaining, comfortable to the patient. These

curve and are highly flexible, thus providing both retention and causing

palatal lift.

Wu & Schaaf 153 (1989) conducted a study to compare the weight

reduction in different designs of solid and hollow obturators and found that

hollow obturator designs had weight reduction from 6.55 % to 33.06%

depending on the size of the defect.

Birnbach & Barnhard 18 (1989) described a single appointment technique

to convert a solid obturator to hollow obturator prosthesis by removing the

acrylic resin that fills the bulb from the palatal aspect, creating a bevel and

dove tail on the margin and then construction a lid out of autopolymerizing

resin.

Huryn & Piro 56 (1989) described the fabrication of maxillary immediate

surgical obturator and the treatment protocol including preoperative,

operative and post operative guidelines.

Parr et al 103 (1989) described a series of Aramany’s obturator design

templates and discussed the relative considerations for each. In all

situations, they advocated the quadrilateral or tripodal design over linear

design pattern. As they allow a more favourable leverage design

application that will aid in the support, stabilization and retention of the

prosthesis.

25

Tobey & Lincks 137(1989) did the acoustic analysis of speech changes

after maxillectomy and prosthetic management and found that the

prosthetic management resulted in the reduction of resonances by either –

complete elimination of resonances, reduction in amplitude or by changing

the frequency of resonances to more nearby regions of the vowels.

Khan 68 (1989) described the fabrication of soft palate obturator in light

cure resin, which is done chair side, is convenient and time saving.

Jacob RF 60 (1990) in her work on soft palate obturator design stated that

the prosthesis design of indirect retainers without anterior clasps and

various designs of molar clasp arrangements is esthetic, retentive, and

functional and preserves existing structures. This design should also be

used in congenital soft palate defects where anterior teeth are not

replaced. When modification spaces must be restored, it may be

necessary to include anterior clasps. Whether the indirect retainer acts as

a lever or only redistributes forces around the dental arch remains to be

answered.

DaBreo and Ghalichebaf 36 (1990) described a method for designing and

fitting a provisional fixed restoration (instead of removable partial denture)

for a patient of cleft lip and palate and emphasized that the provisional

restoration provides an alternative treatment option that allows the dentist

to plan the definitive restoration while providing the patient with an esthetic

and functional restoration.

Masumi et al 81 (1990) described the use of sectional prosthesis

consisting of a nasal retainer; hollow obturator and hollow complete

denture retained together by samarium cobalt magnets to restore a partial

maxillectomy defect.

DaBreo 37 (1990) presented a new method of making a maxillary interim

obturator with visible light cured resin, which allows the dentist to make

and deliver the prosthesis at the same visit using minimal time and

equipment.

Shifman 127,128 (1990) described the clinical applications of visible light

cure resin material as a tray, denture base and reline material in

Maxillofacial Prosthodontics.

Gardner et al 47 (1990) in a clinical report presented a technique to

fabricate a combination nasal-support breathing flange with hollow

obturator in a patient with Aramany class VI defect.

26

Turner & Williams 140(1991) described the role of fluoroscopy and

nasoendoscopy in designing palatal lift prosthesis and also suggested

procedural guidelines in patient management.

Jhanji & Stevens 64 (1991) described the fabrication of a one- piece

hollow obturator using silicone putty as obturating material in the

fabrication procedure instead of sugar, asbestos or foam and hence, is a

controlled process in which the thickness of the obturator could be easily

modified by adding to or reducing the dimensionally stable putty and did

not involve autopolymerizing resin.

Gardner et al 48(1991) described a simplified technique for the fabrication

of a hollow obturator prosthesis using vinyl polysiloxane.

Williams 148 (1991) described a technique to make the impression for a

palate repaired by a bulky tongue graft providing selective pressure to the

residual palate while relieving the graft, in order to fabricate the prosthesis.

Jacob & Yen 61 (1991) discussed the role of processed record bases for

the edentulous maxillofacial patient. Its use increased the accuracy of

registration of jaw relations and minimizes the defects in occlusion,

aesthetics, lip support and buccolingual tooth placement.

DaBreo 38 (1991) studied the dimensional change in maxillary prosthetic

obturators and found that light polymerized one was most stable followed

by heat cured and then autopolymerized resin.

Polyzois G. L. et al 110(1992) described fabrication of an open partial

denture obturator prosthesis utilizing a visible light cure denture base resin

and a resilient liner polymerized by visible light.

According to them, the technique had following advantages:

a) Easy and rapid fabrication.

b) Better control of thickness and resiliency of the obturator

prosthesis.

c) Easy to repair, by using increments of resilient materials.

d) Combination open obturator prosthesis provides a stable record

base for securing jaw relation records.

e) Can be used for partially edentulous or completely edentulous

patients after maxillary resection.

Black W 19 (1992) described the fabrication of a stable, versatile surgical

obturator for dentulous patient made in acrylic and wrought wire, based on

the swinglock concept, which allows for simple transition from surgical to

even definitive obturator.

27

Schmaman J 121 (1992) presented a technique utilizing silastic foam to

make impressions for maxillary defects to overcome withdrawal problems

as flexible but harder material traumatizes tissue while hydrocolloids have

low tear strength.

Kaplan 65 (1992) described a way of using polyether to form a palatal

contour guide for positioning retentive framework for the obturation of a

maxillectomy defect.

Maurice Didier 42(1993) utilized a new thermoplastic material polysar

(polyisopren family) to create a hollow obturator extension for immediate

lightweight obturator prosthesis inserted at the time of surgery. The obtu-

rator prosthesis consists of three sections, the denture base silicone,

elastomeric material intermediatory section and the obturator extension.

The advantage of Polysar was weight reduction of almost 42 % compared

to silicone prosthesis and as it was thermoplastic, it could be readapted to

conform to the changes in tissues due to healing.

Wolfaardt et al 150(1993) carried out a pilot study to establish the

effectiveness of palatal lift appliance in treatment of patient with

palatopharyngeal incompetencies. They observed that only in 2.3% cases

use of an appliance followed by speech therapy was preferred treatment.

In the same study, 6.9% preferred surgery followed by speech therapy.

Wolfaardt et al developed a decision protocol for management of

palatopharyngeal incompetency.

Shimodaira et al 130 (1994) used an obturator prosthesis with small

flexible silicone extensions placed at the nasal and oral sides across the

mobile anterior margin of the soft palate and found it to be most effective

for patients with few remaining teeth having extensive maxillary defect

extending into the soft palate but added that long term follow up is

advisable as soft silicone material may harden and lose flexibility.

Vojvodic et al 141(1996) described a case of cleft palate where they used

root copings, telescopic and veneer crowns with rests and metal base

partial prosthesis to provide satisfactory function, esthetics and alleviation

of the deformities.

Light 75(1997) described the functional assessment in maxillofacial

prosthetics. In speech aid prosthesis; speech language pathologists can

do both quantitative and qualitative analysis. The quantitative tests include

tongue pressure and endurance test, tongue/palate placement and range

of motion, tongue rate of movement, speed of swallow and nasal emission.

28

The qualitative tests include quality of life indices, clinical tests of

performance, indirect palatography, oral speech performance, drooling and

speech intelligibility tests.

Roumanas et al 119 (1997) conducted a clinical evaluation of implants

retaining edentulous maxillary obturator prostheses. They concluded that

edentulous maxillectomy patients could benefit from implants. Many

factors such as radiation status, available bony sites and surgical

procedures may influence implant prognosis and the design of the

obturator components. The anterior maxillary segment is a key site for

implant placement, however anterior implants showed more bone loss

(almost three fold) than the posterior implants, indicating higher level of

stress anteriorly.

They also advised against placement of implants during surgical

resection due to the high recurrence rate and mortality in these cases.

Also, implants irradiated after placement demonstrate low survival rate.

Hence, implants placed within the surgical defect have low probability of

survival and are difficult to restore and maintain.

Wang & Hirsch 144(1997) described an easy time saving procedure that

uses visible light activated denture base materials as a reline material to

close an open type interim obturators. Also it can be used in patients using

definitive obturator for correcting leakage problems.

Wang 143 (1997) described the use of sectional prosthesis retained by Sr–

Co for total bilateral maxillectomy patient.

McAndrew et al 86(1998) described an innovative investment for the

fabrication of closed hollow obturator prosthesis, which eliminates the need

for the fabrication of a heat processed denture base when retention and

stability of the removable record base can be readily achieved, allowing for

accurate maxillomandibular relation records to be recorded.

Wang R 145 (1998) described the advantages of presurgical orthopedics in

a cleft patient and the rationale and use of a thermoplastic resin reline

material to remold and modify bulb prosthesis to compress a severely

rotated premaxilla to a desired position before cheiloplasty.

Blair & Hunter 20(1998) described in a case report of making a hollow box

interim obturator by using a copy of the existing prosthesis to make a final

closed mouth impression and using a plaster- pumice core to make a

hollow box obturator.

29

Shifman et al 129 (2000) described speech aid prosthesis for neurogenic

velopharyngeal incompetence and stated that a wire extension speech aid

prosthesis is an effective treatment approach and nasopharyngoscopic

control is mandatory for maximizing the effect of closure around the

nasopharyngeal section of the prosthesis in function and it still allows nasal

breathing.

Brosky et al 22(2000) described the fabrication of radiation bolus

prosthesis for the maxillectomy patient for postoperative brachytherapy.

This custom made prosthesis is simple, efficient and atraumatic to the

patient while providing homogenous adequate radiation to the tissues.

Esposito et al 46 (2000) used palatal lift and augmentation prostheses to

improve dysarthria in patients with amyotrophic lateral sclerosis and

concluded based on the positive results that these speech aid prostheses

should be considered in this adult onset neurodegenerative disorder.

Ziada & Donovan 156 (2000) described a technique using visible light cure

resin to reduce the vertical height of a hollow box interim obturator to

compensate for the tissue changes without remaking the entire obturator.

The cap like piece 4 mm in height is cut and the obturator without the lid is

tried and checked for extensions and adjusted followed by sealing of the

lid by Triad light cure resin material.

Dexter & Jacob 41 (2000) discussed the reconstruction of maxillectomy

defect by temporalis flap. Historically, the consensus has been not to

surgically obturate the defect, but they favoured immediate reconstruction

because of its psychologic benefit to patient, presence of diagnostic

monitoring tools like nasoendoscopy, MRI and CT, which could offset the

loss of visibility of defect to check for recurrence, it may eliminate the need

of an obturator.

However, a temporalis flap placement is obstructed by the

zygoma, which may need to be sacrificed leading to loss of masseteric

attachment and compromised chewing ability. Use of implants also

becomes necessary, as there is loss of natural undercuts and the support

from foundation is not adequate. This prosthesis should also be

considered as an obturator as it replaces tissue and restores function to a

maxillary surgical site and additional time and expertise are required to

fabricate the prosthesis.

Mac Carthy & Murphy 77 (2000) described a simple technique to replace

the silicone extension of an existing two piece obturator utilizing the same

30

denture base to make a pick up impression in polyether of a wax shell

impression of the defect, pouring a split cast and fabricating the extension

in molloplast B.

Matsumura & Kawasaki 83 (2000) in a clinical report described the use of

a magnetically connected removable sectional denture for a maxillary

defect with severe undercut.

Okay et al 94 (2001) introduced a classification system of defects for

prosthodontic guidelines for the surgical reconstruction of maxilla.

Palatomaxillary defects were divided into 3 major classes ad 2 subclasses.

The aim of this classification was to organize and simplify the complex

nature of the restorative decision making process for the maxillectomy

patient.

Cotert et al 34(2001) described a modified flasking technique for

processing an obturator with continuous pressure injection by aligning the

wax pattern perpendicularly. They also used a modified channel design

and a simple method to pull back the injection funnel to increase the

volume of the flask. The pulled back funnel is kept in position by means of

a stone spacer; sprue channels completely surrounded with plaster are

used to obtain continuous pressing of the mixed resin into the farthest

regions of the flask.

Parel et al 101 (2001) described the use of remote implant anchorage for

rehabilitation of maxillary defects especially using the zygoma and malar

buttress. These implants provide support for cantilevered prosthetic

extensions and reduce stress to teeth in the native site.

Pigno & funk 108 (2001) in a clinical report described a method to extend

the obturator into the nasal aperture space to augment retention. After

conventional obturator was made an impression is made with soft liner,

removed, reoriented with base, a stone index made and the nasal

extension made in autopolymerizing resin. The path of insertion has to be

modified as the obturator has to be placed in the posterior oral cavity and

then moved antero-superiorly to engage the nasal aperture.

Pigno 109 (2001) in a clinical report discussed the prosthetic rehabilitation

of a maxillary defect following free flap reconstruction. However, there are

problems, as although, the reconstructed defect provided vertical support,

it did not allow for the attainment of a border seal or extension of the defect

to augment retention. Therefore, it is not always beneficial for a patient to

31

undergo reconstruction as it may even diminish, the eventual prosthetic

and overall treatment outcome.

Rilo et al 117 (2002) described the use of titanium and visible light cure

resin to fabricate an obturator, which provides a biocompatible lightweight

alternative, which can be relined easily.

Tapia et al 134(2002) describe a technique for the duplication of the

pharyngeal part of the interim speech aid for transfer to the definitive

speech aid. This technique saves a lot of chair side time as it eliminates

the reshaping the new pharyngeal part for the definitive prosthesis.

Sigurgeissdoiter et al131 (2002) described a case in which they used

swinglock design which allowed the patient to negotiate the path of

insertion of the obturator section inspite of trismus while the innovative use

of ERA attachment provided a satisfactory locking mechanism and

enabled the replacement of the male cap and long term use.

Parr & Gardner 104 (2003) gave a brief overview of the evolution of the

obturator framework design right from Ambrose Pare who described the

first button shaped sponge and metal obturator to the present day complex

surgical-prosthodontic coordination and the use of vascularized free flaps

with osseointegrated implants.

Chambers et al 31(2004) described the obturation of the partial soft palate

defect, which may result from the surgical resection of the posterior border

from the medial or lateral portion of the soft palate. Reconstruction is tried

but, if it fails, obturation needs to be done and the residual flap complicates

the successful obturation. In these patients the position and level of the

obturator prosthesis in the nasopharynx is determined by the position of

movement of the remaining mechanism.

Generally in such patients the closure of the soft palate defect

against the posterior pharyngeal wall should extend about 5-7 mm in

vertical height, with closure at the level of the palatal plane and anterior

tubercle of the Atlas vertebra. The author also has outlined a method to

record the contours of the partial soft palate defect for proper prosthetic

obturation.

Habib & Driscoll 53 (2004) have described an alternative technique for

fabricating a closed hollow obturator, which is convenient and time and

cost saving.

During packing acrylic is packed to form the apex of the bulb

followed by a sheet of acetate to act as separator and the rest of the mould

32

is packed. After curing, the lid is pried of. Obturator tried in mouth and

made hollow. It is inserted without the lid. On recall, the obturator is

checked and if acceptable, then the lid is sealed with autopolymerizing

resin.

Marunick M 80 (2004) described the design considerations for a hybrid

gate design framework that incorporates both conventional cast direct

retainers and the gate design concept in the same framework.

33

The roof of the oral cavity is formed by the anterior hard palate and

posteriorly by the soft palate. The hard palate is formed by the premaxilla

anteriorly(which supports the incisors) and the palatal process of the

maxillae and horizontal process of the palatine bones which are joined

together by the intermaxillary, palatomaxillary and the mid palatine

sutures.16

Understanding of the developmental biology of the face and palate

is best attained on a platform of biological paradigms and information

drawn from the multidisciplinary worlds of classical embryology, devel-

opmental biology, and, today, from the exciting worlds of molecular

biology. The advent of many new and exciting clinical intervention

strategies for the treatment of birth defects now allows clinicians to treat

the most delicate of craniofacial abnormalities, conditions that until recently

Fig.5: A view of the roof of the mouth.

Fig. 6: Diagram of the bony anatomy of the palate and nearby structures.

34

were beyond the realm of treatment even for skillful practitioners due to

lack of appropriate technologies.

This text provides a highlighted developmental blueprint followed

in human craniofacial morphogenesis, with a special focus on defects of

the face, palate, and associated structures.

Although recent advances in developmental and molecular

craniofacial biology have contributed heavily to our understanding of face

and palate morphogenesis, the almost exponential expansion of the

fundamental knowledge base in these areas clearly centers on the almost

universal phenomena that affect craniofacial "building block" cells at one or

several points in their life cycle.

These fundamental phenomena include patterns of early DNA

signaling; biochemical organizers; nuclear and cellular differentiation; and

proliferation, migration, and patterns of interactive behaviors at intracel-

lular, cell surface, and extracellular matrix levels. Complete or partial

interruptions of any one or combination of these phenomena have been

implicated in the identification of etiologic and pathogenic causes of

mammalian birth defects, including those of the human craniofacial

regions.

The building block cells for the head and face are identifiable both

premorphologically and morphologically as early as the second intrauterine

week. Once mapped out, these cells continue with their peak period of cell

differentiation, proliferation and migration through the second intrauterine

month. Although the classical picture of craniofacial morphogenesis can be

framed on the morphogenesis of the primary germ layer cells (i.e.,

ectoderm, mesoderm, and endoderm), there is little doubt that the current

understandings of and excitement about mammalian, including human

craniofacial morphogenesis have been significantly advanced by a

plethora of studies of the origins and behavior of embryonic neural crest

cells.

Morphogenesis of the facial regions depends heavily on the timely

differentiation, directed migration, and selective proliferation of these crest

cells which arise as a product of neural tube formation as the neural tube

progressively pinches off from the overlying skin along the body's dorsal

axis. As will be discussed later, cells and tissues within each of the

embryonic facial primordia arise from neural crest cells that have migrated

35

into the facial regions, as cell clusters called rhombomeres, from their sites

of origin along the portions of the neural tube which form the brain.

The determinants of crest cell migrations have been variously

hypothesized as including intrinsic cell "targeting" factors and chemical

signaling from cells lining the extracellular cleavage planes through which

the crest cells migrate. Crest cells from the developing midbrain regions

migrate into upper facial regions, whereas crest cells from hind brain

migrate selectively into the lower facial regions. Importantly, once the crest

cells migrate into specific facial regions, they differentiate into

mesenchymal cells that subsequently give rise to connective tissue and

muscle cells of those specific facial regions.

Although the predominantly neural crest-derived mesenchymal

cells in the facial regions do co-mingle with mesodermally derived

mesenchymal cells, the interactive nature of their co-mingling, or lack

thereof, remains uncertain. Consistent with the tenets of the

"developmental field concept" in human morphogenesis, both human and

experimental studies generally have hypothesized that significant and

early interference with the normal differentiation, proliferation, and

migration of embryonic cells, including especially the craniofacial neural

crest cells, can lead to isolated and syndromic craniofacial defects, called

neurocristopathies, whose occurrence and severity depend on a

combination of environmental and genotypic factors specific to a given

individual.

As the embryo's cephalo-caudal axis is established, a facial

developmental field is one of the first of the head regions to appear.

Centrally located in this region is a discrete bilaminar tissue plate, called

the oropharyngeal membrane, whose structure and location marks the

junction between the oral ectoderm and the endodermal digestive tube.

This membrane progressively degenerates through the normal process of

programmed cell-death" which involves increased phagocytic or lysosomal

activity along the inner and outer surfaces of the membrane. Once the

degeneration of the oropharyngeal membrane is completed at 4 weeks,

continuity then is established between the spaces of the early oral cavity

and the pharyngeal portions of the digestive tube. Only rarely does the

oropharyngeal membrane fail to degenerate. Interestingly, a similar

ecto-endodermal plate lies at the depth of a groove which separates the

first branchial from the second branchial arch.

36

At 4 weeks, a series of lateral surface elevations, called branchial

arches, become quite prominent on the lateral side of the head. The

branchial arches contribute significantly to the formation of the face, palate,

and associated structures. Most congenital malformations of the head and

neck have their beginnings during the cellular transformation of the

branchial arches into their adult derivatives. As examples, branchial cysts

and fistulae can occur in those rare instances in which human branchial (or

gill) clefts fail to smoothe over on the lateral side of the neck.

As mentioned earlier, cell masses, which contribute to the bulging

prominence of the arches are the neural crest cells that have migrated into

the branchial arches from specific brain regions, and which eventually

differentiate into mesenchymal cells and give rise to skeletal and muscular

structures specific to a given branchial arch.

The first pair of branchial arches is most important in shaping the

human face and associated structures and will receive the most attention

in this text. The first branchial arch, often called the mandibular arch,

develops as two elevations around the oral opening, which was filled in

earlier by the oropharyngeal membrane. The larger, and lower regions of

this arch form much of the mandibular anatomy and the malleus and incus

middle ear bones, whereas the smaller and upper regions of the first arch

on either side of the oral opening give rise to the anatomy of upper lip,

teeth, maxilla, zygomatic bone, and squamous portions of the temporal

bone.

The second branchial arch is located beneath the first arch and is

often called the hyoid arch because it contributes significantly to the

formation of the hyoid bone and the third of the three middle ear ossicles,

the stapes. These two branchial arches, like each of the other four

branchial arches, are separated from each other by a surface branchial

groove, which grows inwardly to meet an endodermal out pocketing from

the developing pharyngeal region (i.e., the first pharyngeal pouch). As is

the case with most branchial grooves and pharyngeal pouches, the contact

zone between a branchial groove and a pharyngeal pouch is a bilaminar

plate of ectoderm and endoderm which eventually degenerates, again

through the process of "programmed cell death" and increased phagocytic

activity.

In the case of the first arch, however, this bilaminar plate is

separated by invading crest-derived mesenchymal cells, which have been

37

linked with the failure of that specific plate to degenerate and persist

normally throughout life as the adult eardrum, or tympanum. The elevated

margins around the first branchial groove develop through the selective

proliferation of mesenchymal cells beneath the skin into six separate

mesenchymal swellings, called auricular hillocks. These auricular hillocks

progressively (from both the first and second branchial arches) enlarge,

migrate, and consolidate through programmed cell activity and eventually

give rise to the external ear, or auricle. Failure of the auricular hillocks to

develop normally can result in auricles of abnormal size, shape, and

position as seen in a variety of isolated and syndromic craniofacial birth

defects (e.g., first and second branchial arch syndrome, hemifacial

microsomia, and microtia). The complete absence of the auricle (anotia) is

a rare event.

To complete this picture of the branchial arches, it is important to

note that cell activity within the arches, is supported by pairs of blood

vessels, called aortic arches, that distribute blood from the embryonic heart

upward through the tissue of each arch toward the brain and then down to

the body. As with the branchial arches themselves, not all of the aortic

arches persist in humans. The aortic arches of the third, fourth, and sixth

branchial arches do persist and become greatly modified throughout the

embryonic period as they are reconstituted as the common carotid arteries

which supply the neck, face, and brain. Especially important in this

dynamic development of the craniofacial vasculature is the shifting of the

primary arterial supply to the embryonic face prior to, during, and following

the formation of the secondary palate.

Unlike in the adult, prior to the seventh week, the primary source of

blood to both the superficial and deep head tissues is the internal carotid

artery and its branches. At about 7 to 8 weeks when the embryonic palatal

shelves are experiencing their most critical stages of closure, an important

shift occurs in the primary blood supply to the face and palatal tissues from

the internal carotid to the external carotid arterial system. This transition

involves a temporary vascular shunt between internal and external carotid

systems provided by the stapedial artery. Failure of either the stapedial

artery to form or a failure to make complete and timely transition has been

hypothesized as possible sources of the pathogenesis of conditions such

as cleft palate and mandibulofacial dysostosis.

38

Considerably dependent on the timely set of morphogenic events

that have occurred from the time of implantation through the fourth week,

the embryonic face continues through its own "developmental critical

period," which spans the fifth through seventh intrauterine weeks. During

this time period, human craniofacial morphogenesis is most susceptible to

either known or suspected birth-defect-producing agents, or teratogens.

Arising from the first branchial arch are four primordial, or building block,

tissue masses that surround the large central depression of the primitive

oral cavity. Continued morphogenesis of the facial prominences depends

heavily on the continuing migration, proliferation, and differentiation of the

neural crest cells, under the direction of developmental morphogens, to a

point in time when the facial prominences, or primordia, are clearly

identifiable as the single median frontonasal prominence, paired maxillary

prominences on either side of the frontonasal process, and two mandibular

prominences beneath the oral opening. The shape and size of these

prominences, as well as development of the specific skeletal and muscular

structures of each branchial arch, are critically dependent on the continued

viability and differentiation of the neural crest cells, which are especially

sensitive to teratogens (e.g. retinoic acid, cortisone).

It is important to note that the outcomes of several distinct,

brain-skin interactions in placode formation are also essential in early facial

morphogenesis. By the beginning of the fifth week, oval patches of skin

ectoderm lateral to the median frontonasal prominence interact with brain

tissue to set off an ecto-ectodermal interaction resulting in the

development of tile two thickened nasal placodes located at the

ventrolateral regions of the frontonasal prominence. Neural crest-derived

mesenchymal cells along the margins of the nasal placodes; proliferate

rapidly to produce horseshoe shaped elevations around the placode,

called the medial and lateral nasal prominences, whose continued rapid

growth gradually forms the nasal pits, or early nostrils. The forward growth

of each lateral nasal process forms the ala of the nose, whereas the

medial nasal process contributes to the formation of the nose tip,

columella, the philtrum, tuberculum and frenulum of the upper lip and the

entire primary palate. Through the process of relative growth in this area,

nasal placodes gradually "sink" to the depth of each nasal pit.

A second important skin-brain interaction gives rise to localized

thickenings of surface ectoderm, on each side of the embryo's head which

39

will form the eye's lens, retina, and optic nerve. Apparently, and as will be

discussed later, these eye fields are first located on the lateral aspects of

the embryo's head and progressively migrate to the frontal midline at about

the time the facial prominences are consolidating into the complete face.

Selective differentiation and proliferation of mesenchymal cells

cause the maxillary prominences to enlarge and migrate medially toward

each other and Lateral and medial nasal prominences. This migration is

associated not only with patterns of cellular growth within the maxillary

prominences, but also with the migration of the eye fields from the lateral

to the frontal regions of the embryo's face during the fifth through eight

weeks. Disturbances in normal eye field formation have been suggested

as one possible cause of median facial clefting and the conditions of hypo-

and hypertelorism.

Continued medial migration of the maxillary prominences on both

sides also moves the medial nasal prominences towards the midline and

each other. By the end of the sixth week, each maxillary prominence

blends, or merges, with the lateral nasal prominence along a line, which

demarcates the future nasolacrimal groove and duct. This event then

establishes the continuity between the sides of the nose, or alar region,

formed by the lateral nasal prominence with the thick region formed from

the maxillary prominence.

A combination of reduced cell numbers and abnormal migration

of mesenchymal cells can lead to the abnormal merging or consolidation of

the maxillary and lateral nasal prominences. Although seen infrequently,

this can lead to facial defects involving oblique facial clefts, persistent

nasolacrimal grooves, and failure of the nasolacrimal duct to develop.

Between the fourth and eighth weeks, the medial nasal

prominences merge with each other, small lower portions of the lateral

nasal prominences and with cells in the larger maxillary prominences. This

subsurface merging of cells, especially between the medial nasal and

maxillary, prominences, results in the continuity of upper jaw and lip. As

part of this consolidation of the medial nasal and maxillary prominences in

upper lip formation, two important morphologic events need to occur: -

q There is a deepening and downward growth of the nasal pit

toward the oronasal cavity as a blind-ending sac whose

floor eventually degenerates through programmed cell

death, resulting in the formation of the primitive choanae,

40

which, allows a continuity between the spaces of the

primitive nasal cavity and the common oronasal cavity.

q An event occurring concomitantly with nasal pit

morphogenesis is the formation of the seam between the

intermaxillary segment and the maxillary prominence. As

these two segments come together in the sixth week, the

developmental surface seam of cells between them also

elongates as the nasal pit elongates, deepens, and moves

downward. This developmental seam, called the nasal fin,

essentially forms the floor of the nasal pit and progressively

degenerates by increased activity among phagocytic cells

on either side of the seam. Once the programmed cell death

of the nasal fin is essentially completed at about the

seventh week, mesenchymal cells from both the

intermaxillary and maxillary prominences intermix leading to

fusion of the upper lip segments into the upper lip and its

cupid's bow. The completion of the embryonic lips generally

occurs about I week earlier than the formation of the palate.

Thus, the lips and palate have different "developmental critical

periods," and teratogens might affect the lips or palate either separately or

in combination. The intermixture of mesenchymal cells within the

consolidated lip segments gives rise to connective tissue components and

muscle fibers within the orbicularis oris ring of the upper lip. Complete or

incomplete failure of the nasal fin to degenerate has been associated with

unilateral and bilateral clefts of the upper lip which variously involve

abnormalities of the orbicularis oris muscle in terms of the number and

distribution of its muscle fibers as part, of the orbicularis ring. Lateral clefts

of the lip may, or may not be associated with clefts of the palate.

Mesenchymal cell deficiency that results in partial or complete failure of the

two medial nasal prominences to consolidate into a philtrum can contribute

to the formation of such defects as a bifid nose or the rare median cleft

("hare lip") of the upper lip, as characteristically seen in the autosomally

recessive Mohr syndrome.

As the consolidation of facial processes progresses through the

embryonic period, neural crest-derived mesenchymal cells within the

maxillary prominences proliferate rapidly and differentiate into tissues

which form mesenchymal cell fields from which the muscles of facial

41

expression develop, and whose myofibers are innervated by the cranial

nerve to the second arch (i.e., the facial nerve).

Similarly, crest-derived mesenchyme in the maxillary and

mandibular portions of the first branchial arch differentiate predominately

into the muscles of mastication which are innervated by the trigeminal

nerve of the first branchial arch. Cells within the mandibular prominence

give rise to muscle and connective tissue structures of the lower lip, chin,

and lower cheek regions. With the reshaping and consolidation of the five

major facial prominences, a recognizable human face is evident by the end

of the eighth prenatal week.

Morphogenesis of the mammalian palate is an even more complex

process, which depends heavily on a balance of genetic, hormonal and

various growth factors. As the face nears the completion of its develop-

mental critical period, the lateral palatine processes, which form the

secondary palate, grow out from the walls of the still common oronasal

cavity. The developmental critical period for the palate is from the end of

the sixth week through the eighth intrauterine week, or 1 week longer in

duration than that of the lip.

These palatine shelves first grow medially, then, become oriented

inferolaterally to lie on either side of the tongue, which is quite precocious

in its own development as a muscle-filled epithelial sac that fills much of

the oronasal cavity. Nearing 8 weeks, the vertically oriented palatine

shelves are progressively repositioned above the tongue mass. This

repositioning of the shelves is thought to involve a combination of

concurrent events, including a downward contraction of the tongue, an

amoeboid-like reshaping of the shelves which gradually places them over

the tongue surface, an increases in extracellular shelf "forces" (or shelf

fluid turgor) which reposition the shelves in a horizontal position and a

downward repositioning of the lower jaw.

In reality, normal or abnormal horizontalization of the palatine

shelves is related to a combination of these three events. Palatal shelf ele-

vation begins in the posterior regions of the shelves, depressing the

tongue downward and forward. This allows the more anterior regions of the

shelves to first contact one another near the posterior edge of the primary

palate, or in the region of the future incisive canal. Once the shelves are in

a horizontal position, the shelves contact each other, and essentially stick

together by a combination of interlocking shelf surface microvilli and a

42

proteoglycans surface coating. Once the shelves make contact, there is a

degeneration (i.e., programmed cell death) of epithelial cells along the

abutting shelf linings, and a directed movement of crest-derived

mesenchymal cells from one shelf to the other. This process of epithelial

degeneration along with intershelf bridging of mesenchymal cells is called

fusion.

The embryonic palatine raphe, or future midpalatine suture, marks

the line of fusion between the palatine shelves. From the site of first shelf

contact and fusion near the future incisive foramen, fusion of the more

posterior regions of the shelves takes place over the next 2 weeks. Fusion

also occurs between the shelves and the inferior edge of the nasal

septum, except in the more posterior regions where the soft palate and

uvula remain free.

Once fusion of the shelves of the secondary palate is complete,

their mesenchymal cells differentiate into osteogenic cells, which form the

skeletal elements of the premaxillary, maxillary, and palatine portions of

the palate. Formation of the soft palate and uvula follows a slightly

different course than that of the regions of the secondary palate, which

give rise to the hard palate.

The soft palate and uvula develop from two separate masses found

at the most posterior portions of the secondary palatine shelves. Unlike the

fusion mechanism, which is in place along much of the length of the

palatine shelves, the consolidation of these two separate masses is

brought about by a selective proliferation of mesenchymal cells located

deep in the valley between the masses. As that proliferation, called

merging, continues the valley between the two distal shelf masses is

obliterated, which results in a smoothening of the contour of the soft palate

and uvula. Failure of the merging process in soft palate and uvula

development can result in complete or partial clefts of the soft palate and

uvula.

Clefts of the palate, with or without clefts of the lip, are relatively

common depending on the population group of the individual. Whereas

occurrence figures for cleft of the- lip (with or without cleft palate) are about

I in 1,000 live births, clefts of the palate (with or without cleft lip) occur once

in 2,500 live births depending on the population group of the individual.

Most clefts of the lip and palate generally correlated to interplay of

genetic and environmental factors (i.e., multifactorial inheritance).

43

Although animal studies have provided some insight into the molecular

and cellular bases of these defects, precise explanations, especially

involving teratogens in the etiology of clefts of the human lip and palate are

still wanting. Some clefts of the lip, with or without cleft palate, are seen

regularly in a number of single mutant gene syndromes. Other clefts are

associated with chromosomal syndromes, especially in trisomy. A

complete cleft palate represents a maximum degree of clefting and is a

birth defect in which the cleft extends from the incisive foramen region

through the soft palate and uvula. The incisive foramen region is the

demarcation used in distinguishing the two major groups of cleft lip and

palate. Anterior cleft types include cleft lip, with or without a cleft of the

alveolar region of the maxilla. Complete anterior cleft extends through the

lip and alveolar region to the incisive foramen region. The pathogenesis of

anterior clefts is related to a deficiency of neural crest-derived

mesenchymal cells, chiefly within the intermaxillary segment of the lip. The

posterior cleft type of birth defect generally includes cleft of the secondary

palate that extend from the incisive foramen through the soft palate and

uvula.

The observation that the female secondary palate has longer

developmental critical period than the male embryo (by approximately I

week) offers some explanation of why isolated cleft palate is more

prevalent in females (66%) than males (34%). In general, the pathogenesis

of posterior palatal clefts is related to abnormalities in a combination of

events ranging from deficiency in mesenchymal cell numbers to perturba-

tion in the shelves' extracellular matrices to abnormal elevation and fusion

of the shelves, or lack thereof, as complicated with a number of

hypothesized teratogens, like excess doses of retinoic acids,

glucocorticoids and dioxins.

In summary, the understanding of the natural historical clinical

delineation, and clinical management of defects involving the face and

palate has progressed significantly over the last 20 years and will continue

to do. Though human craniofacial morphogenesis is clearly a culmination

of a very complex series of diverse overlapping developmental events, all

of these events can be categorized into four fundamental happenings,

which span mammalian development.

44

q Cell differentiation, the process through which the myriad of

building block cell types invoked in facial morphogenesis,

are generated from the single-celled zygote

q Morphogenesis, the process or set of processes through

which the complex form of the face and its constituent cells,

tissues, and organs will emerge in a timely fashion along

patternable individual land population lines.

q Growth, the collective results of differentiation and

morphogenesis

q Dysmorphogenesis and abnormal growth.

The most exciting challenges we face today as we strive to understand

how environmental influences interact with and cause changes in the

expression of the genetic factors governing the behavior of the cells that

will give rise to the entire human body, especially the face and palatal

regions. The treatment of defective genes is very much a part of the

clinical agenda dealing with craniofacial defects. Although the basic

scientist, the Dysmorphologist, the clinician, and, importantly, those with

natural or acquired craniofacial defects have gained significantly from the

critical use of available information coming from classical and experimental

studies of human morphogenesis

These approaches should and will increase our knowledge base on the

patterns and underlying causes of normal and abnormal craniofacial

morphogenesis.

The velopharynx10,16 is a musculomembranous valve extending from the

caudal margins of the oral cavity to the posterior pharynx. The anterior

opening of the velopharynx, the oropharyngeal isthmus is bounded on

either side by the palatoglossal arches and inferiorly by the dorsum of the

tongue. The anterosuperior limit of the velopharynx is the line of

attachment of the soft palate along the posterior margin of the palatine

bones.

The notion of the soft palate as forming the true roof of the pharynx

is best appreciated if the soft palate is considered in its elevated position.

45

In this position, the oral surface of the soft palate is continuous with the

posterior and lateral walls of the pharynx. The superior limit of the

velopharynx thus becomes defined as the line of apposition of the soft

palate with the posterior pharyngeal wall.

Cineradiographic studies indicate that the level of velar apposition

with the posterior pharyngeal wall lies about I cm above the level of the

atlas, very close to the plane of the pharyngeal tubercle on the basilar part

of the occipital bone.

In its relaxed position, the posterior border of the soft palate defines

the anterior limits of a large aperture in the velopharynx, the oropharyngeal

isthmus or hiatus nasopharyngeus. The lateral borders of the na-

sopharyngeal isthmus are defined by the ridge produced by the

palatopharyngeus muscle proper (the so-called palatopharyngeal

sphincter) and posteriorly by the pharynx above the pharyngeal ridge (of

Passavant). Jones suggested that the ridge of Passavant itself was the

true posterior limit of the nasopharyngeal isthmus, although studies in

living subjects indicate that the line of apposition of the soft palate is

normally above the ridge. This superior limit approximates the level of the

tori tubarii and thus includes the "true" pharyngeal part of the nasopharynx

in the velopharynx. Identification of the soft palate with the roof of the

pharynx excludes the space behind the choanae traditionally referred to as

the nasopharynx. Various terms have been suggested for this region,

including epipharynx, although that suggested by Negus- posterior nasal

cavity-seems most appropriate.

Basic Structure of the Velopharynx

Excluding the vascular and nerve plexus, the pharyngeal part of the

velopharynx consists of four layers:

- Internal layer of mucous membrane

- Internal fibrous layer

- Muscular layer

- External fibrous layer.

46

The internal fibrous layer is continuous superiorly with the

pharyngobasilar fascia, whereas the external fibrous layer is usually

termed the buccopharyngeal fascia..

Mucous Membrane: The velopharyngeal mucous membrane is typical oral

rnucosa consisting of nonkeratinizing, stratified squamous epithelium, with

a well-developed lamina propria. Along the border of the nasopharyngeal

isthmus, there is a transition from the typical stratified squamous

epithelium of the velopharynx to the respiratory type of ciliated columnar

epithelium.

Inferiorly, the velopharyngeal mucosa is continuous with the mucosa of

the remainder of the pharynx and oesophagus.

The palatoglossal arch contains the palatoglossus muscles and

associated connective tissue. The palatopharyngeal arch contains

connective tissue and vertically running muscle fibres traditionally referred

to as part of the palatopharyngeal muscle. These fibres are called as

Palatothyroideus.

