THE TRIAL DENTURE BASE

Rola M. Shadid, BDS, MSc

Trial Denture Assessment on Articulator

1.1. Impression surface examinationImpression surface examination FitFit ExtensionExtension

2.2. Polished surface examinationPolished surface examination Position of lower teethPosition of lower teeth position of upper teethposition of upper teeth inclination of polished surfaceinclination of polished surface

3.3. Occlusal surfaceOcclusal surface

Impression surface examination

1.1. FitFit The bases of the trial dentures should be The bases of the trial dentures should be

accurately adapted to the casts so there will be accurately adapted to the casts so there will be no movement when finger pressure is applied no movement when finger pressure is applied to occlusal surfaces.to occlusal surfaces.

The impression surface should be checked for The impression surface should be checked for any sharp projections, roughness, or excessive any sharp projections, roughness, or excessive undercuts. undercuts.

2.2. ExtensionExtension The border regions of the dentures should be The border regions of the dentures should be

shaped to conform to the depth and width of shaped to conform to the depth and width of the sulci on casts.the sulci on casts.

In the upper jaw the base should be extended In the upper jaw the base should be extended posteriorly to the post-dam cut in the cast, and posteriorly to the post-dam cut in the cast, and in the lower jaw over the retromolar pad.in the lower jaw over the retromolar pad.

Polished surface examination

Position of lower teethPosition of lower teeth The teeth on a lower denture should be positioned to conform The teeth on a lower denture should be positioned to conform

to the crest of the mandibular ridges. If there are gross to the crest of the mandibular ridges. If there are gross discrepancies between the position of the teeth and the discrepancies between the position of the teeth and the ridge, the teeth may not be in the neutral zone, and could ridge, the teeth may not be in the neutral zone, and could become the cause of instability in the mouth.become the cause of instability in the mouth.

Position of upper teethPosition of upper teeth The position of the anterior teeth should be checked in The position of the anterior teeth should be checked in

relation to the incisive papilla,and the posterior teeth relation to the incisive papilla,and the posterior teeth according to guidelines in the previous lecture.according to guidelines in the previous lecture.

Inclination of polished surfaceInclination of polished surface The buccal and lingual aspects of the polished surfaces must The buccal and lingual aspects of the polished surfaces must

converge occlusally; converge occlusally; so that pressure from the surrounding so that pressure from the surrounding muscles of the cheeks, lips and tongue contributes to retention rather muscles of the cheeks, lips and tongue contributes to retention rather than displacement.than displacement., the exception to this is the upper anterior , the exception to this is the upper anterior area area where the labial surface of the flange faces where the labial surface of the flange faces upwards and outwards.upwards and outwards.

Example of position of lower teeth

Occlusal view of two Occlusal view of two lower dentures: (a) the lower dentures: (a) the teeth follow the crest teeth follow the crest of the ridge; (b) of the ridge; (b) marked discrepancies marked discrepancies between the position between the position of the teeth and the of the teeth and the crest of the ridge are crest of the ridge are present, suggesting present, suggesting that the teeth will not that the teeth will not be in the neutral zone.be in the neutral zone.

a b

Occlusal surface examination

There should normally be There should normally be bilateral even contact in the bilateral even contact in the intercuspal position. Opposing intercuspal position. Opposing cusped teeth should cusped teeth should interdigitate accurately.interdigitate accurately.

Trial Denture Assessment in the

Mouth

Trial denture assessment in the mouth The denture should be assessed individually The denture should be assessed individually for:for:

1.1. Physical retentionPhysical retention2.2. StabilityStability3.3. Extension of denture basesExtension of denture bases4.4. Relationship to the neutral zoneRelationship to the neutral zone

The dentures should then be assessed The dentures should then be assessed together for:together for:

1.1. OVDOVD2.2. CR position CR position 3.3. EstheticsEsthetics4.4. Phonetics Phonetics

Establishment of the posterior palatal sealEstablishment of the posterior palatal seal

Don’t Overlook Problems

Difficult/impossible to change Difficult/impossible to change after processing after processing

May require removal, resetting & May require removal, resetting & re-processingre-processing

Procedures more costly & time Procedures more costly & time consumingconsuming

Physical retention

If the prognosis for the retention If the prognosis for the retention in the upper jaw is good, in the upper jaw is good, dislodgment may be difficult.dislodgment may be difficult.

