Controversies in orthodontics /certified fixed orthodontic courses by Indian

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Controversies

in Orthodontics

CONTENTS

Introduction Controversies in Classification of Malocclusion Controversies in Diagnosis a. Diagnostic value of plaster models in

contemporary orthodontics b. Reliability of Digital vs Conventional

cephalometric Radiology Controversies in Etiology of malocclusion a. Genetic V/s environmental factors. b. Role of nasal obstruction and tongue thrust. c. Third molars – a dilemma! Or is it? Controversies in Treatment planning a. Extraction versus Non-extraction. b. Timing of Orthodontic Treatment

Controversies in Treatment modalities Orthopedics in orthodontics; fiction or reality Controversies in PEA: - Torque in the Base vs Torque in the Face

- 018” vs 022” slot - Controversies in Bracket prescription

Controversies in Orthognathic Surgery Root resorption related to orthodontic treatment

Orthodontic treatment and temporomandibular disorders

Conclusion and References

CONTENTS

Introduction

Controversy – A prolonged argument/ dispute especially when conducted publicly.

Orthodontics traditionally has been a specialty in which opinions of leaders were important, to the point that professional groups coalesced around a strong leader

Angle, Begg, Tweed societies still exist- “disagreements are then a risk rather than exception”.

Cults and charismatic leaders have been more instrumental in establishing our value systems than has any demonstrated superiority of one method over another.

Result

Thus its more “Opinion –based” rather than “evidence – based”.

Such science can neither validate the superiority of a technique nor help to make rational choices among alternatives.

In time, for most clinicians, practice becomes routine, standardized and decreasingly introspective.

Hence, clinical experience + common sense assume a more commanding role in Decision making.

Controversies In

Classification of Malocclusion

Ambiguities of Angle’s classification : 1989 No. 4, 295 - 298Donald J. Rinchuse, Daniel J. Rinchuse.

In 1900, Edward H. Angle wrote that all teeth should be considered when classifying cases

In 1907, he emphasized using the maxillary first molars as reference teeth.

Arguments are presented to illustrate the confusion in relying solely on Angle’s system of classification

The changes in Angle’s thinking and writings between 1900 and 1907 have created a dilemma:

Should the orthodontist use only the permanent first molars to determine the classification of an Malocclusion?

Or, should the canines be included?

If so, which teeth, the molars or canines, should be given priority when determining the classification of an occlusion?

Or, should the orthodontist use all the teeth to assign a case to one of Angle’s Classifications?

The situation arising where one side of a dentition is in a Class II relation, while the other side is in a Class III relation, is beyond the parameters of Angle’s Classification

A dilemma could arise when the first molars are in a Class I relationship and the rest of the dentition is in a Class II relation.

Ambiguities of Angle’s classification : 1989 No. 4, 295 - 298Donald J. Rinchuse, Daniel J. Rinchuse.

What does “subdivision left” describe?

Some orthodontists believe that it refers to an asymmetrical occlusion, with a Class II molar relationship on the patient’s left side and a Class I molar relationship on the right side. Other orthodontists perceive just the opposite.

As a result, orthodontists in the United States cannot agree on the meaning of a Class II Division 1 subdivision malocclusion.

A matter of Class: interpreting subdivision in a malocclusion.Am J Orthod Dentofacial Orthop. 2002 Dec;122(6):582-6.

A survey was sent to the chairperson of eachorthodontic department in teaching facilities in

theUnited States. Fifty-seven surveys were mailed.

Thesurvey consisted of a 1-page questionnaire that asked whether, in the orthodontic residency program’s philosophy, subdivision refers to the Class I side or the Class II side.

Thirty-four surveys were returned (return rate about 60%) with mixed results. Twenty-two respondents believe that subdivision refers to the Class II side, 8 believe it refers to the Class I side, and 3 teach their students neither meaning for subdivision.

The premolar classification was put forth by Morton Katz as a modification to the Angle’s classification

The canine classification

From the above discussion it is clear that the system of classification we use today is inadequate in describing a dental anomaly in it’s entirety, aid in treatment planning or be easy to use. A universal classification system will be necessary which will be accepted by all orthodontists around the world. This would help us in standardizing malocclusion rather than disagreeing on the very nature of problem the patient has.