On the posterior wall of the pharynx, a horizontal ridge (Ridge of

Passavant) can be observed in some subjects. This ridge may be

produced by the fibres running horizontally from the palate to the superior

pharynx, which is referred to as part of the true palatopharyngeus muscle.

In the region of the torus tubarius, three ridges are usually

apparent. Running almost anteriorly from the lateral ledge of the torus is

the small salpingopalatal fold. From below the opening of the auditory

tube, a ridge formed by the levator palati muscle (the torus levatorius) runs

anteromedially into the soft palate. Also, from the opening of the auditory

tube medial to the torus levatorius, the salpingopharyngeal fold runs

almost vertically downward.

Internal and External Fibrous Layers of the Velopharynx: Though generally

thin, they constitute a supporting framework for the velopharynx.

Superiorly, the internal fibrous layer extends beyond the superior border of

the superior constrictor muscle and is considerably thickened. This thick

layer, generally termed the pharyngobasilar fascia, is firmly attached to the

basilar part of the occipital bone, the pterygoid tubercle, and the adjacent

surface of the petrous part of the temporal bone.

47

The internal fibrous layer is thin over the constrictor muscles,

particularly over the inferior constrictor, and its extent is difficult to discern

in gross dissection.

The palatine, or velar, aponeurosis is a sheet of fibrous connective

tissue extending to about I cm posterior from the posterior border of the

hard palate. Generally, its posterior limit lies along a line joining the hamuli,

but medially its fibers thin out gradually and pass more posteriorly than this

limit. Although commonly referred to as the aponeurosis of the tensor

palati, the palatine aponeurosis receives contributions from the epimysial

coverings of the velar musculature and the salpingopharyngeal fascia.

The external fibrous layer, or buccopharyngeal fascia, is thinner than the

internal fibrous layer, and its precise extent is difficult to discern.

Superiorly, it merges with the pharyngobasilar fascia and laterally with the

carotid sheath and fascia overlying the buccinator muscle.

Velopharyngeal musculature: In the broadest terms, the musculature of

the velopharynx consists of four U-shaped muscular slings that converge

on the soft palate (the levator palati, the palatoglossi, the palatothyroidei,

and the palatopharyngei), and a paired muscle mass (the musculi uvulae)

lying on the soft palate.

Associated with these muscles are paired longitudinal muscles running

from the auditory tube (the salpingopharyngei), a U-shaped muscle sheet

forming the superior pharynx (the superior constrictors), and a pair of

L-shaped muscles contributing to the palatine aponeurosis (the tensors

palati).

Physiology of the Velopharynx

Primary velopharyngeal movements can be divided roughly into two

groups:

q Movements of the velum toward the posterior pharyngeal wall

q Mesial movements of the lateral pharyngeal walls.

48

Anterior movements of the posterior pharyngeal wall and bulging of the

nasal surface of the velum are also often considered while discussing

velopharyngeal function. Numerous techniques, including ultrasound,

cineradiography, endoscopy, and observation of anatomic relationships

have been employed to study the contributions of velopharyngeaI muscles

to these movements. However, the majority of these reports utilized

electromyography (EMG) to relate muscle activity to velopharyngeal

movement patterns. Although it might seem intuitively attractive to relate

muscle activity directly to movement of structures, interpretation of such

data must be made with some caution.

Velar Elevation

During breathing at rest and nasal sound production, the velum is

maintained in a lower position to allow for the movement of air between the

oral and nasal cavities. During attempts to produce oral speech sounds,

the normally functioning velum moves posteriorly and superiorly to contact

the posterior pharyngeal wall. The elevated velum is typically highest at its

middle segment, whereas contact against the posterior pharyngeal wall is

accomplished in its third quadrant. Velar height and displacement will, of

course, vary during connected speech as a function of phonetic context. It

is generally well accepted that the muscle primarily responsible for velar

elevation is the levator palati. It is suggested that the superior constrictor,

palatopharyngeus (palatothyroideus), and palatoglossus muscles may

influence velar elevation in some subjects.

Velar Lowering

Fig. 7: Primary components of palatopharyngeal function.

49

Given that levator muscle activity results in movement of the velum toward

a closed position, it would seem logical to assume that velar lowering

would involve a cessation, or at least a reduced level, of levator muscle

activity. This pattern has, in fact been observed by all investigators

studying velar movement. There is, however, some disagreement about

the precise mechanism, involved in lowering the velum. In her study of

three subjects, Bell-Berti suggested that in addition to cessation of levator

activity, velar lowering was accomplished by the natural tendency of tissue

to return to its rest position, and not from increased activity in any muscle.

This possibility is supported by the observation of elastic fibers in the

anterior faucial pillars.

An alternative explanation for velar lowering involves muscle activity.

Historically, increased activity in two muscles has been associated with

velar lowering. It was suggested that the tensor palati is favorably situated

to pull the palate down and forward. More recent study, however, has cast

doubt on the role of the tensor palati during speech production. Fritzell

found that the tensor was consistently active during swallowing and

chewing only. During speech, the muscle was typically inactive, and when

active, it bore no relations to speech. Tensor palati activity does appear to

be related to respiration.

The second muscle thought by some to contribute to velar lowering

is the palatoglossus. Anatomically, the palatoglossus is in a position to

lower the palate Fritzell and Lubker et al found the palatoglossus to be

active during palate lowering. They asserted that opening involves more

than simple gravitational forces following cessation of levator palati activity

and that the palatoglossus pulls the palate down for nasal sound

production and at the end of phonation.

50

Lateral Pharyngeal Walls

It is well established that mesial movement of the lateral

pharyngeal walls contributes to velopharyngeal closure. Much less

established is a description of how this is accomplished. Early reports

attributed lateral pharyngeal wall movement to the salpingopharyngeus

muscle. However, its contribution to such movement has since been

discounted. Current explanations for lateral pharyngeal wall movement

center on two muscles: the levator palati and the superior constrictor

Posterior Pharyngeal Wall

In the mid-1800s, Passavant described a bulging forward of the

posterior pharyngeal wall in a cleft palate subject. Passavant's ridge has

since been reported in normal subjects as well. Delineation of the exact

mechanism by which this ridge is formed is not clear. However, it is most

Fig. 8: Schematic view of sphincteric mechanism of velopharyngeal closure. Dotted lines show palatal and pharyngeal position at rest, while the solid lines are the same structures during velopharyngeal closure.

51

likely to be caused by the horizontal fibres of the palatopharyngeus. It is

also believed by some, that the superior constrictor might contribute to the

ridge. It has been found that Passavant's ridge does contribute to

velopharyngeal closure in some patients who demonstrated the ridge. This

is especially true in patients with repaired palatal clefts. However, others

have concluded that in normal speakers the observed magnitude of

anterior movements of the posterior pharyngeal wall is probably not signifi-

cant in the production of speech.

Velar Bulging

Until recently, much less attention has been focused on the musculi uvulae

relative to the other velopharyngeal muscles. Historically, it was believed

that the contraction of the musculi uvulae shortened the velum, an action

that might oppose velopharyngeal-closing movements. Others have

proposed that the musculi uvulae contribute to the convexity of the nasal

surface of the soft palate and according to them the primary role of these

muscles was to add bulk to the dorsal surface of the soft palate, which

would aid in occlusion of the velopharyngeal part during speech and

deglutition.

Two possible roles for the musculi uvulae have been proposed: a stiffness

modifying mechanism and a velar extensor mechanism.

As a stiffness modifying mechanism, the musculi uvulae would act to

control the velar-distorting forces of the levator palati muscle. That is,

levator contraction in association with compliant musculi uvulae might

result in distortion of the velum by stretching the top layer upward instead

of moving the entire velum. The velum must be stiff enough to avoid such

distortion but at the same time have enough compliance to allow it to

stretch in reaching the posterior pharyngeal wall.

As a velar extensor, the musculi uvulae might act as either a flexible beam

or a pulling force about a boundary. The curved beam model is based on

the fact that the musculi uvulae lie in the top half of the curved velum and

are attached anteriorly to the palatal aponeurosis. On contraction, a com-

pressional force is exerted along the nasal side of the velum. Because the

oral side of the velum is relatively compliant, the compressive force would

act to straighten the curved vellum and extend it posteriorly. The pulling

force model is based on the fact that the musculi uvulae extend across the

dorsal aspect of the levator sling. The sling acts as a boundary around

52

which the musculi uvulae can exert a force, thereby extending the velum

posteriorly.

PATTERNS OF CLOSURE OF THE VELOPHARYNGEAL COMPLEX17

Nasal endoscopy has provided a perspective from above about the

velopharyngeal portal, which has led to the refinement of the 4-

velopharyngeal closure patterns initially described by Skolnik from base

view video fluoroscopy.

1. Coronal Pattern:

The majority of the valving is palatal and accomplished by the full

width of the soft palate contacting the posterior wall. The lateral walls

exhibit limited movement to contact the lateral walls of the velum. There is

no posterior wall movement.

2. Sagittal Pattern:

The majority of the valving is pharyngeal. The lateral walls move

extensively to the midline and approximate each other. The velum does

not contact the posterior pharyngeal wall but elevates to contact the

approximated lateral walls. The posterior pharyngeal wall does not

contribute to the closure.

3. Circular Pattern:

There is essentially equal participation from the soft palate and the

lateral pharyngeal walls, with the contracting musculus uvulae acting as a

focal point. The lateral walls contact the musculus uvulae as it contracts

and contacts the non-mobile posterior pharyngeal wall.

4. Circular Pattern with Passavant’s ridge:

The same pattern is followed as the circular closure, except that the

posterior pharyngeal wall (Passavant’s ridge) moves forward to complete

the closure pattern around the musculus uvulae posteriorly.

53

SPEECH 17,97,125

The development of the vocal sound into meaningful speech was

one of the major accomplishments, which enabled man to reach the

pinnacle of the animal kingdom, and speech as the basic and fundamental

means of communication became the cornerstone for the establishment

and organization of society.

Speech is a learned process, which makes use of the anatomical

structures designed primarily for respiration and deglutition. The production

Fig. 9: Velopharyngeal closure patterns.

54

of speech requires the selective modification and control of the outgoing

air stream. Most girls master normal articulation by 6.5 years of age

whereas boys require an additional year.

TYPE OF SOUND

AGE AT WHICH

AVERAGE CHILD HAS

MASTERED IT

Vowels During first year

Labials 3 years

Dentals and

gutturals

3.5 to 4 years

Labiodentals 5 years.

Complicated

tongue sounds

During 6th year

Sibilants and

blends

During 7th year

Components Of Speech:

Speech has been divided into the following components-

1. Respiration

2. Phonation

3. Resonation

4. Articulation

5. Neurologic innervation

6. Audition.

Respiration: During respiration the inhalation and exhalation are

approximately equal but during speech, the inhalation phase is shortened

while the exhalation phase is prolonged and not repetitive. Prolongation of

exhalation is achieved by the valve mechanisms along the laryngeal,

55

pharyngeal, oral and nasal components of the respiratory tract. These,

valves impede the expired air and help to create speech signals. Subglottic

pressure is maintained by the balanced elasticity between the inspiratory

intercostal musculature and the expiratory abdominal musculature. If the

vital capacity of the lungs is compromised like in emphysema, speech will

be perceived as breathy. The poor projection of voice in such cases is due

to the reduced volume and pressure of the expired air.

Phonation: The larynx provides the first level of constriction for controlling

the respiratory air stream. The primary function of the vocal folds is to

protect the lungs and the lower respiratory tract from inhalation of

particulate matter. This, protective mechanism requires a simple, forceful

approximation of the vocal folds. Speech conversely, requires a multitude

of positions varying from tensions and vibratory cycles and an intricate

coordination of the vocal cords with other structures. If the vocal folds are

partially or completely adducted, they impede the expired air. With the

proper degree of tension and sufficient subglottic pressure, the vocal folds

may be set in vibration and thus impart phonation to the airstream.

Whereas phonation is required for certain sounds, others do not need

phonation; hence the vocal cords are left open or abducted.

In the production of low-pitched sound the vocal folds are flaccid and thick

while for high-pitched sounds the margins of the approximated folds are

thin and tense.

Resonation: The sound produced during phonation is augmented and

modified by the chambers and the structures above the glottis i.e. the

pharynx, oral cavity and the nasal cavity. These act as resonating

chambers and amplify certain frequencies while muting others, thus

refining the tonal quality.

The dimensional changes in the pharyngeal tube like cavity due to the

action of the constrictor muscles of the pharynx influence the resonant

characteristics of the pulsating air stream, as it emerges from the larynx.

The velopharyngeal mechanism proportions the sound and /or airstream

between the oral and nasal cavities and influences the voice quality (basic

sound) that is perceived by the listener. If the velopharyngeal closure is

compromised, or if the structural integrity or relative size of the oral,

56

pharyngeal or nasal cavities has been altered, voice quality can be

compromised.

Articulation: Amplified, resonated sound is formulated into meaningful

speech by the articulators namely the lips, tongue, cheeks, teeth and

palate, by changing the relative spatial relationship of these structures. The

tongue is considered to be the most important articulator of speech as it is

able to affect rapid changes in movement and shape. The tongue may

impede, selectively restrict, and channel airstream with precise contact

against the teeth and palatal areas thus, articulating the basic laryngeal

sound or the non-phonated air stream into recognizable speech. If the oral

structures like the tongue, jaws or lips are surgically altered surgically and/

or neurologically, articulation may be compromised,

Neural Integration: Speech is integrated by the central nervous system

both at the central and peripheral levels. The sequential and simultaneous

movements required throughout the speech process demand precise

coordination. It is estimated that at least 17,000 motor patterns are

required during speech. Neurologic impairments may compromise a

specific component of the speech mechanism, such as the vocal folds, soft

palate or tongue, or it may indirectly affect the entire speech system. A

cerebrovascular accident may compromise the ability of the patient to

comprehend and / or formulate meaningful speech, even though all the

structures are individually normal.

Audition: It is the ability to receive acoustic signals is vital for normal

speech. Hearing permits reception and interpretation of acoustic signals

and allows the speaker to monitor and control speech output.

Compromised hearing can preclude accurate feedback and hence, affect

speech.

Phonemics:

A phoneme is a unit of speech by which we distinguish one

utterance from another and which collectively make up the phonemics of

the language. There are about 44 phonemes in the English language.

Speech is further classified into Surds, Sonants and Consonants.

57

Surd: is any voiceless sound and is produced by separation of the vocal

cords (glottis open) with no marginal vibration. The friction of the airstream

makes the sound as it passes through the appropriate cavities. The initial h

sound as in huh and the voiceless sibilants s, z, zh pronounced initially are

examples of surds.

Sonants: These are voiced sounds and include all vowels and vowel like

sounds. They are produced by the vibration of some portion of vocal folds

to establish the original sound wave, which is augmented by cavity

resonation. The vowels require minimal articulation and are classified

according to the tongue position in the oral cavity (i.e. high, mid or low) and

the position of the lips. Vowel combinations are called Dipthongs e.g. ie

Consonants: These are articulated speech sounds, and all require

articulation to impede, constrict, divert or stop the airstream at the proper

place and time to produce the desired sound.

Consonantal articulation: Consonants are classified according to the

type of articulation into Stops, Fricatives, Affricatives and diversions of the

airstream.

a) Stops: These are characterized by the stoppage and sudden

release of the airstream and require complete occlusion of the

articulators involved.

The plosives p and b produced by the closure of the lips to

permit momentary buildup of the airstream, followed by a

sudden explosive release.

The tongue contacting the hard palate to stop the airstream

before suddenly releasing it produces the t and d sounds.

The k sounds are produced by the tongue and soft palate

closing the oral cavity at the same time the soft palate and the

pharynx close the nasal cavity to stop the airstream prior to

plosive release.

b) Fricatives are produced by the airstream being forced through

loosely closed articulators or a narrow passageway.

58

For the labiodentals f and v, the lower lip articulates with the

maxillary anterior teeth to constrict the airstream.

The linguodental th is produced by incomplete articulation of

the tip of the tongue and maxillary incisors to constrict the

airstream.

The sibilants s, z, sh, and zh are produced by the tongue blade

articulating with the lateral aspects of the hard palate,

permitting the airstream to be forced through the groove

created in the tongue apex.

c) Affricates j and ch are produced by a combination of stop and

friction, accomplished by the articulation of the tongue and the

anterior hard palate.

d) Diversion of the airstream is characterized by stoppage at one

point to permit escape at another. The nasal m is produced by

the lips occluding to seal the oral cavity and permit emission

through the nose. The nasal n is produced by the articulation of

the tongue and the hard palate closing the oral cavity while the

sound escapes through the nasal cavity.

The nasal ng is produced by the tongue and soft palate closing

off the oral cavity to permit nasal emission.

For the lateral l, the tongue apex occludes the anterior portion

of the oral cavity while the sound escapes the lateral portion.

MANNER OF PRODUCTION

PLOSIVE FRICATIVE AFFRICATIVE SEMIVOWEL NASAL

PLACE

Bilabial

p(pole)

b(bowl)

w(watt) M(sum)

Labial

Dental

f (fat)

v (vat)

Lingual

Dental

0(thigh)

α(thy)

59

Lingual

Alveolar

t(toll)

d (dole)

s(seal)

z(zeal)

l(lot) n(sun)

Palatal ∫(ash)

z(azure)

ch(choke)

J(juke)

Velar k(coal)

g(goat)

ng(sing)

DEGREE OF OBSTRUCTION

COMPLETE

OBSTRUCTION

PARTIAL

OBSTRUCTION

ORALS

LOCUS OF

OBSTRUCTION

VOICELESS

VOICED VOICELESS VOICED

NASALS

(VOICED)

BILABIAL /p/ /b/ /wh/ /w/ /m/

LABIODENTAL /f/ /v/

Fig. 10: Relative positions of the soft palate and tongue in the formation of the consonant sounds indicated by the letters.

60

LINGUODENTAL /th/ /th/

ALVEOLAR /t/ /d/ /s/ /z/,/l/ /n/

POST

ALVEOLAR

/ch/ /j/j /sh/ /zh/,/r/

PALATAL /y/

VELAR /k/ /g/ /ng/

GLOTTAL /h/

Speech and Maxillofacial Prosthetics:

Velopharyngeal incompetence is the functional inability of the soft

palate to effect a complete seal with the posterior or lateral pharyngeal

wall. It can be due to a variety of causes apart from cleft palate and these

includes traumatic injuries to the neuromotor systems or the peripheral

efferent cranial nerves, cerebrovascular accidents, brain stem tumours,

neuromuscular disease such as multiple sclerosis and cerebral palsy. The

prime clinical effect of this incompetence is an escape of air resulting in

nasal speech that may be unintelligible.

Patients with acquired defects or congenital malformations of the

soft palate may exhibit excessive nasal resonance, because, without

surgical and/or prosthodontic intervention, they are unable to control and

divert sufficient airflow into the oral cavity. Whereas the degree of

velopharyngeal closure remains the major determinant of resonance

balance, other factors such as tongue position relative to assistance in

velar elevation and structural resistance within the nasal cavity influence

the perceived oral-nasal resonance balance.

Resonance defects manifest as:

q Excessive nasal resonance (Hypernasality, nasality and/or rhinolalia

aperta) In this excessive air escapes into the nasal cavity and the

patient sounds as though he/she talking through his/her nose.

61

q Insufficient nasal resonance (Hyponasality, denasality or rhinolalia

clausa.) Patient shows insufficient airflow through the nasal cavity. This

condition may occur due to use of obturator.

Articulation deficiencies are primarily seen in patients with the acquired

defects of the mandible. Congenital cleft lip and palate patients may exhibit

errors both in articulation and resonance.

Errors in articulation may be classified as three types:

a. Errors of distortion- most commonly occurring problem. Commonly

known as whistling /s/. Some types of lisping are these defects.

Also patients with dysarthria, paralysis and prosthodontic patients

show this.

b. Errors of substitution- in this one sound is replaced by another.

May be seen in a prosthodontic population. Patient might say /th/

instead of /s/; a sort of lisp.

c. Errors of omission- Children, in developing speech skills, will often

show omissions when they have failed to learn the sounds. Also

persons learning a new language and people suffering from

hearing problems. For example- “Ink” for “sink” /s/ is omitted –

wrong word.

Cleft palate patients may show all three types of articulatory disturbances.

When hypernasality and articulatory deficiencies coexist, resonance and

articulation are difficult to differentiate.

The speech considerations that need to be observed in constructing the

prosthesis are as follows:

I) Construction of the prosthesis

a) Palatal Section:

q Should establish occlusion between the anterior maxillary and

mandibular teeth to aid in the production of the labiodental,

linguodental and linguoalveolar sounds.

q Should be free from obstructions (such as protruding

malpositioned teeth), which would interfere with the free

movement of the tip of the tongue.

q Should be vaulted to produce an oral cavity of as near normal

size as possible.

62

q Should provide adequate retention so that the movements of

the appliance will not interfere with speaking.

b) Velar section:

q Should be constructed to compensate for lateral movement of

velar tissue in unoperated or redivided cases in order to prevent

leakage of air or sound into the nasal cavities during speaking.

q Should be placed as high as is anatomically and prosthetically

possible to avoid interference with tongue movements and to

restore an oral cavity of normal size.

q Should provide a sturdy support for the pharyngeal section.

c) Pharyngeal section:

q Should be located at the point of maximum constriction of the

pharynx as determined by muscle trimming during deglutition.

q Should be large enough for the pharyngeal musculature to

grasp during deglutition and to approximate during speech

production.

q Should not be over-infraextended, i.e. it should not extend

inferiorly into the oropharynx and, thus, reduce the size of this

important resonating cavity, nor should it be over-

supraextended.

q Should be constructed of some readily modifiable material,

which will permit adjustment as muscular development results

from speech training.

II) Age factor in prosthesis.

The prosthesis can be employed to prevent the development of

serious speech defects. The speech pathologist recommends that

temporary prosthesis be made for children as soon as the deciduous teeth

have erupted sufficiently to provide retention and the child will cooperate.

III) Management of postoperative cases

Before prosthesis is constructed for a patient whose palate is

insufficient or immobile, a thorough study of the lingual and mandibular

movements employed in speech production should be made by a speech

pathologist.

63

Skilled diagnosis and treatment planning are essential for adequate

treatment of the patients handicapped by congenital and acquired

maxillofacial defects.

The maxillofacial prosthodontist serves, primarily as a member of a

team and must cooperate with the other members in planning rehabilitative

treatments for patients. The other team members include the surgeon,

paediatrician, speech pathologist, psychologist, psychiatrist,

physiotherapist, radiologist, orthodontist, otolaryngologist and social

workers.

The maxillofacial prosthodontist must be acutely alert towards the

medical health of the patient because of the ever-present possibility of

recurrence, or the modified nature of tissues due to age, therapy or

disease itself. Further, the maxillofacial prosthodontist must be familiar with

the operating rooms, recovery rooms and various hospital protocols.

He/she may advise the surgeon about the natural history, any existing

dental pathology and advise about the preservation or excision of tissue

for the benefit of the subsequent prosthetic treatment. He/ she may assist

in the surgery and fit the immediate surgical obturator.

Similarly, the maxillofacial prosthodontist must interact with the

radiotherapist to render opinion on extraction of teeth, maintenance of the

irradiated area, because at a later stage the irradiated tissue may alter the

design of the prosthesis. The prosthodontist can contribute immensely

towards preventing the unnecessary radiation to surrounding structures by

making Brachytherapy appliances.

The psychologist and sometimes even the psychiatrist need to be

consulted while dealing with the patents with defects and even the parents

of children with congenital defects need counseling.

64

The clinical social worker and vocational rehabilitation counselor

can provide solutions regarding finance, family and reemployment

problems. This helps to allay fear, misconception of the patient and goes a

long way in effecting social rehabilitation.

The pediatrician must be consulted for cleft lip and palate

prosthesis. The pediatrician along with the obstettrician is usually the first

to make the diagnosis and to discuss the deformity with the parents. The

health of the cleft patient must be assessed and the nutritional status of

the patient maintained under the guidance of the pediatrician.

The otolaryngologist’s role is to prevent or treat those middle ear

problems, which are uniformly present in these children.

An orthodontist’s role is very important in cleft palate and lip

patients for arch correction and the orthopedic correction in procedures like

presurgical nasoalveolar moulding. In addition, the prosthodontist may call

upon the services of co-specialists like periodontist and pedodontist

towards the successful management of these patients.

Last but not the least is the role played by the speech pathologist. It

is very important that the prosthodontists interact with speech pathologists

to gain knowledge about the mechanics and physiology of speech so that

the prosthesis can be designed in a way, which can fulfill requirements of

resonance, phonation and articulation.

It is highly imperative that a maxillofacial prosthodontist

understands the various diagnostic procedures used in the assessment of

speech and their application. Therefore, a detailed account of these

procedures is presented.

Diagnostic Procedures Used In The Assessment And Treatment Of

Speech Defects 15,17,140

To define the severity of the dysfunction and to identify the most

appropriate treatment plan, the pattern(s) of speech production should be

evaluated by the speech pathologist.

65

An oral assessment is made to identify possible problems related to

structural anatomy; an assessment of palatopharyngeal function for

speech cannot be made from a functional assessment. Special tests,

which have been described, are used. A standard speech sample is used

to assess. Turner and Williams have described this standard sample.

According to them, the selection of a clinical speech sample should include

phrases that would normally require the palatal port to be completely

closed and other phrases that would require the palatal port to close, open

and close again. The sample used is the sentence “In the evening, Connie

watches TV with me”. This sentence contains 10 oral consonants and 6

nasal consonants requiring the rapid opening and closing of the

palatopharyngeal port for normal sentence production. The palatal port

opens four times for the nasal consonants (/n/ of In, /n/ and /ng/ of

evening, /n/ of Connie, and /m/ of me). In addition, there are three points of

closure that are associated wit the oral consonants. The proximity of /n/

and /ng/ in the word evening and the two /n/ s in the word Connie result in

a single opening of the palatal port during the production of each of these

words. Knowing the pattern of production for this sentence as

demonstrated by normal speakers provides a baseline to compare the

pattern produced by individuals with suspected palatopharyngeal

dysfunction.

1. Articulation Tests:

These are used to record sounds that are produced correctly as

well as errors in speech including omissions, distortions and substitutions

of normal or compensatory sound errors.

Rating of the speech sample is done for intelligibility and acceptability.

Intelligibility is how well an individual’s speech can be understood by

others while the acceptability is the pleasing ness of sound and the

appearance of speech. Both these ratings range from normal (1) to the

unintelligible/ unacceptable (5/7).

2. Cephalometrics:

Velopharyngeal valve in three dimension and its attributes cannot

be captured on a midsagittal view alone. Also it can be filmed at a single

point in speech production and there is no information gained about the

lateral pharyngeal wall.

66

Cephalometrics is used to define the structures and growth pattern of

pharynx, velum and lymphatic tissue and to determine skeletal

characteristics and growth disturbances in pathologic conditions.

3. Cine videofluoroscopy:

Cine fluoroscopy (X rays recorded on motion picture film) and

videofluoroscopy (X rays recorded on videotape) with simultaneous voice

recordings are done to assess the velopharyngeal mechanism. The key to

the development of the motion x-rays was the advent of image

intensification. Video recording involves lower radiation dosage than does

cine fluoroscopy.

4. Multiview videofluoroscopy:

Skolnick introduced it. Fluoroscopic X ray technique allows the

visualization of velopharyngeal port or valve during speech in several

different planes. This is important as speech involves movement of the soft

palate, lateral and posterior pharyngeal walls. It includes lateral, base,

Towne’s, frontal, Water’s and oblique views. Not all views are required in

all patients. View selection depends upon the information needed,

anatomy of skull and the anatomy and function of the vocal tract.

Generally three views are taken –

q Lateral view

q Base or Towne’s view

q Water’s or oblique view

These are recorded and maintained on videotape with audio recording of

the speech sample for the purpose of interpretation and comparison by the

radiologist and the speech pathologist.

Radiation dose is kept minimal by the following measures –

q Videofluoroscopy rather than cinefluoroscopy is used.

q X ray coning is done to localize it to the minimal possible area

q Minimum amount of radiation required to produce image is used

q Lead shields are used to protect other areas.

Technique:

67

To enhance the velopharyngeal area high-density barium is instilled into

each nostril using a syringe and plastic tip. This results in barium coverage

of the soft palate, lateral and posterior pharyngeal walls and the posterior

aspect of the tongue.

Standard speech sample is used during each view.

Lateral View:

Patient is sitting upright and the judgment made about the length

and thickness of soft palate, depth of the pharynx, size and location of

adenoids and tonsillar tissue. The anteroposterior excursion of the soft

palate and anterior movement of the pharynx and the velopharyngeal

contact during speech is assessed.

The disadvantage is that the velopharyngeal contact along its width

cannot be studied but the lateral view provides excellent visualization of

the tongue and is helpful in differential diagnosis of the compensatory

errors. In some cases the tongue is observed to elevate soft palate to

effect velopharyngeal closure for velar stop sounds /k/ and /g/. Abnormal

laryngeal elevation and abnormal movement of the glottis are also seen in

this view.

Frontal View:

It is used to determine the degree and location of mesial

movements of the lateral pharyngeal walls. The lateral pharyngeal wall

movement may occur at a specific location in the vocal tract or in an

extensive area. This information is useful in planning approximate width of

the pharyngeal flap or designing the speech aid prosthesis.

Technique: The patient is upright facing the image intensifier with head in

a position that the Frankfort’s Horizontal plane is parallel to the floor.

Coating of the nasopharynx is done with barium and standard speech

sample is used. When the overlying bony structure obscures the lateral

pharyngeal walls, Water’s view is the alternative in which the head is tilted

up by 45 degrees from the Frankfort’s horizontal plane to prevent bony

overlapping.

Base and Towne’s Views: These views outline the shape of the

velopharyngeal valve, pattern, symmetry and consistency of

68

velopharyngeal valving movements and the size and location of

velopharyngeal gaps during speech.

Towne’s view is more useful than base view when soft palate

approximates the adenoid tissue during valving creating oblique areas of

velopharyngeal closure or when patients have large tonsils or posterior

compensatory tongue movements.

In the base view the patient lies prone on the X ray table in a sphinx like

position with the head hyper extended.

In the Towne’s view the patient is seated upright with his/her head in the

horizontal plane. The camera is then rotated in relation to the face until the

velopharyngeal valve is visualized.

During these procedures a standard speech sample is used and

Multiview videofluoroscopy can be performed in patients as young as 3-4

years of age.

5. Ultrasonography:

It is a device that has been employed for lateral pharyngeal walls.

Not suitable for displaying motion of velum as there is problem in

transmitting the waves through the bone overlying the structures under

observation.

6. Video Nasopharyngoendoscopy:

It involves inserting a flexible fibreoptic tube through the nose to

obtain a direct superior view of the velopharyngeal valve and the vocal

tract during speech.

It is used to determine and test the following –

- Anatomy and function of the velopharyngeal valve during speech.

- Relative size, location and consistency of the velopharyngeal gaps.

- Function of the posterior aspect of the tongue during speech to

determine the differential.

- Diagnosis of the compensatory articulation errors.

- Anatomy and function of the laryngeal structures.

- Useful in identifying pulsations in the pharynx which may be

indicative of abnormally placed carotid arteries which is seen in

Velocardiofacial Syndrome that might preclude pharyngeal flap or

sphincter pharyngoplasty surgery.

69

- Used to assess the outcome of surgery, prosthetic aid or speech

therapy.

- Used for Biofeedback therapy to enhance velopharyngeal

movements during speech and correct some compensatory

articulatory errors.

For young children flexible nasopharyngeal endoscope of the distal tip

diameter of 2- 3.7 mm is recommended.

Technique: Topical local anesthetic is applied to the nostril to allow easy

passage of the scope through the nostril into the middle meatus of the

nasal passage to first visualize the velopharyngeal area to document the

anatomy and function and to check for any pulsations. Scope is then

passed down to the vocal tract to document the anatomy and function of

the tongue and larynx. A standard speech sample is used and audiovisual

recording done. However, false positive or negative results can come if the

distal end of the scope not placed directly over the velopharyngeal port.

7. Nasometer:

It is a computer-based instrument produced by Kay Elemetrics

which is designed to measure the relative amount of nasal acoustic energy

compared to oral acoustic energy during continuous speech production.

The instrument uses sound separator placed on the patient’s upper lip.

Microphones on either side of the sound separator sense oral and nasal

acoustic energy during speech and this energy is filtered and digitized by

the custom electronic module. Computer with the special software

processes the information and produces a Nasalance score. This score is

a ratio of nasal to oral acoustic energy multiplied by 100. Nasal and oral

acoustic energy is averaged during the production of vowels and

consonants in test sentences to produce nasalance score.

Interpretation: An abnormally high nasalance score during production of

non nasal consonants suggest velopharyngeal inadequacy and

hypernasality while abnormally low nasalance score during production of

nasal consonants is suggestive of Hyponasality and/or nasal airway

impairment,

The disadvantage is that it is less useful in patients who exhibit

velopharyngeal inadequacy and nasal airway impairment.

70

8. Aeromechanical Measurements:

These aerodynamic studies are based on a modification of a theoretical

hydraulic principle, which assumes that the smallest cross sectional area

of a section, can be determined if the differential pressure across the

structure is measured simultaneously with the rate of airflow through it.

Warren & Dubois Technique:

Measurement of nasal airflow and difference in air pressure above

and below the velopharyngeal port may be used to estimate area of the

velopharyngeal orifice during the production of stop consonants and also

the resistance of port to the airflow.

These pressure flow measurements provide information about the

coupling of the oral and nasal cavities during speech and about the

resistance in the system.

The disadvantage is that it does not describe the movement of

particular structures, such as the velum or the lateral or posterior

pharyngeal walls or the location and configuration of any opening that is

present.

PERCI- Palatal Efficiency Rating Computed Instantly

Warren introduced PERCI. It records and displays the difference in air

pressure in the mouth and the nose. Warren studied 75 patients and

concluded that patients with differential pressure reading greater than 3.0

on PERCI had velopharyngeal orifice areas of 10 square millimeters or

less. PERCI readings of less than 1.0 had areas greater than 20 square

millimeters. PERCI readings between 1.0 and 2.9 associated with

velopharyngeal orifice of area between 10 and 20 square millimeters.

TONAR – The Oral and Nasal Acoustic Ratio

Introduced by Fletcher and Bishop. They advanced the study of oral and

nasal sound intensity measures as indices to study hypernasality.

The instrument prints out voltages associated with nasal and oral signals

and also a trace reflecting the ratio of the voltages from the sound

detected in the oral and nasal chambers.

Based on these tests lot of findings have been made about:

71

Velopharyngeal orifice size: it has been found that the velopharyngeal

orifice should be less than 0.2 square cm during the production of plosive

and fricative sounds. If the opening is greater than this then, the respiratory

effort has to be increased to compensate for it and provide improved oral

pressure for speech. Oral pressure greater than 3 cm of water is

considered adequate for plosive and fricative phonemes. Increase in oral

pressure along with velopharyngeal inadequacy may improve articulation

but the nasal airflow is increased which in turn, may increase the perceived

level of nasality.

Nasal resistance: the resistance to nasal airflow may contribute to

increased oral pressure and consequently improve the effectiveness of

speech for patients with large velopharyngeal orifices. It is the sum of the

resistance provided by the velopharyngeal mechanism, nasal resistance

and the increase in the respiratory effort that determines the oral pressure.

Warren studied the airflow and found that cleft palate patients had

significantly greater nasal resistance to airflow. But, patients with repaired

bilateral clefts of lip and palate have larger airway, less nasal resistance

and consequently less effective speech articulation as compared to

patients with unilateral clefts. Therefore, a nose that is good for breathing

may be bad for speech under these circumstances.

Nasal valve: The valve is considered to be the area between the upper

and lower lateral cartilages, the piriform aperture and the anterior terminus

of the inferior turbinate. In physiologic terms, the nasal valve is considered

as the regulator, with the smallest cross sectional area within the nasal

cavity based on the anatomical and flow resistive characteristics. The

nasal valve dilates during inspiration and both active and passive flattening

occurs during expiration. Therefore, the nasal valve is an active participant

in the breathing process rather than a passive conduit of airflow.

Oral versus nasal breathing also depends on the average cross sectional

area of the nasal valve, which is 0.63 square cm +/- 0.17 square cm. When

it is lesser than 0.40 square cm – it is an impaired airway and patients will

be predominantly oral breathers.

72

It can then be summarized that there is not a direct linear relationship

between velopharyngeal orifice size and the level of perceived nasality.

This is understandable when the number of variables including the nasal

resistance and timing, which can impact the aerodynamic characteristics of

the speech mechanism, are understood

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Psychological Considerations9,17,29,135

The assessment of the patient’s demeanor is important to the

success of the treatment. It determines whether the proposed treatment

can be performed efficaciously or understood and appreciated by the

patient once it is completed. The prognosis for a successful treatment

outcome is dependent upon the prosthodontist making a correct diagnosis

and anticipating issues beyond the realm of dentistry alone. This is even

more important while dealing with patients having oro – facial defects as

the maxillofacial region is of crucial importance during one’s early

development. It is involved in all interpersonal relationships and relates to

some of our deepest needs. During the earliest stage of development, the

most salient portion if the infants existence is oral. It is because of this that

Freud and subsequent analysts termed the first year of life as the “oral

stage” it is with the mouth that the self is first revealed to the environment.

Psychological Classification and interpretation:

Routine classification to categorize the mental status of patients fall

short in classifying those patients with life threatening diseases or those

who have suffered recent traumatic events. Additionally, those patients in

whom the face is disfigured and/or those who have lost an important

biological function such as speech or swallowing will experience changes

in social acceptance that impact the psyche and sense of well being.

As the maxillofacial patient’s quality of life is altered and social

integration becomes difficult, the patient’s expectations to return to

normalcy often collapse. Underlying emotional issues that were

subconsciously buried may come to the surface, or unachievable

expectations and unreasonable demands may arise that hinder the

prosthodontist’s ability to provide adequate treatment. Further, in such a

case it is critical to assess whether treatment should be carried out at all,

delayed until the patient’s demeanor is more conducive to treatment and/or

coordinated with services of supportive professionals like social workers

and psychologists.

The prosthodontist’s goal is a successful treatment outcome, but

not at the expense of one’s emotional and mental well being or that of the

staff. A health care provider is not required to “heal” every patient that

74

walks through the front door. It means that if at the examination level one

recognizes a patient with underlying psychological conditions or

confounding emotional factors, it may be best not to treat until these are

addressed. There must be an unconditional commitment to the same

treatment goals by both doctor and the patient. Therefore, it becomes

paramount that the prosthodontist understand the various psychological

diagnoses, ranging from subtle emotional nuances to overt psychological

disorders that potentially undermine prosthetic treatment.

Psychological impairments are characterized by disturbances in a

person’s thoughts, emotions or behavior. These impairments can range

from those that cause mild distress to those that severely impair a person’s

ability to function, individually, in family or in a community.