In lower denture retention is poor In lower denture retention is poor because of the relatively small because of the relatively small denture bearing area and the denture bearing area and the difficulty in obtaining efficient difficulty in obtaining efficient border seal.border seal.

Physical retention

If the physical retention of an upper trial If the physical retention of an upper trial denture is not as good as would be denture is not as good as would be expected from the anatomical conditions expected from the anatomical conditions existing in a particular patient, the cause existing in a particular patient, the cause should be identified and, if found to be a should be identified and, if found to be a fault in the denture, must be corrected. fault in the denture, must be corrected. Denture faults may include absence of a Denture faults may include absence of a border seal resulting from:border seal resulting from:

• • Under-extensionUnder-extension • • Inadequate width of flangeInadequate width of flange • • Ineffective seal at the posterior borderIneffective seal at the posterior border • • Poor fit of the denture base.Poor fit of the denture base.

Stability

Movement of denture more than 2 Movement of denture more than 2 mm suggests lack of stability of the mm suggests lack of stability of the denture.denture.

This could be due to:This could be due to:

1.1. Lack of fit of the dentureLack of fit of the denture

2.2. Displaceability or unfavorable Displaceability or unfavorable shape of the denture bearing areashape of the denture bearing area

Extension of denture bases

The accuracy with which the denture The accuracy with which the denture borders conform to the depth and width of borders conform to the depth and width of the sulci must be determined.the sulci must be determined.

The all-important posterior extension of The all-important posterior extension of the dentures over the retromolar pad in the dentures over the retromolar pad in the lower jaw and to the post dam seal the lower jaw and to the post dam seal area in the upper jaw must be checked.area in the upper jaw must be checked.

If marked overextension of the denture If marked overextension of the denture flanges is present, stretching of tissues flanges is present, stretching of tissues will occur when the dentures are inserted will occur when the dentures are inserted and their elastic recoil will cause denture and their elastic recoil will cause denture dislodgmentdislodgment

Overextension of denture bases if the denture is if the denture is displaced displaced

immediately immediately after being seated, after being seated, over-extension should be suspected. over-extension should be suspected. A small degree of over-extension A small degree of over-extension may cause dislodgement of the may cause dislodgement of the denture when the dentist gently denture when the dentist gently manipulates the lips and cheeks or manipulates the lips and cheeks or when the patient raises the tongue.when the patient raises the tongue.

Overextension of denture bases

The exact location of such an error The exact location of such an error can only be determined by can only be determined by carrying out a careful examination carrying out a careful examination inside the mouth.inside the mouth.

Overextension of denture bases When over-extension is present in When over-extension is present in

areas where the visibility is good, areas where the visibility is good, displacement of the sulcus tissues will displacement of the sulcus tissues will be seen as the denture is seated. be seen as the denture is seated. However, in the lingual pouches, However, in the lingual pouches, visibility is poor, so the dentist will visibility is poor, so the dentist will have to make an assessment based on have to make an assessment based on the behavior of the lower denture as the behavior of the lower denture as the tongue is moved. the tongue is moved.

Overextension of denture bases In the lingual pouches, overextension In the lingual pouches, overextension

can be assessed according to denture can be assessed according to denture behavior during tongue movementbehavior during tongue movement

When the lower denture is inserted, When the lower denture is inserted, it should remain in place when the it should remain in place when the mouth is half open and the tongue is mouth is half open and the tongue is positioned so that its tip lies just positioned so that its tip lies just behind the lower anterior teeth.behind the lower anterior teeth.

Correction of over-extension Correction of over-extension is by Correction of over-extension is by

reducing the depth of the reducing the depth of the offending flange. If this is not offending flange. If this is not carried out, the finished dentures carried out, the finished dentures will traumatize the mucosa in that will traumatize the mucosa in that area and will be unstable because area and will be unstable because of the large displacing forces of the large displacing forces exerted by the soft tissues.exerted by the soft tissues.

Under-extension of denture bases The presence of under-extension is The presence of under-extension is

determined primarily by intra-oral determined primarily by intra-oral examination, when the depth of the sulcus examination, when the depth of the sulcus will be seen to be greater than that of the will be seen to be greater than that of the denture flange. denture flange.

In the case of the upper denture, however, a In the case of the upper denture, however, a preliminary indication of under-extension willpreliminary indication of under-extension will

be given by the existence of poor physical be given by the existence of poor physical retention. retention.