Diagnostic value of plaster models in

Contemporary Orthodontics

Models are the only three dimensional records available to represent dentition in a functional occlusion

Advantages of Models Measurement of dentition and arch

length are easier As per ABO study models allow for

grading system evaluating treatment results

They also serve as a Medico legal record

Diagnostic value of plaster models in Contemporary Orthodontics: Chad Callahan, P. Lionel Sadowsky and Andre Ferreira. Seminar in Orthodontics 3rd issue 2005

20 Orthodontic patients( 11 Class I, 7 Class II, 2 Class III ) were selected

Four Orthodontists participated with a experience of 8 to 30 years

Initially Extra oral photographs, Radiographs are provided

Following which a questionare is given consisting of 20 diagnostic criteria including Molar relationship, Canine relationship, Arch form, Overbite, Overjet, Crowding etc.

Plaster models were later provided and the Diagnosis and treatment plan were revisited to evaluate whether models added any value to the diagnosis

Results: 83 Diagnostic values changed of a

possible 1600 i.e, about 95 % of the Diagnostic values remain unchanged.

Only 5 out of 20 Diagnostic values were determined to be statistically significant include Molar, Canine relationship, Overjet, Overbite, Depth of curve of spee.

Rheude B, Sadowsky Pl, Ferriera A, Jacabson A. An evaluation of the use of digital study models in orthodontic diagnosis and treatment planning Angle Ortghod 75: 292-296, 2005

They compared Digital models to plaster models

They found 14 out of 20 diagnostic criteria showed variation

They concluded this variation as clinically insignificant

Han U. Consistency of orthodontic treatment decisions relative to diagnostic recordsAJO DO 1991, 100: 212-219

In contrast to previous studies, Diagnostic models could provide adequate amount of information for treatment planning in 55% of cases

Current view point Diagnostic changes made following the

addition of study models to the other records proved not to be clinically significant.

Plaster models are currently being replaced by digital models and have been proven to be excellent alternative

Reliability of Digital

vs Conventional cephalometric

Radiology

Cephalometrics remains the only practical quantitative method that permits investigation and examination of the spatial relationships between both cranial and dental structures

Advantages of Digital Cephalometrics

Instantaneous image acquisition

Reduction of radiation dose

Facilitated image enhancement and archiving

Elimination of technique sensitive developing process and its costs

Facilitated image sharing

Reliability of Digital vs Conventional cephalometric Radiology: A comparative evaluation of landmark identification error. Scott R. Mclure etal Seminar in Orthodontics 3rd Issue 2005.

Purpose: The accuracy of landmark identification utilizing these two different image acquisition methods should be compared

19 commonly used cephalometric landmarks are used in the analysis

Method The landmarks location on the digital

images and transparent acetate films could then be described by using X and Y co-ordinates with the aid of computerized program

The average position for each landmark was also used to facilitate accurate superimposition in the creation of scatterograms for each landmark.

Results: 1. Three of the 19 landmarks indicated

statistically significantly higher landmark identification error for film based identification methods than for digital image based identification

2. But the error is less than 1 mm indicating unlikely clinical significance.

Trpkova etal Conducted similar study in 15 skeletal

landmarks Concluded Landmark identification

using digital images had more precision in both x and y dimensions than conventional film based landmark identification.

Current view point

The advantages of digital cephalometry coupled with proven clinical performance equal to that of film may lead to shift in what is considered the standard for cephalometric radiography in future.

ETIOLOGY OF

MALOCCLUSION

A strong influence of inheritance on facial features is obvious to recognize.

It is also apparent that certain types of malocclusion run in families.

e.g. Hapsburg jaw www.indiandentalacademy.co

Malocclusion could be produced by inherited characteristics in two possible ways:

Inherited disproportion between the size of teeth and that of the jaws-producing crowding/spacing.

Inherited disproportion between size/shape of upper and lower jaws –producing improper occlusal relations.