International surveys have demonstrated that from 30 to 40% of

people in a given population experience a mental illness during their lives.

They also reveal that anxiety disorders are more common than depression.

In children and the elderly, rates and forms of mental illness change with

age and gender. Depression and anxiety occur at the same rate among

girls and boys until mid adolescence, when girls account for more. Among

prosthodontic patients, children most often present with congenital defects

or alterations in growth and development whereas adolescents and young

adults often present with developmental defects or trauma. Mental illness

has grown in the elderly as greater portion of the population live beyond

the age of 65. Dementia, characterized by impaired intellectual functioning

and memory loss, occurs mostly among the elderly, and may overlap with

the ablative cancer patient groups.

The highest rates of mental illness occur in people in the lower

socioeconomic classes and rates of all mental illnesses decline as levels of

education and income increase. Therefore, the ability of maxillofacial

patients to integrate into society and to be employable will be critical to

their mental status. The overall prevalence rates between men and women

are similar, however, men have much higher rates of antisocial personality

disorder and substance abuse. The acquired maxillofacial cancer/defect

population correlates with this group of substance abuse. Women suffer

anxiety disorders and depression more than men.

1. Anxiety Disorders:

75

These involve excessive apprehension, worry and fear. The disorders

included in this group are panic disorder, obsessive compulsive disorder

(OCD), posttraumatic stress disorder (PTSD), social phobia and

generalized anxiety disorder in which people experience constant anxiety

about routine events in their lives. Phobias are fears of specific objects,

situations or activities.

Panic disorder is an anxiety disorder in which people experience

sudden, intense terror and physical symptoms like tachycardia and

dyspnoea. Panic disorder typically strikes in young adulthood. Women are

twice at risk and it is likely to be seen with depression and substance

abuse.

Obsessive-Compulsive Disorder is a condition in which the patients

experience intrusive thoughts or images (obsessions) or feel compelled to

perform certain behaviours (compulsions).

Posttraumatic Stress Disorder (PTSD): In this condition, patients relive

traumatic experiences from their past and feel extreme anxiety and

distress about the event. PTSD can develop at any age including

childhood and more commonly seen in women. This occurs frequently in

people who have spent time in war zones, after violent personal assaults

like rape, mugging, domestic violence, terrorist attacks, natural disasters

and accidents. Depression and substance abuse generally accompany

PTSD.

Social phobia is seen more in women. The disorder typically begins

in childhood or early adolescence and is often accompanied by depression

and may lead to substance abuse.

2. Mood Disorders: Depression and Mania.

These are also called affective disorders, which create

disturbances in a person’s emotional life. Depression is a serious condition

frequently seen after heart attack, stroke, diabetes and cancer but is

treatable. Depression increases the incidence of other somatic illnesses

like myocardial infarction. Symptoms of depression include feelings of

sadness, hopelessness, and worthlessness as well as complaints of

physical pain and changes in appetite, sleep patterns and energy level.

In mania on the other hand an individual experiences an

abnormally elevated mood, often marked by exaggerated self-importance,

irritability, agitation, and a decreased need for sleep.

76

In bipolar disorder or manic-depressive illness, a person’s mood

alternates between extremes of mania and depression.

3. Schizophrenia and other psychotic disorders:

People with these disorders lose contact with reality. Symptoms

include delusions and hallucinations, disorganized thinking and speech,

bizarre behavior, diminished range of emotional responsiveness and social

withdrawal. Men and women are equally affected.

4. Personality Disorders:

Generally these patients have poor perceptions of themselves or others.

They may have low self-esteem or overwhelming narcissism, poor impulse

control, troubles social relationships and inappropriate emotional

responses.

5. Cognitive and Dissociative Disorders:

Cognitive disorders such as dementia and delirium involve a significant

loss of mental functioning. Dementia is characterized by impaired memory,

difficulties in speaking, abstract thinking and ability to identify familiar

objects. These occur due to medical conditions, substance abuse or as

adverse reactions to medication or poisonous substances.

Dissociative disorders include disturbances in a person’s

consciousness, memories, identity and perception of the environment.

These include amnesia that has no physical cause, dissociative identity

disorder in which a patient has two or more distinct personalities that

alternate in their control of the patient’s behavior, depersonalization

disorder characterized by a chronic feeling of being detached from one’s

body or mental processes and dissociative fugue that is an episode of

sudden departure from home or work with an associated loss of memory.

These disorders also include possession states or trances.

6. Somatoform and fictitious disorders:

These are characterized by the presence of physical symptoms

that cannot be explained by a medical condition or other mental illness.

These include conversion disorder or hysteria in which a person

experiences blindness, deafness or seizures though the physicians cannot

find an organic cause in the person. Hypochondriasis is one condition in

77

which a person feels a constant fear that he/she will develop a serious

disease and misinterpret minor physical symptoms as evidence of illness.

People with factitious disorders intentionally produce or fake

physical or psychological symptoms in order to receive medical attention

and care.

7.Substance Related disorders:

These result from the abuse of drugs, side effects of medication or

exposure to toxic substances. These are regarded as behavioral or

addictive disorders.

8. Eating Disorders:

These are disturbances in eating behavior occurring most

commonly in young women. These include, anorexia nervosa in which

people have extreme fear of gaining weight and refuse to eat adequately

and Bulimia nervosa in which people repeatedly engage in episodes of

binge eating followed by self induced vomiting or the use of laxatives,

diuretics or other medications to prevent weight gain.

9.Impulse control disorders:

In these people cannot control an impulse to engage in harmful behavior

such as explosive anger, stealing (kleptomania) etc.

After this brief review of the common psychological impairments the

psychological changes in the maxillofacial patient are as follows.

Maxillofacial patients are classified according to the aetiology of their

diagnosis i.e. acquired, congenital and developmental defects.

Patients with acquired maxillofacial defects have had ablative cancer

surgery or trauma. These two groups are similar in that in both situations a

person who had a relatively normal anatomy and physiologic function and

subsequently lost them overnight. Cancer patients differ from trauma

78

patients and they express “why me?” and are often faced with the

possibility of recurrence, more surgery, chemotherapy or radiotherapy and

the futility of the process. Patients with smaller defects are generally more

demanding with higher expectations than the ones with larger, more

debilitative defects. The trauma patient is usually younger than the cancer

patient, particularly when the trauma is self-inflicted. It is noticed in the

cases that attempted suicides that their demeanor is relatively but

superficially upbeat. Additionally, with the self-inflicted trauma patient,

there is a ‘la belle indifference’ demeanor when confronted with the

upward struggle of multiple, difficult procedures to restore the patient’s

face.

Congenital defect patients intuitively understand that they are different

from the norm and may believe that they are genetically damaged or sub-

human as they may not fit in with their peer or age groups. They also face

the knowledge that there may be a genetic predisposition to recurring

incidence in their own progeny. Parents may have difficulty in accepting

their child or blame themselves for the birth defect, resulting in family

dysfunction and loss of family unity. Congenital maxillofacial patients

usually face multiple and sequential surgeries, orthodontics and

prosthodontic procedures over several years in an attempt to correct their

defects.

Anomalies in growth and development may not be readily apparent at first

in the developmental defect patient but will ultimately become so. The

developmental defect patient may display emotional responses similar to

the congenital defect patients but as the defect becomes apparent over a

period of time, the patient may or may not learn to deal with the evolving

process.

Loss and Grief in Maxillofacial Defects:

Once patients realize they have cancer, or have experienced any

other debilitating crisis creating a loss, they perceive it as both an

immediate and future loss. This may manifest itself in the form of anxiety,

depression or a posttraumatic stress disorder. In any event a cycle of loss,

grief and reintegration must be completed by the patient and understood

by the prosthodontist.

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Loss has been defined as a “state of being deprived or being without

something one has had and valued”(Peretz 1970). The loss of a facial

feature or other body part due to cancer can be one of the most painful

experiences in life. This loss not only includes the deprivation of the

feature but also subsequent deprivation of some of life’s experiences.

Patients will be subject to possible rejection by their spouses, friends,

business associates and their community. In addition, a loss of a

maxillofacial feature may mean a loss in social groups or in one’s career. If

patients cannot develop successful psychological and physical coping

skills, they may experience severe psychological trauma, even if the loss

appears minimal.

Peretz has divided loss into four categories: loss of a significant

person, loss of a part of the self, loss of material objects and

developmental loss. The meaning of loss depends on the one who feels

the effect. Loss can threaten the integrity of one’s self esteem, which will

remain easily damaged for sometime after the fact. Even the threat of loss

can be emotionally devastating. It can trigger the fear of death at the

deepest level.

Grief:

Fig.11: Overlapping psychosocial concerns of the head & neck cancer patient.

80

Stages of the grief process include

Shock and denial: Changes occurring in sleeping pattern and eating, often

symptomatic of depression. The past is idealized. Patients are at risk for

suicide if their depression is severe.

Guilt, anger, and a search to find ways to discharge emotional pain: The

feeling of anger at this stage is really secondary to the driving feeling of

fear of the unknown and unfamiliar. The patient may be subject to possible

substance abuse.

Adjustment, acceptance and growth: the patient comes to realize that the

past had its faults and the future may not be so bad. This stage signals

acceptance of loss, healthy adjustment and new life patterns. Integration of

the prosthesis is possible.

The reaction of grief is an adaptive function to “assure group

cohesiveness in species where a social form of existence is necessary for

survival”. Unfortunately, our society emphasizes competency, adequacy

and strength; this often prevents patients from sharing their feelings.

A prosthodontist needs to empathize with the patient. A prosthodontist

will not have had to experience the same level of loss as the patient, but

remembering losses of loved ones, friends and property will help the

practitioner to be empathetic with the patient and to be in a better position

from which to gauge the patient’s psychological progress. This, empathy

will assist the prosthodontist to make a decision regarding the referral to a

psychotherapist.

At the same time the prosthodontist needs to be wary of any

unresolved grief that may be triggered in response to the patient’s grief

experience.

Regardless of how effectively grieving is done, it cannot be rushed.

Grieving requires time out from routine living and often makes the one

grieving appear disturbed. Improper recognition of this can cause

prosthodontists to misinterpret behavior and add confusion to the suffering.

This can create lack of self-confidence in patients, weaken their sense of

self, bring despair, or trigger self-destructive behavior.

Grief is the opposite of mental health, which is the ability to cope, to

love and to work. Grief can cause physical illness, poor judgement,

weakened inhibition, clouded intellect, and blurred perception. Patients

who experience traumatic losses will experience great ambivalence

between wanting to be active and passive, dependent and independent,

81

exploitive and helpless. Grief is so overwhelming that it has often been

viewed as an illness that may end only in partial recovery. This partial

recovery or unresolved grief can be triggered even after a significant

amount of time following the initial loss, by other losses or become the

impetus for a range of physical or mental disorders. Therapy for children in

such cases is strongly indicated. Children often grieve their losses openly

and dominant emotional response is anger. Also due to their egocentricity

children can blame themselves for losses and feel guilty. Improperly guilt

and anger can set the stage for later emotional difficulties s adolescents

and adults.

The maxillofacial patient’s quality of life is impacted which

predisposes him or her to a variety of psychological impairments. Quality

of life (QOL) surveys are done in patients suffering from various diseases

to measure the differences occurring due to the disease process.

There are ways to evaluate the psychological impairment status by

psychometric testing like Minnesota Multiphasic Personality Inventory,

Cornell Medical Index, Eysenck Personality Inventory and the Social

Adjustment rating scale but the Prosthodontist should limit the evaluation

by sensing the patient’s presentation – attitude, demeanor, appearance,

emotional state, mood, manner of speech, cognitive processes and then

make the appropriate referral.

The disorders mentioned earlier have varying effects on the

patient’s ability to withstand surgical procedures or to accept prosthesis.

The prosthodontist should consult a social worker, psychologist or

psychiatrist as a part of the treatment team to aid in preparing a plan that

will achieve the desired goal of the patient. Also, the quality and content of

communication between the patient and the prosthodontist significantly

affects the patient’s ability to accept the prosthesis and the successful out

come of the treatment plan.

Family Support and patient centered treatment involve knowing

how to enlist the support of the patient’s family and significant others in the

treatment and the aftercare process. Support from family and friends can

be a great help in coping with trauma. Patients feel isolated and lonely;

communications with people who care and try to understand help the

patient overcome this isolation.

Patient centered treatment planning needs to be done which is the

highly individualized process designed to respond to the expressed needs

82

and desires of the individual. The patient’s choices and preferences should

always be considered if not granted. The patient’s cultural background

must be recognized and valued in the decision making process.

Referral to Mental Health Services: Before referring, the prosthodontist

must know whether the patient is at a stage of acceptance of their

maxillofacial deficiencies to accept referrals. Referrals can be made to the

following professionals: social workers who tend to involve the family and

the environment of the patient, psychologists who are more

psychodynamic or individual focused and the psychiatrist who are

specialized physicians who can prescribe medication.

Suggestions for the prosthodontist for dealing with patients with

maxillofacial defects:

i.) Recognize the existence of the emotional component of illness

for the patient as well as for the health care worker. The

patient’s resistance to follow the recommended treatment plan

may be caused due to psychological barriers.

ii.) Make an effort to listen to what the patient does and does not

say. Do not assume that no difficulty exists because the patient

offers none.

iii.) Establish a routine office practice of referring the patient to a

clinical social worker or other qualified therapeutic agent for

psychosocial evaluation and treatment and consultation

services as needed. Talk to the worker personally in making the

referral.

Psychological health and spiritual well-being are integrated and related

states. In addition, a traumatic incident can itself aid in improving the

patients outlook toward life. Loss can often build strength of character.

Benefits of adversity to trauma patients include changed life priorities,

increased sense of self-efficacy, enhanced sensitivity towards others,

improved personal relationships and increased spirituality.

However, maxillofacial patients will not see the benefits of adversity till

they are able to attach a meaning to the adverse event. Once a patient is

able to apply meaning to the life threatening traumatic event, the

83

introduction of benefit related concepts could be attempted and discussed.

This is a technique of psychotherapy called “ Reframing”, where an event

is relabeled to search for the positive aspects in relation to the patient’s

ability to face serious problems. If this can be achieved, the patient can be

urged to think about ways that they have benefited, making the traumatic

event seem more palatable and easier to think about and cognitively

process. Positive outcomes of prosthetic treatment would be anticipated at

this point because patients have stopped seeing themselves as victims

and instead as capable human beings.

Therefore, if health care professionals subscribe to the premise that the

treatment goal is to maximize function, bio-behavioral interdependence

follows as a necessary corollary. Recognition of this relationship may aid in

making comprehensive dental health care a reality rather than an abstract

ideal.

Review Of Materials Used in Maxillofacial Prosthetics 17,29

A number of materials are available and have been for maxillofacial

prostheses. These include wood, wax, metals, and, recent times,

polymers. While the new materials have exhibited some excellent

properties, they also have exhibited frustrating deficiencies. As yet, a

material has not emerged that does not possess distinct and important

undesirable characteristics. Much effort has been expended recently in

studying existing materials in the hope of ameliorating them. A discussion

follows of desirable physical, biologic, and clinical properties, emphasizing

those properties most important for achieving clinical success and patient

acceptance.

IDEAL PROPERTIES OF MAXILLOFACIAL PROSTHETIC MATERIALS

Proposed Maxillofacial Elastomeric Requirements And

Specifications:

IDEAL PHYSICAL AND MECHANICAL PROPERTIES

1. Dynamic properties comparable to tissues

2. High edge strength

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3. High elongation

4. High resistance to abrasion

5. High tear strength

6. High tensile strength

7. Low coefficient of friction

8. Low glass transition temperature

9. Low specific gravity

10. Low surface tension

11. Low thermal conductivity

12. Odourless,

13. Non-inflammable

14. No water sorption

15. Softness compatible to tissue

16. Translucent

17. Variable flexibility without addition of leachable plasticizer.

IDEAL PROCESSING CHARACTERISTICS

1. Adjustability

2. Chemically inert after processing

3. Dimensionally stable during and after processing of

colorants

4. Ease of mold fabrication

5. Ease of processing

6. Ease of repair or refabrication if needed.

7. Fidelity of detail reproduction

8. High enough viscosity for maintaining even dispersion of

colorants

9. Long shelf life

10. Long working time

11. Low enough viscosity for ease of processing

12. Low processing temperature

13. Low sensitivity to contamination during processing

14. Non-inflammable

15. No polymerization by-products

16. Non-toxic components

17. Non-porous after processing

18. No color change after processing

85

19. Odorless before and after processing

20. Reusable molds

21. Retain intrinsic and extrinsic coloration during use

22. Short processing time

IDEAL BIOLOGICAL PROPERTIES

1. Non allergenic

2. Compatible with supporting tissues

3. Non toxic

4. Cleansibility without loss of detail at surface or margins

5. Cleansible with disinfectants

6. Color stability

7. Dimensionally stable

8. Flexibility comparable to tissue

9. Flexibility stable at extreme of temperatures (- 40 to

140°F)

10. Inert to solvents and skin adhesives

11. Resistance to growth of microorganisms

12. Softness maintained during use

13. Usable life of 2 or more years

14. Inexpensive

15. Permeable to moisture release from underlying tissue

16. Resistance to environmental discoloration

Fabrication:

Materials that are easily processed with available instrumentation offer

distinct advantages. Polymerization, or conversion from liquid to solid,

occurring at temperatures low enough to permit reusability of molds

(epoxy, dental stone, etc.) is desirable. Blending of individual components

should be easy, allowing some margin for error. Suitable working time is

likewise beneficial. The material should be adaptable to intrinsic as well as

to extrinsic coloration.

Physical properties:

Ideally, the prosthesis should possess sufficient flexibility for use on

movable tissue beds. The materials should be dimensionally stable, be

86

light in weight, and possess suitable edge strength to permit thinning or

feathering of margins. Variations in temperature should not affect physical

properties, and thermal conductivity should be sufficiently low to permit

comfortable use in cold environments.

Biologic and chemical properties :

The material should remain stable when exposed to environmental

assaults, such as ultraviolet rays, oxygen, secretions (sebaceous,

perspiration, nasal, and salivary), and adhesives and their solvents. The

material should not be toxic, allergenic, or carcinogenic, and it must be

biocompatible. Last, it is highly desirable that the prosthesis be durable

and have the capability of being used for at least 6 months without

significant compromise of esthetics and physical properties.

CLASSIFICATION OF MATERIALS AVAILABLE:

1. POLY (Methyl Methacrylate)

Palamed

2. Vinyl Polymers and Copolymers

Dicor

Geon 121 (Prototype 1, II, III)

Prototype III Soft

Chloronated Polyethylene

3. Polyurethane Elastomers

Epithane

Dermathane

Isophorone Polyurethane

4. Silicone Elastomers

HTV Silicones

ES-4524U

Q7-4635

Q7-465081

Q7-4735

Silastic 4-4514

Silastic 4-4515

RTV Silicones

A-0102

A-2186

Cosmesil

MDX 4-4210

MDX 4-4210 (Modified)

Silastic 382 (Opaque White)

Silastic 386 (Foam)

Silastic 399 (Translucent)

87

Acrylic Resin:

Heat polymerizing methyl methacrylate is preferred over the

autopolymerizing form because of the presence of free toxic tertiary

amines in the latter.

Rigidity is the primary disadvantage of acrylic resin. Its usefulness is

compromised in highly movable tissue beds leading to local discomfort and

exposure of margins. Its relatively high thermal conductivity may

precipitate discomfort in cold climates. Duplicate prostheses are not

possible because of the destruction of the mold during removal from the

flasking apparatus.

Also, it is easily repaired or relined with either a tissue conditioner, or

temporary denture reliner, and it can be quickly and easily processed.

Light Activated Denture Base Resins:

The dental community has known a visible light cure denture base

resin system for years. It is a composite having a matrix of urethane

dimethacrylate, microfine silica, and high molecular weight acrylic resin

monomers. Acrylic resin beads are added as fillers,. Visible light is the

activator, while camphoroquinone serves as the initiator for polymerization.

Its use has been advocated in maxillofacial prosthodontics as a denture

base, reliner and tray material by a lot of authors because of its ease of

use and much lesser polymerization shrinkage compared to

autopolymerizing or heat cured acrylic.37,38,68,110,127,128,144

Soft denture liners: Plasticized resins, which are chemically activated,

are generally used as denture liners. These polymers are supplied in

powder form and mixed with liquids containing 60-80 % of a plasticizer,

which is generally dibutyl pthalate. The distribution of the large plasticizer

molecules minimizes the entanglement of the polymer chains, thereby

88

permitting individual chains to “slip” past one other, resulting in the

flexibility of the material. However, the liquid does not contain acrylic

monomers, hence these material are short term.

Heat activated liners are more durable and are available as powder liquid

system. The powder contains acrylic resin copolymers and acrylic resin

polymer. The liquid contains monomer and plasticizers. When mixed these

form pliable resins with glass transition temperature below mouth

temperature. However the plasticizer leaches out over time.

Acrylic copolymers

Acrylic copolymers are soft and elastic but have not received wide

acceptance because of a number of objectionable properties. They

possess poor edge strength, poor durability, and are subject to

degradation when exposed to sunlight. Processing and coloration are

difficult. The completed restorations often become tacky, predisposing to

dust collection and staining. A well-documented discussion of the

properties and fabrication of prostheses with Palamed (a plasticized methyl

methacrylate) is provided by Cantor and Hildestad.

Development of a new generation of acrylic monomers, oligomers, and

macromeres was reported by Antonucci and Stansbury. They reported that

these materials can be polymered easily by using different polymerization

methods: thermal, chemical, photo-initiated, or even dual-cure initiators.

Their approach is to incorporate highmolecular-weight acrylic polyemers

with molecular blocks of other types of polymers (e.g., poly-etherurethane,

-hydrocarbon, -fluorocarbon, or -siloxane) that can eliminate the

shortcomings of traditional acrylic copolymers and meet the requirements

of a maxillofacial elastomer. A wide spectrum of physical and mechanical

properties which may satisfy the requirements in maxillofacial application

can be obtained by varying modes of polymerization. However, the results

of laboratory and clinical tests of potential polymers have not yet been

published.

Silicone liners are more durable as they do not contain leachable

plasticizer but the ahesion to acrylic is difficult and hence, rubber-

poly(methyl methacrylate) cements have to be used which serve as

chemical intermediaries that bond to both soft liner and resin base.

Silicone Elastomers

89

Silicones are a combination of organic and inorganic compounds.

The first step in their production is the reduction of silica to elemental

silicon. Then, by various reactions, the silicon is combined with methyl

chloride to form dimethyl dichlorosiloxane which, when it reacts with water,

forms a polymer. These polymers are translucent, watery, white fluids

whose viscosity is determined by the length of the polymer chain.

Polydimethyl siloxane, commonly referred to as silicone, is made from

these silicon fluid polymers. Most rubbery forms of silicone are

compounded with fillers that provide additional strength. Additives are used

to provide color. Antioxidants and vulcanizing agents are used to transform

the raw mass from a plastic to a rubbery resin during processing. The

long-chained polymers, when tied together at various points (cross-linked),

create a network that can be separated only with difficulty. This network

makes the silicones especially resistant to degradation from ultraviolet light

exposure.

The process of cross-linking the polymers is referred to as vulcanization.

Vulcanization occurs both with and without heat and depends on the

catalytic or cross-linking agents utilized. Using a chain of silica and oxygen

atoms, and attaching suitable side chains or organic radicals to them, a

material evolves with the inertness of quartz and the flexibility of the

organic plastics. The silicone elastomers are available in 2 forms: those

requiring heat to effect vulcanization (HTV) and those that vulcanize at

room temperature (RTV).

Silicones are classified into 4 groups, according to their applications.

1. The first classification is Implant Grade, which requires the

material to undergo extensive testing and must meet or exceed

FDA requirements. Recent health problems caused by silicone

breast implants have created controversies regarding the safety of

the material to be implanted interstitially.

2. The second classification is Medical Grade, which is approved for

external use only. This is the material most commonly used in

fabrication of maxillofacial prostheses. Adverse reactions caused

by direct contact between Medical Grade silicone and human skin

have not been reported. Very often, the term. medical grade.

creates confusion among clinicians.

3. Clean Grade.

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4. Industrial Grade, which is mostly used for industrial applications.

HTV silicones

Designed for higher tear resistance in engineering applications, this

type of polymer requires more intense mechanical milling of the solid HTV

stock elastomer compared with the soft putty RTV silicone, especially for

incorporating the required catalyst for cross-linking, and for pigmentation.

The prosthetic device is cured at elevated temperature in a

heat-transferring metal mold. Pigment - elastomer milling represents a

significant advance in the state of the-art overcoming the problem of hand

mixing pigments in viscous, air entrapping RTV silicone stocks.

The HTV silicones processed by milling compared with RTV silicones are

generally most prominent in industrial silicone technology, particularly for

long-term mechanical durability and chemical resistance.

Silastic 370, 372, 373, 4-4514, 4-4515

HTV silicone is usually a white, opaque material with a highly

viscous, putty-like consistency. The material may be supplied as a

1-component or 2 component putty. The catalytic, or vulcanizing, agent of

the HTV silicones is dichlorobenzoyl peroxide or platinum salt, depending

on the type of polymerization used (condensation reaction or addition

reaction, respectively). These silicones can be preformed into various

shapes for alloplastic implantation or facial prostheses. Varying amounts of

filler are added to these polymers, depending on the degree of hardness,

strength, and elongation desired. Generally, the more filler, the harder and

less resilient the compounded rubber will be. The filler is usually a very

pure, finely divided silica with a particle size of about 30µ. In addition. the

copolymerization of silicone with small amounts of methyl vinyl, or methyl

phenyl siloxy radical, varies the relative softness and tear strength.

Processing of heat-cured silicones requires sophisticated

instrumentation and high temperature. An excellent description is provided

by Chalian. These silicones exhibit excellent thermal stability, are

color-stable when exposed to ultraviolet light, and are biologically inert.

However, they do not possess sufficient elasticity to function in movable

tissue beds. Polydimethylsiloxane oligomer (Electronic Fluid 200, Dow

Corning) may be added to reduce the stiffness and hardness of the

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prostheses. Also, the material itself has low edge strength and may require

nylon reinforcement at the margins. Important objections are their opacity

and lifeless appearance. They do not readily accept extrinsic coloration. so

the internal colorants must be incorporated into the gum stock with a

milling device. Because high temperatures are required for vulcanization,

metal molds are necessary.

PDM siloxane

A HTV silicone was developed by the Veterans Administration.

Results of studies by Lontz show that the material exceeded values

considered clinically acceptable and is used intra orally.133

Q7-4635, Q7-4650, Q7-4735, SE-45240

A new generation of HTV silicones evaluated by Bell were shown

to have improved physical and mechanical properties compared to

MDX4-4210 (a RTV silicone) and MDX 4-4514. The processing

characteristics of Q7-1635 and SE-45240 were particularly favorable

because of their single component system with unlimited shelf life.

In general HTV silicones have better physical and mechanical properties

than do RTV silicones. The drawback of the material is its opacity, difficulty

in intrinsic coloration, high superficial surface hardness, and difficulty in

processing.

RTV Silicones

Designed for rapid room temperature curing, the RTV silicones

continue to serve the needs of the maxillofacial restorations but with some

limiting aspects. With some grades, owing to the white source elastomer,

internal coloring is difficult. In mixing stock elastomer with the catalyst for

the curing (vulcanizing), air entrapment persists in the finished cured

prosthesis, which tends to initiate tear and accumulation of skin exudates.

Tear resistance of RTV grades is generally inadequate to maintain edge

resistance. Once started at an edge void or a nick, tearing propagates

gradually across the prosthetic device, requiring skilled repair by applying

proprietary silicone adhesive or reinforcement with fabric. RTV silicones

formulated with silica fillers to enhance tensile strength and to mask

yellowing or discoloration sacrifice considerable translucency, making it

difficult to attain proper internal (intrinsic) coloration. Also, discoloration in

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some RTV grades of silicone introduces a negating feature esthetically. To

correct for these deficiencies, a transparent proprietary RTV-grade silicone

(Dow Corning MDX 4-4210) is an improved alternative but requires

considerably longer curing time of up to 16 hours at ambient temperature.

The curing time can be reduced by heating up to 150° C for as little as 5

minutes, which would require forming special expensive metal molds. The

improvement in tear resistance is significant, but nick tear sensitivity under

tension prevails, as does the propensity to entrap air during blending and

pigment mixing

Silastic 382, 399

This viscous silicone polymer includes a filler, a stannous octoate

catalyst, and a orthoalkyl silicate cross-linking agent. The polymerization is

by condensation reaction. Fillers, usually diatomaceous earths. are used to

improve strength. The properties of the original RTV silicones (Silastic 382,

399) are similar to the HTV types. They are color-stable, biologically inert,

and retain their physical and chemical properties at wide temperature

ranges. They are available as clear solutions that enable the fabrication of

translucent prostheses. The RTV are much easier to process than the

heat-cured forms. Molds of dental stone can be used. The RTVs share

some of tile undesirable properties of the HTV silicones in that they have

poor edge strength and are difficult to color. In our experience, at delivery,

the cosmetic appearances of these materials is inferior to that of the

polyurethanes. acrylic resins, and polyvinylchlorides.

Silastic 382 is used for intraoral use.133

MDX4-4210

This medical-grade silicone elastomer has shown to be the most

popular among clinicians. Moore reported that it exhibits improved qualities

relative to coloration and edge strength. This material is not heavily filled,

making it translucent. It has a chloroplatinic acid catalyst and hydra-

methylsiloxane as a cross-linking agent. The polymerization reaction is an

addition reaction with no reaction by-products. The cured material has

been shown to exhibit adequate tensile strength. More importantly,

increased elongation and resistance to tear have reduced the need for

reinforcement of the thin edges of the prosthesis. In addition, the surface

texture and Shore A hardness measurements are well within the range of

human skin. Modifications of the physical properties can be accomplished

93

by the addition of silicone fluid. In the study by Moore, the material was

found to be nontoxic, color stable, and biologically compatible. Early

clinical testing reveals Silastic MDX 4-4210 to be quite desirable and it

appears to be compatible with most skin adhesive systems. Shade guides

for intrinsic coloration have been developed. Accelerated aging testing

have shown that the elastomer is very color stable.

Extensive testing on the physical and mechanical properties of MDX

4-4210 has been documented. Results indicate that, even though it is not

the ideal material, MDX4-42 10 has shown many improvements when

compared to earlier materials, and it possesses many desirable

characteristics.

Processing is simple, as molds of dental stone are acceptable. A 5%

solution of mild soap can be employed as a releasing agent. Care should

be taken to avoid contamination of the mold with petrolatum or clay

residues. The prepared molds are placed in a dry heat oven at 50°C for

approximately 30 minutes prior to their use. Warming all the mold

segments will assist in retaining the position of the custom colors used for

intrinsic shade matching. After appropriate surface detail has been

reproduced, a syringe is loaded and used to fill the mold parts with the

material that has recovered its viscosity after mixing. The mold is closed

with finger pressure and a web clamp is secured in position to hold the

sections together tightly. The mold is returned to the dry heat oven and the

temperature is elevated to 80°C. The mold is left in the oven for 1 hour.

Surface characterization can be achieved with pigments immersed in a

silicone adhesive.

Using unflasked gypsum mold in dry heat for multiple processing will

dehydrate the gypsum and cause loss of surface detail or disintegration of

the mold. Flasking of the mold and using moist heat will increase the

longevity of the mold. Research on porosity and density of both RTV and

HTV silicones, using various processing techniques by Kent, indicates that

de-airing the fluid silicone prior to packing, using a controlled injection

packing technique, and soaking of a flasked mold in slurry water prior to

moist heat application will result in a dense and porosity-free prosthesis.

Superior cosmetic results are achieved with this material.

Silastic 891

Udagama and Drane first reported the use of this material, also

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known as Silastic Medical Adhesive Silicone Type A, for fabrication of

facial prostheses. It has gained popularity among clinicians. Twenty-five

percent of clinicians surveyed use this material". It is a translucent,

non-flowing paste which polymerizes at room temperature on contact with

moisture in the air. It can also be processed in a gypsum mold. Metal

molds are not recommended because its surface may react with acetic

acid, which is liberated as a by-product of polymerization. The advantages

of the material are no catalyst is required and it is compatible with a wide

range of colorants. However, the material does share some of the

disadvantages of RTV silicones. In 1987, Udagama reported improving the

edge strength of silicone prosthesis fabricated by Medical Adhesive Type

A by bonding the prosthesis to a prefabricated polyurethane film using

primer, S2260 (Dow Corning Corp.). Farah studied the mechanical

properties of mixtures of Adhesive Type A and uncatalyzed MDX 4-4210

base elastomer. It was reported that different mechanical properties can be

obtained by varying the amount of MDX 4-4210 base elastomer to Medical

Adhesive Tune A to allow for better simulation of facial tissues.

Cosmesil

Cosmesil is a RTV silicone which can be processed to varying

degrees of hardness as described by Wolfaardt. The material was shown

to have higher tear strength at failure than MDX 4-4210. Studies on

surface texture, wettability, and hardness were also reported by Veres.

A-2186

A-2186, a recently developed material (Factor II Inc., Lakeside,

Ariz.), initially showed Improved physical and mechanical properties when

compared to MDX 4421093. However, Haug reported that, after subjected

to environmental variables, the A-2186 elastomer did not retain its

improved physical and mechanical properties when compared to

MDX4-4210.

Foaming silicones: Silastic 386

A form of RTV silicone that has limited use in maxillofacial prosthetics is

the foam-forming variety. The basic silicone has an additive so that a gas

is released when the catalyst, stannous octate, is introduced. The gas

forms bubbles within the vulcanizing silicone. After the silicone is

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processed, the gas is eventually released, leaving a spongy material. The

formation of the bubbles within the mass can cause the volume to increase

by as much as sevenfold.

The purpose of the foam-forming silicone is to reduce the weight of the

prosthesis. However, the foamed material has reduced strength and is

susceptible to tearing. This weakness can be partially overcome by coating

the foam with another silicone. This coating adds strength but increases

stiffness.

Siphenylenes

Siphenylenes are siloxane copolymers that contain methyl and phenyl

groups. The catalyst is similar to that of Silastic 382 and 399. These

polymers possess many desirable properties of RTV silicones, including

biocompatibility and resistance to degradation on exposure to ultraviolet

light and heat. In addition, they exhibit improved edge strength, low

modulus of elasticity, and colorability over the more conventional

polydimethyl siloxanes. Clinical testing will determine whether this

compound represents a significant improvement.

New materials:

Silicone block copolymers Silicone block copolymers are new materials

under development to improve some of the weaknesses of silicone

elastomers, such as low tear strength low-percent elongation, and the

potential to support bacterial or fungal growth. It has been found that

silicone block copolymers are more tear-resistant than are conventional

cross-linked silicone polymer. The type of block copolymer being

investigated is one that incorporates Poly Methyl Methacrylate (PMMA)

into siloxane blocks-. Various methods of synthesis are under

investigation. Data on physical and mechanical properties of silicone block

elastomers have not been reported.

Polyphosphazenes

Polyphosphazenes fluoroelastomer has been developed for use as a

resilient denture liner (Novus tm Hygenic Corp.) and has the potential to be

used as a maxillofacial prosthetic material. Modifications of physical and

mechanical properties of this commercially available elastomer may be

needed to satisfy the requirements for fabrication of maxillofacial

prostheses.

96

Polysar: It is a thermoplastic material that is malleable at 80 degrees

centigrade either in hot water or against hot-pulsed air. It belongs to the

polyisopren (rubber) family and is available in the form of 61 cm X 45 cm X

3 mm thick smooth sections. Didier has described its use for the fabrication

of a hollow surgical obturator. 42

Metals for framework of definitive obturators: 117

Metal frameworks for obturator prosthesis are typically made of Co-Cr

alloy; however, Ni, Co or Cr may sometimes cause sensitivity, including

not only local responses such as gingivitis and stomatitis but also

generalized manifestations like eczema or dermatitis with or without

mucosal lesions. By contrast Titanium and its alloys have very high

biocompatibility and excellent corrosion resistance in the oral cavity as

titanium oxide that is formed on its surface is highly stable and inert.

Commercially pure titanium has been in use for over a decade and has

been recommended for the fabrication of complete denture & overdenture

frameworks and removable partial dentures.

Titanium is less dense than conventional alloys, which is of key importance

in view of the large size of obturator prostheses. Titanium frameworks

have been reported to be 40 % lighter than Co-Cr frameworks and 60 %

lighter than Ni-Cr frameworks.

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PROSTHETIC MANAGEMENT OF THE DEFECTS OF HARD AND SOFT

PALATE

A rewarding area of prosthodontics is the rehabilitation of patients

with congenital and acquired maxillary defects. The dentist contributes to

all facets of patient care from diagnosis and treatment to rehabilitation.

Resection of the hard and soft palate and related structures result

in a variety of anatomic and functional defects in the oral cavity and

Oropharynx. Such defects are inconvenient to the patients because of the

loss of oro-nasal separation, which substantially interferes with the

important functions of speech swallowing and appearance of the patient.

The region is susceptible to lesions like epidermoid carcinoma, salivary

gland tumours, lymphoepitheliomas, lymphosarcomas, Wegener’s

granulomatosis, mucormycosis and aspergillosis which require resection of

the palate, maxilla and some facial structures.

The extent to which an ablative technique may reasonably be

applied in this anatomic region is determined by the degree to which

restorations of satisfactory function and acceptable appearance may be

achieved. Teamwork between the head and neck surgeon and

maxillofacial prosthodontist is necessary to provide a solution to these

problems.

Methods of Resection:

Palatectomy: The mucosal incisions are outlined to give 5- 10 mm margin

around the tumour, depending upon the histopathology observed in the

biopsy.

- The incisions are made through to the periosteum and sufficient bone

exposed.

- If the soft palate is also involved a generous margin or the entire soft

palate is resected.

- After soft tissue resection the bone is resected using a power saw or

osteotome.

- If the nasal septum or medial wall of maxillary sinus is involved, they

are included in the resection.

98

- If the lesion approaches the greater palatine foramen, then the

posterior alveolar ridge and the pterygoid plates should also be

resected.

After resection, the bony edges are smoothened and contoured, then

covered with the periosteum and mucosa. The raw tissues in the surgical

defect are covered with split- thickness skin grafts. Packing is placed in the

defect and an immediate surgical obturator is inserted and wired to the

teeth or alveolar ridge.

Maxillectomy: It is required if the tumour is very malignant and invades

the nasal cavity or paranasal sinuses.

- Complete exposure of the maxilla is obtained by the Weber- Fergusson

Incision in which the lip is split and the incision extended around the

nose up to the orbit and along the eyelid.

- The mucosal cuts on the palate are as described above. The

periosteum is raised and the bone is resected using osteotome, power

saw or Gigli wire saw.

- The orbital rim is spared if the orbital contents have not been invaded.

- The pterygoid plates and the soft tissues of the pterygomaxillary space

are resected at the base of the skull using a curved osteotome.

- A split thickness skin graft is placed under the soft tissue flap to line the

surgically produced cavity.