Correction of any under-extension Correction of any under-extension will usually entail taking a new will usually entail taking a new impression in the trial dentureimpression in the trial denture

Neutral zone

The positioning of teeth in the The positioning of teeth in the neutral zone is of particular neutral zone is of particular importance in the case of the importance in the case of the lower lower denturedenture

When the lower denture is inserted, When the lower denture is inserted, it should remain in place when the it should remain in place when the mouth is half open and the tongue is mouth is half open and the tongue is positioned so that its tip lies just positioned so that its tip lies just behind the lower anterior teeth.behind the lower anterior teeth.

Neutral zone

If displacement of the denture If displacement of the denture does occur, the cause must be does occur, the cause must be identified and the denture identified and the denture modified to correct the instability. modified to correct the instability.

An area where this difficulty An area where this difficulty commonly arises is the lower commonly arises is the lower anterior region where the lip may anterior region where the lip may exert excessive pressureexert excessive pressure

Neutral zone Correction of this type of fault should be carried Correction of this type of fault should be carried

out at the chairside so that the effect of the out at the chairside so that the effect of the alterations can be assessed in the patient’s alterations can be assessed in the patient’s mouth.mouth.

The offending teeth may be reset in the correct The offending teeth may be reset in the correct relationship to the soft tissues or they may be relationship to the soft tissues or they may be removed and replaced with a wax rim which is removed and replaced with a wax rim which is shaped with a wax knife until a stable denture shaped with a wax knife until a stable denture is produced. is produced.

The dental technician is then asked to reset the The dental technician is then asked to reset the teeth in the position indicated by the rim.teeth in the position indicated by the rim.

Neutral zone

When the tongue is relaxed, it When the tongue is relaxed, it should be able to rest on the should be able to rest on the occlusal surfaces of the teeth – occlusal surfaces of the teeth – a situation which favors a situation which favors retention of the lower dentureretention of the lower denture

Assessment of the Assessment of the occlusal vertical occlusal vertical

dimensiondimension

Verify OVD & Interocclusal Distance

Same techniques used previouslySame techniques used previously Critical to measure & feel 2-4 Critical to measure & feel 2-4

mm of interocclusal distance mm of interocclusal distance No tooth contacts during closest No tooth contacts during closest

speaking spacespeaking space

Changing OVD

Effects:Effects:Occlusion Occlusion Facial Facial estheticsesthetics

a

As the mandible opens (ie. byincreasing the occlusal verticaldimension) the incisal edge movesdownward and backward. Byincreasing the vertical dimension,more overjet is obtained and there isa tendency toward moving to askeletal Class II situation.

• As mandible moves downward As mandible moves downward (opening or increasing OVD)(opening or increasing OVD)

• Incisal edge moves backIncisal edge moves back

• Increases overjetIncreases overjet

• Helpful Angles Class IIIHelpful Angles Class III

• Problem Angles Class IIProblem Angles Class II

• As mandible moves downward As mandible moves downward (opening or increasing OVD)(opening or increasing OVD)

• Incisal edge moves backIncisal edge moves back

• Increases overjetIncreases overjet

• Helpful Angles Class IIIHelpful Angles Class III

• Problem Angles Class IIProblem Angles Class II

Vertical Dimension Alterations

One or both arches may One or both arches may require changerequire change

Made by the laboratoryMade by the laboratory May require resetting of all May require resetting of all

teeth in at least one archteeth in at least one arch Height of both anterior & Height of both anterior &

posterior teeth must be in posterior teeth must be in harmonyharmony

Vertical Dimension Alterations

If only posterior teeth are changedIf only posterior teeth are changed Undesired effect on: Undesired effect on:

Overbite relationshipsOverbite relationshipsEstheticsEstheticsBalancing contacts Balancing contacts

Assess how changes will affect Assess how changes will affect overall appearance overall appearance

Assessment of CR Assessment of CR Position Position

If a relatively large occlusal discrepancy is If a relatively large occlusal discrepancy is present, the dentist will be able to see this present, the dentist will be able to see this without any difficulty. However, the without any difficulty. However, the existence of smaller faults may be deduced existence of smaller faults may be deduced from evidence such as slight tipping or from evidence such as slight tipping or lateral movement of the dentures as they lateral movement of the dentures as they occlude.occlude.

The dentist must approach the problem The dentist must approach the problem with negative attitude.with negative attitude.