There is considerable anthropological evidence that population groups that are genetically homogenous tend to have a normal occlusion

e.g: Melanesians of Philippine islands, this is the result of genetic isolation and uniformity.

Based on this evidence, workers of the yesteryears were tempted to conclude that the great increase in population and its mobilization was the primary explanation for the increase in malocclusion in modern man They blamed this on the improper function

of jaws under degenerate modern conditionswww.indiandentalacademy.com

The earlier part of the 20th century Development of classical Mendelian genetics.

The new view was that malocclusion is primarily the result of inherited dento-facial disproportions strengthened by the breeding experiments carried out by Prof. Stockhard (1930).

Later part of 20th century

A revival and a swing back to the earlier concept that jaw function is related to malocclusion.

A number of familial and twin studies in the latter part of the century by workers like Lundstrom (1984), Corrucini (1980), Potter (1986), Bolton and Brush, Harris and Johnson (1991) gave a more balanced view showing that there is no single explanation for malocclusion in terms of function, heredity or environment, but is a result of a complex interplay of these elements.

Current view point:

RESPIRATORY PATTERN

Respiration is the Primary determinant of jaw and tongue posture.

Altered respiratory pattern change posture of head, jaw, and tongue alters equilibrium jaw growth and tooth position affected.

Harvold, Tomer and Vargevik (1981)

Total nasal obstruction in monkeys, for a prolonged time led to the development of malocclusion.

Placing a block on the roof of the mouth, forcing the tongue to a more downward position, producing a variety of malocclusion.

Because total nasal obstruction in humans is so rare, the important question is whether partial nasal-obstruction is a risk factor in causing malocclusion ?

Does nasal obstruction equates mouth breathing + lip-apart posture ?

Ballard andGwynne-Evans (1958)

Nose breathers, who have a lip - apart posture, usually have post seal with tongue against soft palate as an adaptive mechanism.

Wood side, Linder, Aronson, Lundstrom (1991)

Concluded that change from mouth-open to mouth-closed breathing after adenoidectomy for severe nasopharyngeal obstruction in 38 children

Greater mandibular growth expressed at chin in both sexes:

3.8mm in males & 2.5mm in girls Greater facial growth expressed

at midface, only in males. No change in maxillary growth

direction.www.indiandentalacademy.co

Bushey

Found no relationship between nasal respiration and linear measurements of adenoids in lateral cephalogram before and after adenoidectomy.

Fields et al (1991) Compared respiratory mode in normal and

long-faced subjects. Results:

Long-faced significantly smaller component of nasal air flow (40%) but total volume and nasal cross-sectional area were similar.

He concluded that Significant difference in airway impairment does not have direct effect on breathing mode behaviorally determined than structurally dependent.

RME and Nasal obstruction

RME for transverse maxillary deficiency correction also increases nasal airflow.

Hartgerick et al (1987) -No increase in % of nasal breathing. -Can decrease in nasal resistance. -Did not change respiratory mode of the patient

Bell (1977) andSpalding et al (1991):

No decreased nasal resistance and no increased % of nasal airflow.

Provides another example why clinicians and researchers should not assume that because one of the parameters of nasal respiraton is affected, others like cross-sectional area, peak nasal flow rate and respiratory mode will all be similarly affected”.

Contemporary view

2 opposing principles, leaving large gray area between them:

1. Total nasal obstruction likely to alter pattern of growth and lead to malocclusion. – High percentage of oral respiratory is over represented in long-face population.

2. Majority of individuals with long-face deformity have no evidence of nasal obstruction because some other etiological factor as principal cause.

More recent findings suggest that nasal-oral breathing per se is not necessarily harmful to cranio facial growth. However, in instances where the naso-pharyngeal or oro-pharyngeal air space is small, exaggerated postural responses in obligatory mouth breathers may be detrimental to craniofacial growth. www.indiandentalacademy.co

Tongue-thrust as etiologic factor

Definition- placement of tongue-tip forward between incisors during swallowing.

The term tongue-thrust is a misnomer, since it implies that the tongue is forcefully thrust forward.