- The wound is packed, the immediate surgical obturator is placed and

the Weber- Fergusson incision closed.

The high potential for recurrence is a strong argument for the need for

follow up and observation of the margins of the defect instead of surgical

reconstruction.

Fig. 12: Bony cuts for maxillectomy.

99

Total maxillectomy is the complete resection of one of the two maxillae

or resection to the midline, whereas partial maxillectomy is a bony

resection, which is less than a total maxillectomy.

Post-surgical anatomy of the region:

Resection of the maxilla results in a continuity of at least the oral,

nasal and maxillary sinus cavities. If the tumor involves the roof of the

antrum (floor of the orbit) then the orbital contents will also be exenterated

creating a continuous defect from the oral cavity that extends through the

orbit to the facial surfaces.

The anatomic defect of maxillectomy, may be bounded

medially by the nasal septum, posteriorly by a vertical plane through the

anterior border of the soft palate, laterally and inferiorly by the inside of the

graft-lined cheek, superiorly by the floor of the orbit and cribriform plate,

inferiorly by a horizontal plane extending from the residual hard and soft

palate to the fibrous contraction band which forms at the juncture of the

buccal mucosa and skin graft which corresponds to the superior region of

the mucobuccal fold on the resected side.

It is important that the prosthodontist knows what structures are in

and around deformity, which is to be restored. The prosthesis should not

impair the function of the adjacent tissues or produce undesirable changes

in the tissues.

When the bony margins of a defect are sharp and the overlying

tissue is thin, a resilient material can be utilized to aid retention. When the

bony margins of the defects are covered with a generous amount of

overlying tissue, it may not be necessary to use a resilient restorative

material. The turbinate bone should not be utilized to absorb stresses

transmitted through the prosthesis. A less prominent post dam is indicated

on the final prosthesis when a tissue seal cannot be obtained.

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CLASSIFICATION OF MAXILLECTOMY DEFECTS94

Defect classification systems enable surgeons and prosthodontists to use the

characteristics of a particular defect to establish a functional prognosis.

1. Ohngren’s classification system (1933) for maxillectomy defects. Following

this, a number of oncologically oriented classification schemes have

served to describe the anatomic boundaries of the maxillectomy defect.

2. Aramany’s Classification (1978)7 addresses removable partial framework

design and prosthetic rehabilitation of the partially edentulous maxillectomy

patient in six categories.

3. Spiro et al proposed a classification in 1997 that focuses on infrastructure

defects; however, it does not specifically address the involvement of

adjacent structures such as the orbit and the zygoma. Defects are termed

as “limited” or “subtotal” on the basis of the number of maxillary “ walls”

involved in the resection.

4. Davison et al (1998) proposed a reconstruction algorithm based on a

review of 108 patient treatments involving prosthetic obturation, non

vascularized bone grafts, local flaps, regional flaps and microvascular free

tissue transfer. Davison divided patients in two broad categories of “

complete” and “partial” maxillectomy defects. Davison proposed a wide

range of reconstructive techniques, but the lack of a specific defect

oriented classification system outlining the remaining portion of the hard

palate, dentition, orbit and zygoma make such an algorithm difficult to

apply as a reconstructive guide.

5. Brown (1996) was the first to discuss a multidisciplinary (surgical and

prosthodontic) approach to palatomaxillary reconstruction. His more useful

defect classification scheme is based on both the vertical and horizontal

dimensions of a defect. The vertical component of the defect ranges from

minor resections with no oro-antral fistula to radical maxillectomy defects

with orbital exenteration.

The horizontal component ranges from a small hard palate defect without

the involvement of dentition to a total palatectomy defect. According to

Brown’s scheme, the classification of the horizontal dimension of the

defect is based upon the remaining palatal surface. Although the residual

palatal surface plays an important role in determining the best form of

reconstruction for the edentulous patient, the dentate patient can rely not

only on the remaining surface but also on the remaining dentition for

101

retention. Furthermore, the state of the orbital floor and zygoma, which

play an important role in both the function and the cosmetic results of the

midface, are not specifically addressed in the Brown’s system. Defects

involving either of these areas are poorly managed by prosthetic

rehabilitation and often require hard tissue reconstruction.

6. A classification system of defects for the prosthodontic guidelines for the

surgical reconstruction of the maxilla was been proposed by Okay et al

(2001)94 by reviewing 47 consecutive patient treatments of palatomaxillary

reconstruction at the Mt. Sinai Medical Center. All patients were

rehabilitated with a tissue borne obturator, a local advancement flap, a

fasciocutaneous free flap or a vascularized bone containing free flap.

Palatomaxillary defects are divided into 3 major classes and 2 subclasses.

Probably, the most common of all intraoral defects of the maxilla

are in the form of an opening into the nasopharynx. The prosthesis

needed to repair the defect is termed as an 'obturator'.

The term obturator is taken from the Latin meaning "to stop up".

More specifically, from a dental standpoint obturator is defined as a disc or

plate, natural or artificial, which closes an opening of the hard or soft

palate, or both.

FUNCTIONS OF OBTURATOR17

i. It serves to close the defect.

ii. It can serve in lieu, of a naso-gastric tube for feeding purposes.

iii. It can be used to keep the wounds or defective area clean and it

also enhances the healing of traumatic or post-surgical defect.

iv. It helps to reshape and contours the soft and hard palate and also

improves lip and check position.

v. It reduces the flow of exudates in the mouth and improves

deglutition and mastication if impaired.

vi. It can be used as a stent to hold dressings or packs post surgically.

vii. It improves speech in some cases.

viii. It can benefit the morale of the patients with maxillary defects.

102

CLASSIFICATION OF OBTURATORS

According to Rahn and Boucher112, obturators may be broadly

classified according to :

A) The origin of discrepancy:

a) Congenital defect obturator.

b) Acquired defect obturator.

B) The location of the defect

a) Labial or buccal reflex obturator.

b) Alveolar obturator

c) Hard palate obturator

d) Soft palate obturator

e) Pharyngeal obturator

C) The type of obturator attachment to the basic maxillary prosthesis

a) Fixed obturator

b) Hinged or movable obturator

c) Detachable obturator

D) The physiologic movement of the oral, nasal and pharyngeal

tissues adjacent to or functioning against the obturator

a) Static obturator

b) Functional obturator

Prior to surgery the prosthodontist should examine the patient

thoroughly, make impressions for diagnostic casts, obtain a jaw relation

record and appropriate dental radiographs (IOPA, OPG, Lateral oblique,

Dental CT SCAN) and photographs of the patient. Interaction between

surgeon and prosthodontist is necessary for achieving optimum

rehabilitation post operatively by considering certain modifications of

surgery that may improve the prognosis for prosthetic rehabilitation.

103

Surgical modification enhancing prosthetic prognosis

i) An attempt should be made to save as much of the maxilla as

possible consistent with tumor control. The premaxillary segment if

saved can improve the prosthesis, prognosis immeasurably by

enhancing stability and support for the prosthesis.

ii) At times in resections extending posteriorly, it may be advisable to

remove the coronoid process of mandible since it might

interfere/impinge upon the distobuccal aspect of the obturator.

iii) The surgeon can improve the tolerance and retention of the

obturator if he lines the reflected cheek flap with a split thickness

graft. Such a graft is more flexible and resistance to abrasion. The

graft also contracts about 50 % of its volume. Contracture is mainly

affected by the amount of residual bony support and ancillary

therapies such as radiotherapy.

iv) Scar band formed at a skin graft - mucosal junction often creates a

sizeable lateral undercut superiorly. Engaging the scar band

superiorly and inferiorly with prosthesis enhances stability retention

and support.

v) Retention of key teeth may lead to improved function. The

transalveolar resection should be made as distant as feasible from

the tooth adjacent to the resection.

Fig. 13: Transalveolar resection done through the middle of the socket of extracted tooth to save bony support for the adjacent tooth.

104

vi) If the surgeon can save some of the palatal mucosa normally

included in the resection and reflect this tissue during the bony

resection of the palate, it can be used later to cover the cut bony

margins of the palatal bones, because the defect which is covered

with keratinized mucosa is a better denture bearing surface and

can provide lateral stability.

vii) In cases where only posterior portion of the soft palate remains

post surgically, it should be removed along with the entire soft

palate because it may contract superiorly and thus hinder

prosthesis reconstruction by blocking access to the area of greatest

motion of the lateral and posterior pharyngeal walls. An exception

has to be made for edentulous patients and even posterior third of

the soft palate left behind, as the extension of the obturator

prosthesis onto the nasal side of the residual palate is an

advantage that outweighs the possible speech and leakage

problems that might occur due to the contraction.

viii) Access to the superior and lateral portions of the defect should be

provided by excision of the turbinates and the oral mucosal bands.

Maintaining the turbinate precludes the extension of the medial wall

of the obturator bulb into the nasal cavity, and the hence, it cannot

prevent the rotation of the prosthesis during function. Engaging the

Fig. 14: The remainder of the soft palate is subject to rapid contraction anteriorly and superiorly during the first three weeks after surgery and can compromise velopharyngeal closure.

105

lateral nasal side of the orbital floor provides support for the

obturator.

ix) Implants can be placed during the resective surgery in the

premaxillary segment or the tuberosity region. The use of implants

within the defect should be discouraged, as it is very difficult to

maintain hygiene around them. Also the use of pre or post

operative radiation does not preclude the use of implants it has

been found that radiation doses above 5000 centigray, compromise

the remodeling of bone around the implant and thus predispose to

bone recession and premature implant loss.

General Outline For Prosthetic Rehabilitation Of Hard Palate Defects

The prosthodontic therapy for patients with defects of the maxilla can be

arbitrarily divided into two phases of treatment with each phase having

different objectives.

I) First phase/initial phase - surgical obturator construction

II) Second phase - Definitive prosthesis construction.

I) Surgical Obturator : These prosthesis initially is limited to the

restoration of palatal integrity and the reproduction of palatal contours.

It entails the placement of a prosthesis at surgery or immediately there

after. This prosthesis must be modified at frequent intervals to

accommodate for the repaid soft tissues changes that occur within the

defect during organization and healing of the wound.

Surgical obturators are of two types according to Beumer & Curtis17

- Immediate surgical obturator

- Delayed surgical obturator / Treatment obturator/Transitional

i) Immediate surgical obturator - It is placed at the time of surgery.

It can be of utmost importance in the successful post-operative

management of person who will have resulting oral and facial

deformities.

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Advantages of immediate surgical obturation

- Provides a matrix on which the surgical packing can be

placed.

- The prosthesis reduces oral contamination of the wound

during the immediate post surgical period.

- Enables the patient to speak more effectively

postoperatively by reproducing normal palatal contours and

by covering the defect.

- The prosthesis permits deglutition, thus the nasogastric

tube may be removed at an earlier stage.

- The prosthesis lessens the psychologic impact of surgery

by making the postoperative course easier to bear.

- The prosthesis may reduce the period of hospitalization,

Construction of immediate surgical obturators:

Beumer and Curtis17 have given several principles relative to the design of

immediate surgical obturators.

- The obturator should terminate short of the skin graft mucosal

junction. As soon as the surgical packing is removed, extension

into the defect may be accomplished with tissue treatment, or

interim soft reline materials.

- It should be simple, lightweight, and inexpensive.

- The prosthesis for dentulous patients should be perforated at the

interproximal extensions with a small dental bur to allow the

prosthesis to be wired to the teeth at the time of surgery.

Fig. 15: the cast is modified as per the out line of resection decided by the surgeon.

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- Normal palatal contours should be reproduced to facilitate

postoperative speech and deglutition.

- Posterior occlusion should not be established on the defect side until

the surgical wound is well organized. Anterior teeth may be

incorporated at times for esthetics.

- In some patients the existing complete or partial prosthesis may be

adapted for use as an immediate surgical obturator. However, the

flange of the prosthesis corresponding to the proposed defect should

be reduced and the posterior denture teeth removed prior to surgery.

Procedure of surgical obturator construction for dentulous patients:

Rahn and Boucher112 have described this. The patient is seen

preoperatively, and an alginate impression is made of the maxillary arch.

The impression should involve area of soft palate as well as overextension

into the buccal vestibule. This amount of tissue coverage is necessary

because the resection usually involves the pterygoid area side of the

tumor. The stock impression tray may be altered by addition of wax or

Fig. 16: The holes for interdental wiring and recesses made

Fig 17: Inserted surgical obturator with interdental wiring.

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removal of portion of tray to cover all desired areas or when the tumor

protrudes orally respectively. The impression is border molded in the soft

palate area by asking the patient to bend forward and then turn slowly from

side to side, causing the functional limits of the palate to be recorded.

The impression is poured in artificial stone. The area to be

resected should be determined by the surgeon and sketched onto the cast.

The teeth are removed in the designated area and eighteen gauge

wrought wire retainers or ball-type retainers are constructed on the teeth

so as to give proper retention to the completed restoration. Most of the

time a retainer is given on tooth adjacent to the defect. If conservation of

time is essential, an autopolymerizing acrylic resin can be added to the

cast by using sprinkle on technique and the cast is placed in a pressure

cooker for 10 min. If time is not a factor, the obturator should be waxed

up, to two thickness of base plate wax. Artificial anterior teeth can be

placed, if further esthetic qualities are desired and the teeth are expected

to not cause trauma to the defect area. The obturator can be invested and

processed for nine hours using hear cure acrylic resin.

A clear, heat-cure acrylic resin is usually desirable because the

pressure areas can be easily detected and relieved when the obturator is

placed immediately after surgery in the operating room.

Surgical obturator for edentulous patients.

These obturators can be constructed very easily and the procedure

is almost the same as for dentulous patients. But, since the retention is

sought from a source other than the teeth, by the technique of pinning the

obturator to maxilla using a palatal screw, suturing into surrounding

mucosa or using ligature wire around the zygomatic arch and through the

obturator is often used. This requires additional time. Some surgeons

would prefer to wait at this stage until the pack is removed and then

recommend a treatment obturator.

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Bone screw retention for a surgical obturator in an edentulous

patient can be achieved by using a 13-16mm long self-tapping bone screw

(made of titanium or stainless steel). It is placed through a predrilled hole

in the acrylic resin plate in the mid-palate at the anterior peak of the palatal

vault and screwed into the vomer. The hole in the acrylic plate should allow

free movement of the screw before placement into the bone and must

have a countersink to hold the head of the screw. If the vomer is resected,

two screws placed at conflicting angles through the denture at the lateral

hard palate at the junction of the alveolus and palatal vaults should be

used. The contralateral maxillary sinus may be entered with the screws. A

small plug of tissue conditioner or silicone added over the head of the

screw to keep the screw attached to the plate, in case the patient

dislodges the surgical obturator.

In an irradiated patient, the placement of bone screw is avoided

and sutures placed at the periphery of the prosthesis may be secured into

the soft tissues at the height of the vestibule, against the bone of the

remaining maxillary alveolus, while the surgical side is secured against the

cheek.

The patient’s existing denture should not be used as maintaining

the occlusion while securing the obturator with bone screws, wires or

sutures is almost impossible. The patients need to be instructed to

discontinue use of the mandibular denture due to these occlusal

Fig. 18: Surgical obturator for edentulous patient with holes for transalveolar wiring and recesses for the ligature wire.

Fig. 19: Obturator in place with transalveolar wiring.

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discrepancies. As facial contracture occurs, the anterolateral border of the

denture requires significant reduction, which involves the facial reduction of

teeth or even their removal. If it is not done then the lips unseat the

prosthesis. Therefore, the patient must be counseled to accept a baseplate

without dentition for surgical obturation.

Revision of the surgical obturator:

After the gauze pack is removed, the obturator generally needs

revision. This is accomplished by building up the defect side of obturator

in modeling plastic and border moulding the area. After this, the obturator

is invested and modeling plastic is removed and replaced with

autopolymerizing acrylic resin. In order to reduce the weight, the newly

added bulb portion may be hollowed out superiorly. This type of revision

can be performed quite easily without the patient having any discomfort.

Another technique is to do chairside incremental addition and shaping of a

tissue conditioner material. The viscous mix of the material is placed at

the periphery of the surgical obturator, arbitrarily shaped, then placed in

the mouth and patient is asked to do the movements as described later in

the impression procedure for definitive obturator. Excess material is cut

away, and after sufficient adaptation is achieved a wash type of impression

can be made by a thinner consistency of the tissue conditioner.

ii) Delayed surgical obturator/Treatment obturator:

An alternative to the placement of prosthesis at surgery is the placement of

a delayed surgical obturator 7 to 10 days post surgically. If the patient is

edentulous and the surgical defect is extensive this approach may be the

treatment of choice.

It is constructed, right after the surgical pack is removed, and about

seven days post operatively. Irreversible hydrocolloid impression is made

in a stock metal tray very carefully after covering all the margins of the tray

with beading wax. The obturator is fabricated and inserted before the

patient leaves the hospital. In dentulous patients as healing progresses,

posterior occlusal ramps can be established with the addition of

autopolymerizing acrylic resin. In edentulous patient the delayed obturator

is regularly relined. This restoration is used until the defect area has

healed sufficiently, usually about 3 months, and a more definitive obturator

can be constructed. Because, depression develops in many patients

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during this post-operative period, a surgical obturator can have far

reaching psychological value.

Treatment obturators for dentulous and edentulous patients

These techniques have been described by Rahn and Boucher112. If the

patient has an existing denture, it can be utilized in the construction of a

treatment obturator. If there is excessive underextension an alginate

impression can be made over the denture while it is in place in the mouth.

A plaster cast is made from the impression. Cold cure acrylic resin is

added to the periphery of the old denture on the cast. The tissue surface

is cleaned and covered with resilient adhesive. The resilient denture lining

material is placed on the tissue surface and readapted. This type of

obturator can be used until a more effective treatment obturator can be

fabricated

Procedure :-

After a satisfactory impression is made, it is poured in artificial

stone. On the stone cast a pencil line can be drawn slightly inferior to

where the oral mucosa and skin graft meet on the cheek. This area can be

easily palpated on the patient as a fibrous band running horizontally on

cheek and at the height where the buccal vestibule would have been. This

band will generally extend posteriorly and become part of the posterior

portion of the defect.

After this retainers are constructed if the patient is dentulous. The

retainers should be placed as close to the defect as possible and at

maximum distance from each other135. This is different from the earlier

concept that the clasps should be placed as close to and as far from the

defect as possible (Desjardins 40). Such a configuration might not

necessarily place clasps as far apart as possible and might in fact, place a

clasp on a tooth that serves as an indirect retainer, rendering the clasp

nonfunctional.

The resin portion of the obturator prosthesis should contact the

axial surfaces of the remaining teeth whenever possible to provide

maximum stability and wider stress distribution.

The addition of teeth should be limited to satisfying esthetic needs

and assisting in speech production. Occlusal function should not be

restored.

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Two thickness of baseplate wax is adapted over the designated

area. All undercuts alone the walls of the defect side are blocked and the

prosthesis is processed in a conventional manner. The prosthesis after

processing is checked in a patient’s mouth. The acrylic resin cavity on the

palatal side of the obturator is filled with wax until proper contour of the

palate is established. This procedure is carried out in order that an

artificial or false palate can be added to the prosthesis.

A thin layer of separating media is placed over the wax and onto

the acrylic resin. A plaster cast is then poured over the wax and extended

onto the acrylic resin to a point where reorientation of the core can be

easily done. The wax is removed from the defect side and an acrylic resin

separating medium is placed over the superior portion of the core. Over

this core is sprinkled auto-polymerizing acrylic resin to a thickness of 1-2

mm. The core is then invested and pressed into contact with the

prosthesis and hold firmly till resin has set properly.

All excess acrylic resin is trimmed away and the obturator is

polished. Some dentists may prefer to wax the defect side so that it will be

processed entirely of resin and then hollow it out as a port of revision

procedure.

The patient is examined periodically and instructed regarding

maintenance and cautioned that further adjustments are likely as the

surgical area heals and contracts.

Interim Obturation: bridges the gap between immediate surgical obturator

and the definitive prosthesis. There is very little distinction as both

immediate and interim obturators provide comfort and function to the

patient till definitive obturation can be done.

The reasons for fabricating a new prosthesis are:

- The periodic addition of interim lining materials increases the bulk and

weight of the obturator and the temporary material become rough and

unhygienic with time.

- Addition of teeth to the obturator provides great psychological relief to

the patient.

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- The retention and stability can be made better than the immediate

obturator.

- The interim prosthesis may prove useful as a backup prosthesis to the

definitive one.

Instructions to patients for delayed surgical and interim obturators:

- The patient should be instructed not to keep the obturator out for more

time than is required to clean the prosthesis or the surgical defect area

as ensuing tissue edema may alter the fit of the prosthesis.

- Denture adhesives can be used with acrylic resin dentures not lined by

tissue conditioner.

- Patients must be instructed and made to practice the placement &

removal of the prosthesis and instructions for cleaning the prosthesis

must be given before the patient leaves the office.

- Patients should be told that the head- upright position during

swallowing would decrease the leakage of fluids into the nose.

- Patients should be instructed not to use effervescent denture cleaners

when tissue conditioner material is used to reline.

II) Definitive Obturation

Three to four months after surgery consideration may be given to

the construction of definitive obturator prosthesis. The timing will vary

depending on the size of the defect, the progress of healing, the prognosis

for tumor control, the effectiveness of the present obturator, the use and

timing of post surgical radiation therapy and the presence or absence of

teeth. The defect must be engaged more aggressively for edentulous

patients to maximize support, retention and stability.

Therefore the recovery period is extended for these patients, as changes

associated with healing and remodeling continue to occur in the border

areas of the defect for at least one year, but are primarily related to the

peripheral soft tissues rather than to the bony support areas.

If osseointegrated implants are placed at the time of the tumour resection,

fabrication of the definitive prosthesis is delayed until the implants are

exposed and peripheral soft tissues around them have healed.

Also the information regarding the prognosis of the tumour control as well

as general health and desires of the patient need to be considered.

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A patient's poor prognosis, or poor health does not preclude the

construction of definitive obturator prosthesis, but the treatment plan

should reflect the possible altered needs of such a patient.

Treatment Concepts Regarding The Definitive Obturator Prosthesis:17

Following factors should be considered.

i) Movement of the Prosthesis: The obturator prosthesis will be

displaced superiorly into the defect with the force of mastication and will

tend to drop without occlusal contact. The degree of movement will vary

with the number and position of teeth that are available for retention as

well as with the size and configuration of the defect.

ii) Tissue changes: Dimensional changes will continue to occur for at least

a year secondary to scar contracture and further organization of the

wound. Movement of the prosthesis, during function may, itself contribute

to tissue changes. Hence, the obturator portion should be made in acrylic

resin so as to facilitate reline or rebasing to compensate for these

changes.

iii) Oro-Nasal Partition: Obturators for acquired defects of the maxillae

are basically covering prosthesis serving primarily to re-establish the oral

nasal portion. The obturator prosthesis is extended into the defect in order

to enhance retention, stability and stability. The contours of the defect are

relatively static during function, aside from the movement of the soft tissue

displaced by the movement of the coronoid process, the anterior border of

the ramus, elevation of the soft palate and slight movement of the lips and

cheeks. In contrast, obturators that restore palatopharyngeal incompetency

must function in concert with tissues exhibiting extensive functional

movement.

iv) Extension into the defect: is dependent on the requirements of

retention, stability and support. If adequate maxillary structures are

present, extension into the defect need not be extensive. In addition the

extension of the prosthesis into the defect will vary according to the

configuration of the defect and the character of its lining tissue. Extension

of the prosthesis superiorly along the nasal septum offers little mechanical

advantage. In addition its lining mucosa is not amenable to tolerate stress.

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In comparison, extension superiority along the lateral margin of the defect

will enhance, retention stability and support. Stress is well tolerated by the

skin graft and the oral mucosa lining the cheek surface of the defect.

v) Teeth: The presence of teeth enhances the prosthetic prognosis.

Every effort should be made to maintain and enhance the longevity of

teeth, or even roots of teeth, to assist in the retention, stability and support

of the prosthesis.

vi) Implants: The placement of osseointegrated implants dramatically

improves the function of obturator prosthesis. Implants can be placed

either at the time of tumour resection or at some appropriate time

thereafter.

vii) Weight: Bulky areas should be hollowed out to reduce weight so that

teeth and supporting tissues are not stressed unnecessarily especially

when the obturator prosthesis is suspended without bony or posterior tooth

support on the defect side. Wu and Schaaf153 have found that hollowing

the obturator prosthesis reduces weight by 7-33% depending on the size

of the defect. The superior surface can either be left open or closed.

Clinicians who prefer closed top state that if the obturators are left open,

nasal secretions accumulate leading to bad odour and added weight.

Advantages of leaving the top open are that the weight of the obturator is

further reduced as there is no lid, it is easier to adjust and speech is better.

The effect of length of extension into the defect and top configuration

(open/closed) was studied by Aramany and Drane (1972) and Oral96; and

they found that the speech quality using the limited extension prosthesis

was better than with the maximally extended obturator prosthesis. The

lengthy superior extension along the lateral and disto lateral aspect of the

defect is essential for stability, support and retention. If a lid is added to the

hollow obturator, the obturator bulb occupies significant portions of the

nasal and maxillary sinus cavities.

Sharry(1962) has stated that it is not necessary for the obturator to occupy

the entire defect superiorly for effective obturation.

If a closed bulb is used, then it may change the configuration,

resonance balance and airflow characteristics of the nasal cavity. The

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open obturator design may be less obtrusive in the nasal cavity and

permits more normal airflow, nasal resonance and speech.

Though Chalian29 recommends closed top obturator, Beumer and

Curtis17 advocate the open top obturator and have experienced that

occasionally a patient may be required to be converted to closed top bulb.

Also, a drainage channel for the collected secretions may be made. A

diagonal opening may be made in the inferolateral floor of the open

obturator through the cheek surface for drainage154. The cheek will close

against the opening and hence, the seal will not get compromised. A pipe

cleaner can be used to maintain patency and cleaning this channel.

Definitive Prosthesis construction for hard palate defects is divided

into

A) a) For Edentulous patients

b) For Dentulous patients

B) a) For total Maxillectomy

b) For Partial Maxillectomy

PROSTHETIC CONSIDERATIONS FOR EDENTULOUS PATIENTS

WITH TOTAL MAXILLECTOMY DEFECTS

It is a prosthodontic challenge to restore such patients as air leakage, poor

stability and support, reduced bearing area compromise adhesion,

cohesion and peripheral seal. Therefore, the contours of the defect must

be used to maximize retention, stability and support.

The prosthesis exhibits a lot of movement about the axis of rotation, which

is located along the medial palatal margin of the defect.

In a posterior maxillary defect, where the premaxilla is preserved, the axis

of rotation shifts posteriorly. This is a favourable situation as more support

is available.

- Remaining palatal structures determine the available support and

stability. An ovoid or square arch form provides better support than the

reduced amount and undesirable angulation of the palatal shelf found

in tapering arches. If pendulous soft tissues are present, they should

be excised to improve the prognosis.

- The undercut above the scar band at the junction of the split skin graft

with the oral mucosa should be engaged to enhance retention and

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support of the prosthesis. Since, the lateral portion of the obturator

exhibits greatest degree of movement, retention can be improved by

appropriate obturator tissue contact supero-laterally.

- Additional retention gained by extending the prosthesis along the nasal

surface of the soft palate or anteriorly into the nasal aperture.

- The lateral portion of the orbital floor can also gain support if it has

been lined by skin graft.

- Impressions are made as described later.

- Jaw relations may need to be recorded on processed bases as

described by Curtis 35 & Jacob 61as support and stability are difficult to

achieve with a conventional temporary base. Temporary base can be

used if stability and support is adequate. Trismus complicates the

recording of vertical relation. It can be countered by the use of flexible

baseplate type of plate made of silicone as described by Lauciello.

However, it is subject to rapid deterioration and fungal infections, it

needs to be replaced frequently. Extreme trismus can also be

managed in a way described by Taylor in a patient with a contiguous

orbital defect. The prosthesis is button shaped and fabricated in

silicone. It is snapped in position from the top to plug the defect. It is

possible only when the orbital defect is large.

Normal parameters are used to adjust the maxillary rim and the vertical

dimension. Compensation for the contracted lip and cheek has to be

done on the surgical side. Often it may be necessary to gradually

create a negative horizontal overlap or end-to-end occlusion extending

from the midline to the posterior dentition. Lip closure may be a

problem due to contracture and shortening of the upper lip. It can be

compensated by reducing the vertical dimension slightly or by the

adjustment of buccolingual placement of teeth. The latter should be

preferred as if the former technique is employed; there might be tongue

or lip biting on the normal side.

- Due to the size of the maxillary cast a high post articulator such as

TMJ articulator is recommended. Transfer should be done with a face

bow record.

- Graphic centric records by intra or extra oral tracing are

contraindicated as the lack of support introduces inaccuracy. Use of

bite registration paste to record the centric relation is advocated along

with stabilization of the record bases by the operator during closure.

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The maxillary base should be carefully observed for movement or

shifting during interocclusal record making.

- Teeth should be arranged using Monoplane teeth with reduced size to

minimize stress 25. Monoplane teeth also allow negative horizontal

overlap on the surgical side. Roberts advocated balanced occlusion

while according to Beumer & Curtis nonanatomical and /or functional

posterior teeth are arranged according to neutrocentric or lingualized

occlusal concepts as these minimize lateral forces and deflective

occlusal contacts and thus improve stability. The teeth are set in

centric relation and all lateral interferences eliminated. The trial denture

is checked and jaw relations verified.

- At the try-in appointment the palatal contours must be evaluated. The

vault may be too high or low. It can be evaluated easily by sweeping

the thumb across the palate from one side to the other. Palatograms

can be used to evaluate further. Pressure indicating paste is streaked

across the palatal contour and then the patient is asked to swallow and

speak. Heavy contact areas should be trimmed while the deficient

areas built up in wax. If there is heavy tongue contact on the palatal

surface of the teeth on the defect side, tongue space should be

regained by reducing the width of the occlusal surfaces.

- The denture can be made hollow, with a closed or open top, or have a

silicone obturator section as described later in the different techniques

that are used.

- Denture processing should be done at 165 F for 15 hours to prevent

porosity if thicker sections of acrylic are present. If the processed

bases were used then the prosthesis can be cured at a lower

temperature than the first curing .The clinical significance of the

distortion created with multiple processing of the resin is negligible.

- During denture delivery pressure indicating paste should be used to

delineate areas of excessive tissue displacement. Clinical remount

should be done to perfect occlusion.

Instructions to the patients:

- Patients should continue to wear the maxillary prosthesis at night as

the sinus secretions and saliva cannot be managed without it. If not

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worn then tissue edema at the periphery of the defect will cause

difficulty in placement of the prosthesis.

- Patients should be instructed to masticate from the nonsurgical side of

the arch in cases where the surgical defects are very large.

- Patients should be taught how to use denture adhesives and to

maintain hygiene of the prosthesis.

PROSTHETIC CONSIDERATIONS FOR EDENTULOUS PATIENTS

WITH PARTIAL MAXILLECTOMY DEFECTS

These are similar to the total maxillectomy patients, however the prognosis

is better as more of the hard palate remains and hence, the prosthesis has

more stability and support. However, the retention may be compromised

as the access to and use of the defect is more limited. Implants are

especially useful for this group of patients as the premaxillary segment is

available for placement of implants and as the access to the defect may be

difficult.

PROSTHETIC CONSIDERATIONS FOR DENTULOUS PATIENTS WITH

TOTAL MAXILLECTOMY DEFECTS

Treatment concepts – These are concepts that are unique for dentulous

patients and should be considered by the prosthodontist.

i. Location of the defect – The tumour location and size will dictate the type

of remaining arch following resection of maxillary tumors. Invariably, the

surgical resection includes the distal portion of the maxilla and rarely does

a distal abutment tooth remain after surgery. The extent of the surgical

resection anteriorly does vary considerably. Therefore, a Kennedy class II

partial denture with an extensive lever arm is required for most patients.

ii. Movements of the prosthesis – With resection of the maxilla the mucosal

and bony support are compromised or may be lacking completely. Hence,

the defect must be employed to minimize the movement of the prosthesis

to reduce the stresses on the abutment teeth. In most defects, if forceful

mastication occurs on the defect side, the prosthesis can be displaced

significantly into the defect, which causes the abutment teeth to be

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exposed to damaging lateral torquing forces. The lateral portion of the

obturator exhibits the greatest motion; retention can be improved by

appropriate obturator tissue contact supero-laterally.

iii. Length of the lever arm – In conventional prosthodontics, the most

common Class II removable partial denture involves an edentulous area

distal to the cuspid. However, considerably longer lever arms are

encountered in patients with intraoral surgical defects. It is not uncommon

for the defect to extend form the middle anteriorly into the soft palate area

posteriorly.

iv. Arch form – Square or ovoid arch forms possess more palatal bearing

surface perpendicular to occlusal stresses. This results, in a more stable

prosthesis during function. This support area must be utilized by the

prosthodontist in the same manner as the buccal shelf is used for support

for the mandibular partial prosthesis. Tapering arch form provides less

palatal support area; therefore, support is compromised possibly leading to

Fig. 20: Illustration showing the greatest motion in the lateral portion of the obturator.

121

significant rotation and subsequent movement of the prosthesis up into the

defect, during mastication.

v. Teeth – Preservation of the remaining teeth is of particular importance,

because retention of the prosthesis is far less in the corresponding

edentulous patient. Partial denture designs must anticipate and

accommodate to the movements of the prosthesis during function without

exerting pathologic stresses on the teeth. Maximum retention, stability and

support should be derived from the defect and close attention should be

directed to the occlusion on the defect side to minimize occlusal forces.

vi. Partial denture design: The basic principles should be followed.

- Major connectors should be rigid.

- Occlusal rests should direct forces along the long axis of teeth.

- Guide planes on the palatal surfaces facing the defect to be used to

facilitate stability and bracing on maximum teeth possible as it resists the

rotational dislodgement of obturator. The longer the guide planes, better is

the resistance to rotational dislodgement. These can be incorporated in

the cast crowns, casted bonded metal contours or bonded resin contours.

- Retention should be within physiological limits of the periodontal ligaments

of the remaining teeth. The retainers should be placed as near to the

defect and as far away from each other.

- Maximal support and stability should be gained from the residual soft

tissue denture base area including the defect.

PROSTHETIC CONSIDERATIONS FOR DENTULOUS PATIENTS WITH PARTIAL MAXILLECTOMY DEFECTS

These are similar to those for total maxillectomy patients, but these have

better prognosis as the margin of resection moves posteriorly. With the

preservation of the canine or even the lateral, the advantages are

dramatic as the fulcrum line shifts posteriorly. As this happens the

distolateral extension of the obturator should be lengthened for better

mechanical advantage as it will be at a right angle and most distant to the

fulcrum line. Indirect retainers should be placed as far anteriorly as

possible from the fulcrum line. Retainer placed on the tooth adjacent to

the defect increases stability and retention. The construction for the

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prosthesis is similar to total maxillectomy patients, however when the

defects are very small, they should be packed with gauze, to prevent

escape and lodgment of the impression material. Occasionally,

edematous turbinates extend into the oral cavity, which should removed

surgically before the prosthesis is made.

CLASSIFICATION OF PARTIALLY EDENTULOUS DENTAL ARCHES

WITH MAXILLECTOMY DEFECTS:

Defects of the partially edentulous patients have been categorized into 6

groups by Aramany (1978)7 based on the relationship of the defect area to

the remaining abutment teeth. Class sequence reflects the frequency of

occurrence in a patient population of 123 patients treated during a period

of over 6 years.

Class I: The resection in this group is performed along the midline of the

maxilla, with the teeth maintained on one side of the arch. This is the most

frequent occurring defect and most patients falls into this category.

Class II: The defect in this group is unilateral, retaining the anterior teeth

on the contra lateral side. This type of surgical resection is favoured more

rather than the classical maxillectomy. The central incisors and sometimes

all the teeth anterior to canine or premolar are saved.

Class III: The palatal defect occurs in the central portion of the hard palate

and may involve part of soft palate. The surgery does not involve and

remaining teeth.

Class IV: The defect crosses the midline and involves both sides of

maxilla.

Class V: The surgical defect in this situation is bilateral and lies posterior

to the remaining abutment teeth.

Class VI: It is rare to have an acquired maxillary defect anterior to the

remaining abutment teeth. This occurs mostly in trauma or congenital

defects rather than as a planned surgical intervention.

This classification excluded patients who have large palatal defects

involving both sides of the dental arch and those who have only one tooth

remaining. For these patients, the principle of design is similar to that for

edentulous maxillectomy patients. The remaining teeth or tooth are

reduced in height to improve the crown- root ration and support is derived

primarily from the residual soft tissue. These teeth are either covered by an

overdenture or clasped with a flexible wrought wire clasp.

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DESIGN OF THE METAL FRAMEWORK FOR PARTIALLY

EDENTULOUS MAXILLECTOMY DEFECTS- ARAMANY (1978) 8

The design of the metal framework obturator will vary greatly is each

group. However, the design objective is to select most suitable

components to resist various forces without applying undue stress on

remaining teeth and soft tissues. The patterns of forces affecting the

obturator prosthesis are complex because of their concurrent occurrence.

These forces may be categorized as vertical dislodging forces, occlusal

vertical force, torque or rotational lateral force and anterior posterior forces.

The weight of the nasal extension of the obturator exerts dislodging and

rotational forces on abutment teeth. Obviously, then it would be desirable

that the nasal extension superiorly helps resist such forces.

Occlusal vertical force is activated during mastication and swallowing.

Wide distribution of occlusal rests will help counteract such forces.

Preservation of teeth or part of residual ridges across the midline will

greatly improve obturator stability. Maximum support should be planned

through utilization of full palatal coverage. Lateral forces are minimized by

proper selection of an occlusal scheme, elimination of premature, occlusal

contact, wide distribution of stabilizing components, and covering medial

wall of the defect with palatal flap, can help resist lateral forces. Guiding

planes on the proximal abutment teeth help resist anterior-posterior

movement. Properly designed retainers will reduce stress transmitted to

the abutment teeth’s while maintaining obturator in place. Stabilization and

indirect retention components must be strategically positioned to effectively

retard movement of the nasal extension portion away from its terminal

position, which in turn will reduce stresses on the abutment teeth.

CLASS I

The design can be either linear when the remaining anterior teeth were not

to be used for retention and support and a tripodal design when the

anterior teeth were used.

Class I – Curved arch form:

Support: It is provided and shared by the remaining natural teeth, the

palate and any structure in the defect that may be contacted for the

purpose. The goal is to ensure that the functional load is distributed as

equally as possible to each of these structures via a rigid major connector.

The natural teeth are aided in this action, when the support regions of the

124

palate and the defect are loaded to their maximum without physiologic

overload.