Methods of occlusal assessment

Visual (touch & slide method)Visual (touch & slide method)

Patient perceptionPatient perception The patient should be asked if the The patient should be asked if the

dentures are contacting evenly. Many dentures are contacting evenly. Many patients are able to detect occlusal patients are able to detect occlusal unevenness which is so slight that it unevenness which is so slight that it could be overlooked by the dentist.could be overlooked by the dentist.

Touch & Slide Touch & Slide MethodMethod

1. Guide the mandible into CR

The patient is guided into centric The patient is guided into centric relation by a thumb placed on the relation by a thumb placed on the anteroinferior portion of the chin anteroinferior portion of the chin and the index fingers bilaterally on and the index fingers bilaterally on the buccal flanges of the lower trial the buccal flanges of the lower trial denture.denture.

As tooth contact approaches, the As tooth contact approaches, the dentist's index fingers should rise dentist's index fingers should rise off the buccal flanges, pressure on off the buccal flanges, pressure on the buccal flanges or stretching the buccal flanges or stretching the lip with index fingers will the lip with index fingers will create the risk of posteriorly create the risk of posteriorly displacing the lower trial denture, displacing the lower trial denture, then the patient closes tightly.then the patient closes tightly.

2. 2. The patient closes slowly so that The patient closes slowly so that the dentist can observe the the dentist can observe the initial initial occlusal contact.occlusal contact.

3. The final occlusal relationship is 3. The final occlusal relationship is not so reliable, as an uneven not so reliable, as an uneven occlusion may have been masked by occlusion may have been masked by compression of the mucosa beneath compression of the mucosa beneath the denture, tipping of the denture the denture, tipping of the denture or posturing of the mandible.or posturing of the mandible.

4. 4. The ideal occlusal contact is that The ideal occlusal contact is that at first contact, even maximum at first contact, even maximum intercuspation at CR without intercuspation at CR without denture shifting or instability & denture shifting or instability & without pain; and all the teeth that without pain; and all the teeth that occluded uniformly on articulator occluded uniformly on articulator must have equally uniform must have equally uniform contacts in the mouth contacts in the mouth

5.Errors in occlusion may prevent 5.Errors in occlusion may prevent intercuspation of some teeth intercuspation of some teeth when the first contact is made.when the first contact is made.

6. Further closure will allow the 6. Further closure will allow the teeth to slide into CO as teeth to slide into CO as tipping tipping of the denture or deviation of of the denture or deviation of the mandible will occurthe mandible will occur

What is your management if you found that CR not coincide with CO?

You need to register new CR, mount on You need to register new CR, mount on articulator according to new CR, and then articulator according to new CR, and then reset teeth according to this new CRreset teeth according to this new CR

This is done either by removing the This is done either by removing the posterior teeth from the lower occlusion posterior teeth from the lower occlusion rim and both occlusion rims are placed in rim and both occlusion rims are placed in the mouth and a new centric relation record the mouth and a new centric relation record is taken; is taken; OROR register new CR by applying register new CR by applying bite registration material on occlusal bite registration material on occlusal surfaces of lower teeth.surfaces of lower teeth.

Removing the posterior teeth from the lower occlusion rim To register the new centric relation, the To register the new centric relation, the

posterior teeth are removed from the lower posterior teeth are removed from the lower occlusion rim and both occlusion rims are occlusion rim and both occlusion rims are placed in the mouth and a new centric placed in the mouth and a new centric relation record is taken, the closure is relation record is taken, the closure is stopped stopped when the anterior teeth have when the anterior teeth have the same vertical overlap as they had the same vertical overlap as they had before the posterior teeth are removed before the posterior teeth are removed thus the vertical relation of the two thus the vertical relation of the two

jaws will not be changed jaws will not be changed **

Apply Minimal Registration Material on Lower Occlusals

Improves record Improves record accuracy accuracy Less resistance Less resistance

during closureduring closure Reduces Reduces

chance of chance of deflection when deflection when checking checking record record

✔✔

✘✘

✔✔✘✘

Small Amount of Registration Material

Opposing cusps should not Opposing cusps should not penetratepenetrate

Cuspal indentations improve Cuspal indentations improve accuracy compared to flat accuracy compared to flat wax rimwax rim

Accurate Mounting

Teeth interdigitate Teeth interdigitate perfectly perfectly No space around the No space around the

cuspscusps Mandibular cast Mandibular cast

removed from removed from mounting ringmounting ring

Mounting plaster Mounting plaster ground thinnerground thinner

Cast remounted, Cast remounted, using the new recordusing the new record

Evaluation of the Evaluation of the EstheticsEsthetics

EstheticsCheck:Check:

Amount of incisal displayAmount of incisal display Harmony of the maxillary Harmony of the maxillary

teeth teeth with the smile linewith the smile line**

Accuracy of the midlineAccuracy of the midline

During a normal smile, incisal and middle During a normal smile, incisal and middle thirds of maxillary anterior teeth are visible thirds of maxillary anterior teeth are visible in almost all patients and the cervical third in almost all patients and the cervical third in approximately half the patients.in approximately half the patients.