Laboratory studies indicate that individuals who place the tongue tip forward when they swallow do not have more tongue force against teeth than those who keep tongue tip back- in fact, tongue force may be lower. – Profitt (1972)www.indiandentalacademy.co

The term tongue-thrust is a misnomer, since it implies that the tongue is forcefully thrust forward.

Laboratory studies indicate that individuals who place the tongue tip forward when they swallow do not have more tongue force against teeth than those who keep tongue tip back- in fact, tongue force may be lower. – Profitt (1972)www.indiandentalacademy.co

Tempting to blame tongue-thrust as a cause for open bite, since these individuals keep their tongue between the anterior teeth when they swallow.

The mature/ adult swallow pattern appears in some normal children as early as age 3, but not present in majority until about age 6 & is never achieved in 10 - 15% of a typical population

Some times children & adults who place their tongue between anterior teeth are spoken of as having a retained infantile swallow- this is clearly incorrect, since only brain damaged children retain a truly infantile swallow in which posterior part of the tongue has little or no role. (Profitt)

Equilibrium theory: Light but sustained pressure by tongue against the teeth would be expected to have significant effect. Tongue-thrust swallowing simply has too short a duration to have an impact on tooth position.

Tongue pressure against the teeth during a typical swallow is < 1 seconds. A typical individual swallows about 800 times in a day, while awake, but has only a few swallows / hour while asleep. Hence – total/ day is < 1000 times, & thus 1000 seconds of pressure has little/no effect.

Current view point:

Tongue –thrust is primarily seen in 2 circumstances:

In young children with normal occlusion – transitional stage in normal physiologic maturation.

In individuals of any age with displaced anterior teeth – adaptive.

Current view point:

Hence it is more a “Result” than a “cause”

However tongue posture is more important.

Light pressure for more duration change in tooth position.www.indiandentalacademy.co

THIRD MOLARS – A DILEMMA! OR IS IT?

Third molars are usually considered as Vestigial organs which may be reserves for mutilated dentition.

The role that mandibular third molars play in lower anterior crowding has provoked much speculation in the dental literature.

In a survey of more than 600 orthodontists and 700 oral surgeons, Laskin found, that 65% were of the opinion that third molars sometimes produce crowding of the mandibular anterior teeth.

As a result of such opinions, the removal versus the preservation of third molars became the subject of contention in dental circles.

The differing views Third molars should be removed even on a

prophylactic basis, because they are frequently associated with future orthodontic and periodontal complications as well as other pathologic conditions.

There is no scientific evidence of a cause and effect relationship between the presence of third molars and orthodontic and periodontal problems.

“Pressure from behind” theory: The late lower arch crowding is caused

by pressure from the back of the arch. But whether this pressure results from: 1. Dev. 3rd molar. 2. Physiologic mesial movement /

drift. 3. Anterior component of force

derived from forces of occlusion on

mesially inclined teeth. Is not sure

Relationship between 3rd molars and

incisor crowding Bishara et al (1989 and 1996) reviewed

changes in Lower incisor that occur with time in untreated populations between 12 and 25 years and again at 45 years

Increase in tooth size arch length discrepancy with age – consistent decrease in arch length.

Average changes 2.7mm in males; 3.5mm in females. These changes were attributed to a consistent decrease in arch length that occurred with age. www.indiandentalacademy.co

Fastlicht (1970) found that in orthodontically treated subjects- 11% had 3rd molars, but 86% had crowding.

Little et al (1981) observed that 90% of extraction cases that were well treated orthodontically ended up with an unacceptable lower incisor crowding.

Orthodontic treatment patients

These long term studies indicated that the incidence as well as the severity of mandibular incisor crowding increased during adolescents and adulthood in both the normal untreated individuals as well as orthodontic treated patients, after all retention is discontinued.

Studies relating 3rd molar to crowding of dentition:

Bergstrom and Jensen (1961) Cross-sectional study examined 30

dental students of whom had unilateral agenesis of upper 3rd molar and 27 had agenesis of one lower 3rd molar.

More crowding in the quadrant with 3rd molar present than in the quadrant with the third molar missing.