A broad square or ovoid palatal form aids by providing greater tissue

bearing surface to resist upward force (occlusal force) and a greater

potential for tripodization to improve leverage. A tapering arch is less of an

aid. Rests are placed on the most anterior abutment (closest to the defect)

and the mesio occlusal surface of the most distal abutment tooth when the

alignment and occlusion will permit. The mesio-occlusal posterior rest,

most often located between adjacent posterior teeth, is accompanied by a

rest on the disto-occlusal surface of the more anterior adjacent tooth. This

additional rest will prevent wedging and separation of the two adjacent

teeth and will decrease the possibility or periodontal damage from food

impaction. The completed obturator often requires a compound path of

insertion as undercuts and support regions within the defect will be

negotiated before the teeth are engaged. Guide planes will assist in the

precise placement of the prosthesis once the teeth are contacted. They will

also ensure more predictable retention and add a greater stability to the

prosthesis. Guide planes on the anterior abutment should be kept to a

minimum vertical height (1-2mm) to limit torque to the abutment teeth and

should be physiologically adjusted. This is important as movement can be

expected during function because of the extensive lever arm provided by

the defect and the dual nature of the support system. This consideration

becomes more important as the curvature of the arch decreases and the

potential mechanical advantage of the indirect retainer is decreased. In

this instance, it is especially important to use the palatal surfaces of the

posterior teeth for additional bracing and stability.

An indirect retainer is usually located perpendicular to the fulcrum line

(which connects the most anterior and posterior rests) and as far forward

Fig. 21: Class I

125

as possible. This is usually a canine or a first bicuspid. Strategically placed

indirect retainers allow maximum use of leverage to resist movement of the

prosthesis in a downward direction by the pull of gravity acting on the

defect side.

Retention: It is supplied by direct retainer designs that allow maximum

protection of the abutment teeth during functional movements. On the

anterior abutment, a 19 or 20 gauge wrought wire clasp of the “I- bar”

design is often used to engage a 0.25 mm undercut on the midlabial

surface of this abutment or a gate design. Additional protection is afforded

to this tooth by splinting it to one or two adjacent teeth with full crowns

whenever possible or acid etch composite resin techniques when crowns

are not possible. Other possibilities include a variety of cast clasp

assemblies located on the height of contour for frictional retention only.

The posterior retainer is most often a cast circumferential clasp utilizing a

0.25 mm undercut on the buccal surface. The placement of posterior

clasps facing in both anterior and posterior direction will aid in retaining

both anterior and posterior portions of the prosthesis.

CLASS I : LINEAR ARCH FORM

The linear design is used for a class I defect when one does not desire to

use the anterior teeth, when the arch form is linear and the remaining

posterior teeth are in a relatively straight line.

Support: in the linear design the remaining posterior teeth and the palatal

tissues provide support. The palate becomes more important in the linear

Fig. 22: Class I

126

design because the use of leverage to resist vertical dislodging forces is

decreased.

Miller states that a unilateral design requires bilateral retention and

stabilization on the same abutment teeth. A diagonally opposed retention

and stabilization system can be used.

Retention: is provided by the combined use of buccal premolar retention

and palatal molar retention. Stabilizing components are placed on the

palatal surfaces of the premolars and buccal surfaces of molars.

CLASS II DESIGN : In this, the design is similar, to Kennedy’s class II

removable partial denture. A bilateral tripodal design is recommended.

Primary support is placed on the tooth nearest the defect, as well as the

most posterior molar on the opposite side. Double rests are used on

adjacent posterior teeth. Guide plane location and size is similar to the

class I situation with full use of the palatal surfaces of the posterior teeth.

Guiding planes are located proximally on the distal surface of anterior tooth

and the last molar. Retention and stabilizing components are placed on

buccal and palatal surfaces of abutment teeth respectively.

The abutment tooth closest to the defect is critical to for retention and

should be engaged with a direct retainer design that resists downward

displacement but tends to rotate, disengage or flex when upward forces

are applied. A cast circumferential clasp or an I-bar clasp is frequently

used in a 0.25 mm undercut when the retentive terminus can be located on

the fulcrum line. A 19 gauge wrought wire clasp in a 0.5 mm or less

mesiofacial undercut is also a frequent choice. Additional protection can be

provided for this tooth by splinting it to one or two teeth adjacent to it. The

posterior retainer is most frequently a cast circumferential clasp using a

0.25 mm distobuccal undercut. The placement of posterior clasp

Fig 23: Class II

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assemblies facing in both an anterior and posterior direction will aid in

retaining both the anterior and posterior portions of the prosthesis. The

anterior facing clasp will also serve to aid any additional clasps placed

opposite to the fulcrum line from the defect. The canine is frequently the

location of an indirect retainer and also serves as an additional (optional)

retentive site, engaged with a 19 gauge wrought wire clasp in a 0.25 mm

undercut. The canine is important in resisting occlusally directed forces

and will receive severe stress. If an additional clasp is required on the

canine, it should be a more flexible clasp in less than the normal amount of

undercut or a less flexible clasp on the height of contour so that frictional

retention will be supplied.

A combination of buccal and palatal retention is almost never indicated for

this classification for the following reasons:

a. Additional bracing and cross arch stabilization will be lost when palatal

retention is engaged.

b. Increased rotation will be noted with an actual decrease in retention

because of the short length and shallow gingivally located curvature of

the palatal surfaces of the molar teeth and disengagement of the

lingual undercut on slight displacement.

c. The location of palatal retentive clasps often results in a major

connector that has multiple small regions that trap food or irritate the

tongue.

Occlusion on the defect side is important because the occlusally

directed forces can be destructive. Occlusal schemes with fewer,

smaller teeth, located further toward the anterior side and devoid of

premature or deflective contacts is desirable.

CLASS III DESIGN : The design is based on quadrilateral configuration.

The remaining natural teeth via widely separated and bilaterally located

rests supply support. The canines and molars are usually selected to

generate the largest quadrilateral shape possible while avoiding alignment,

occlusion and hygiene problems and providing good aesthetics. Little or no

support is derived from the palate or the defect. Bilateral symmetry of the

major connector design and avoidance of the rugae area is desirable when

possible.

128

Guide planes are usually short because they are located on the palatal

surfaces of the posterior teeth. The proximal surfaces may be liberally

used if edentulous spaces are present. Very little movement of the

prosthesis should occur in function, therefore these guide planes may be

long and physiological adjustment may not be necessary.

Indirect retention is not required because a direct retainer supports each

terminus; therefore, rotation around a common fulcrum should not occur.

Retention is often provided with cast retainers using 0.25 mm undercuts on

the facial surfaces of the teeth. These may be circumferential retainers, I

bars or modified T-bars depending on the location of the retentive sites,

the esthetic requirements and the presence of tissue undercuts.

Combination type retainers can be used to an esthetic advantage because

they can engage a deeper undercut and may thus be placed in a less

conspicuous zone.

CLASS IV DESIGN : The design is linear, Support is located on the centre

of all remaining teeth. Channel rests or multiple mesio-occlusal and disto

occlusal rests are designed. The defect should also be engaged to use, as

much as possible, any sites within the defect that may be contacted. These

are the midline of the palatal incision, when palatal mucosa has been

preserved to cover this region, the floor of the orbit, the bony pterygoid

plates and the anterior surface of the temporal bone. If these regions are

covered by respiratory mucosa, little added support can achieved.

Retention is located buccally on the premolars and palatally on molars.

Stabilizing components are palatal on premolars and buccal on molars.

This leads to loss of bracing, increased rotation and the creation of small

irritating spaces in the major connector. (As discussed in Class II design)

Fig. 24 Class III

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Retentive sites should ideally be located on teeth and the lateral wall of the

surgical defect via the superolateral extension of the obturator section in

the engagement of the lateral scar band.

Reduced posterior occlusion (size and number of teeth) is also useful.

If no lateral scar band exists, because a split thickness skin graft was not

given or because one could not be maintained, the prosthodontist may

have no choice but to use a combination of buccal and palatal retention.

CLASS V DESIGN :

In this, splinting of at least two terminal abutments on each side is

suggested.

Rests located on the mesio occlusal surfaces of the most posterior

abutment provide support. These rests define the fulcrum line around

which most of the expected movement will take place. If adjacent posterior

teeth are involved, double rests are used. Stabilization and bracing is

provided by broad palatal coverage and contact with the palatal surface of

the remaining teeth.

Fig. 25: Class IV

130

Indirect retention is provided by rests located as far forward of the fulcrum

line as possible. This usually places them on central incisors, which often

presents an occlusal problem that may require minor occlusal equilibration.

The location of the indirect retainer essentially converts the design to an

efficient large tripod that uses leverage to resist downward movement of

the prosthesis. Positive rest seats are a critical necessity to eliminate the

strong labial force generated by the downward movement of the

prosthesis.

Retention: I-bar clasps are placed bilaterally on the buccal surfaces of the

most distal teeth. Located in a 0.25 mm midbuccal undercut very close to

the fulcrum line, it provides for resistance to dislodgement and rotation in

function. When the remaining soft palate is scarred and relatively immobile

it can also be used to provide added retention for the posterior portion of

the prosthesis. A gate prosthesis is a viable alternative for these patients

if they can tolerate splinting of all of the remaining teeth.

CLASS VI DESIGN :

In such defects, two anterior teeth are splinted bilaterally and connected

by a transverse splint bar. A clip attachment may be used with out an

elaborate partial framework. If the defect is large, or remaining teeth are in

less than optimal condition, a quadrilateral configuration design is followed.

In this the support is derived from rests located on the anterior and

posterior abutment teeth. Greater stability is provided by placing additional

rests as far posteriorly as possible. The most posterior rests, similar to the

Kennedy Class IV situation, may be considered as indirect retainers,

Fig. 26: Class V

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resisting the vertical downward movement of the anterior segment of the

prosthesis.

In extremely large Class VI situations indirect retention may not be

possible. The remaining natural teeth provide all of the support with little

support derived from the defect. Guide planes are usually located on the

proximal surfaces adjacent to the defect and should be kept of minimal

length (1-2mm) to avoid trauma to the abutment teeth during expected

movements of the prosthesis.

Retention is most often provided simply with cast retainers using 0.25 mm

of facial undercut. I bar or combination retainers can be used on anterior

abutments.

Effective accessory retention can be achieved by extending the prosthesis

anteriorly into the nasal aperture. Cosmetic support of the nose and upper

lip is also possible when adequate retention is present.

Fig. 27: Class VI

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OTHER DESIGN CONSIDERATION'S FOR PARTIAL DENTURE

FRAMEWORK FOR OBTURATOR PATIENT

i) Stress breaker concept

Since the maxillofacial prosthetic patient has an added problem of movable

basal seat, which is made up of grafted bone and skin covering over it

(instead of mucous membrane). So there is more movement of the base

in function than severely resorbed alveolar ridge. Also, the restoration of

the lost parts is usually heavy and bulky, and this adds to the load on the

remaining teeth.

The remaining teeth in these patients are extremely valuable to them and

stress breaking should be considered.

a) When relatively few teeth are left and a partial denture is indicated,

the combination clasp that Applegate described with one arm

consisting of a flexible wrought wire and the opposing arm

consisting of a rigid cast arm should be considered. The wrought

arm supplies gentle retention and the cast arm is kept out of the

undercuts and serves only to stabilize the appliance against lateral

movements.

b) A double or split-bar type of stress breaker is effective where the

abutment teeth are all posterior to the denture base. This design

prevents rotation about the anterior rest. The great advantage of

such a split bar is in its ability to transfer the fulcrum or center of

rotation to the most posterior tooth.

c) The truss bar retainer is indicated, where a large number of healthy

teeth remain and maximum retention is needed to support an

obturator or other large appliance.

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II) SWING LOCK PARTIAL DENTURE FRAMEWORK DESIGN

CONCEPT - Javid & Dadmanesh (1976) 63

The lack of a residual alveolar ridge and soft palate in hemimaxillectomy

patients complicates the design of removable partial dentures for these

patients. With conventional clasp design, because of the lack of the

supporting residual alveolar ridge the prosthesis moves towards the tissue

more than the conventional removable partial dentures. Also during

masticatory function, depending on the magnitude of forces, kind of food

and the size of the occlusal table, the retentive clasp arm might be bent or

broken. As a result, the prosthesis may lose its retention and stability,

affecting speech as well.

A swing lock - design for clasp retention of the obturator prosthesis is

suggested. A “gate clasp” was first described by Ackerman in 1955 and

swinglock concept was introduced by Simmons in 1963.

The design should include multiple retentive bar clasps engaged in the

appropriate undercuts (0.010 inch) utilizing as many teeth as possible. This

kind of design may have an orthodontic effect, depending on the size of

the occlusal table, degree of masticatory forces, and the number of teeth

involved in retention. The reduction of the amount of masticatory force is

not possible but the resisting force should include as many teeth as

possible.

This concept has been used in the fabrication of a surgical obturator by

William Black (1992) 19

Technique: On the preoperative casts the outline of resection is marked. A

0.036 wire is contoured into a double arch wire across the buccal surfaces

of the remaining teeth. Posteriorly the wire is passed through a 0.51-inch

inner diameter steel tubing to provide a hinge axis. Anteriorly, the wire

ends are looped to provide for elastic anchorage. After blockout, a custom

swinglock gate of autopolymerizing acrylic resin is made. This is

incorporated in the remaining prosthesis. At the time of surgery this is

placed and gate retention is either obtained by elastics or wire. Even

interdental or suspension wiring can be done to retain. After a week

following surgery the prosthesis is relined, the interproximal holes are filled

and the prosthesis is used as a removable prosthesis with gate retention

134

till a definitive obturator can be made. The advantage is that there is easier

transition from wire stabilized to removable obturation.

Marunick (2004) 80 described a hybrid gate design framework, which

incorporates both conventional retainers as well as the gate design

concept.

III) DUAL PATH OF INSERTION CONCEPT – King & Gay 49

Patients with an acquired maxillary defect, have essentially a unilateral

support problem that is compounded by the need to support the obturator

portion of the prosthesis. The use of facial and lingual retentive arms has

been the classic way of designing unilateral removable partial dentures.

The use of facial retentive and lingual reciprocating arms is based upon

the premise that there will be cross-arch clasping. When it is impossible to

provide cross-arch clasping, as in maxillectomy, a unilateral support

situation exists, and the value of using both facial and lingual retention in

the same arch becomes apparent. The obturator's downward movement

can be resisted by the lingually placed clasps on the supporting teeth, as

well as by the soft tissues that approximate its lateral border.

The dual path of insertion is a reliable concept that can be of great value in

obtaining retention with a guiding plane when that plane has access to an

undercut before final seating of the prosthesis. When a lateral or central

incisor is the posterior abutment on the defect side of a maxillectomy

patient, the dual path may allow retention to be obtained with the guiding

plane and obviates the need to clasp the teeth.

Fig. 28: A hybrid gate prosthesis

135

Application of Resin Bonding: 135 The discovery of resin bonding by

Rochette in 1973 has paved the way for a lot of advances in dentistry. The

possibility of altering the tooth contours with techniques that do not require

full veneer preparations have greatly reduced the cost of preparing the

mouth for the complex removable partial dentures. Additive mouth

preparation is appropriate for the creation of rest seats, guide planes,

whether primary or associated with minor connectors and indirect

retainers; retentive contours for conventional clasping and in carefully

selected cases bonded precision attachments. Bonded contours can either

be in composite or in metal that is microetched and then bonded.

Fig. 29: Wax up for bonded contours

Fig. 30: Spruing for the multiple contours.

Fig. 31: Lingual guide planes and cingulum rest bonded.

136

Precision & semi precision attachments:

Bonded attachments are indicated in cases where the terminal abutment does

not lend itself to conventional clasping. For e.g. when a central or lateral incisor

is next to a large defect. Attachments that permit some measure of rotational

freedom are most appropriately selected. The life of the attachment can be

increased when the attachment does not become the rest s well as the

retentive component. Milled rest seats developed on the casting that holds the

attachment allow the stress to be transferred to the long axis of the abutment

rather than to the cantilevered extra-coronal attachment.

Fig. 32: Definitive obturator in position.

Fig. 33: Wax up of multiple guide planes with CEKA attachment on central incisor.

Fig. 34: obturator casting seated on master cast. The plate of the framework rests on solid rest seats placed in the anterior bonded castings.

137

PROSTHESIS DESIGNS FOR OTHER ACQUIRED MAXILLARY

DEFECTS as described by Chalian 29

1) Snap on prosthesis for marginal defects.

When there is a marginal defect of the maxilla but with no associated

palatal or vestibular communication with the maxillary sinus cavity, a snap

on removable partial prosthesis may be constructed for retention and

esthetic purpose.

2) Snap on Prosthesis for Anterior segmental defect.

The versatile snap-on mechanism can also be adapted to provide

transpalatal splinting when the anterior palatal defect is large. To minimize

tilting, looseness, and occlusal stress on the remaining teeth, a clip

attachment is centrally placed to engage the palatal rod.

3) Prosthesis for lateral segmental defects of edentulous maxilla with no

palatal opening. Often trial dentures are made to permit the patient to have

a positive experience of closure and centric stop for occlusion. Then,

when facial symmetry and patient comfort have been achieved, the final

prosthesis is fabricated.

ADVANCES IN SURGICAL RECONSTRUCTION AND ITS IMPLICATION

ON MAXILLOFACIAL REHABILITATION 94

New prosthodontic guidelines that relate to the surgical reconstruction of

the maxilla seem to be mandated as a result of advances in microvascular

surgical techniques. Microvascular free flap surgery allows the transfer of

muscle, connective tissue, skin and bone to the recipient sites. A vascular

supply to the graft can be provided after donor blood vessels are re-

anastomosed to recipient vessels of the head and neck region.

Fasciocutaneous and osteomyocutaneous free flaps can provide closure

of the oral cavity for acquired maxillary defects.

Major factors in the prosthodontic rehabilitation decision-making process

include whether a maxillectomy defect should be reconstructed; if so, what

type of free flap should be employed; and how the chosen free flap will

affect the patient’s oral function.

138

Okay et al state that soft tissue flaps can provide closure of the oral cavity

in smaller defects but are unsupported and may not provide a stable

palatal base for a removable prosthesis. If a removable prosthesis is

planned along with surgical closure provided by a fasciocutaneous flap,

the support of the prosthesis should be derived from the remaining palate

and the dentition. For larger defects, the use of vascularized bone

containing free flaps (VBCFF) for maxillary reconstruction can provide the

restoration of a stable palatal base.

The biomechanical principles relevant to prosthetic rehabilitation of

maxillectomy defects should be utilized if surgical reconstruction is

anticipated. Indications for the use of fasciocutaneous flaps and VBCFF’s

can be derived from the application of these biomechanical principles and

from the anatomy of the remaining dental arch and palate.

To assess the functional outcome and patient satisfaction that surgical

reconstruction can provide a classification system of defects based on a

selected patient population at the Mt. Sinai Medical Centre was

established. All the defects reviewed were rehabilitated with a tissue borne

obturator, a local palatal island flap, a fasciocutaneous free flap, or a

vascularized bone containing free flap. Design considerations for surgical

reconstruction and prosthodontic rehabilitation focused on 4 objectives:

q Closure of the oral cavity.

q Provision of a stable base for the restoration of function.

q Restoration of midface symmetry.

q Support of orbital structures.

Palatomaxillary defects were divided into 3 major classes and 2

subclasses. Eight different defects of the hard palate and maxilla were

characterized within this classification system. The size and location of the

defect, remaining dentition, and palate influenced the design of the

microvascular free flap and prosthodontic restoration. Maxillectomy defects

involving the floor of the orbit and/or zygoma also played a role in the

donor site selection and the design of the microvascular free flap.

Class I a: These are the defects involving the hard palate but not the tooth

bearing alveolus. These could be rehabilitated with an obturator, a local

advancement flap, or a fasciocutaneous free flap. In general, prosthetic

rehabilitation is stable and well tolerated.

139

But, local island flaps can also be used as a simple method to reconstruct

if the defect covers less than one third of the hard palate. This obviates the

need for a dental prosthesis.

If a patient is radiated or the defect too large then a fasciocutaneous free

flap should be used.

Class Ib: Defects that involve any portion of the maxillary alveolus and

dentition posterior to the canines or that involving the pre maxilla. These

defects involve a small portion of the dental arch; the anterior sextant, and

a unilateral posterior quadrant of teeth remain intact.

As a result, the theoretic cantilever forces over the defect are minimized.

The movement of the obturator around the fulcrum line can be stabilized

due to the superior root morphology of the canine approximating abutment

and the considerable arch length provided by a sound anterior sextant and

a unilateral posterior quadrant. The ability to clasp teeth perpendicular to

Fig. 35: Class Ia

Fig. 36: Class Ib

140

the fulcrum line of the framework and the support afforded by the

remaining palate further stabilizes the prosthesis and improves the

prosthetic prognosis.

If surgical reconstruction is planned, a soft tissue flap is indicated

without osseous reconstruction because the remaining dentition and palate

are able to support the occlusal contacts over the reconstruction with a

removable partial denture. With a removable partial denture, the support is

derived from the remaining dentition and palate and not the flap. A radial

forearm fasciocutaneous free flap works well for closure of the oral cavity

because of ample soft tissue of the donor site and low donor site morbidity

relative to those of the other sites.

In an edentulous patient, the bone of the remaining maxillary

alveolus has to be sufficient to accommodate osseointegrated implants.

Forgoing osseointegration of implants in the remaining natural maxilla and

surgical closure of the defect with a fasciocutaneous free flap can result in

a difficult or impossible situation for prosthetic rehabilitation. This is due to

the inability to extend the obturator bulb into the defect and engage

anatomic undercuts for stability and retention.

Class II: Defects that involve any portion of the tooth bearing maxillary

alveolus but includes only one canine. The anterior margin of these

defects is within the pre maxilla. Also included within this class are anterior

transverse palatectomy defects that involve less than one half of the

palatal surface. Total maxillectomy comprises the majority of defects in this

class in which an incisor serves as the terminal abutment.

Fig. 37: Class II

141

Prosthetic rehabilitation of class II defects is less predictable than class I

defects. Factors that contribute to instability are fewer teeth for clasping,

reduced arch size and form and a significantly reduced supporting palate.

Further, an obturator alone is inadequate to restore cosmesis to the

midface if the orbital floor or zygoma is resected.

Some class II defects are best restored with VBCFF’s. Vascularized bone

offers the ability to re-establish the bony dental arch for the placement of

osseointegrated implants which allows the distribution of the masticatory

forces across an intact maxillary arch and thereby reestablishes a

favourable biomechanical condition in the maxilla. Furthermore, VBCFF

permit the primary reconstruction of the orbital rim and the prominence of

the zygoma tic body with autologous tissue.

Class III: Defects that involve any portion of the tooth bearing maxillary

alveolus and include canines, total palatectomy defects and anterior

transverse palatectomy that involve more than half of the palatal surface.

These defects leave little or no residual palate or dentition for the secure

retention of an obturator, which leads to a poor prosthetic prognosis. Class

III defects are best restored with VBCFF, although the soft tissue closure

serves to effectively partition the oral cavity from the nasal cavities and

maxillary sinuses, oro-dental rehabilitation is severely compromised.

Bones containing free flaps however, serve to separate the cavities along

with providing vascularized bone capable of retaining implants. Palatal

reconstruction provides a stable base to oppose the restored mandibular

arch.

Fig. 38: Class III

142

Subclasses f and z:

Defects that involve the inferior orbital rim are categorized as subclass f,

where as defects that involve the body of zygoma are categorized as

subclass z.

.

Extensive palatomaxillary defects commonly involve a vertical

component of the maxilla. The creation of subclasses, relate to the status

of the orbital floor and the zygomatic body and are essential to provide an

accurate description of the palatomaxillary defect. The orbital floor and the

zygomatic body play both functional and cosmetic roles as the ablation of

the vertical maxilla commonly results in a significant disruption of the

midface and orbit and has profound effect on function. Enophthalmoses

and diplopia can occur if the orbital contents are not supported. In addition

these patients may suffer from a cosmetic deficit that is impossible to

restore with an obturator.

VBCFF serve best to restore bone to the load bearing palate by

restoring bone to the orbital rim and the zygomatic body. It also permits the

placement of osseointegrated implants for the retention of an orbital

prosthesis.

Fig. 39: Subclass f Subclass z

143

This algorithm is used for functional reconstruction, midface restoration

and oro-dental rehabilitation according to the palatomaxillary defect

classification.

Impression Making Procedure's:

i) Conventional Impression: By Beumer and Curtis17

The objective of the preliminary impression is to record the

remaining maxillary structures and the useful portions of the defect.

An edentulous soft metal tray is selected according to the configuration of

the remaining maxilla. The medical and anterior undercuts are blocked out

with gauze lubricated with petrolatum. Adhesive is applied to the tray and

wax. The irreversible hydrocolloid material is mixed and located in the tray

with ample care to load the material laterally so as to record the lateral

configuration of the defect and a diagnostic cast is obtained.

The undesirable undercuts recorded in the cast are blocked out

with suitable wax prior to constructing the custom tray. Relief of one

thickness of base plate wax is provided for the skin graft-mucosal junction

and the superior lateral aspect of the defect. The residual palatal

structures are relieved in the customary way and the tray fabricated with

self-cure acrylic resin.

After checking the custom tray so that it extends 2-3 cm into the

cavity and extends beyond the scar band and superior to the cut edge of

the hard and soft palate, conventional border molding be carried out it is

advisable, that border molding be completed initially on the unresected

side since this serve to stabilize and orient the tray over the defect. The

lateral, posterior and anterior aspects of the defect are recorded

144

sequentially in two sections. First the area below the skin graft mucosal

junction is molded. Next, the area above the scar band is molded. In

molding the posterolateral aspect the patient should be instructed to

perform eccentric mandibular movements to account for the movement of

the anterior border of the ramus, and the coronoid process of the

mandible.

The patient should be directed to use routine head and mandibular

movements during the border moulding. The impression of the surgical site

requires that the patient perform exaggerated head movements turning left

to right with the head level, and then again with the neck flexed and

extended. The mouth should be opened and closed, and the mandible

moved laterally.

Speech and swallowing evaluation should be done to check the

seal before making the final impression. The patient should be made to

speak m and b and if there is distinction then the seal achieved is

adequate. If they are not distinct, then there is some air leakage present.

The modeling plastic is relieved approximately 1 mm in all areas,

prior to obtaining the final impression. Several perforations are made for

escape of the impression material with at least three perforations being

made along the median palatal margins. Prepare mixes of regular and

light body rubber base impression material; spatulating the regular material

slightly in advance of the light bodied material. The light body is injected

into the defect and the regular body-containing tray is seated over it.

If the anterior margin of the soft palate exhibits considerable

elevation during speech and swallowing, the portion of the impression that

engages the soft palate both superiorly and inferiorly is cut away with a

scalpel and a functional impression is made with thermoplastic wax. If the

patient exhibits extreme trismus, surgical obturator can be used for making

final impression with tissue treatment material.

For dentulous patients a preliminary impression is made in a stock

tray with irreversible hydrocolloid in a suitably modified stock tray. The tray

extensions can be extended in the defect area by using modeling

compound. Same precautions are taken as in an edentulous patient. The

design of the prosthesis is decided, necessary mouth preparation done

and the final impression of the non-defect side is made for framework

fabrication. This impression should include sufficient amount of the defect

region so as to allow the extension of the framework into the defect without

145

interference from remaining anatomic structures. The final impression of

the defect area is made only after the framework has been fabricated and

physiologically adjusted in the mouth. Autopolymerizing resin is added to

the retentive meshwork to serve as an impression tray for the obturator

portion extending into the defect. A wax occlusal rim may also be added to

assist in evaluation of facial support, tooth position and occlusal

registration. It is difficult to make the impression as the incremental

addition of impression or reline material increases the weight and causes

incomplete seating or rotation of the prosthesis away from its original

position. Adding an occlusal stop onto the occlusal rim, before the

impression is made can prevent this. With each increment added the

patient is instructed to bring the teeth together in maximum intercuspation,

thereby reseating the framework in its intended position. After border

moulding is done in the similar way as for edentulous patients, final

impression can be made in light body silicone material and can be further

refined by impression wax as discussed earlier.

ii) A foam impression technique for maxillary defects- by J. Schmaman and

L. Carr (1992). 121

TECHNIQUE:

An intraoral impression of the maxilla and entry into the defect is taken

in the conventional manner with alginate following which a special tray is

fabricated on the cast. A mushroom shaped acrylic resin retention-

relocating button is added to the special tray. A 20 ml, disposable plastic

syringe is modified to receive a latex-feeding nipple. The tip of the nipple

is cut to widen the aperture to about 5 mm. The nasopharynx and orifices

are blocked with gauze.

After adhesive is applied silicone rubber impression material is

loaded on to the tray while the button is excluded. An impression of the

residual structures, including the perimeter of the defect is taken in the

normal manner. The impression is withdrawn, checked and inserted back.

The patient is instructed to breathe through the mouth. The desired

volume of silastic foam liquid is poured in the syringe & the catalyst added

and rapidly mixed with a thin spatula.

The plunger is replaced and nipple inserted into the nostril that is

continuous with the defect. The foam is rapidly injected through the nostril

into the nasal cavity, and the syringe is removed. The defect and nasal

146

cavity are filled with foam, which expands to 4 times its original volume and

then extrudes from the nostril. After setting, this excess is removed with

scissors.

The tray with rubber impression is removed from the mouth, and

the button is withdrawn from the extremely elastic foam. The foam

impression is removed by inserting a finger into the nostril and pushing the

foam downwards and simultaneously, pulling the foam from inside the oral

cavity, as it disengages from the undercuts.

The foam impression of the defect is relocated onto the button and

is luted with sticky wax. To fabricate the cast, the foam is initially painted

with a thin coat of stone. When this sets, the cast is poured in

conventional manner. The advantage of this technique is that the

impression can be easily removed from the severe undercuts and that it is

easier when trismus is present. This disadvantage is that the rapid

reaction of the foam liquid to the catalyst limits the time.

Fig. 40: The defect. Fig. 41: Special tray and silicone impression in position.

Fig. 42: Injecting foam with modified syringe and nipple.

Fig. 43: Withdrawing the impression.

147

Procedure for two-piece hollow bulb obturator: 29

This technique is most frequently used although it is less hygienic

and esthetic as compared to the one-piece technique.

Once the master cast is obtained, clasps are placed in the

appropriate area and the baseplate wax of 2 mm thickness is adapted over

it. This includes the defect area, the base, and the medial, posterior and

lateral walls, keeping open the palatal ridge side. Next, modeling clay is

put into the defect area and with the patients normal palatal ridge being

used as a guide, the false palate and ridge are shaped and contoured in

the clay, leaving an approximately 2 mm thickness for the wax pattern on

the reshaped palate and ridge.

Next, the wax lid is prepared by keeping a tinfoil on the clay as a

separating medium. The wax lid is then separated, the tin foil and

modeling clay are discarded from the master pattern, setting of artificial

teeth is done and wax pattern are flasked separately and processed in

heat-cured acrylic resin.

The margins of the lid portion is perforated or undercut for retention

and then sealed over the main base by autopolymerizing methyl

methacrylate resin.

Fig. 44: Recovered impression.

148

Fig. 45: A. palatal view of waxed up obturator. B. waxed up obturator with the modeling clay in the defect area. C. tin foil applied over the modeling clay. D. false palate-ridge is separated. E. false palate perforated and seated over processed base. F. palatal view of the finished temporary obturator. G. tissue side view of the hollow bulb temporary obturator. H. temporary obturator inserted in the mouth.

149

Obturator bulb fabrication for edentulous patient: - by Chalian29

After the final impression is obtained, a cast is poured and

undesirable undercuts are blocked.

A stabilized base plate is made and flowed in the defect area, at

this stage; a wax lid is fitted over the defect area to leave it hollowed and to

provide the effect of a complete palate.

Then occlusal wax rim is adapted to prepare the cast for centric

and vertical records. With resulting records the casts are mounted on the

semi adjustable articulator. The teeth are selected, and arranged into the

rims. Then the wax try in is done. Finally the case is ready for laboratory

processing.

The palatal defect is filled in with modeling clay and given a palatal

shape. A false lid is made from autopolymerizing acrylic resin. This is set

aside while the case is flasked and processed.

The lid is then added to the master base to close the palatal portion

of the hollow bulb, and is sealed with quick-curing acrylic resin. Usual

finishing and polishing of the denture follow this.

Procedure for One Piece Hollow Obturator – Chalian

After the wax try in of the trial denture, the denture is festooned and

finally waxed as any conventional denture. The denture is flasked and

boiled out in the usual manner. When the case is completely flushed with

boiling water and thoroughly dried, a shim is constructed. The undercut

areas in the defect are blocked out and the entire defect area is relieved

with one thickness of baseplate wax. Three stops deep enough to reach

the underlying stone of the master cast are placed in the wax to facilitate

proper positioning of the shim. One thickness of base plate wax is also

placed in the top half of the flask over the teeth and the palate area to form

the top wall of the shim. This also allows for the thickness of heat cure

acrylic on the palatal side of the denture. Autopolymerizing resin is mixed

and rolled to about 2 mm in thickness after reaching the dough like stage.

A layer of resin is then contoured over the wax relief in the defect side, with

another layer on the wax in the top half of the flask. The flask is then

closed and allowed to set for a minimum of 15 minutes.

150

After curing, the flask is opened and wax is flushed off the shim

with stream of boiling water. The excess acrylic is removed and the shim

is placed back using the 3 stops as a guide. Heat-cure acrylic resin is

mixed and a layer is placed to the bottom of the defect, and shim is

inserted for final processing. The heat-cure resin is placed in the top flask

and the case is trial packed under pressure (1000 pounds). After the final

Fig. 46: A schematic drawing of the construction of one piece hollow obturator.

151

closure, the case is cured, deflasked, finished and polished in the

customary manner.

This technique has the following advantages:

i. There are no lines of demarcation on the denture to discolor.

ii. The undercut areas of the defect are thick enough to allow for

adjustment if necessary.

iii. It is simple and consumes very little more laboratory time than a

conventional denture.

iv. Accuracy is assured.

Other Important Methods Of Fabricating Hollow-Bulb Obturators:

I) THE SILICONE RUBBER OBTURATOR - Described by Rahn and

Boucher.112 Before the advent of resilient denture materials hollow bulb

obturators were used as a means of gaining additional retention and also

as a means of carrying supplemental forms of radioactive materials for

treatment of recurrent tumors. But, sometimes not all the available

undercut areas in the defect could be utilized and retention was not always

satisfactory.

Most of the disadvantages can be overcome by fabricating the

base portion of such prosthesis with one of the heat vulcanized medical

grade silicone rubber materials. Their excellent dimensional stability and

resilient character, aid in providing satisfactory retention, by permitting

closer engagement of the undercuts areas, thus providing a seal for the

palatal openings. These materials also ensure accurate delivery of

brachytherapy tubes, which are to be placed, in closure and intimate

relationship to the tumor site, unlike acrylic resin bulb, which cannot by

pass the undercut areas easily.

Method of fabrication:

After duplicating the master cast. The crown portions of the remaining

teeth are cut from the cast down to the gingival crevice. The wax pattern is

formed to the design desired to be reproduced in the silicone rubber

material.

152

When using silicone rubber, a flask should be used which can be

bolted together. After flasking and boiling out the wax pattern, all the stone

surfaces are treated with silicone rubber mold release material.

There are two types of silicone rubber sheet material, depending upon

specific needs. The material is available in varied durometer hardness,

and may be used together when a different degree of firmness is needed

in a specific area or a reinforcement is supplied by an inlay of a silicone

rubber impregnated Dacron.

The mold is packed in a similar fashion, as is acrylic resin.

Polyethylene separating sheets are used during the trial packing phase to

ensure separation and withdrawal of the flask halves. The flask halves are

pressed together in a bench press slowly so that putty-like material has an

opportunity to flow. The excess flash is cut away with a sharp instrument

and necessary reinforcement if necessary, in areas like labial frenum, the

portion distal to last tooth or any thick isthmus is done before the final

closure.

After final closure, the flask halves are bolted together and the entire

assembly is placed in the processing oven, which should be a dry heat,

natural air circulating type oven, with an accurate temperature control

system. The air circulation provides for the escape of by products of

vulcanization. The flask is left in the oven for one hour at 300oF. After

removing, it is then allowed to bench cool, and is finally separated. The

molded form may be trimmed off any excess flash at this time, but it must

be returned to the over for a period of 4 hours at a temperature of 400oF in

order to complete the curing process. It is during this later period of time,

that the by-products of vulcanization the driven out from the rubber mold.

Upon removal, from the oven, the rubber base is finished neatly

and placed on the master cast and super structure of the denture is

constructed in a conventional manner. The depth of the defect is filled with

wax or plaster, so that base plate material could be adapted over it, by-

passing the depression. Occlusal rims are constructed and the baseplate

and rubber base are united together by application of pressure sensitive

silicone adhesive. This procedure facilitates accurate intraoral recording of

centric relation and vertical dimension. After mounting on the articulator,

the occlusion unit areas is set and wax-try in is accomplished.

If a wax plug is used to bypass the depression, it is adjusted at this

time to form a collar, which fits into a portion of the concavity. This

153

provides additional support for the hollow bulb against lateral stress and

also allows for greater surface contact for the bonding agent.

The wax pattern superstructure is then removed, flasked separately and

upon recovery, finished and polished.

The base-contacting surface of the acrylic resin is ground,

roughened and lined with a silicon primer. The rubber base is cleansed

with ether or chloroform. Care is taken to see that both surfaces are not

contaminated in any way by fingers or anything else.

The permanent bonding material between resin and rubber base is

another form of silicone rubber, which cures at room temperature.

To ensure proper alignment, the lower complement of the articulator is

used, making certain that incisal pin contacts the guide table and vertical

dimension and centric relations are maintained. Upon closure of the

articulator, the excess adhesive material will be pressed and will fill the

space created therein. The excess is carefully removed. The articulator is

held together with rubber bands to ensure that the two components do not

shift their relationship. A minimum of 12 hours is required for the adhesive

to set. After this, the components may be further finished with moist free

pumice.

II) INFLATABLE OBTURATOR PROSTHESIS- described by A.G.L.Payne

W.G.Welton (1965) 105

It consists of a latex rubber balloon attached to a denture by means of a

silicone rubber former, into which is incorporated an air valve. The balloon

is inflated with air to fill the surgical defect.

PROCEDURE

Preparation of the denture; The upper denture is constructed in the usual

way and finished with the solid acrylic resin obturator extending only about

3mm into the defect. By working form the fitting surface, the obturator is

hollowed out as far as possible and a hole 1cm in diameter is cut through

the labial flange over the lateral incisor tooth. This aperture will give

access to the air-retaining valve. A groove 2mm deep is cut out into the

inner aspect of the periphery of the hollowed out portion, about 2mm below

its edge.

154

The valve mechanism:

The most suitable air-retaining valve is an automobile valve. In the

completed assembly, the valve is subjected to torque when the inflator is

connected. It is necessary, therefore to attach tags to the valve sleeve to

prevent its displacement. As the valve is to be embedded freehand in

silicone rubber, it is essential to decide the ideal position in order that no

portion of the valve or its tagging will be exposed. The air exit aperture

must be sealed with wax, and a wax column is extended vertically to give

an indication of the position of the valve after the embedding is complete.