The incisal third of the mandibular teeth will The incisal third of the mandibular teeth will be visible in most patients.be visible in most patients.

The lower lip is a better guide for the The lower lip is a better guide for the vertical orientation of anterior teeth than the vertical orientation of anterior teeth than the upper lips. In most patients the incisal edges upper lips. In most patients the incisal edges of the natural lower canines and the cusp of the natural lower canines and the cusp tips of the lower first premolars are even tips of the lower first premolars are even with the lower lip at the corners of the with the lower lip at the corners of the mouth when the mouth is slightly open.mouth when the mouth is slightly open.

Esthetics

When the teeth are When the teeth are above the lip at the above the lip at the corners of the corners of the mouth, any one or mouth, any one or a combination of a combination of the followings may the followings may exist: exist:

1.1. the plane of occlusion the plane of occlusion may be too highmay be too high

2.2. the vertical overlap the vertical overlap of the anterior teeth of the anterior teeth may be too muchmay be too much

When the lower teeth When the lower teeth are below the lip at are below the lip at the corners of the the corners of the mouth, the opposite mouth, the opposite situations may existsituations may exist

Esthetics

a)a) This figure shows This figure shows reverse smile linereverse smile line

b)b) The fig. shows the The fig. shows the midline is slanting midline is slanting to one sideto one side

c)c) The dental midline The dental midline should coincide should coincide with the midline of with the midline of the facethe face

Esthetics

CheckCheck Angle of the occlusal Angle of the occlusal

planeplaneThe errors in location and The errors in location and

inclination of occlusal plane inclination of occlusal plane can cause serious esthetic can cause serious esthetic problems, in addition to problems, in addition to functional problems and functional problems and problems of stability. (The problems of stability. (The figure shows errors in figure shows errors in occlusal plane)occlusal plane)

EstheticsCheck Check

Proper soft tissue Proper soft tissue profile, contoursprofile, contours

Lip supportLip support Display of the vermilion Display of the vermilion

borderborder Correct nasolabial angleCorrect nasolabial angle

Esthetics

Ask patients for their opinion Ask patients for their opinion prior to voicing your opinionprior to voicing your opinion

Avoids biasing the patientAvoids biasing the patient May be helpful to have family May be helpful to have family

or friend attend the wax try-inor friend attend the wax try-in

EstheticsIf you or the patient have If you or the patient have

reservations about appearancereservations about appearance Resolve prior to final processingResolve prior to final processing Never attempt to persuade a Never attempt to persuade a

patient out of a concern patient out of a concern Problems will be yours later, if Problems will be yours later, if

the patient does not like the the patient does not like the appearanceappearance

Evaluation of the Evaluation of the PhoneticsPhonetics

Phonetics

Easier to assess Easier to assess Teeth have replaced bulky Teeth have replaced bulky

rims rims Crowded tongue space can Crowded tongue space can

adversely affect phoneticsadversely affect phonetics

Phonetics If have not worn dentures for If have not worn dentures for

extended period extended period oror

Dramatic changes Dramatic changes (Contour, (Contour, Tooth Position, Vertical Dimension):Tooth Position, Vertical Dimension):

Allow the patient to read a out Allow the patient to read a out loud for loud for 5-10 minutes5-10 minutes to assess to assess phonetics and comfortphonetics and comfort

Lisping

Non-uniform overjet Non-uniform overjet of the anterior teethof the anterior teeth

Diastemas between Diastemas between teethteeth

Palatal contoursPalatal contours Diamond-shaped Diamond-shaped

openings between openings between incisorsincisors

Bilabial sounds (p, b, m)

Causes of defect in these sounds:Causes of defect in these sounds: Insufficient support of lips by Insufficient support of lips by

teeth or denture baseteeth or denture base Anteroposterior position of Anteroposterior position of

anteriors & thickness of labial anteriors & thickness of labial flangeflange

Incorrect OVDIncorrect OVD

Labiodental (fricative) sounds (f,v)