Mesial displacement of lateral dental segments on the side with 3rd molar present in the mandibular arch not in the maxillary arch.

The unilateral presence of a third molar did not have an effect on the midline.

Schwarze (1975)

Compared a group of 56 patients with third molar germectomy to 49 subjects with third molars. He found significantly greater forward movement of first molars associated with increased lower arch crowding in the non extraction group.

Lindquist and Thilander (1982)

Extracted third molar unilaterally in 52 patients and found more stable space conditions (less increase in crowding) on the extraction side compared with the control side in 70% of cases.

Studies indicating lack of correlation between

mandibular 3rd molar and post retention

crowdingwww.indiandentalacademy.co

Retrospective studies Kaplan (1974) :. The sample consisted of 75

orthodontically treated patients on whom pretreatment, post treatment and 10 years post treatment study models and lateral cephalograms were obtained.

-Mandibular third molars and post retention crowding Kaplan R. AJO DO 1974 ;66:411-430

The sample was divided into three groups: The first group consisted of 30 persons with

both third molars erupted to the occlusal plane, in good alignment buccolingually, and of normal size and form.

The second group consisted of 20 persons with bilaterally impacted third molars. All patients in this group were candidates for surgical removal of the third molars on the basis of postretention periapical radiographs.

The third group consisted of 25 patients with bilateral agenesis of the mandibular third molars.

Presence of 3rd molar does not produce a greater degree of lower anterior crowding or rotational relapse after cessation of retention.

Ades et al (1990)

in a cephalometric study on a similar sample found :

No significant differences in mandibular growth patterns between various 3rd molar groups – erupted, impacted or agenesis.

Majority of cases have incisal crowding, but no correlation with 3rd molars.

Although the mandibular third molar probably does exert an insignificant force on the dental arch during its eruption, an objective review of the existing information regarding this topic must conclude that the third molars do not significantly influence the lower anterior crowding.

Current view point

EXTRACTION vs

NON-EXTRACTION

The only life and death

situation in orthodonticsis whether to

Extract

“To extract or not to extract” was one of the early debates that clouded orthodontic world ever since its beginning.

2 main reasons for extraction:

Provide space to align remaining teeth in crowding.

Allow teeth to move for camouflaging skeletal malocclusion- Cl-II/Cl-III

Late 1800

Late 1800 saw a casual attitude towards extraction

Angle proposed 2 key concepts:

Skeletal growth Influenced readily by external forces.

Proper function of dentition would be the key for maintaining teeth in their correct position.

Early 1920’s

For him “relapse” meant – adequate occlusion not reached.www.indiandentalacademy.com

“If correct occlusion is produced then result is stable, if result is not stable it was the fault of orthodontist and not the theory”.

Angle’s proposal and Beliefs

Ideal facial esthetics would result when the teeth are placed in ideal occlusion.

He believed this can be achieved when the dental arches are expanded so that all the teeth were in ideal occlusion.

Calvin Case

Argued that although the arches could always be expanded so that the teeth could be placed in alignment, neither esthetics nor stability would be satisfactory in the long term for many patients

Dewey vs Case

The controversy culminated in a widely publicized debate between Angle’s student Dewey and Case in the dental literature of 1920’s.

- The Extraction debate of 1911 by case, Dewey and cryer. Discussion of case: The question of extraction in orthodontia. AJO 50: 751,1964www.indiandentalacademy.co

Angle followers won : Extraction disappeared between World War I & II.

Even in South America, where removable (Crozat) or twin wire appliances were used accepted non –extraction and its philosophy under pinning.

From 1930’s – 1970’s Charles Tweed re-treated the relapse

cases with extraction; previously treated with non-extraction methodology, & found occlusion to be much more stable.

He supported his theory by Cephalometrics

late 1940’s

Extraction reintroduced widely

Raymond Begg popularized “Begg” appliance for extraction treatment.

This was further strengthened by Prof. Stockard’s experiments which showed that malocclusion could be inherited

So why the total change in philosophy?

Instability of non extraction results due to Arch length collapse in particulary

1. Lower anterior crowding 2. Reversion to original class II malocclusions and

procumbencies.