With the valve supported from the front, silicone rubber is spatulated into

the hollowed obturator so as to embed the valve completely. Care must be

taken to fill the grooves previously made. When the silicone rubber has

cured, it is smoothed and trimmed to the shape of the obturator base and

the wax column is removed down to the valve exit.

The inflator: The cap for the valve is reduced in length, and a hole 1mm in

diameter is drilled through the center of the cap and its rubber washer.

The washer is removed and a tube 5mm in diameter, about 1.5 cm long is

soldered onto the valve cap. After the washer is replaced 2.5 cm of well

roughened metal tube, 1.0 mm in diameter is passed through the valve cap

until about 2mm of the tube is left extending above the washer. This tube

is held in its central position inside the larger bore tube by self-curing

acrylic resin. The projecting tube in the valve cap is reduced carefully till it

just depresses the valve core when valve cap is screwed tight on the

valve. Thus an easy passage of air, and restoration of seal immediately

when the inflator is removed is assured. The modified cap is connected by

means of a short length of rubber tubing to an air bulb having a simple

one-way valve.

Fig. 47: Denture made with solid acrylic obturator that extends 3mm into the surgical opening.

155

ASSEMBLY AND USE OF THE OBTURATOR

A latex balloon is stretched over the silicone rubber former that contains

the valve. The former is then pressed into the hollowed out obturator. The

silicone rubber former is retained by the engagement of the silicone rubber

into the groove initially made. Inflation of the balloon causes it to stretch

and automatically seal itself to the acrylic resin of the obturator in the

denture. The size of inflation can be adjusted and experience soon

dictates the most advantageous size for each patient. The valve aperture

on the labial surface is sealed with a small silicone plug.

This appliance has following advantages.

- It provides a perfect oronasal seal and is self adjusting to changes

in the shape of tissue after surgery

- The balloon may be inflated after insertion and therefore, this

appliance may be used in cases with severely limited opening.

Fig. 48: Obturator hollowed out to receive the silicone rubber former that will carry the air valve. The groove just below the top edge serves to lock the silicone former in place. The hole in the labial surface will accommodate the inflator.

Fig. 49: Valve shown in position with a wax column (C) that will maintain an airway from the obturator into a balloon while a silicone rubber former is made to fill the hollow obturator. Metal tabs are soldered to the valve housing to prevent its rotation in the silicone rubber former.

Fig. 50: the denture with the silicone rubber former. Note the groove on top that will lock it in position, while the hole in the top of the former that was maintained by the wax column.

Fig. 51: the inflator is connected to the valve cap through the aperture in the labial surface. The latex balloon is in position and inflated. The opening into the valve through the labial surface is closed with a silicone plug.

156

- It is light in weight and its simple construction permits easy

cleansing and maintenance.

III ) EMERGENCY TEMPORARY OBTURATOR

- OSCAR E. BEDER (1968) 11

A temporary emergency type of obturator made for patients with acquired

palatal, defect these obturators can be made in single patient visit, if

necessary, since the speed of construction may be essential for some

patients.

PROCEDURE

i) Make a master cast from an impression of the maxillary arch.

ii) Contour strategically placed wire clasp on the teeth of the cast.

iii) Upon this cast adapt a softened sheet of easily manipulated wax,

trim it to the correct border outline, and add wax for contour and

thickness as indicated.

iv) Cut index grooves in the master cast. Coat all exposed plaster with

a separating medium and pour a plaster core over the wax,

extending it to the master cast.

v) Immerse the cast and core in hot water until the wax is soft.

Separate the core from the cast and peel out the wax.

vi) Cut a funnel shaped hole through the plaster core and extend it to

the obturator region. Cut an air vent hole approximately 1/8” in

diameter through the core over the intact vestibular area. Clean all

plaster surfaces and coat them with a tinfoil substitute.

vii) Pour a small amount of monomer in the mold and empty it out

quickly. Pour some fluid cold cure acrylic resin into the obturator

part of the cast. Reassemble the parts and pour an adequate

Fig. 52: Assembled cast and core to illustrate the funnel shaped hole and vent.

157

amount of the acrylic resin into the funnel-shaped hole in a thin

stream until it flows out of the air vent.

viii) Place the entire complex into a pressure pot and raise the air

pressure to 25 pounds.

ix) After curing, carefully remove the plaster and recover the

prosthesis.

x) Trim excess acrylic resin, and polish before delivery.

IV) FABRICATING A HOLLOW OBTURATOR USING TWO FLASKS

WITH INTERCHANGEABLE PARTS.

This technique has been described by A.S. El Mahdy'(1969). 45

PROCEDURE:

Flasking the appliance: Two identical flasks are required [flask U-L and F1

- F2]. Their upper and lower halves should be interchangeable and they

should fit accurately. The trial prosthesis is invested in flask U-L in the

usual manner of investing an upper trial denture.

Elimination of wax: Flask U-L is immersed in hot water, opened, and the

wax is eliminated.

Waxing the impression surfaces of the prosthesis in the lower half of the

flask [L]: An appropriate thickness of baseplate wax is added to establish

the desired thickness of acrylic resin in part A of the obturator. This

amount of wax should eliminate all undercuts if present. Add a thin layer

of wax to part B. Cover the wax with a wet sheet of cellophane and make

a trial closure of the two halves of flask U-L. There should be metal-to-

metal contact.

Waxing the polished surfaces of the obturator in the upper half of the flask

[U]: Add baseplate wax to establish the desired thickness of acrylic resin

on the polished surfaces of the obturator part. This wax should contact the

wax on the impression surface and make a seal at S. Again cover the wax

Fig. 53: A cross section of flask U-L shown after elimination of wax. U – upper half, L –lower half, A- obturator part, B – conventional part of the prosthesis.

158

with wet cellophane and make a second trial closer. There should be

metal-to-metal contact.

Preparing the processing flask: Separate the two halves of flask U-L. The

teeth of the conventional part of the prosthesis B in the upper half U are

protected by two layers of thick tinfoil as indicated by the dotted line T.

Coat the inner surface of the second flask F1-F2 with petroleum jelly to

facilitate the separation F1 is related to L and F2 to U. The wax patterns in

L and U are flasked using colored plaster.

PROCESSING THE PROSTHESIS:

The wax patterns in flasks F1-L and F2-U are substituted with acrylic resin,

which is cured in the first step of processing. This is done in the following

manner. Eliminate the wax from flasks F1-L and F2-U. Pack acrylic resin

and cure without removing the cellophane. The cellophane facilitates

separation of F1 and F2. Any wrinkles in the acrylic resin from the

cellophane will provide better union with added acrylic resin in the second

processing procedure. The cellophane protects the acrylic resin from

contamination by the flasking plaster. Separate flasks. Section F1 and F2

will come apart more easily than sections L and U.

Fig. 54: A cross section of the second trial closure of flask U-L which shows wax up of both upper & lower halves S- wax seal Dot and dash line C-C – cellophane sheet

Fig. 55: Flasking the wax patterns which represent the impression surfaces of the appliance in the flask F1- L and the polished surface of the obturator in flask U- F2. T (dotted) is the tin foil protecting the teeth in the conventional part of the appliance

159

Remove the colored investing plaster, which identifies F1 and F2, and also

remove the cellophane from the cured acrylic resin. Remove the tinfoil (T),

which was used to protect the teeth on the conventional part of the

prosthesis. Do not disturb the contents of sections L and U. Make a trial

closure of sections U and L and make sure metal-to-metal contact is

achieved. Any acrylic resin in the seal area must be reduced to proper

thickness. Clean the acrylic resin surfaces and prepare for the addition of

a new mix of acrylic. Any excess thickness can be reduced at this stage to

further reduce the bulk and weight.

SECOND PROCESSING

Join the two halves of flask U-L. This unites the two previously processed

segments and will cure the remainder of the conventional part of the

prosthesis. Make a new mix of acrylic resin and place it along the edges of

the two parts and in area T. Make trial closure to ensure sufficient acrylic

resin. Remove the cellophane and process. Remount and finish in the

conventional manner.

Advantages of this method are: -

- Control of thickness and weight are achieved.

- Accuracy is assured because the relationship of various

components is maintained.

- The method is easy to learn and teach.

- It can be used in conjunction with a metal framework.

V) A SIMPLIFIED TECHNIQUE FOR FABRICATING A LIGHTWEIGHT

OBTURATOR. This technique was described by Yoshinobu Tanaka, Henry

O Gold and Samuel Pruzansky (1977). 17

Fig. 56: A cross section of the reassembled flask U-L, which contains the completed appliance with the hollow bulb obturator.

160

This procedure does not deviate from the usual technique of obturator

fabrication until the waxed prosthesis has been flasked and the wax has

been boiled out in preparation for packing with acrylic resin. They utilized

polyurethane foam for the core-fabrication.

PROCEDURE

The defect is covered with a single layer of base plate wax. Excessively

deep undercuts are blocked out to facilitate removal of the polyurethane

foam core and to allow for later adjustments without, risk of perforating the

core. Several 2mm perforations are made through the wax in the top and

the bottom of the flask in the region of the defect. 4mm sections of 2mm

diameter heat cured acrylic resin rods are cut placed into the perforations

and allowed to project approximately 2mm into the region of the defect.

The projections attach to the polyurethane foam and acts as guide to

centre the core. A liquid foil separator is applied to the wax surface.

Polyurethane foam base is catalyzed and approximately one

fifteenth of the chamber of the defect is filled and the flask is quickly

closed. The flask is heated for 10 minutes at 120oC in a dry oven after

which it is opened, and the wax is then peeled off the foam core. Boiling

water should not be used to soften the wax over the core since it will

destroy the foam. The foam core is coated with a waterproof separator to

avoid direct contact with the acrylic resin monomer, which would soften the

foam. The coated polyurethane foam core with its acrylic resin guides for

centering the core is coated with thin layer of heat-cured acrylic resin of

putty like consistency. A thin layer of the acrylic resin is placed over the

defect in both halves of the flask, which has been treated with a foil

substitute. The coated polyurethane core is pressed into position in the

top half of the flask. Additional acrylic resin is packed in the remaining

portion and the flask is then closed, the foam core is sufficiently rigid to

withstand the intra flask pressure. The acrylic resin is then cured in a hot

water bath following the manufacturer's specification. The completed

obturator is deflasked finished and polished.

ADVANTAGES:

i) It is not necessary to fabricate a hollow obturator to achieve a

significant reduction in weight. Polyurethane core filler

accomplishes the same result while providing greater strength.

161

ii) Economical because of the time saved and the ease of fabrication.

iii) Ten fold reduction in weight compared to acrylic resin obturators.

iv) Easy to repair.

VI) HOLLOW SILICONE OBTURATOR ATTACHED TO A HOLLOW DENTAL

PROSTHESIS- Described by Robert H. Wood & William Carl (1977) 151 -

described a technique for fabrication of, by utilizing flexible impression

trays for making impression of the defect.

PROCEDURE: -

A preliminary impression is made in alginate and a diagnostic cast

is obtained. Custom trays are then made on diagnostic cast that will

approximate the anteroposterior and buccal extent of the impression. An

impression using irreversible hydrocolloid is then made and a cast is

poured which is used to fabricate a flexible impression tray.

Regular body rubber base is spatulated into the defect in the cast

and allowed to set. The center is hollowed out with a scalpel and scissors

to increase flexibility. The flexible tray is now coated with rubber base

adhesive and the final impression is now made in low body rubber base

material. Because of its flexibility, filling of undercut is easy and can be

accomplished without the loss of any impression material. Minimal seating

pressure is applied to avoid distortion and removal of final rubber

impression is no problem.

The cast obtained after pouring the impression made in flexible tray

is used for making the all silicone obturator. A single layer of base plate

wax is adapted across the palatal opening of the cast. The borders of the

cast are notched and a stone cover is poured. The two halves are then

separated and the wax is eliminated. Silicon rubber is mixed with catalyst

and packed into the defect. The model is closed and rotated during

polymerization. Before inserting the obturator all rough edges are trimmed

with scissors and stones. This is used as temporary obturator.

Wood also described hollow obturator with acrylic resin palatal

section. It consisted of silicone obturator attached to hollow palatal section

of the denture.

162

Fabrication of silicone obturator: -

It is made in accordance with the technique described by Hahn54.

A double thickness of baseplate wax is adapted into the defect surface

within the cast without leaving internal undercuts and extended to the

palatal borers. A thin ring of wax serving as a retentive lip is added to the

inside just superior to the palatal border. Another keyed stone cover

extending into the wax up is poured for the master cast.

Silicone rubber is mixed and placed in the cast and the cover is

then seated and clamped or held with rubber bands until the silicon has

cured. The resulting obturator is next reseated in the master cast and a

plaster core is poured up to the retentive lip. Self-curing acrylic resin is

sprinkled, poured or moulded over the palatal surface in a thin layer. The

acrylic resin must be adapted under the retentive lip inside the obturator.

The obturator section will be retained against the acrylic resin section in

the undercut.

Fabrication of hollow palatal section: -

The dental section of the prosthesis is an extension of the acrylic

resin palatal section. Wax occlusal rims are added to the acrylic resin

section. A rim of maxillary teeth may be pre-assembled in the laboratory in

occlusion with a cast of the mandibular teeth. The obturator with a

softened wax rim is inserted into the mouth and the assembled tooth rim is

placed against the mandibular teeth and held while the patient closes

gently into the wax. A vertical dimension of occlusion is determined by

phonetics and esthetics. The wax trial prosthesis is completed with the

palatal section hollowed out as much as possible to reduce weight. A

ledge is carved in the palatal wax just lingual to the teeth.

After processing of the denture one to one and a half thickness of

base plate wax are adapted to the palatal ledge to provide normal palatal

contour. The sheet of wax is processed and attached to the denture.

163

Disadvantages of this method are: -

i) It is large and heavy, making it difficult to insert.

ii) Retention will be marginal at the best.

iii) Vertical displacement occurs because of absence of superior stops.

iv) Esthetically less pleasing.

v) Discomfort from mucosal contact.

VII) TECHNIQUE UTILIZING DOUBLE INVESTMENT PROCEDURE

PROCESSING AGAINST ICE: This procedure has been described by

Aaron Schneider (1978) 122

PROCEDURE:

Make a master cast in the usual manner and outline the borders.

With plaster, block out undercuts created by surgery. Wax up of the base

is done making sure to wax the internal part of the cavity as thin as

possible. Invest the cast with defect in the lower half of the flask. Paint the

plaster investment and the wax up with petroleum jelly and plaster of paris

is poured in the upper half of the flask. After setting of plaster, separate

the flask and set the second part aside, followed by covering the open part

of the cavity and wax to complete a full palate. Pour the third part of the

flask and separate when it hardness. Wash out all the wax, with boiling

water and thoroughly clean the plaster and paint with a separating

medium. Mix acrylic resin; pack the cavity in the first invested flask. Trial-

pack several times and remove all excess acrylic. Process in the usual

manner. The next step can be performed in one of the following two ways.

Fill the cavity with water and place in a freezer overnight or fill the cavity

with crushed ice. Make another mix of acrylic resin and when dough stage

is achieved pack it over the ice-filled cavity and process the resin.

Remove the processed obturator from the flask, trim and polish it. Create

a hole to remove water, which is later resealed with cold cure acrylic resin.

Complete the denture, by making the jaw relation records and arrange

teeth directly on the finished bases.

164

VIII) COMPLETELY HEAT CURED ACRYLIC RESIN HOLLOW

OBTURATOR USING A FILLER MATERIAL THAT IS ABSENT FROM

THE FINAL PROSTHESIS. – Described by Worley et al (1983) 152

PROCEDURE:

It consists of conventional technique of teeth arrangement,

festooning, flasking and wax elimination. The defect side is covered with

baseplate wax on both sides of the flask. Damp asbestos strips mass is

wrapped in a sheet of wet cellophane and placed into the waxed defect

area and the flask is closed. The asbestos will conform to the shape of the

waxed defect. The final form of the asbestos is preserved and the wax

eliminated. A split pack technique is used for packing. The acrylic resin

covering the defect should be as nearly as possible the same thickness as

the wax blockouts and there should be no undercuts of acrylic resin

existing on either side of the flask.

Before packing the acrylic resin, tinfoil substitute is applied and

allowed to dry. Acrylic resin is then packed and asbestos form with

cellophane around it is gently placed into the defect area. Trial pack two or

three times, with the asbestos form remaining each time to control the

thickness of the acrylic resin on the walls of the defect. Before final

closure, remove the cellophane from the asbestos form and replace the

cellophane with a sheet of elastophane. Two sheets of elastophane

between the flasks are placed to keep the two acrylic resin sections from

curing together. The flask is final closed and the resin cured.

After curing elastophane and asbestos are removed and a new mix

of acrylic resins applied at the junctions of obturator section and the

denture base and closed again for curing. The method besides being

accurate also controls the thickness of hollow obturator prosthesis.

IX) TECHNIQUE FOR THE FABRICATION OF CLOSED HOLLOW

OBTURATOR PROSTHESIS- by Minsley et al (1986).

This technique allows for control of wall thickness of the obturator

extension thereby minimizing the weight of the prosthesis. In addition, the

junction between the lid and the palatal portion is remotely located in

relation to the lid thus minimizing micro leakage.

TECHNIQUE: -

165

After blocking out the undercuts in the defect, the cast along the defect is

covered with two sheets of pink baseplate wax, which is processed in a

conventional manner to obtain the acrylic base with obturator extension. A

recess is cut around the palatal opening of the obturator extension to a

depth of 1.5 mm. The interior of the hollow extension is filled with damp

pumice to within 1-1.5 mm of the edge of the recess.

An irreversible hydrocolloid impression of the entire palatal portion

of the obturator excluding, the joining is made and is reinforced with plaster

backing. The cast so obtained from above impression is then used for

making autopolymerizing acrylic resin lid, which is then checked over the

palatal opening of the obturator for fit and is fixed to the obturator opening

with acrylic resin.

A second ledge is then cut parallel to the flange of the obturator

and across the posterior palatal seal. This ledge should be 4-5 mm below

the top of the flange, 1 mm in depth ending in a but joint. Wax rims are

then attached to the base of the prosthesis, maxillomandibular records,

teeth arrangement is then carried out by conventional procedures.

X) LIGHT CURED HOLLOW OBTURATOR: It was described by I.C.

Benington (1989)14

TECHNIQUE:

i) Duplicate the obturator prosthesis.

ii) Add impression compound to the immediate prosthesis to indicate the

extent of the desired obturator.

iii) In regular viscosity polysulfide rubber, record a final impression of the

defect at the trial stage to procure the best fit possible for the new hollow

obturator.

iv) Pour a stone model and when hard, sandwich the mold between a

plaster base and lid. The artificial teeth are invested in the superior plaster

layer.

v) Boil out the wax and remove the impression material.

vi) Where the cavity undercuts are deep, section the master cast to

facilitate accurate adaptation of the resin to the cast walls and for ease of

removing the obturator after curing.

vii) Coat the stone cast with sodium alginate separating medium and allow

drying.

166

viii) Carefully adapt sheets of light-cure resin to cover the walls of the

defect. When the individual cast sections are assembled on the plaster

base, the obturator is complete except for the junctions.

ix) Apply prescribed bonding agent to the margins of each section and

firmly adapt thin cords of resin along each junction. Verify a complete seal

and uniform thickness of resins on the walls.

x) Using a light-cure source, cure for 4-5 minutes. Then pack resin into

the plaster lid to engage the teeth. Fit the lit on the mold and observe that

the resign margins in the plaster lid are adapted to the cured hollow

obturator section and cure.

xi) Remove the cured base from the mold and seal it on obturator section.

xii) Unite the base and obturator section by adapting a thin cord of resin

around the junction and cure.

xiii) Trim and polish the completed obturator before insertion.

Advantages:

i. The ease and rapidity of the technique expedites rehabilitation by

introducing the hollowing obturator at the earliest opportunity.

ii. The technique is versatile because the base and teeth may be cured in

conventional poly (methyl methacrylate) and bonded to the light cured

obturator when necessary.

iii. Easy to repair by using increments of visible light- cured resin

iv. Impermeable to oral fluids.

v. A light accurately fitting obturator aids in the retention of the prosthesis

and resonance of the voice.

XI) AN INNOVATIVE INVESTMENT METHOD FOR FABRICATION OF A

CLOSED HOLLOW OBTURATOR PROSTHESIS: - This technique is

described by Karen Mc Andrew, Sandra Rothenbeger et al (1998) 86

PROCEDURE:

Create the master cast design and fabricate the metal framework. Verify

the fit of the metal framework clinically. Make a functional impression of the

defect area and fabricate an altered cast. Fabricate a wax or

autopolymerized acrylic resin record base and wax occlusion rim. Record

the maxillomandibular relations. Set the teeth in wax and verify clinically

with wax try in finish the waxing and seal it to the cast for investing and

carry out dewaxing. Once the wax has been eliminated, open the flask and

167

block out the undercuts along the floor and walls of the defect area with

wax to a minimal thickness of 3 mm.

Cover the area of the palate with a 3 mm layer of wax. It is

important to cover the retentive portion of the framework so that this area

will eventually be replaced with processed acrylic resin (to minimize the

possibility of leakage along the framework resin interface.) Wax a ledge

around the periphery of the defect to leave an opening to the defect area.

Verify the fit of the portion of the flask containing teeth. Relieve any areas

of wax that prevent full seating of the flask. Place another top flask onto

the waxing of the hollow defect. Invest with plaster and boil out the wax.

Separate the flask and smooth the plaster index of the hollow section.

Pack and process the hollow section and palate with heat-polymerized

acrylic resin.

Fig. 57: Metal framework has been fabricated, verified intraorally for accurate fit and seated on master cast.

Fig. 58: Investment of completed waxing after clinical verification of esthetics and accurate registration.

Fig.59. Master cast flask after wax investment and boil out.

168

Fig. 60: Block out of undercuts in defect area on master cast.

Fig. 61: Left: Tooth retained portion of initial upper flask after wax boil out. Right: Plaster impression of hollow portion of defect area after wax boil out. Center: Master cast invested in lower portion of flask.

Fig. 62: Master flask after processing with hollow obturator flask. Plaster has been retained in hollow section. Fabrication of “cap” to close hollow obturator.

Fig. 63: Master flask with processed and sealed hollow portion of obturator and corresponding flask with teeth ready for processing.

169

Separate the processed flasks, with the plaster remaining in the obturator

section. Bevel the outer edges of the acrylic resin section and fabricate a

light- polymerized resin cover to fit over this area. Gently remove the

plaster from the obturator section with a bur and reduce the thickness of

resin within this section. Do not perforate the floor or walls of the section

and leave a minimal thickness of 3mm. Lute the cover to the opening with

visible light polymerizing or autopolymerizing acrylic resin.

Place the initial flask, with the invested teeth, onto the flask containing the

processed base. Relieve, any areas that prevent complete seating of the

flask. Roughen all areas of the processed base the pack heat-

polymerizing acrylic resin and process teeth onto the obturator followed by

deflasking the denture and equilibration of occlusion. Polish and deliver

the prosthesis.

Advantages:

i. This technique provides a lightweight and seamless obturator.

ii. It can be used for either complete or partially edentulous cases.

iii. It uses one master flask against two separate processing flasks.

iv. Clinical and laboratory time are minimized.

v. A durable virtually water tight prosthesis is obtained that can be used

alone or in conjunction with an extra oral prosthesis.

Fig. 64. A, Polished palatal surface of completed obturator. Coverage of “cap” junction surrounded with heat-processed acrylic resin. B, Tissue view showing extension of hollow obturatorsection.

170

OPEN OBTURATOR

This technique was described by Arie Shifman (1983) 126

TECHNIQUE

Box the final impression and pour the cast in artificial stone. Leaving the

floor of the defect uncovered, two layers of baseplate wax is added to the

vertical walls of the defect. Additional wax may be added where future

reduction of the obturator is anticipated.

Drill two holes into the base portion of the cast, where the defect is present

and cement 2 handpiece burs in it. The proximal end of burs should

protrude 2-3 cm into the defect portion. Trial pack a silicon based material

without the accelerator to determine the correct amount required to fill the

defect portion of the cast to the level of remaining palate. Mix the

predetermined amount of silicone with the accelerator according to

manufacturer instruction and pack it into the defect portion.

After the silicone has set, soften and remove the wax liner from the cast

and remove the hardened silicone from the inverted burs. The burs are

index for the detachable silicones core of the obturator. Proceed with an

accepted technique for the laboratory fabrication of an obturator. Cut the

silicone core into pieces and remove it from the finished obturator.

Advantages of this method:

i. Processing is better with improved vision and control of proper

extensions of the obturator.

ii. Deflasking is easier and the acrylic resin proceed against silicone has

a smoother surface than against gypsum material.

iii. With this method, retention and stability are not altered, as the lateral

and anterior wall heights as well as medial and posterior extensions

remain the same. The weight is also favorably reduced.

iv. This design produces improved speech, intelligibility, facilitates hygiene

and is easier to fabricate.

171

HOLLOW OBTURATOR WITH REMOVABLE LID – Phansokol & Martin

(1985) 106

It is an alternative to closed or open hollow obturators and has the benefits

of both and allows the patient to clean the inner surface. In this technique

an obturator is made with any acceptable technique with the superior

border 5 mm thick and at least 5 mm from the superoinferior border. It

must not touch soft tissue. A line is drawn on the obturator 4 mm from the

superior border, a large fissure bur or disk is used to make a ledge along

the outer border. A groove on the lower half of the ledge is made with No.

6 round bur. The edges are rounded and polished. The hollow extension is

filled with modeling clay to make flat surface. An impression of the

obturator is made in alginate, poured in stone and mouthguard material is

used by vacuforming to make the removable lid.

A lot of techniques have been presented for modifications of an existing

obturator.

Ziada & Donovan (2004) 156 described a procedure for reducing the vertical

height of the hollow box obturator in which a cap like piece of 4 mm height

from the highest point is cut, and tried in the patient to the desired height.

A lid is then fabricated with light cured denture base material.

Wang and Hirsch (1997) 144 described a procedure to convert an open

hollow obturator into a closed one.

Technique:

- The tissue side of the obturator base is first relined by

chairside reline material, which acts as an impression

material.

- The remainder of the acrylic base is lubricated with petroleum

jelly.

- The relined obturator is boxed with 2 3/4th high adhesive

paper.

- The cast is poured with a mixture of fast set stone and

plaster.

172

- The cast is separated carefully and reline material removed

and then visible light cure resin material used to close the

open end.

Implant Retained Prosthesis For Maxillary Defects.17,100,101,119,135

Cantilevering forces, which are generated by prosthesis for maxillectomy

defects, are disadvantageous gravitationally and can be progressively

destructive, even when fulcrumed with multiple rests and minimal undercut

engagement. This is particularly evident when a few sound teeth are called

upon to support a contralateral prosthetic dentition, even with a gate hinge

type of load distribution. Osseointegrated implants can play a pivotal role in

the rehabilitation process by augmenting the available retentive base or by

replacing critical missing teeth.

Implants provide retention; enhance support and stability of the prosthesis.

The anteroposterior defects as seen in congenital defects are more

amenable to implant restoration because lateral (cross arch) stability can

often be attained. Lateral defects, are more difficult restorative problems

as cross arch stability is missing and resistance to superior displacement is

missing unilaterally.

The number of implants and their location is determined by the nature of

the defect and the available bony sites. The most ideal location in the

edentulous total maxillectomy patients is the residual premaxillary segment

because of two reasons.

- It is directly opposite to the most retentive portion of the defect

located along the posterior lateral wall.

- Generally satisfactory bone is found in the region.

The maxillary tuberosity is considered when the premaxilla is not found to

be suitable as the bone in the tuberosity region is not very dense.

The other sites considered are:-

- Pterygoid plates in which longer and mesially incline implants

are placed.

- Edentulous posterior alveolar process if there is at least 10mm

of available bone beneath the maxillary sinus. (The

predictability of sinus lift and bone grafting in maxillectomy

patients is yet to be determined)

173

- The Zygoma has been used for placement of implants. It

requires an intraoral access to the zygomatic buttress through a

trans-sinus approach. Once a suitable window has been

created, piloting and implant placement are carried out with

direct visualization of the receptor site from the sinus opening

and tissue reflection to the exit area. Healing for integration

usually requires 5 – 6 months before impressions and

subsequent prosthetic construction can be initiated. To

minimize the complication of diverse angulations, the head of

the zygoma implant has been engineered to allow prosthesis

attachment at an angle of 45 degrees to the long axis of the

implant. This creates the opportunity to keep away the screw

access sites relatively parallel throughout the span of the

restoration. To avoid potentially damaging off-axis loading to

these and the additional standard implants, it is important that a

rigid bar or casting assembly be used to join the implants

across the arch. Prosthetic retention can be attained through a

variety of mechanisms, which may include O-rings, precision or

semi-precision attachments, magnets or bar clips.

The use of implants within the defect should be discouraged, as it is very

difficult to maintain hygiene around them. Also the use of pre or post

operative radiation does not preclude the use of implants it has been found

that radiation doses above 5000 centigray, compromise the remodeling of

bone around the implant and thus predispose to bone recession and

premature implant loss.

Clinical procedures: Following implant placement, they are left buried for 6

– 8 months. During this period the patient uses the surgical or interim

obturator.

During the second stage surgery it is advisable to thin the mucoperiosteum

to create a zone of keratinized, attached mucosa around the implants. This

will go a long way in achieving better maintenance of the implants.

There are two ways to go about the prosthetic procedures.

- If there is inadequate interocclusal space then healing

abutments can be attached and the retentive bar fabricated

using the UCLA abutment technique.

174

- When conventional abutments are used, the length should be

so selected that they project 1-2 mm above the peri- implant

tissues. Healing abutments should be used for 2-3 weeks to

allow for healing to get complete

The fabrication of definitive prosthesis: It is usually desirable to fabricate a

trial denture before designing the retentive apparatus. Tapered impression

copings, which engage either the abutment cylinders or implant fixtures,

are selected, inspected and screwed tightly in position. A primary

impression is made in irreversible hydrocolloid using a stock tray with

adhesive. Care should be taken to record the lateral wall of the defect and

desirable undercuts. Following the removal of the impression, impression

copings are removed, attached to either abutment analogues or fixture

analogues and inserted into the impression. A preliminary cast is pored.

A special tray is fabricated with the design to record the position and

angulation of these copings as well as the residual normal tissues and the

defect. The final impression is made in elastomeric material, the fixture

analogs are screwed in the tapered impression copings and the master

cast is poured.

Record bases are fabricated. If conventional abutments are used, then the

gold cylinders are incorporated within the acrylic resin record base. If

UCLA technique is used, then record base is fabricated after blocking out

the area around the fixtures. Jaw relations are recorded and transferred to

an articulator, which can accept bulky maxillary cast. The teeth are

arranged. Neutrocentric concept or lingualized occlusion is used in these

cases.

After try in and verification of the jaw relations, the trial dentures are

repositioned on the articulator and a stone template is fabricated with the

maxillary teeth incorporated within it.

This stone template is mounted on the lower member of the articulator and

used to design and prepare the wax pattern for the retentive apparatus.

Retentive bar design:

The factors that complicate design in maxillectomy patients are:

- Fewer implant sites available leading to limited antero-posterior

spread of implants.

- Multiple axis of rotation due to occlusal loads.

- The use of bar and attachments lead to exposure of implants to

unwanted, destructive lateral torquing forces,

175

Davis did a photoelastic study to compare the forces applied and found

that -

a) Anterior loads caused higher and more concentrated stresses

around the anterior and middle implants, as compared to posterior

loads, since more posterior loads are partially supported by the

residual edentulous denture bearing surfaces.

b) The addition of occlusal rests on the bars between the implants

increased the stability of the prostheses and alleviated the stresses

around the posterior implant when a posterior force was applied.

c) The O ring resulted in most favourable force distribution but least

retention.

Beumer and Curtis have given the following suggestions for the design:

With the use of attachments like ERA (which allows vertical compression),

the addition of occlusal rests improves load distribution.

The concave rest should be milled into the occlusal surface of the bar, in

the shape of a half circle, is the only part of the bar that is to be engaged

by the prosthesis other than the attachment. The placement of rests at

either end of the bar enables the prosthesis to rotate around these rests

and reduces the wear on the attachments and directs more of the occlusal

forces along the long axis of the implants.

Design outlines:

1. If the entire premaxilla remains – the number of implants,

distribution and design of retention bar follows conventional

prosthodontic principles.

2. If only 2 implants are placed , one each in canine region – a

Hader bar design is used.

Fig. 65: Two implants placed which are joined by a retentive bar that is perpendicular to midline and parallel to occlusal plane

176

3. If 4 or more implants are used. The support is provided

posteriorly by the residual denture bearing surfaces and

anteriorly by the implants. The attachments connected to the

distal portion of the bar allow for the compression of the distal

extension area of the prosthesis into the denture bearing area

without applying excess torquing force onto the implants.

4. If 6 or more implants are used and the antero-posterior spread

is greater than 2 cm, the overlay obturator prosthesis can be

designed so that occlusal forces are primarily supported by the

implants.

5. Maxillary defects where only one or both maxillary tuberosities

remain are particularly difficult to restore. Implants are useful in

retaining these restorations, but should not be used to provide

support or be the primary means to provide stability. In such

cases O-ring attachments are used as they allow rotation of the

prosthesis in multiple planes when functional or gravitational

forces are applied.

Fig. 66: Six implants placed anteriorly with sufficient A-P spread allow obturator to be implant supported.

177

GENERAL OUTLINE OF PROSTHODONTIC REHABILITATION OF

SOFT PALATE DEFECTS

Velopharyngeal dysfunction may be congenital, developmental

or acquired, it affects all age groups

It may occur as insufficiency or incompetency.

Velopharyngeal Insufficiency: denotes speech and resonance

aberrations related to a congenital or acquired anatomic defect of the

soft palate that makes the sphincter incomplete such as that occurring

in cleft palate or post surgical resection

Velopharyngeal Incompetence: denotes dysfunction of an anatomically

intact velopharynx that occurs in patients with the following disorders.

The soft palate and pharynx are innervated by a nerve plexus

(pharyngeal plexus) including fibers originating from the IX, X, and XI

cranial nerves and possibly some fibers from the VII nerve. Any

disease or disorder that affects the normal function of any of these

cranial nerves or their central origins can have significant effects on the

function of the palatopharyngeal complex.

1. Traumatic brain injuries, cerebrovascular accidents or post

neurosurgical treatments of brain/ meningeal tumours.

2. Central or peripheral degenerative or metabolic disorders of the

nervous system such as – multiple sclerosis, Parkinsonism, bulbar

poliomyelitis, cerebral palsy, Amyotrophic lateral sclerosis, dystonia

and myasthenia gravis.

3. Muscle or connective tissue disease – myotonic dystrophy or mixed

connective tissue disorder.

Other conditions related linked to incompetence of anatomically

intact velopharyngeal valve: these are behavioral mislearning, tonsillar

upper poles hypertrophy, hypotonic (dyskinetic) velopharynx, overly

stressed velopharynx (wind instrument playing).

178

As general rule, palato-pharyngeal insufficiency is treated with a

pharyngeal prosthesis or speech bulb prosthesis if the surgical procedures

like palatal push back, pharyngeal flap or posterior wall implants cannot be

carried out.

Palatopharyngeal incompetence is treated with a palatal lift.

Prosthetic restorations of post cancerous defects, occurring in the soft

palate area vary according to the site and extent of such defects.

The most important factor pertaining to the type of prosthetic

treatment is the integrity and function of the posterior border of the soft

palate; the prime objective of treatment in patients with oronasal

communication is a return to the physiologic functions of mastication,

deglutition and speech. If these objectives are achieved the other

sequelae of surgical procedure such as seepage of nasal fluid into oral

cavity, and escape of food into the nasopharynx will normally be corrected.

Obturator prosthesis fabricated for patients with palatopharyngeal

deficits vary with the location and nature of the defect or deficiency. In

contrast with the obturator prosthesis constructed for hard palate defects,

prosthesis for palato-pharyngeal deficits must function in concert with soft

tissues displaying considerable movement.

179

CLASSIFICATION OF SOFT PALATE OBTURATOR PROSTHESIS: -

This classification has been given by Beumer and Curtis17 and is according

to the location and nature of defects of soft palate and palatopharyngeal

defects

Structures Involved Cause(s)

TOTAL SOFT

PALATE

DEFECTS

Entire soft palate Surgical excision of

neoplastic disease,

unoperated cleft palate,

surgically redivided cleft

palate

POSTERIOR

BORDER

DEFECTS

Median

defects

Posterior half of palate. Surgical excision of

neoplasia, post surgical

cleft palate with in-

sufficient length

Lateral

defects

Lateral half of soft palate

and often lateral

pharyngeal wall

Surgical excision of

neoplastic disease

SPECIAL

OBTURATOR

PROSTHESIS

Palatal lift All structures intact or

when posterior border

defect (combination)

Neurological disease,

Postsurgical cleft palate

with insufficient length

and movement.

Meatal Hard and soft palate Unoperated cleft palate

Surgical excision of

neoplastic disease.

180

B. ARAMANY MOHAMMED (1978) classified defects of palate as

i) Total resection of the soft palate retaining a part of the hard palate: -

In this type of resection, the soft palate is totally removed, including all its

muscles. The function of the superior constrictor muscle of the pharynx

remains intact. The prosthesis for such defects involves speech aid

prosthesis extending posteriorly from the base of the prosthesis into the

pharyngeal region separating the oropharynx from the nasopharynx. At

rest position, there is a space around the pharyngeal part of the prosthesis

to effect nasal breathing.

ii) Median resection of the palate: -

The resection may involve parts of the hard and the soft palate. However

the levators, tensor, uvula, palatoglossus and palatopharyngeous muscles

are left functionally intact. The normal physiologic movement of the palate

will take place on eliciting the velopharyngeal mechanism whereas; the

presence of the defect will make this movement functionally inadequate.

The anterior margin of the defect is not mobile, whereas the posterior

aspect of the defect will move superiorly and posteriorly, increasing the

size of the oronasal communication.

The prosthesis extension from the parent prosthesis passes through the

soft palate defect to permit the sphincter action of the margin of the defect

to produce an oronasal seal.

iii) Lateral resection involving approximately half of the soft palate: -

Lateral resection often jeopardizes the integrity of the remaining halves of

the muscles of soft palate. Since the palate is intended to function through

a paired mechanism, the loss of half of the mechanism drastically alters

the function of the palate during swallowing and speech.

It the defect is small, velopharyngeal closure may be effected without the

help of prosthesis. If the defect is large or the patient is unable to develop

compensatory movement, a retro velar speech aid is constructed. A

181

pharyngeal extension from the base of the prosthesis passes through the

defect till the potential space behind the remaining segment of the soft

palate. Velvopharyngeal closure is attained by the levator action of the

remaining soft palate and the contraction of the pharyngeal muscles

against the pharyngeal extension of the prosthesis.