F & v are made between F & v are made between the upper incisors and the the upper incisors and the the posterior one third of the posterior one third of the lower lip the lower lip

Affected by the Affected by the anteroposterior position of anteroposterior position of upper anteriors and their upper anteriors and their lengthlength

If upper anteriors short, v If upper anteriors short, v sound will be more like an fsound will be more like an f

If upper anteriors long, f If upper anteriors long, f sound will be more like vsound will be more like v

Linguoalveolar sounds (t,z,s,d,v,L,ch,sh)* Valve formed by contact of tip of tongue with Valve formed by contact of tip of tongue with

the most anterior part of palate or lingual the most anterior part of palate or lingual side of anterior teethside of anterior teeth (linguoalveolar)(linguoalveolar)

The upper and lower incisors should The upper and lower incisors should approach end to end but not touch.approach end to end but not touch.

Affected by the length of the upper & lower Affected by the length of the upper & lower anterior teeth (including their vertical anterior teeth (including their vertical overlap)overlap)

Also affected by horizontal overlap of Also affected by horizontal overlap of anteriors anteriors ¶¶

Linguoalveolar sounds

Incisors should approach end Incisors should approach end to end relationshipto end relationship

a

Normalrelationship ofincisors in CR

Relationship of the incisorsduring pronunciation of the

sibilants. If the lower incisal edgeis anterior or posterior themaxillary incisal edge, this

indicates an error in the overjet.

“S” sound

The “s” sound is the most interesting The “s” sound is the most interesting one because it is influenced by the one because it is influenced by the teeth and palatal part of maxillary teeth and palatal part of maxillary prosthesis.prosthesis.

Clinical experience suggests that Clinical experience suggests that ss & & tt can cause most problems in a can cause most problems in a prosthodontic context.prosthodontic context.

“S” sound

The tip of tongue is placed far forward, The tip of tongue is placed far forward, coming close but never touching the upper coming close but never touching the upper anteriors (touch rugae area)anteriors (touch rugae area)

A small sagittal groove is formed in the A small sagittal groove is formed in the upper front part of the tongue for air to upper front part of the tongue for air to escape between the tongue & alveolusescape between the tongue & alveolus

The tongue dorsum is flatThe tongue dorsum is flat Mandible will move forward and Mandible will move forward and

downward, with the teeth almost in contactdownward, with the teeth almost in contact

“S” sound

WhistleWhistle on “S” sound on “S” sound ““S” sound sounds as S” sound sounds as “sh” “sh” oror

“th”“th” Causes……Causes…… Management……..Management……..

Denture Base Contours

Affect Affect phonetics, phonetics, comfort and comfort and retentionretention

Should not Should not be slightly be slightly convex in convex in shape shape

ConvexConvex ConcaveConcave

Denture Base Contours

Ensure that the denture base is not Ensure that the denture base is not unduly thick or thinunduly thick or thin Excess bulk will impair comfortExcess bulk will impair comfort

Feel between index finger & thumbFeel between index finger & thumb Base that is too thin will be Base that is too thin will be

weakenedweakened Should not be able to see throughShould not be able to see through

It was concluded that It was concluded that malformation of the palatal malformation of the palatal parts of the denture parts of the denture influenced speech influenced speech production more than production more than differences in OVD did.differences in OVD did.

Establishment of the Establishment of the posterior palatal sealposterior palatal seal

CONVENTIONAL APPROACH

After assessing all the previous After assessing all the previous parameters there are certain parameters there are certain instructions given to the patients:-instructions given to the patients:-

1.1. To rinse with an astringent mouth To rinse with an astringent mouth wash that is remove to stringy wash that is remove to stringy saliva that might prevent clear saliva that might prevent clear transfer marking. There are steps transfer marking. There are steps to be followed to be followed

2. Location of pterygo maxillary notch is 2. Location of pterygo maxillary notch is done by moving the T burnisher posterior done by moving the T burnisher posterior to the maxillary tuberosity until it drops to the maxillary tuberosity until it drops into the pterygo maxillary notch. This is into the pterygo maxillary notch. This is necessary as there are times when small necessary as there are times when small depression in the residual ridge may depression in the residual ridge may resemble pterygo maxillary notch.resemble pterygo maxillary notch.

3. Identification of posterior vibrating line 3. Identification of posterior vibrating line by asking the patient to say “AH” in a by asking the patient to say “AH” in a normal unexaggerated fashion.normal unexaggerated fashion.

4. Identification of the anterior vibration 4. Identification of the anterior vibration line. This is done by asking the patient line. This is done by asking the patient to say “AH” with short vigorous bursts to say “AH” with short vigorous bursts (Valsalva Maneuver can also be used(Valsalva Maneuver can also be used))

PROCEDURE

A line is placed with an indelible A line is placed with an indelible pencil through the pterygomaxillary pencil through the pterygomaxillary notch & extended 3-4 mm antero-notch & extended 3-4 mm antero-laterally to the tuberosity laterally to the tuberosity approximating the mucogingival approximating the mucogingival junction. The same is done on the junction. The same is done on the opposite side. This complete the opposite side. This complete the outlining of pterygomaxillary sealoutlining of pterygomaxillary seal

The posterior vibrating line is marked The posterior vibrating line is marked with an indelible pencil by connecting with an indelible pencil by connecting the line through the pterygomaxillary the line through the pterygomaxillary seal with line just drown demarcating seal with line just drown demarcating the post palatal sealthe post palatal seal

The resin or shellac denture base is The resin or shellac denture base is inserted into the mouth & seated inserted into the mouth & seated firmly to transfer the marks from the firmly to transfer the marks from the mouth. mouth.

Denture bases are then returned to Denture bases are then returned to master casts to transfer the markings master casts to transfer the markings to the master casts. to the master casts.

The base is trimmed until the The base is trimmed until the posterior vibration line so that it posterior vibration line so that it decides the posterior extent of the decides the posterior extent of the denture border.denture border.

(A) A T burnisher is (A) A T burnisher is used to palpate for used to palpate for the hamular the hamular process.process.

(B) Palpating for the (B) Palpating for the pterygomaxillary pterygomaxillary notchnotch

Demarcation of Demarcation of anterior & anterior & posterior posterior vibrating lines in vibrating lines in the patient mouththe patient mouth

Transferring Transferring these lines to these lines to denture basedenture base

The shape of post palatal seal is like the The shape of post palatal seal is like the cupid bow, because of the projection of cupid bow, because of the projection of the posterior nasal spine.the posterior nasal spine.

Kingsley scraper is used to score the cast, Kingsley scraper is used to score the cast, the deepest areas are located on either the deepest areas are located on either side of midline, one third the distance side of midline, one third the distance anteriorly from the posterior vibrating anteriorly from the posterior vibrating line. It is usually scraped to a depth of line. It is usually scraped to a depth of approximately 1-1.5 mm . approximately 1-1.5 mm .

The tissue covering the medial palatal The tissue covering the medial palatal raphe cannot withstand the same raphe cannot withstand the same compressive force as the tissue lateral to compressive force as the tissue lateral to it; so it is scraped to depth of it; so it is scraped to depth of approximately 0.5-1 mm within the approximately 0.5-1 mm within the outline of cupid bow.outline of cupid bow.

The scraping tapers to a feather edge as The scraping tapers to a feather edge as it approaches the anterior vibrating line.it approaches the anterior vibrating line.

Failure to taper the posterior seal leads Failure to taper the posterior seal leads to tissue irritation.to tissue irritation.

Finally………..

Patient Input

Use open ended Use open ended questionsquestions

““How do you like the appearance?”, How do you like the appearance?”,

rather than rather than

““Don’t the new dentures look great?”Don’t the new dentures look great?”

Patient Input

If the patient sounds If the patient sounds unconvinced unconvinced ask more questionsask more questions

Do not Do not rush this step to save rush this step to save time!time!

References

BaskerBasker’’s Prosthetic Treatment of s Prosthetic Treatment of the Edentulous Patient. Fourth the Edentulous Patient. Fourth edition.Chapter 13edition.Chapter 13

Boucher's Prosthodontics Boucher's Prosthodontics Treatment for Edentulous Treatment for Edentulous Patients. Twelfth Edition. Chapter Patients. Twelfth Edition. Chapter 1919

Complete Denture Complete Denture Prosthodontics, 1Prosthodontics, 1stst Edition, 2006 Edition, 2006 by John Joy Manappallil, Chapter by John Joy Manappallil, Chapter 1717

Dalhousie coninual educationDalhousie coninual education