OBTURATOR PROSTHESIS FOR SOFT PALATE DEFECTS: 17,135,136

Sharry 125 describes the pharyngeal obturators that are used in

patients with congenital or acquired soft palate defects to separate the

nasopharynx and oropharynx during speech and deglutition. The

prosthesis consists of a complete or partial denture base and a pharyngeal

extension that will not only physically modify the pharyngeal airway but

also provide an object against which the surrounding muscles can function

to provide a seal between the oropharynx and nasopharynx during function

1. Hinged Obturator: Delabarre and Snell first introduced it in early

1820’s. Modifications by Stearn and Kingsley made it the prosthesis of

choice in the latter half of the nineteenth century. In this type, the

pharyngeal section is attached to the prosthesis by means of a hinge.

The objective is to create a movable obturator that functions in a

manner similar to the normal soft palate. This obturator relies on the

activity of the superior pharyngeal constrictor muscles and residual soft

palate muscles to function.

Its success depends upon the muscle activity of the residual palate and

the stability and retention of the denture base, which has to support the

Fig. 67: Hinge type pharyngeal obturator

182

additional weight of the hinge and mobile obturator section. Also the shape

of the nasopharynx changes at rest and in function, hence, it is very

difficult to obtain adequate nasopharyngeal closure

2. Fixed or horizontal Obturator: Introduced by Suerson in 1868 and

advocated by Fitzgibbon in 1920’s. It is placed in a fixed position within the

pharynx at the site of maximal muscle activity or approximately the level of

the palatal plane. During physiologic function, the obturator is contacted by

the posterior pharyngeal wall and the lateral pharyngeal musculature, thus

creating a separation between the oropharynx and nasopharynx. It is the

most commonly used type.

3. Meatus Obturator – was introduced by Schialit in 1946 and is

described in detail later.

Beumer and Curtis17 have described obturation of acquired defects of the

soft palate in three stages.

1) Immediate surgical obturator

2) Delayed surgical obturator

3) Definitive obturator

Fig. 68: Fixed or horizontal pharyngeal obturator.

183

1) Immediate surgical obturator:

The principle advantage of immediate surgical obturator for soft

palate defects is support and retention of the surgical packing. Immediate

surgical obturators, constructed presurgically are approximations with

regard to the level of placement and the contours of the lateral and

posterior margins.

There are differences between surgical obturator for hard palate

defects compared to the ones for defects of the soft palate and the

contiguous structures as:

- The drape of the soft palate precludes the clinician from

obtaining the impression of the nasopharynx, where normal

velopharyngeal closure occurs and where the surgical obturator

should be located.

- Functional measurements of the velopharyngeal mechanism

cannot be recorded prosthodontically either prior to or during

surgery.

- Pharyngeal tissue peripheral to the defect will exhibit little

movement during function in the immediate postoperative

period.

- The extent of these tumours is more difficult to visualize; hence

it is more difficult to delineate the surgical margins

presurgically.

An extended impression, of the soft palate is obtained and the cast

is altered to correspond to the proposed defect. The plane of the hard

palate determines the superior- inferior plane of the obturator and that of

the soft palate determines the width. Adjustment at surgery is done to

avoid excessive tissue contact. It is kept 7 to 10 days post-surgically

following which, the prosthesis is removed along with the surgical packing,

and is altered by adding soft interim reline material for changed tissue

contacts. The patient is monitored with sequential appointments until the

definitive prosthesis can be constructed.

184

2) Delayed surgical obturator:

Patients with smaller defects of the posterior or lateral borders of

the soft palate often are best served with delayed surgical obturation as

the small defects are masked by postoperative oedema in the immediate

postoperative period. In edentulous patients, consideration should be

given to attaching the delayed surgical obturator to the existing maxillary

denture.

3) Definitive obturator:

Patient exhibiting considerable movement of the residual

palatopharyngeal complex during function have an excellent prognosis for

achieving normal speech with prosthesis.

If the patient is edentulous, the prosthesis can be attached to the

existing dentures. If the patient is dentulous a removable partial denture

framework retains the obturator. It is a fixed platform of acrylic resin that

provides surface contact for the remaining musculature of the

palatopharyngeal mechanism during function. However, a space exists

between the surrounding tissues structures and the prosthesis during rest.

Guidelines for location of the obturator segment of the prosthesis: -

- The obturator for an adult patient should be located in the

nasopharynx at the level of normal palatal closure.

- The inferior margin of the obturator should be placed at the level of

greatest muscular activity exhibited by the residual

palatopharyngeal complex.

- The inferior extension of the obturator will usually be an extension

of the palate plane as extended to the posterior pharyngeal wall.

- The superior margin of the obturator should not extend above the

level of muscular activity.

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Design Considerations:

1. Support: it is provided by the following:

- Occlusal rests on natural teeth.

- Major connector.

- Denture bases.

2. Retention:

- Retentive clasps on the primary abutments.

- Skin graft – host tissue junction creates the retentive undercut.

- Residual ridges and hard palate in edentulous patients provide

retention.

- Indirect retainers on the secondary abutments away from the

fulcrum line prevent rotation of prosthesis away from tissue.

- Endosseous implants provide direct retention.

3. Stabilty is provided by the major and minor connectors and the denture

flanges which prevent lateral motion and distribute stress.

I) Prosthetic outline of total soft palate defects rehabilitation:

Impression procedure - (Functional impression technique):

First a diagnostic cast is obtained by making an impression in a

stock tray with palatal portion extended in wax. The cast obtained

will assist diagnostic procedure, tray preparation and establishing

design for cast partial denture framework.

The partial denture design must have provision for multiple

occlusal rests on either side of the fulcrum line and multiple

retainers with the retentive arm engaging distal undercuts. A wire

loop or tray resin is added to the framework as retentive meshwork

to approximate the area of the defect.

Next, modeling plastic is placed in the region of tray resin

for to purpose of border molding. The patient is instructed to flex

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the neck fully to achieve contact of the chin to the chest. This

movement will establish contact of the posterior aspect of the

obturator with the soft tissue covering the anterior tubercle of the

atlas. Lateral aspects of the obturator are formed by rotation and

flexion of the neck to achieve chin contact with the right and left

shoulder respectively. The compound is then warmed and inserted

and the patient is asked to speak and swallow, so that the

remaining palatopharyngeal musculature is activated and shapes

the modeling plastic. Since swallowing precipitates a more forceful

closure it is performed at the end to avoid under extension.

A completed molding will appear dull, and is confirmed by

asking the patients to speak, swallow and to breath through the

nostrils to test the effectiveness of formed obturator. Speech should

sound normal, with the patient able to articulate plosive sounds

such as p and b and yet be able to form the nasal consonants m, n

and ng. If the position and contours are satisfactory, all extensions

are reduced approximately 1 mm with a sharp scalpel.

Next, mouth temperature thermoplastic wax is added to the

obturator, flamed, tempered and placed in the mouth. The

functions activating the palatopharyngeal musculature are

repeated, to reestablish the contours of the obturator. The use of

thermoplastic wax ensures against overextension. Adequate areas

of contact demonstrate a dull-stippled appearance, whereas a

shiny surface indicates a lack of contact. The obturator prosthesis

is left mouth for 5-7 minutes before removing it.

After removal from the mouth, the prosthesis is checked for

overextension. Any area in which, modeling plastic is visible, the

plastic is scrapped and new layer of wax is applied. The wax is

flamed and tempered, before reinserting. When speech and

swallowing are normal and the contour of the obturator appears

adequate the prosthesis is tempered in a water bath and replaced

in the mouth for an extended period (1 to 3 hours). The patient is

instructed to wear the prosthesis without removal and is

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encouraged to speak, swallow and perform previously described

movements.

Size and position of the obturator: The lateral dimensions of the

obturator the determined by lateral and posterior pharyngeal wall

movement if the obturator is positioned correctly at the level of

greatest internal and posterior pharyngeal wall movement a

superior extension of approximately 10 mm into the nasopharynx is

sufficient. A further superior extension, may add additional width

and extra weight, and will occlude the nasopharynx resulting in

difficulty with nasal breathing and hyponasal speech. Conversely, if

the obturator is placed too low into the oropharynx, tongue function

will be disrupted and gagging may be precipitated.

Processing and delivery of the prosthesis

The obturator is processed in a customary manner, with either heat

activated or auto - polymerizing methyl methacrylate. Following

processing, gross excesses is removed. The oral surface of the

obturator should be concave to provide adequate space for the

tongue. The superior surface should be convex and well polished to

facilitate the deflection of nasal secretions into the oropharynx.

Also, the lateral margins of the obturator are lightly polished to

improve hygiene and the deflection of secretions.

Speech evaluation following obturator placement

Speech is usually within normal limits immediately following

placement of prosthesis for acquired soft palate defects. As these

patients produced normal speech prior to surgical impairment, the

prosthodontist will often require the assistance of a speech

pathologist to evaluate articulation errors and inappropriate nasal

resonance.

2. Obturation of soft palate posterior border defects

The objective for obturation of these defects is similar to the

obturation of total soft palate defects. However, the prosthetic

approach differs since the remaining intact position of the soft

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palate must be circumvented to place the obturator at proper level

in the nasopharynx.

There are two basic approaches for construction of

obturators for posterior order defects. First method is to record the

soft palate at rest and after the residual soft palate is circumvented,

the obturator is extended superiorly behind the soft palate to the

proper level for obturation. This is basically suitable for short taut

palate.

Second method is to displace the residual soft palate

superiorly with the extension, to place the obturator in the proper

position into the nasopharynx. Such prosthesis is termed palatal lift.

Patients with long or immobile palates should be considered for

palatal lift prosthesis.

a. Median Posterior border defects

The preliminary impression should include the residual soft

palate, plus the defect posterior to the soft palate. The cast

obtained will serve diagnostic purpose and for adaptation of the

wire loop extension for the obturator. Next functional impression is

made as described for total soft palate defects.

The level of placement of the obturator is the same as in

patients with a total soft palate defect. However, a more lengthy

superior extension may be necessary to reach the level of normal

closure, since direct visualization of the area of normal

palatopharyngeal closure may not be possible. If the posterior

border of the resected soft palate is severed, and exhibits little

motion, it may be necessary, to extend the obturator across the

nasal surface of the soft palate to obtain retention.

After processing and prior to insertion, the superior surface

of the obturator is trimmed and rounded slightly to form a convex

surface and the extension of resin across the soft palate is thinned

as much as possible. This extension will be approximately 10 mm

wide and 2 to 3 thick, also the nasal extension may require, to be

reduced to facilitate insertion.

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If the level of normal palatopharyngeal closure is

considerably above the posterior border of the soft palate, the

inferior surface of the obturator may be reduced further.

b) Lateral posterior border defect

In these situations the post-surgical relationship forces the

clinician to engage the opposite lateral pharyngeal wall behind the

soft palate to achieve palato pharyngeal closure.

Methods of fabrication:

A partial or complete prosthesis is constructed before the

fabrication of obturator. The retention of the obturator is best

provided by a wire loop attached to the conventional prosthesis. In

situations where soft palate exhibits little or no motion a cast

meshwork may be constructed as a component of the partial

denture framework. After the conventional prosthesis is fabricated

and adjusted, the retention for the obturator is adjusted.

The obturator is fabricated following functional pharyngeal

impression techniques. There must be adequate movement of the

residual palatopharyngeal mechanism to control nasal airflow. In

defects with limited mobility during palatopharyngeal function,

continuous contact is maintained between these tissues and the

obturator both at rest and during function. Generally, following

delivery the speech is hyponasal; the lateral extensions of the

obturator are reduced gradually, until nasal breathing is acceptable.

Implant Retained and Supported Obturator prostheses:

In edentulous patients with soft palate defects, the posterior palatal

seal area is altered making it difficult to obtain and maintain peripheral

seal and the long lever action and gravitational force further decreases

retention. If the posterior palatal seal area is relatively intact then, two

implants in the premaxillary segment will suffice. If the posterior palatal

seal area is compromised and residual palatal structures provide

inadequate support and stability, then four or more implants are

required.

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These osseointegrated implants enable the design and fabrication

of complete overlay dentures with retentive capabilities similar to

prosthesis for dentulous patients with fixed partial dentures.

Maximizing the antero-posterior spread of the implants improves

the load distribution. The design of the prosthesis is based on the

status of opposing dentition, number and length of implants, quality of

bone, antero-posterior spread and the size of the defect.

The use of attachments like the Hader bar anteriorly and the ERA

posteriorly allow the prosthesis to rotate around a predictable axis,

permitting residual denture base area to aid in the support of occlusal

loads.

4. Special Obturator Prosthesis 10,16,17,72,120,129,140

The palatopharyngeal mechanism or velopharyngeal valving

mechanism regulates the resonation and speech utterance and

partakes in non-speech oral activities such as swallowing, blowing,

sucking and whistling. Velopharyngeal dysfunction implies the

presence of hypernasality, inappropriate nasal escape, and decreased

air pressure during the production of oral speech sounds.

Compensatory articulations in the form of secondary glottal, lingual and

labial errors are often present. The following modalities are used to

correct these.

a) Palatal lift prosthesis

It was first advocated by Gibbons and Bloomer (1958).51

Fig. 69: The use of Hader Bar anteriorly and ERA attachment posteriorly allows the prosthesis to rotate around a predictable axis, permitting the residual denture bearing surfaces to aid in support of the occlusal loads. a – At rest, b- Under load.

191

There are two prosthodontic procedures available in the treatment of

patients with palatopharyngeal inadequacies.

i) The palatal lift prosthesis.

ii) Combination palatal lift/Pharyngeal section prosthesis.

i) The Palatal lift:

It used to elevate the soft palate to its maximal position during normal

speech and deglutition enabling closure by pharyngeal wall actions.

ii) The combined palatal lift:

It is preferable, if the soft palate is insufficient to achieve proper

palatopharyngeal closure. The prosthesis will elevate the soft palate and

also obturate the palatopharyngeal gap, thereby stimulating

palatopharyngeal activity and pharyngeal muscle contraction.

Fig. 70: In an anatomically normal but paralyzed soft palate, a palatal lift prosthesis is used to get velopharyngeal closure. Pp – palatal plane, ta- median tubercle of atlas.

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Evolution of the palatal lift:

It has evolved from speech problems associated with insufficient

velvopharyngeal closure. These speech difficulties have their origin in

neuromuscular deficiencies, injury to the soft palate, paralysis or

inadequate length, inadequate movement of the soft palate following the

surgical closure of a congenital cleft palate or poliomyelitis, and the

submucous cleft palate. Adequate lateral wall movement is necessary for

lift to be effective.

Parts of a lift prosthesis:

Lamina: The portion of prosthesis, that underlines elevates and

supports, neurologically impaired velum. It consists of

i] Base - that underlies the anterior one third of the velum and is

attached to the basic prosthesis.

ii] Midsection

iii] Vertex - That underlies a variable portion of the terminal one third of the

velum, and contacts with the palatopharyngeal musculature.

Objectives of palatal lift and combination prosthesis:

Fig. 71: in a congenital anatomic insufficiency of velopharynx, a palatal lift plus obturator is used to elevate the soft palate and obturate the velopharyngeal space. Pp – palatal plane, ta- median tubercle of atlas.

193

- To reduce hypernasality (nasal escape of air) by palatal elevation.

- To reduce the degree of palatal disuse atrophy.

- To increase palatopharyngeal function by constant and continuous

stimulation.

- To increase neuromuscular response by gentle stimulation and

speech exercise.

- To assist in the repositioning of the tongue.

Advantages of palatal lift and combination prostheses.

- The gag response is minimized because of the superior position

and the sustained pressure of the lift portion of the prosthesis

against the soft palate.

- The physiology of the tongue is not compromised because of the

more superior position of the palatal extension.

- The access to the nasopharynx for the obturator is facilitated.

- The lift portion may be developed sequentially to aid patient

adaptation to the prosthesis.

- Application to a diverse patient population.

Disadvantages / Contraindications:

- When adequate retention is not available for the basic prosthesis,

- If the palate is not displaceable

- Uncooperative patient.

Pre-requisites of the palatal lift - pharyngeal section combination

prostheses.16

i) The maxillary portion of the prosthesis is designed to achieve optimal

retention and stability.

ii) The lift portion of the prosthesis should be placed so that palatal

elevation occurs in the area where normal palatopharyngeal closure takes

place.

iii) Elevation of the soft palate should be gradual so that the soft palate

becomes less resistant to displacement.

iv) The pharyngeal section should be placed in the region where

constriction of the posterolateral pharyngeal wall takes place to encourage

muscle stimulation and activity.

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v) The reduction of the pharyngeal section, when indicated should be

gradual.

vi) Speech therapy, including lip, tongue, and palatal exercise and

placement should be instituted in conjunction with the construction and

insertion of prosthesis.

Fabrication of palatal lift Prosthesis :

Before starting the fabrication, the prosthodontist must determine

the potential amount of force that will be required to lift the soft palate to

create the desired effect. A mouth mirror or tongue blade should be used

to check the tonicity of the soft palate. Care should be taken during this not

to touch the dorsum of the posterior part of the tongue and/or the tonsillar

pillars to avoid gagging response from the patient. The mirror easily

displaces the soft palate of patients with a flaccid paralysis. However, if the

soft palate resists displacement because of fibrosis or tonicity of the

muscles, a palatal lift may not be successful, as a lot of force will be

required to lift the palate leading to a prosthesis that cannot be kept in

place or in pressure irritation and ulceration of the mucosa of the soft

palate.

Also, the movement of the pharyngeal wall should be clinically

evaluated by asking the patient to say “ahhhh” with the mouth wide open.

If there is complete lack of soft palate and lateral pharyngeal wall

movement, then the prosthesis will be required to occlude the entire

velopharyngeal port to eliminate hypernasality, which will lead to

elimination of nasal breathing.

Since, velopharyngeal incompetency is seen in patients with

neurological deficits; it is important to determine whether they have the

dexterity to manipulate the prosthesis intraorally.

In young patients and patients with needs which may change it is

advisable to make the prosthesis entirely in acrylic. Initially the primary

impressions are made in irreversible hydrocolloid. Care should be taken in

patients with neurologic deficits as protective reflexes may be lacking and

airway obstruction is major risk. The impression must cover areas at least

2cm posterior to the fovea palatini. The tray must support the impression

material so that the soft palate is displaced by the impression. Some

patients with long arches require the use of custom trays.

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Principles for retention of palatal lift prosthesis -

Clasps in palatal lift prosthesis not only retain the prosthesis but

also support the lift portion in its functional position. The ideal position of

the retentive clasps to engage is the disto-buccal undercut on the most

posterior tooth on either side of the arch. This places retentive elements as

close to the cantilever of the lift portion as possible.

- If wrought wire clasps are used, they should engage 0.04 to 0.05

inch of undercut. This is required in molars especially as the length

of the clasp arms makes them flexible.

- If orthodontic brackets are used for retention, the clasps must

approach from the distal aspect and continue anteriorly for at least

two additional teeth to allow the patient to grasp the clasp and

reflect it laterally to disengage the lift. An 18-gauge wire should be

used.

- If sufficient retentive undercut is not available on the most posterior

teeth, additional retention may also be gained by placing composite

resin in the area of the tooth where increased retention is required.

It is also very important to have indirect retention as far anteriorly as

possible to make the retentive clasps effective. The mesial marginal fossa

of the first premolar serves as an effective site as it is sufficiently anterior

to the fulcrum line.

After mouth preparation, the final impression is made and framework

fabricated. The retentive meshwork or wire loop should extend from the

base portion approximately 2 cm. This length provides enough support for

the lift moulding process and is not long enough so as to interfere with the

processing. The loop should be on the same plane as the hard palate but

should have slight relief between itself and the cast to allow for the

impression material and ultimately the acrylic resin to coat the superior

surface.

After the framework is physiologically adjusted the lift generation is

done. It is extremely important that a speech pathologist is present during

this procedure. Various diagnostic aids can be used to assess during the

procedure, whether the lift is adequate and sufficient velopharyngeal

closure has been achieved.

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- The framework is placed in the mouth and modeling plastic is

added to the retentive loop, shaped and flamed to create a smooth

surface and then chilled before placing it in the patient’s mouth.

The first layer should cover the loop evenly and extend several

millimeters beyond. If softened compound is placed in the mouth,

then the soft palate will displace it downward and the lift action will

not be achieved. The goal of the procedure is to displace the soft

palate superiorly and can be achieved by placing hardened

compound.

- The patient is allowed to wear the palatal lift for a few minutes at

this stage to get used to the sensation of the lift.

- Small additions are then made to the compound posteriorly until the

soft palate is brought into light contact with the posterior pharyngeal

wall.

- At this stage there is gap between the soft palate and the lateral

pharyngeal walls. So, the lateral extent of the lift should be

increased sufficiently to close the lateral port.

- Following each addition, the patient is asked to breathe through the

nose and attempt speech.

- Care should be taken not to overextend the compound orally as

any contact of the compound with the dorsum of the posterior part

of the tongue will elicit the gag reflex.

- Enlargement of the lift ceases when the speech pathologist is

satisfied with the result, or when the retentive limit of the clasps is

reached and the soft palate dislodges the prosthesis by the

downward force.

- If the patient cannot breathe nasally, then some compound is

removed from the lateral aspects of the lift until breathing is

restored. Ideally, the lateral pharyngeal wall movement allows the

maintenance of lateral breathing ports that close down, when the

patient speaks. The nasoendoscope can be used very effectively to

check for lateral wall movement.

- Sometimes, entire occlusion of the nasal airway is required to

eliminate hypernasality.

- Finally, the entire surface of the modeling compound is reduced by

1-2mm and impression wax is added and tempered. After placing in

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the mouth, the patient is asked to speak, swallow water and move

the head in all directions to form the wax.

- The lift is removed after 5 minutes and any pressure spots where

compound is exposed are relieved and more wax is added and the

previous step repeated.

- The palatal lift portion is replicated in acrylic resin ensuring that

there are no rough or sharp edges present.

Palatal Lift prostheses in edentulous patients: 120

Conventional palatal lift prosthesis must be securely retained in the

maxillary arch to resist the rebound of the lift. This situation is very difficult

to achieve when the patient is edentulous and there are no teeth to utilize

for retention. Therefore, in edentulous patients palatal lift prosthesis must

include as movable palatopharyngeal section connected to the denture

with Ni-TI wires. The elastic wire shows a unique stress-strain curve with a

plateau of 2% to 5 % strain and a return to almost 0 % strain as the stress

reduces to zero.

Technique:

§ Preliminary impressions are made in irreversible

hydrocolloid.

§ Referring to the cephalogram, soft palate contour is altered

in the cast to simulate the contour of the raised soft palate.

§ Custom tray is prepared for the final impression.

§ Final impressions are made in conventional way and casts

poured.

§ After jaw relationship records and arrangement of teeth, the

palato-pharyngeal section is waxed keeping two openings

to reduce the weight.

§ Process the palatomaxillary section (complete denture) and

the palatopharyngeal section separately. On the master

cast, embed Nickel- Titanium wires in both sections using

autopolymerizing resin

Insertion and Patient Instructions:

198

- The effectiveness of the lift is again evaluated at the insertion

appointment and a pressure indicating paste is used to detect

localized excessive pressure. Only these areas should be reduced

slightly. Arbitrary trimming should not be done.

- The patient should be trained to place and remove the prosthesis

and instructed to wear the lift prosthesis only during waking hours.

- Patients for whom the nasal airway has been completely blocked to

correct hypernasality, should be instructed to use the prosthesis

only when they need to speak and remove during eating food.

- The patient should be seen within 2 –3 days after delivery of the lift.

It’s use should be limited to day time as the mucosa of the palate

must be given enough time to recover from the coverage and pressure.

Also the clasped abutment teeth are at risk of supraeruption due to the

high force application by the retainers and need relief from these forces.

LaVelle and Hardy (1979) 72 defined three satisfactory outcomes for palatal

lift prostheses:

An optimal result occurs when the prosthesis results in

palatopharyngeal port closure during speech production except in

association with production of nasal consonants; that is, the resulting

pattern of closure would be essentially normal.

The result is considered successful when there is palatopharyngeal

closure throughout speech production. These patients generally end up

hyponasal with their prosthesis in place. This is because they are fully

closed and are not able to get airflow when saying their nasal sound as m,

n and ng.

The result is considered only desirable when the palatopharyngeal

port area is reduced so that incompetency is a relatively minor speech

physiology problem.These patients are still slightly hypernasal because the

prosthodontist was unable to apply adequate lifting pressure in the optimal

location to completely occlude the palatopharyngeal port.

b) Meatus-type obturator prosthesis 125,124,136

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Schialit first described this in 1946. The meatus obturator only

provides a static obturation and is not dependent on the surrounding

muscle activity to provide a more physiologic separation between the oral

and nasal structures. It is not located in a region of muscle activity.

Therefore, speech therapy is not effective in refinement of speech as seen

with fixed and hinged pharyngeal obturators and it is not as effective as the

horizontal obturator in cleft palate patients. The need for improved

retention and stability of prosthesis, may suggest its use in some patients.

Obturator of choice for edentulous patients with acquired defects of

the soft palate when retention is a problem as the hinged and fixed

obturators create a long lever arm that encourages dislodgement of the

denture base. These patients with acquired defects retain normal speech

articulation patterns but lack the ability to obstruct the passage of air into

the nose. The change in voice quality is less objectionable in patients with

acquired defects than in patients with congenital defects that have not

developed the oral and pharyngeal function necessary for good speech

articulation.

May be used for patients with extensive defects of the soft palate exhibiting

active gag reflex.

It establishes closure with nasal structures, at a level posterior and

superior to the posterior terminus of the hard palate. The closure is

established against the turbinates, residual vomer and the roof of nasal

cavity. The posterior nasal choanae determine the shape of the meatus

obturator. These openings are bounded laterally by the medial surface of

the medial pterygoid plate of the sphenoid bone, inferiorly by the horizontal

Fig. 72 : Meatus type Obturator

200

plate of the palatine bone, medially by the vomer bone, and superiorly by

the vomer and sphenoid bones immediately inferior to the sphenoid sinus.

These structures are covered by the respiratory epithelium. The

pharyngeal canal that carries the pharyngeal nerve and artery exits

through the sphenoid bone at the most superior extent of the choanae.

There are no muscles or muscle attachments at the level of the posterior

choanae.

In the patient with edentulous maxillae where retention of the

prosthesis is at best difficult, the meatus obturator is above the denture

base rather than posterior to it, as seen with other types of obturators. This

relationship lessens the lever action of the obturator on the denture base.

The posterior choanae of the nares also tend to be narrow in comparison

with the nasopharyngeal size, and the meatus obturator can be made

smaller than a horizontal obturator. The associated reduction in weight and

the decreased lever action of the meatus obturator creates a more stable

prosthesis. In addition, the floor of the nose or scar band of the resected

soft palate can often be engaged from above to enhance retention.

The meatus obturator can only be used in patients with an absence

of mobile soft palate in the midline, as the vertical component of the

obturator will interfere with the soft palate function in patients with

remaining soft palate movement. The meatus obturator is contraindicated

for use in patients whose soft palate defect is narrower than the

nasopharynx in the region of the posterior choanae. A narrow palatal

defect limits the width of the impression and subsequently the width of the

obturator. The meatus obturator is also contraindicated when the path of

insertion of the complete denture is different from the vertical path of

insertion necessary for the meatus obturator. A prominent anterior residual

ridge with labial undercut will prevent seating. Alveoplasty should be

considered but weighed against the subsequent reduction in retention.

Fabrication of Meatal obturator prosthesis:

The fabrication can be achieved in several ways. One of the more reliable

methods entails a corrective cast impression technique at the final wax try

in stage for the complete denture. If the patient’s existing denture is

adequate, the obturator portion may be attached as an additive procedure.

A technique for addition of a meatus obturator to an existing or new

denture base is described.

201

An 18-gauge wire loop is added to the posterior border of the denture with

autopolymerizing acrylic resin. The loop should be extended horizontally to

pass posterior to the remnant of the soft palate. The loop is then extended

vertically into the area of the posterior nasal orifices. The loop should not

contact mucosa at any point and should be narrow enough at the isthmus

to avoid contact with the functioning residual muscles.

A primary modeling compound impression is made by adapting the

softened compound to the supporting loop in sufficient quantity to obturate

the loop in all areas. The denture with softened compound is completely

seated. On cooling, the denture is removed and the compound impression

is reduced in size to ensure absence of tissue contact.

The primary compound impression is then border molded using

additional compound of a lower working range. Border seal will be evident

when the posterior choanae are obturated, as noted by positive tissue

contact and the patient’s inability to inhale or exhale through the nose.

Head, speech and swallowing movements are unnecessary as there are

no movable tissues in this area.

Certain anatomical landmarks can be identified in the impression.

Two lobes denoting the right and left nasal cavities project anteriorly

divided by a groove caused by the posterior margin of the vomer bone.

Lateral depressions are caused by the inferior turbinates. Posterior to the

depression of the turbinates outlines of the orifices of the eustachian tubes

may be evident. The impression should be reduced to avoid blocking the

tube orifices.

When maximum extension has been achieved, the compound

impression is reduced uniformly to provide space for the final impression

material. To assure positive tissue contact, a functional impression

material such as mouth temperature wax is used. The final impression

material should remain in place for 5-7 minutes. On removal, it should be

evaluated for uniform thickness and positive tissue contact.

A cast is poured around the completed impression. The wax and

compound are removed, the cast painted with a separating medium, and

autopolymerizing/ light cure resin processed to the retentive loop.

On removal from the cast, the processed obturator is reduced from the

posterior aspect to minimize bulk, and the obturator is lightly polished.

The prosthesis is inserted in the mouth to verify complete

obstruction of the nasal airway. Vent holes are then placed through the

202

obturator in the area lateral to the contact with the vomer. The vent

openings are placed in the superior third of the anterior surface and angled

downward at an angle of 45 degrees to the posterior surface. This

downward angulation of the vents minimizes the chances of regurgitation

of food and liquid into the nose during swallowing.

The vents are enlarged gradually until breathing through the nose

becomes comfortable. If the quality of speech has deteriorated significantly

with the enlargement of the vents, autopolymerizing acrylic resin may be

added to reduce the vent openings until an acceptable level of speech

versus nasal airway has been attained.

On insertion of the completed prosthesis, instructions should be

given for its use. The possibility of leakage of food and liquids into the

nasal cavity should be emphasized, and the need to remove the prosthesis

frequently for hygiene should be stressed. An erect head position while

eating and drinking may minimize leakage. Mucous build up on the anterior

side of the obturator may necessitate more frequent cleansing. Removal of

the prosthesis at night should be encouraged. The need for regular

maintenance care to assess the adaptation of the prosthesis and evaluate

the health of the oral and nasal structures should be emphasized.

On placing the prosthesis, the nasality should improve, only the

articulative defects remains, and these are not as unpleasant because of

normal nasal quality.

Advantages:

q Meatal extension is not lengthy and is quite thin in anterior -

posterior dimension.

q Light in weight

q Downward displacement force from the obturator extension is

closer to the supporting tissues of the parent prosthesis.

Disadvantages:

q Nasal air emission is not controlled.

q Hyponasal speech and impaired nasal respiration.

q Distortion in nasal resonance because oral cavity and oropharynx

are increased in sizes and nasal cavity is reduced

proportionately.

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q The meatus obturator interferes with the normal physiologic flow of

mucous posteriorly from the nose into the oral cavity.

q It may cause constant irritation to the sensitive respiratory mucosa.

Although the meatus obturator has not gained widespread acceptance for

use in cleft palate habilitation as originally intended by Schialit and Sharry, it

may still be useful in the treatment of edentulous and partially edentulous

patients with acquired soft palate defects where retention and stability of the

prosthesis are difficult to achieve. The meatus obturator can result in a more

stable maxillary prosthesis and permit acceptable speech for these patients.

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The cleft lip and palate deformity is a congenital defect of the

middle third of the face, consisting of tissues of the upper lip or palate. The

aetiology has been discussed in the discussion about the development of

the palato-maxillary region.

Treatment for cleft lip and palate is unique in that it includes

various health disciplines, which are interdependent and interrelated.

Hence a team approach based on total patient care will enhance the level

of rehabilitation.

Classification of cleft lip and palate

Numerous methods of classification have been proposed for these,

congenital anomalies of the middle third of the face. The method proposed

by Stark is the most widely used today, with that proposed by the Cleft

palate association being next common in usage.

Classification by Olinger95

Class I - Fissure in the azygos uvulae

Class II – Fissure in the uvula

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Class III – Fissure in the soft palate

Class IV – Fissure in the soft and hard palates

Class V – Unilateral cleft fissure in the soft and hard palates through the

alveolar ridge at the junction of the maxilla and premaxilla, accompanied

by a cleft of the lip.

Class VI – Bilateral cleft, fissure in the soft and hard palates through the

alveolar ridge, involving both sides of the premaxilla, freeing the

premaxillary bone with a double cleft lip.

Fitz – Gibbon’s Classification 50

Type I – Cleft of the soft palate only

Type II - Cleft of the soft and hard palate

Type III – Cleft of the soft palate, hard palate and unilateral extension on

one side of the pre- maxilla involving the lip as unilateral hare -

lip, sometimes, extending upto the nostril for varying distances.

Type IV – Cleft of the soft palate, hard palate and bilateral extension

through both sides of the premaxilla leaving an island attached

to the base of the septum and bilateral hare-lip extending upto

both sides of the nostril.

These are further described as congenital, acquired, post operative

and dentulous or edentulous.

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.

Cleft Palate

Association

STARK VEAU

Pre Palate

Pre Palate

Pre Palate

Pre Palate

Primary palate

Subtotal unilateral

Subtotal bilateral

Total unilateral

Total bi-lateral

Palate

Palate

Palate(Sub-

mucous)

Secondary palate

Subtotal

Total

Class I

Class II

Pre palate

and palate

Pre palate

and palate

Primary & Secondary

Total unilateral

Total Bilateral

Class III

Class IV

DIAGNOSIS AND TREATMENT PLANNING INCLUDES

- Case history: includes general and dental case history.

- Impressions for study cast,

- Intraoral wax occlusal registration.

- Radiographs -Intraoral full mouth, bitewings, occlusal x-rays.

- Cineradiography - to record on film the function of the mandible,

tongue, velum and surrounding tissue during phonation blowing

and swallowing.

- Laminography - For the study of cranial facial growth and

velopharynx orifice size during a sustained sound.

- Pantomography : Used for clinical diagnosis of the oral facial region

and growth appraisal.

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- Clinical examination of patients: includes both hard and soft tissue

examination.

- Photographs: Intraoral and facial color photographs for diagnosis,

teaching and illustration of before and after treatment.

- Speech recordings: which includes disc, wire or tape recording by a

speech therapist. & sound spectrographic recording.

- Other investigations: measurement of nasal and oral pressure and

flow, otologic and hearing examinations.

- Psychologic and social considerations

Analysis of all factors pertinent to the patient psychosocial status, at

this particular stage in the entire structure of therapy, must be integrated

with the diagnostic data accumulated.

Social services should be available to enable the patient to make full

use of medical dental and speech care both preventive and the

therapeutic, so that he can achieve the fullest possible, physical emotional,

and social adjustment.

General outline of prosthetic management of cleft lip and palate:

Indications for Prosthesis:

1. In Unoperated patients

- Wide cleft with deficient soft palate

- Wide cleft of Hard palate

- Neuromuscular deficiency of soft palate and pharynx

- When patients are high anesthetic risk cases.

- When delayed surgery approach (Zurich Approach) is followed.

- In cases where combined prosthetic and orthodontic appliances

like expansion prosthesis are to be used to improve spatial

relations prior to surgery.

2. Indications of prosthesis in operated palates:

Patients with hypernasality and inadequate speech following push

back and pharyngeal flap procedures.

Contraindications for prosthesis:

a. When surgical repair is feasible and when surgical closure of the

cleft will produce anatomic and functional repair.

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b. A mentally retarded patient who is not capable of controlling and

taking care of his appliances.

c. Uncooperative patient

d. Rampant caries and periodontal breakdown situations

e. When experienced prosthodontic help is unavailable

f. The edentulous condition is not a contraindication for speech aid

prosthesis.

Goals and objective of prosthetic treatment

- It should aid in restoring the basic function of mastication,

respiration, phonation and deglutition.

- It must be worn by the patient without discomfort or damage to the

supporting and surrounding structures.

- It should be shaped so that it will give the remaining anatomic

structures an opportunity to regulate efficiency the functions of

speech, breathing and swallowing without any impediment to these

functions.

- It should be of simple, sturdy construction with special attention to

retention, occlusion and cosmetics.

PROSTHESIS FOR CLEFT LIP AND PALATE

1) For Infants

2) For Young Children and Adolescents

3) For Adults

General Considerations For Impression In Cleft Palate Cases

a) Impressions for infants

Maxillary and mandibular impression trays for infants can be

constructed by adapting a piece of baseplate wax against the ridge.

This wax patterns is then processed in acrylic resin. This can be

repeated in other cases to collect additional trays, for future use.

Also, pre-made trays can be used to make a primary impression.

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TECHNIQUE :

An irreversible hydrocolloid material is used for impression.

The amount of water used for this is 5/6th of that recommended by

the manufacturer, and water is used at 100ºF in order to speed up

the setting of the material. The maxillary impression is made with

the infants head tilted at a downward angle of 15 degrees. This

position make's it possible to maintain a direct view of the oral

cavity at all times and it directs the flow of material towards the

oropharyngeal space.

At least 4 assistants should be available to

i) Hold the infant’s head.

ii) Depress the tongue and hold the suction.

iii) Hold the infant’s body and face

iv) Mix the impression material.

Proper instruments should be available, to gain access to material

should it be dislodged and enter the nasal or oral pharynx. The

tray should not be over packed, nor should too much force be

applied in placing the tray in position. The part of the tray that will

be directly over an undercut should contain less of the impression

material.

b) Impressions in older children and adults

The following suggestions should be kept in mind.

i) If the patient is a child, he should be given the opportunity

to see and examine the tray. He should be told that his

utmost co-operation is needed; otherwise it will be

necessary to make several impressions.

ii) The patient should be empty stomach.

iii) A topical anesthetic is applied to a child who has a

severe gagging reflex.

iv) The tray should not be over loaded. Excess material in

nasopharynx will increase difficulty to removing the

impressions without a fracture.

v) All oral perforations, which are small, should be packed

with gauze that has been saturated with petroleum jelly.

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TECHNIQUE:

Patient should be placed in either an erect or a supine

position. It is suggested, that supine position be used for

preliminary impression and final impression in order that the

dependent tissues do not become displaced.

Depending upon the extent of defect and psychological

state of the patient, it may be necessary to place an airway in the

nostrils and pack the throat with gauze. It may also be necessary

in the same instance, to place several strings in the cavity to aid in

removal of the impression. The lips of the patient should be

lubricated with petrolatum, so that the impression material does not

stick to the lips, and also prevents the lips from cracking during the

procedure. When a stock impression tray used, the edges of the

tray should be covered by beading wax, and the portion of the tray

which will come into proximity with defect should be build up with

beading or boxing wax to direct the impression material into the

defect. Individual acrylic resin trays are made on the stone cast

obtained from the preliminary. A final impression is made with one

of the materials such as rubber base or irreversible hydrocolloid.

1) Prosthetic Appliances For The Infants:

At birth the following variables exert a profound influence on the

rehabilitation of cleft patients.

- Configuration and the extent of cleft

- Growth potential of the patient

- Parental co-operation

- Appliance design

Whether the patient requires maxillary orthopedics, orthopedics

followed by bone grafting or neither depends on a lot of factors and is

decided jointly by the surgeon, orthodontist and the prosthodontist. The

factors, which need to be considered, are the length and position of the

minor segment, position of the anterior portion of the greater segment or

the premaxilla, the degree and location of the apparent tissue deficiency

and the area of coverage or extension of the appliance.

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TYPES OF APPLIANCE

i) Active or expansion type

ii) Passive or holding type

The type of appliance to be placed will be determined by the configuration

of the defect.

i) Active/Expansion Type

it is used if any degree of collapse is present.

- If the collapse appears primarily in the anterior region a fan type

of appliance is used.

- If the collapse of the arch is throughout its length a straight

jackscrew appliance is used

ii) Passive/Holding type:

Indicated if the cleft configuration is wide or the segments appears in an

ideal relationship

All appliances, whether active or passive are fabricated and

inserted prior to lip closure. The primary purpose of the appliance prior to

lip closure is not to proliferate tissue or initiate growth but to guide the

maxillary segments into proper spatial position with each other and with

the mandibular arch.

Salient feature regarding infant appliances:

o Active or holding appliances can achieve and maintain ideal arch

configuration in patients with complete clefts of the lip and palate.

o Once the lip has been surgically closed, the greatest tendency for

additional collapse is seen in those who presented initially with

some degree of arch collapse.

o A high degree/percentage of success is achieved in patients whose

initial arch configuration is wide.

o Lip closure can increase deformation or arch collapse unless

controlled by appliances.

o Parental, co-operation is essential for successful treatment.

The moulding pressure of the surgically closed cleft lip along with

the appliance helps to create an ideal arch form based on the Wolf’s law

that the functional stresses shape bone.

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Nasoalveolar Molding in Early Management of Cleft Lip and Palate 69,135,145

The basic goal of any approach to cleft lip, alveolus, and palate

repair whether for the unilateral or the bilateral anomaly, is to restore normal

anatomy.

Ideally, deficient tissues should be expanded and malpositioned structures

should be repositioned prior to surgical correction. This provides the

foundation for a less invasive surgical repair. Historically, the use of

presurgical infant orthopedic (PSIO) appliances, or molding plate therapy,

has aided significantly in reducing the size of clefts of the alveolus and hard

palate prior to surgery. Since its introduction by McNeil in 1950, various

techniques for molding the intraoral alveolar segments closer together in

unilateral and bilateral cleft situations have been described (Mylin, 1968;

Latham, 1980).

PSIO appliances are generally consist of three components- A bulb

prosthesis made of acrylic resin which fits on the protruding or laterally

displaced premaxilla held in place by elastic straps attached to the bonnet

for extra oral anchorage. Although controversy surrounds the use of PSIO

devices in conjunction with various surgical protocols when employed to

move only the alveolar segments closer together, this text describes a new

approach of presurgical nasoalveolar molding (PNAM) therapy developed at

the Institute of Reconstructive Plastic Surgery at New York University

Medical Center.

PNAM includes not only the reduction of the size of the intraoral

alveolar cleft through the molding of the bony segments, but also the active

molding and positioning of the surrounding soft tissues affected by the cleft,

including the deformed soft tissue and cartilage in the cleft nose. This is

accomplished through the use of a nasal stent that is based on the labial

flange of a conventional oral molding plate and enters the nasal aperture.

The stent provides support and gives shape to the nasal dome and alar

cartilages. Presurgical nasoalveolar molding may be successfully

employed in the early management of the both the unilateral and bilateral

cleft anomalies in newborns.

In the bilateral cleft condition presurgical nasoalveolar molding may

be combined with columellar elongation to create a “neocolumella” through

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a non-surgical approach. When there is a close coordination between the

presurgical phase of treatment and the surgical method employed, these

new techniques greatly improve upon the results usually produced through

traditional PSIO. The result is an overall improvement in the esthetics of

the nasolabial complex in both the unilateral and bilateral cleft conditions

while minimizing the extent of surgery and the overall number of surgical

procedures.

Clinical Method for Correction of the Unilateral Oronasal Cleft Deformity

1. Diagnostic Evaluation: As soon after birth as possible, all members of the

interdisciplinary cleft palate team evaluate the infant. The cleft defect is

examined for the presence of natal teeth, a Simonart band, unusual

undercuts, or other tissue abnormalities. If a tooth is present near the cleft,

it is often removed, as its presence will complicate healing during the

surgical phase of treatment.

2. Impression procedure: An impression of the intraoral cleft defect is

made using high consistency polyvinyl siloxane in an acrylic tray. Light

body material is not used for relining, as the registration of minute tissue

detail is not necessary.

The impression is obtained with the infant fully awake and without

any anesthesia. The infant is held face down to prevent the possible

aspiration of regurgitated stomach contents. One person cradles the

infant securely around the chest and torso, supporting the head and

neck, while another obtains the impression. High-volume evacuation is

also ready at all times also in case of regurgitation of the stomach

contents. Care is taken to ensure that the material has registered the

border regions of the maxilla and premaxilla as well as the cleft region.

It is not necessary, however, to impress deeply into the nasal cavity in

the cleft, reducing the risk of traumatizing the nasal tissues. The infant

should be able to cry during the impression-making procedure. If no

crying is heard, the airway is blocked. A finger motion should be used

to clear any impression material posterior to the tray and to prevent the

infant form closing down on the tray, which also will compromise the air

way. All impressions of clefts in infants should be made in the hospital

setting with a surgeon present as part of the impression team. The

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hospital setting also allows a rapid response by an airway team should

there be an airway emergency.

A nasal impression may be obtained using clear polyvinylsiloxane

(Memosil CD, Heracus Kulzer) expressed directly onto the cleft nose

from the radix to the lip. Cotton plugs attached to dental floss are used

to prevent material from lodging deep in the nostrils. Great care must be

used in obtaining a nasal impression of the cleft infant. The nasal

impression is not used in making the nasal stent portion of the

nasoalveolar-molding device.

3. Preparation of the plate: When the material has fully set

(approximately 2 minute intra orally), the impression is removed and

inspected to ensure all desired landmarks have been captured. Poured

in modified dental stone and the cast recovered. The modification cast is

then lubricated with a thin layer of petroleum jelly. A soft, resilient, slowly

polymerizing acrylic (Myerson permasoft, Austenal,) may be applied to

the undercut region on the cast. The remainder of the oral molding plate

is fabricated from clear methyl methacrylate orthodontic resin using one

of many acceptable techniques acrylic oral molding plate with a uniform

thickness in a relatively short period of time

4. Delivery of the plate: At the delivery appointment, the oral molding

appliance is carefully fitted in the infant’s oral cavity. The appliance must

not fit too tightly, however, as it is primarily retained through extra-oral

facial tapes and elastics. Additionally, no acrylic material should project

into the cleft areas, as this material will ultimately block the intended

movement of the alveolar segments into their desired final presurgical

positions. After initially inserting the oral molding appliance, the baby

must be observed for several minutes while the clinician stabilizes the

appliance against the palate with a gloved index finger. The infant must

be able to easily suckle without gagging or struggling. The thickness of

the palatal portion of the appliance should be checked and reduced if

necessary. Also at the initial insertion appointment for the unilateral cleft

patient, an extra oral retentive button is developed with clear resin at the

site of the cleft in the lip. This retentive button serves to facilitate both

the positive seating of the appliance to the palatal tissues and to secure

the retentive lip tapes and elastic bands. The retentive button should be

215

positioned facing downward on the labial flange at a 45-degree angle

relative to the occlusal plane, allowing for clearance of the upper and

lower lips

Proper retentive taping between appointments is crucial if the appliance

is to be maximally effective. A broader base tape of Suture-Strip (0.5 X

1.5 inch) (Genetic Laboratories Wound Care, St. Paus, MN ) is first

applied to the infant’s cheeks lateral and superior to the commissures.

These base tapes will serve to anchor the thinner (0.25 X 4 inch) suture-

strips that are used to hold the appliance against the palate. Small red

orthodontic elastics (01875 pr 0.25. inch diameter) are incorporated into

the loops of thinner Suture Strips that are folded over on them. The

elastic band is placed over the retentive button, and the Suture-Strips

are pulled and secured to the base tapes on the baby’s cheeks.

Enough retentive force has been exerted when the elastics have been

pulled to twice their original length. The correct force vector on the

retentive tapes and elastics should be directed posteriorly and

superiorly. The Suture Strips and elastic bands are changed as needed

to allow continuous retention of the appliance. The base tapes should

remain in place for a longer period of time, while the thin tapes may

require replacement several times each day. The base tapes prevent

excessive skin irritation of the cheeks that might result from the constant

removal of the adhesive tape. Once the Suture Strips and elastic bands

have been applied, an additional broader tape is applied over the ends

of the thin tape to anchor them to the base tapes.

The lip taping force in conjunction with a molding plate yields a

controlled movement of the alveolar segments and also serves to

improve the alignment of the nasal base region by bringing the

columella toward the midsagittal plane and improving the symmetry of

the nostril apertures. The parents are provided with detailed instructions

on the proper method of lip taping to ensure the maximum effectiveness

of the appliance. A supply of taping materials, adhesive, and releasing

agent is also provided to the parents. This ensures continuous taping

will be maintained between appointments.

5. Modification of plate for moulding: The tissue surface of the appliance is

also modified at the initial insertion appointment to begin the molding of

216

the greater and lesser alveolar segments on either side of the cleft. This

is achieved through the selective removal of acrylic from the region into

which one desires the alveolar bone to move. At the same time,

Permasoft is added to line the appliance to a thickness of approximately

1 to 1.5 mm in the region from which one desires the bone to be

reduced or removed. The usual movement is to direct the greater

segment inward toward the cleft by adding Permasoft to the inner

surface of the labial aspect of the alveolus portion of the appliance while

reducing the acrylic form the palatal aspect of the appliance. The

alteration of the lesser segment of the alveolus is the converse of that

applied to the greater segment.

The usual desired movement is to direct the lesser segment outward

from the cleft. To achieve this, the acrylic is selectively removed from

the inner labial aspect of the lesser segment of the alveolus

(approximately 1 to 1.5mm ) while adding an equal amount of resilient

soft liner on the palatal aspect of the alveolus in the lesser segment.

These minor adjustments are made weekly. The degree and location of

the modification will require a careful consideration of each individual

cleft situation. The ultimate goal of this sequential addition and selective

grinding away of material is to reduce the size of the cleft gap and to

have the two segments of alveolus contact with the configuration of a

proper maxillary alveolar arch form.

6. Weekly monitoring is done

The Nasal Stent

When the cleft gap has been reduced to approximately 6 mm or less, a

nasal stent may be added to the appliance and the phase of active nasal

cartilage molding may begin. The nasal stent is a projection of acrylic that

is formed by the careful addition of small amounts of cold-cure acrylic resin

until the stent is positioned inside the nasal dome on the cleft side of the

nose. The hard acrylic is covered with a thin veneer of soft liner

(Permasoft).

As nasal stenting progresses each week, the nasal tip and dome on the

cleft side should begin to appear more symmetric when compared with the

noncleft side when the stent is in place. The nasal stent also exerts a

reciprocal intraoral molding force against the alveolar segments. As the

217

nasal tissues pouch against the nasal stent, this force is transmitted down

along the nasal stent and provides additional force that aids in reducing the

dimension of the intraoral cleft width.

The parents are again instructed to keep the appliance in place at all times

expect for cleaning.

The goal of the intraoral molding therapy should be to have the

gingival tissues contact on either side of the ridge although a successful

surgical result may be obtained even when a small cleft 1 to 2 mm remains

between the alveolar ridges.

The goal of nasal orthopedics during the later appointments is to

ensure that when the lip segments are drawn together with taping, the

columella has been repositioned to midline location or even overcorrected

prior to surgery. The shape of the nostril and alar rim is also carefully

molded to resemble the configuration of the unaffected side. This may be

achieved by careful molding with Permasoft on the outside of the nasal rim

to support the underside of the expanding soft tissue. This supporting

material helps to produce a symmetric teardrop nostril form rather than a

simple ovoid or elliptical shape.

The nasal molding phase must follow alveolar molding so as to

avoid undue stretching of the alar rim circumference on the cleft side. This

is more likely to occur if the nasal molding is pursued while a very large cleft

alveolar gap remains. It is for this reason that nasal molding should not

begin until the intraoral cleft size has been reduced to 6 mm or less. The

proper sequence of molding (alveolar followed by nasal) is followed to avoid

the production of a “mega-nostril.”

Fig. 73: Unilateral cleft patient with PNAM appliance with nasal stent.

218

At the conclusion of intraoral molding therapy and nasal stenting, the

alveolar segments should be aligned, and the nasal cartilages, columella,

and philtrum should be properly repositioned to facilitate the first surgical

procedure.

This is a one-stage primary lip-nose repair in combination with a

Gingivoperiosteoplasty (GPP) to close the alveolar defect (Millard and

Latham, 1990). This first surgery is usually performed between 12 and 16

weeks of age. This allows one surgical procedure to address the defects of

the entire nasolabial complex in coordination with the oronasal presurgical

orthopedics. The lip nose alveolus repair may be performed at a later age if

it is determined by the members of the team that the infant would benefit

from additional weeks of nasoalveolar molding prior to surgery.

Following surgical repair of the lip, the lip is taped for several

weeks and no intraoral appliance is used. Likewise, no nasal stent or

supporting device is employed.

The palate repair, if indicated, in one stage is done once the infant

shows evidence of phoneme speech development. This usually occurs at

approximately 11 to 13 months of age.

Clinical Method for Correction of the Bilateral Oronasal Cleft Deformity

In the bilateral cleft deformity, presurgical nasoalveolar molding consists of

three distinct treatment phases.

1. First Intraoral Phase: The goal of the first or intraoral phase of

presurgical nasoalveolar molding is to align the posterior lateral alveolar

segments while retraction and derotating the premaxilla.

2. Second Phase: When the premaxilla has been has been returned to the

keystone position within the maxillary arch; the goal of the second

phase is to mold the nasal cartilages by repositioning the apices of the

alar cartilages toward the nasal tip.

3. Third Phase: The last phase of molding in the bilateral cleft infant

focuses on elongation of the columella.

219

Finally, a one-stage surgical repair is undertaken to remove the fibrofat tissue

between the domes of the lateral nasal cartilage’s as they are sutured together.

This is performed along with a bilateral GPP to close the intraoral alveolar

clefts.

One of the most significant benefits of the bilateral application of

nasoalveolar molding is the nonsurgical lengthening of the absent columella.

Using this technique, the columella may be non-surgically lengthened between

4.0 and 7.0 mm (Grayson et al, 1999). Intentional over correction of the

columella is encouraged to minimize post-surgical relapse.

In the infant with a bilateral cleft, it is not unusual that nasoalveolar molding

and columellar elongation will require up to 5 or 6 months of active treatment

before the surgical repair. As in the case of the unilateral molding appliance,

the device is worn continuously and removed only for cleaning. The infant

wears the prosthesis into the operating room. No intraoral appliance or nasal

stent is employed post surgically. The lip however, is taped for several weeks

while the baby heals.

Complications Associated with Presurgical Nasoalveolar Molding and

Columellar Elongation:

1. The Locked-out Segment.

2. Nostril Overexpansion.

3. Tissue Ulceration

4. Failure to Retain Appliance During Oronasal Molding.

Fig. 74: bilateral cleft patient with PNAM appliance.

220

5. Failure to Tape Lip Segments.

Advantages of Presurgical Nasoalveolar Molding and Columellar

Elongation:

- Presurgical nasoalveolar molding allows for the controlled, predictable

repositioning of the alveolar segments without the need for lip adhesion

surgery or for the surgical insertion of a pin-retained dynamic molding

plate.

- The reduction in the size of the cleft gap facilitates the repair of the

entire lip nose alveolus complex in one surgical procedure.

- It also allows the surgeon to perform a GPP with out the need for the

extensive tissue dissection required when the alveolar segments are far

apart. As a result studies have shown no midfacial growth restriction in

children who have under gone a GPP following presurgical molding with

reduction in the size of the cleft gap when compared with children who

had GPPs without presurgical cleft gap reduction.

- PNAM used in conjunction with GPP also reduces the need for

additional surgery to bone graft the alveolus later.

- The nasal component of molding facilitates the final phases of intraoral

molding.

- In the bilateral cleft patient, PNAM combined with columellar elongation

eliminates the need for columellar lengthening surgery

- Both the unilateral and bilateral prostheses improve the infant’s ability to

feed. In their most basic form, the devices serve as obturators that

provide an intact palatal surface upon which the infant will now be able

to generate a suckling force.

Limitations of Presurgical Nasoalveolar Molding and Columellar Elongation.

Despite the numerous advantages of these new techniques there are

several drawbacks associated with PNAM and columellar elongation.

- For optimal effectiveness, the molding process should begin as soon as

possible after the baby is born.

- PNAM and columellar elongation require cooperative parents who must

be well informed of the importance of their integral role in the successful

outcome of the treatment.

221

- These techniques are very labor intensive and require a committed

dental team (surgeon, orthodontist and a prosthodontist)

2. Prosthetic Speech Appliances For Children

Three types of speech aids are constructed for children.

1. An obturator with a palatal-velar-pharyngeal portion.

2. A baseplate type, which functions to obturate the palate and helps

speech

3. An anterior prosthesis, which contours the upper lip and improves

the anterior occlusion.

i) An obturator with a palatal velar-pharyngeal portion

It is used for training, diagnosis and as a temporary appliance. A

training appliance is used, to promote increased muscular activity so that

the coordinated movement of the soft palate and the posterior pharyngeal

wall will achieve velvopharyngeal closure during speech.

The diagnostic appliance may be used, for eliminating certain

tongue habits. The appliance is to be used only as a diagnostic tool, and

aid in increasing muscle activity.

For children 3-9 years of age stainless steel crowns are luted or

bands are adapted on the deciduous second molars and deciduous

cuspids. To these are soldered labial and buccal lugs or protuberances

(buccal tubes), which are used to retain the wrought wire clasps on the

speech aid appliance.

The speech bulb is not as accurately defined and does not achieve

complete efficiency during velvopharyngeal closure. It is used to provide

velopharyngeal closure during speech and yet present an open port for

nasal breathing. The bulb section should be started from a small size (pea

size). With each addition of compound the child is asked to bend his/her

head down as far as possible. This brings the spine forward causing the

posterior pharyngeal wall (tubercle of atlas) to indent the posterior surface

of the impression. The operator now has the means to orient the

placement of more impression of the material and the location of the bulb.

The child is then made to bend his/her head from side to side which

causes the palatopharyngeus muscle to trim the anterolateral portion of the

bulb. The compound is scraped by about 1mm and thermoplastic wax is

added and the movements are repeated.

222

The temporary appliance is used, till a more definitive prosthesis can be

constructed.

ii) Hard palate obturator

This type is used when a perforation exists in the hard palate and

the surgeon desires more growth of the child’s jaws before surgical closure

is done. In this type of case, since the soft palate has been surgically

repaired and is functioning well, a speech bulb is not indicated. Retentive

crowns or bands are placed on the deciduous second molars and the

cuspids while the plate has wrought wire clasps.

iii) Anterior prosthesis:

This type of prosthesis may be constructed when there is midfacial

deformity due to normal growth of mandible and the concomitant arrested

growth of maxilla.

Mandibular prognathism is seen at ages 9 through 14 as a result of

sudden growth of the mandible without comparable growth of the maxilla.

Surgical correction is generally not done. Lip plumper also needs to be

used if it is felt that the scar contracture is inhibiting growth. This prosthesis

restores function to the mandibular dentition and improves profile.

Therefore, the patient benefits from a psychological standpoint. The

appliance will also rebuild the arch form besides tooth replacements for

normal articulation and mastication.

4. Prosthesis For Adults:

a) Fixed Prosthesis

b) Removable Prosthesis

a) Fixed Prosthesis

i) It is the treatment of choice when the ridge defect is small

ii) A fixed appliance is preferable in cases where stability, longevity,

comfort and appropriate hygiene can be accomplished.

iii) Fixed prosthesis provides the much needed facial esthetics.

iv) Fixed prosthesis may/can be used in conjunction with removable

obturator prosthesis.

223

Several factor to be considered for cleft palate crown and bridge

prosthodontics are

i) Most commonly the lateral incisor is missing in cleft palate

patients. Patients with surgically corrected clefts are very likely

to have very high smile line, making the residual soft tissue

defect in the cleft visible and less amenable to conventional

fixed prosthodontic restoration because of the volume of

missing tissue. Hence, a combination of fixed-removable

treatment should be considered.

ii) When the cleft of the alveolus is not reconstructed with a bone

graft, the two segments of the maxilla tend to move

independent of each other. Placing conventional fixed

prosthodontic restorations across the defect puts the integrity of

the cement retaining the prosthesis at great risk of failure due to

cement line failure, washout and caries. Even double abutting

the prosthesis on both sides of the cleft is no guarantee that

cement failure will not occur. Hence, alveolar bone grafting to

close the bony defect should be considered prior to fixed

rehabilitation of the cleft palate patient regardless of the

patient’s age, as it will greatly improve the long-term prognosis.

iii) Full crown coverage is preferable for bridge abutments Full

esthetics crowns can compensate for hypoplastic enamel

formation and errors in morphologic development. In addition,

they provide maximum retention of the bridge.

iv) In younger patients, preparations must be modified relative to

the size of the pulp chamber. Retention pins and grooves

should be used with care and should employ techniques that

utilitize a minimal of tooth reduction and shoulder preparation.

Slight infraocclusion in the cleft area can actually aid in

construction of fixed prosthesis.

Other fixed options are the use of endosseous implants, bonding/

porcelain veneer restorations, Maryland bridges when the pulp

chambers are large and the root configurations of the abutment teeth

are not ideal.

An implant-supported restoration to replace the missing lateral incisor

offers the following advantages17:

224

- The abutment tooth preparation is not required with the decreased

possibility of damage to the dental pulp.

- Increased loading of the abutment teeth is avoided.

- The implant in the alveolar cleft, may transfer functional forces to

the graft, which could decrease the resorption of the graft.

b) Removable prosthesis:

A removable prosthesis is preferred when there is a large anterior

ridge defect and/or the middle third of the face is depressed.

A cleft of the alveolus is generally associated with missing lateral

incisor, crowded and poorly positioned teeth, which are sometimes

hypoplastic. Furthermore, surgical scarring, the lack of orthodontic

guidance, poor oral hygiene and dental disease impact the adult cleft

lip and palate patient. Many of these patients have also lost (or never

attained) adequate vertical dimension of occlusion. The fabrication of

an interim diagnostic overlay removable partial denture at a

substantially increased vertical dimension of occlusion may be

surprisingly well tolerated. The non surgical technique to treat such

patients involves the use of a maxillary overdenture or partial

overdenture that establishes correct vertical dimension, replaces

missing teeth, provides an esthetic result with appropriate lip support

and may support a pharyngeal obturator.

Chalian29 has described removable cleft palate prosthesis in ways

I) - Snap-on type

- Non snap-on type

II) - Prosthesis incorporating a bulb

- Prosthesis without bulb.

Removable partial dentures: these are similar to those for non-cleft

patients. The exception is for patients with velopharyngeal deficiencies,

when the conventional prosthesis must support a palatal lift and/or

obturator prosthesis. Adequate indirect retention is a must in Kennedy’s

Class I and II situation especially due to the long lever arm of the

pharyngeal extension, which becomes very difficult when only anterior

teeth, remain. Also, in cleft palate patients it should be kept in mind, that

when the primary palate has not been bone grafted, tortuous fistula like

openings might remain, which are not overtly visible. These should be

looked out for and plugged with petroleum jelly laden gauze before

225

impressions are made. Larger defects can be utilized for retention. Also

surgically repaired clefts, show various degrees of scarring which may be

unyielding. During fabrication of the partial dentures, the components

should follow these ridges rather than crossing them and the cast should

be beaded only minimally.

Since cleft palate deficiencies are interrelated, for example, when

maxillary constriction occurs it is always associated with discrepancies in

vertical dimensions. Missing and malformed teeth are related to the extent

of the alveolar cleft, and consequently this defective condition is

associated with both maxillary constriction and the discrepancy in vertical

dimension.

I) Maxillary Constriction: The degree of constriction is related to the

severity of the forces imposed by the restricting cleft lip, and possible

tissue deficiencies in the cleft area. A bilateral cleft will result in a cross

bite relationship of the entire arch, except the molar areas. Whilst,

unilateral cleft will result in constriction only on the cleft side and confined

essentially to the immediate cleft area or cleft segment.

II) Vertical Dimension: The lateral and anterior segments may not develop

in the customary downward and forward direction, leading to decreased

vertical dimension and associated over closure. There is thus an excessive

inter-arch distance. When the patient is edentulous, this increases the

disparity even further as the denture teeth must be positioned at a

considerable distance both laterally and inferiorly from the maxillary

foundation area and a Class III relationship is not uncommon.

TYPE OF REMOVABLE PROSTHESIS:

i) Overlay dentures:

The position of maxillary cuspids and the anterior portion of each

lateral segment determine the need for an overlay denture.

A removable overlay is necessary if the cuspids are in an extreme

linguoversion and do not occlude normally, or do not provide adequate

support to the corners of the mouth. The constricted maxilla is

overlayed in the horizontal plane by the flange labial and buccal to the

patient’s own teeth or ridge. Such an extension establishes improved

226

tooth, labial and facial contour by positioning the artificial teeth to

confirm with the lip and opposing mandibular teeth. Thus establishing

an improved occlusion.

The overlay flange should extend distally up to mesial aspect of the

first molar as to enhance esthetics.

ii) Complete maxillary dentures:

An edentulous condition with associated maxillary constriction will

increase the prosthetic management problem. Esthetic and lip

support will require the denture teeth be positioned buccal/Labial to

the edentulous ridge. A full maxillary denture must often support

an obturator. With tissue changes and subsequent settling of the

denture, the distal extension may function as a lever arm, which

can contribute to denture stability. Yet, there is no alternative to

complete prosthetic care. The best results are usually achieved by

compromise only as the lack of a bony palate, poor alveolar ridge

development, shallow depth of the palate, coupled with scarring in

the posterior seal area and lip closure area further complicates the

situation.

The final impression should be made in light body elastomeric

impression material in a custom tray after border moulding in low

fusing impression compound. Due considerations should be give

during border moulding procedure.

- Care should be taken in the labial reflex region to prevent

overextension, especially in relation to the scar bands caused

due to lip closure.

- The posterior palatal seal should not be established across

heavily scarred tissue but should follow the creases or folds in

the region. As the scar tissue can lead to rebound, only slight

beading feathered anteriorly should be done instead of the

butterfly pattern.

Modification of the anterior tooth position and lip support

accompanied with slight reduction of the vertical dimension is

indicated. Occlusion without any lateral interferences and reduction

of the weight of the restorations are mandatory for a successful

prosthesis.

227

The palatal, lingual or pharyngeal tissues should not displace the

obturator section. The patient should be instructed about frequent

adjustments and relining procedure.

iii) Full coverage overdenture

Patient’s remaining teeth should be protected with full

crowns. By covering the crowned teeth with the prosthesis an

improved vertical dimension of occlusion may be established. An

occlusal splint or prosthesis should first be made to verify the new

vertical relationship. This type of prosthesis is both tooth and

tissue borne.

Several methods for retaining full coverage overdenture are

a) The use of denture acrylic in frictional resistance to the

crown.

b) Gold thimbles embedded within the denture base in

conjunction with telescopic crowns.

c) Cervical undercuts associated with full crown may also be

utilized.

d) Internal attachments.

Chalian 29 has also described an unconventional speech aid

prosthesis, which is made in two sections so that the patient can

insert the nasal portion above the palatal shelves, using the

undercut created by the right and left palatal bones. The posterior

portion of this part is muscle trimmed like any other speech bulb till

proper airflow and resonance balance are obtained. The denture

portion is then inserted. The two portions interlock by means of the

gold button placed in the denture. The gold button inserts into a soft

acrylic area, which is elastic enough to allow the patient to insert

and disengage at will. Magnets can also be used to retain the two

portions.

228

Rehabilitation of patients with maxillofacial defects is not merely a

post treatment eventuality. It is a complex interaction of the patient with a

variety of health professionals, the main objective being restoration of

bodily and psychic function to optimum potential and to prevent additional

dysfunction and inconvenience. Rehabilitation involves concern for the

patient as a person, as well as for the patient’s social well being. It implies,

extending to the patient and the family and friends all available resources.

The maxillofacial prosthodontist normally provides appliances and

devices to restore esthetics and functions, to the patient who cannot be

restored to normal appearance or function by means of plastic

reconstruction. The prosthodontist may also be called upon to treat

patients who are at poor surgical risks for extensive plastic surgical

procedures. Rehabilitation of these patients is a challenging task and

should stress upon the psycho-dynamic interactions of health

professionals with the patient and significant persons in the patient’s life

Problems associated with the patient’s needs and special

consideration for prosthesis, potential changes in inter-personal

relationships, identification problems, mutilations, employment, special

work considerations, stress and strain of physical impairment, social

relationships, the face of death, the potential loss of sight, speech and

other important functions; all augur against assuming that the patient can

take, the trauma all-alone.

The most commonly occurring maxillofacial defects are the clefts of

the hard and soft palate. The prosthetic means of correcting these defects

comprises essentially of two forms of appliances i.e. the obturator and the

artificial velum. The literature suggests various types of designs, methods

of fabrication and materials in the fabrication of these prostheses.

This discussion hereby makes an attempt to throw light on

prosthetic philosophies and procedures in rehabilitating these patients.

Prosthodontic principles form the basis of all procedures albeit with

a few modifications to suit the needs of the situation. The partially

dentulous patient with a palatal defect is treated with a definitive

prosthesis, which is basically a removable partial denture with an obturator

extension. The design philosophy for the partially dentate patient is based

on the works of Aramany 7,8 and Desjardins 40. The tripodal design is

229

favoured over the linear design, with multiple support regions to transfer

the stresses. The presence of a large defect with little support gives rise to

a greater lateral torquing force. Desjardins suggested the use of a retainer

as close to the defect and as far from it as possible. Taylor 135 has modified

this slightly and has advocated that one retainer should be located as

close to the defect but the second retainer should be as far apart from the

first retainer as possible. Aramany has advocated the use of bilateral

retention but Taylor has suggested using large guide planes to

compensate for the lack of cross arch stabilization. The use of bonded

metal or composite contours or crowns can be fabricated and used

effectively if the contours of the natural dentition are not ideally suited for

these guide planes.

In implant supported obturator prosthesis the following outlines as

suggested by Beumer & Curtis17 should be considered. If the entire

premaxilla remains – the number of implants, distribution and design of

retention bar follows conventional prosthodontic principles.If only 2

implants are placed , one each in canine region – a Hader bar design is

used. If 4 or more implants are used. The support is provided posteriorly

by the residual denture bearing surfaces and anteriorly by the implants.

The attachments connected to the distal portion of the bar allow for the

compression of the distal extension area of the prosthesis into the denture

bearing area without applying excess torquing force onto the implants. If 6

or more implants are used and the antero-posterior spread is greater than

2 cm, the overlay obturator prosthesis can be designed so that occlusal

forces are primarily supported by the implants.

Retention of the prosthesis is vital. Ambroise Pare 28 is considered

to be the first to design an obturator. He used a sponge and a turnbuckle

to obtain mechanical retention. Pierre Fauchard 28 also used winged

turnbuckles. In the dentate patient interdental wiring retains the surgical

obturator while circumalveolar or circumzygomatic wiring, bone screws and

sutures are used in the edentulous condition. In the definitive prosthesis in

partially dentate patient casted retainers need to be used while wrought

wire clasps can be used for the interim prosthesis. Chalian 29, Roberts also

mention the use of intermaxillary or George Washington springs and

swivels. Swing lock design with multiple retentive bar clasps can be used

as described by Javid & Dadmanesh63 or in combination with conventional

230

retainers as described by Marunick80. Innovative means like utilizing the

anatomical undercuts by inflatable balloons has been advocated by Payne

& Welton105 and Coffey33. Brown 23 has advocated the buttressing the

lateral border of the obturator against the skin graft and placing it as high

and as far away as possible from the rotational path and utilizing the

undercut created at the junction of the split skin graft and the mucosa

junction.

In a young cleft palate patient where an interim obturator or

speech-aid prosthesis is required, retention can be gained by soldering a

buccal tube (lugs) or an orthodontic bracket to a band or stainless steel

crown under which an extended arm wrought wire clasp is given. This is

required, as deciduous teeth do not offer enough undercuts and clinical

height to use conventional clasps.

Magnets (samarium cobalt) can be effectively used to provide

retention for an obturator segment to the main denture in a sectional

prosthesis as described by Boucher21 and Matsumura et al 83.

Use of an overlay (telescopic) crown or a thimble can also be used

for overdentures. Also a Baker/Anderson bar with a clip attachment is used

for a snap-on prosthesis29. Use of precision and semi-precision

attachments provide an aesthetic means of retention and no reciprocal arm

is required. Resilient ERA attachment have been favoured especially in

implant retained prosthesis but care should be taken for controlling the axis

of rotation.17

The weight of the prosthesis is crucial and hence bulky areas

should be hollowed out to reduce weight so that teeth and supporting

tissues are not stressed unnecessarily especially when the obturator

prosthesis is suspended without bony or posterior tooth support on the

defect side. Wu and Schaaf153 have found that hollowing the obturator

prosthesis reduces weight by 7-33% depending on the size of the defect.

The superior surface can either be left open or closed. Clinicians who

prefer closed top state that if the obturators are left open, nasal secretions

accumulate leading to bad odour and added weight29.

Advantages of leaving the top open are that the weight of the

obturator is further reduced as there is no lid, it is easier to adjust and

speech is better. The effect of length of extension into the defect and top

configuration (open/closed) was studied by Aramany and Drane (1972)

and Oral96; and they found that the speech quality using the limited

231

extension prosthesis was better than with the maximally extended

obturator prosthesis. The lengthy superior extension along the lateral and

disto lateral aspect of the defect is essential for stability, support and

retention. If a lid is added to the hollow obturator, the obturator bulb

occupies significant portions of the nasal and maxillary sinus cavities.

Hence, if a closed bulb is used, it may change the configuration,

resonance balance and airflow characteristics of the nasal cavity. The

voice quality achieved with a closed hollow obturator is inferior to the open

obturator96. The open obturator design may be less obtrusive in the nasal

cavity and permits more normal airflow, nasal resonance and speech.

Beumer and Curtis17 advocate the open top obturator. A drainage

channel for the collected secretions may be made. It is a diagonal opening

in the inferolateral floor of the open obturator through the cheek surface for

drainage154. Removable lids can also be placed on the hollow section to

prevent this accumulation106

Often, patients need an extraoral prosthesis, in addition to an

intraoral prosthesis. The closed hollow obturator benefits these patients by

allowing the attachment of intraoral and extraoral prosthesis to each other,

thus providing additional retention and stability.

Many methods have been used to fabricate a lightweight, closed

hollow obturator. A lot of materials have been used to fill the space in the

flask to act as a support to pack the base of the hollow bulb. These include

paper clip attached stone (Nififfer & Shipman92), modeling compound

(Roberts 29), sugar (Matalon & Lafeunte82), ice (Schneider122), silicone

putty (Jhanji64) and plaster-pumice combination (Blair20).

Chalian & Barnet30 described the fabrication of a one-piece closed

hollow obturator by using an acrylic resin shim, while Ohyama et al93 used

an acrylic resin case as a scaffold for a silicone closed hollow obturator.

Fabrication of closed hollow obturator by using sections of

interchangeable flasks was described by Bown24, ElMahdy45 and modified

by McAndrew et al86.

Beder11 used pour type fluid resin technique to fabricate emergency

obturator and Browning26 described the fabrication of a hollow obturator

using fluid resin to allow precise control over the thickness of the resin for

minimal weight but sufficient thickness so as to allow adjustment if

necessary.

232

The use of silicone as an obturator bulb has been described by a

lot of authors. It offers the advantages or flexibility, which allows more

engagement of undercut and is less damaging to the frail tissues in the

defect region. However, it is subject to fungal infiltration and needs to be

changed frequently. Boucher21 used silastic bulb attached to the main

prosthesis by magnets while Hahn54 used an acrylic insert in the denture to

attach the silicone bulb. Wood & Carl151 used flexible impression trays and

fabricated silicone obturator. Taicher et al133 used polydimethyl siloxane

obturators in patients with severe trismus and unyielding tissue.

Vacuforming machines can be used to fabricate immediate surgical

obturators.43,70

The use of visible light cured resin has been described. It is

definitely the material for the future as it is very easy to use, it reduces the

laboratory steps, it is dimensionally accurate, even more than heat-cured

resin due to the absence of the monomer content.

Soft Palate obturation has been done in three different ways. The fixed

horizontal obturator has been found to be the most effective while the

meatus obturator is best for edentulous patients with total soft palate

defects. The hinge type pharyngeal obturators do not find much favour due

to the difficult fabrication, greater weight and reduced efficiency.

Gibbons and Bloomer first described palatal Lift prosthesis. Its use still

remains controversial. The literature has sufficient number of protagonists

to indicate that the palatal lift prosthesis is capable of offering benefits. In

fact, its use has also been associated with the stimulation of muscle

activity leading to reducing the incompetency leading to a situation, where

it is not required. With the increased availability of the advanced

diagnostic aids, the procedure even though complicated can be carried out

for the benefit of the patient.

The treatment of Cleft lip and palate patients has reached a stage where

the team approach of all specialties has been universally acknowledged.

The use of presurgical orthopedics since its introduction by McNeil in 1950

is gaining favour due to highly esthetic results and ease of surgical

technique.

The advances in surgical technique with vascularized bone containing

flaps, the acceptability of implants on radiated sites, use of accessory sites

like zygoma for implants have revolutionized the reconstruction and

233

rehabilitation. Its widespread use will provide the quality of life for the

patients that we as maxillofacial prosthodontics strive to achieve.

Rehabilitation of patients with maxillofacial defects has always remained an

enigma for the prosthodontist due to the unpredictable nature of the defects and

uncertainty of recurrence.

234

An attempt has been made to review to prosthetic aspects of the

rehabilitation of the patients with palato- maxillary defects with a strong

emphasis on the understanding of the anatomical and physiological

considerations and the psychosocial well being of the patient.

The rehabilitation is not merely by closing a defect with prosthesis but goes

much beyond that. To reach these goals a multidisciplinary approach needs to

be adopted

Although, the advances in materials have been remarkable, the

subspecialty has not reached its full potential. There is thus, a need of for

prosthodontists to take interest and involve them in this endeavour to

rehabilitate these patients to feel and function normally and integrate back in

society with confidence.

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