Between 1970-1990’s: Saw the revival of non-extraction

philosophy.

Premolar extraction does not guarantee stability of tooth alignment.

Little, Wallen and Riedel – 1981 AJO. MC Reynolds and Little – 1991 Angle Orthod

Lower anterior crowding recurred post retention Deep bites recurred more readily in all 4 extraction

Argument resurfaces

“If result not stable either way, why sacrifice teeth at

all”. vs

“If extraction cases are unstable, non-extraction

would be worse” www.indiandentalacademy.co

Changing views of esthetics : Fuller profile than orthodontic profile

Change from banding to bonding and introduction of functional appliances.

Between 1970-1990’s:

The ill-famous litigation – Witzig and Spahl (1980)

Premolar extraction causes

distalization of mandible posteriorly, displacement of condyle resulted in perforation of articular disc TMD.

What happened? Why this shift back to an approach to treatment which was discarded 50 years ago?

Management of Non extraction treatment has improved

1. Issue of growth and our ability to influence it 2. Reduction of caries maintaining arch length. (Mixed dentition treatment) 3. Reduced camouflage treatment

Treatment modalities converting borderline cases into non –extraction cases:

Early intervention: Use of ‘E’ space. Proximal stripping of primary teeth. Space regainers with space maintainers. Arch expansion. Use of functional appliances. Molar distalization. Bonded attachments rather than banded

Treatment modalities converting borderline cases into non - extraction cases:

Adult: Molar distalization. Inter-proximal reduction. Arch expansion. Surgery for skeletal

discrepancies.

Expansion vs Extraction

Acceptable range of protrusion in biologic limits – expand.

Control space closure by combination of retraction (anteriors) and protraction (posteriors) – extract.

Importance of soft tissue Lip separation – increases with tooth

prominence. Thick, full lips – can afford prominent

incisors. Cephalometric readings can serve as

guidelines. Size of nose and chin. Lip strain i.e. lack of well defined

labiomental sulcus.

Stability considerations

Limiting forces from cheeks Fenestrations in Buccal cortical

plate (> 3mm)

Beauty lies in the eyes of the beholder and in the face of the beheld

But who is the better judge of the beauty?

Saint Louis university,

63 Border line Extraction and Non extraction patients selected by discriminate analysis

Patients evaluated own pre and post frontal photographs 14 years post treatment

Paquette etal 1991, Johnson etal 1994www.indiandentalacademy.co

57% of Non - Extraction patients thought orthodontic treatment improved Frontal Facial appearance

69% of Extraction patients thought the same

Saint Louis university,

Luppanapornlap and Johnson, AO 1993

Mean start, finish and recall facial Polygons for the extreme extraction and non extraction samples. At recall, it was the non extraction subjects Who tended to have the “flatter” profile

Witzig and Spahl 1987 and Dierkes 1987 have asked

“What are the spaces at the corners of smile from extraction treatment?”

Washington university

Sample of 60 Extraction and Non extraction patients

Panel of 10 lay persons Evaluation of post treatment smile

photograhs

- Johnson and smith 1990www.indiandentalacademy.co

Washington university

No predictible relationship between extraction of premolars and Esthetics of smile

- Johnson and smith 1990

If the inter canine width or arch form is maintained during treatment, whether extraction or non extraction, the width of the smile would be the same post treatment

The effects of buccal corridor spaces and arch form on smile estheticsRoden-Johson D., Gallerano R, English J AJODFO 2005, 127: 343-50

• 60 Dentists, orthodontists, and lay persons evaluated photos of patients with buccal corridor spaces and those without

• No difference in smile scores related to Buccal corridor Spaces

• Lay person have no preference for arch form

• Dentists & Orthodontists like broader arch forms

The claim that the Negative spaces in the Buccal corridor are a routine result of extraction treatment appears to be false. Miss world 2002

Azra akinwww.indiandentalacademy.com

Contemporary Extraction Guidelines:

For Class I crowding / protrusion: Arch length discrepancy < 4mm with no

vertical discrepancy: non-extraction. Arch length discrepancy = 5-9mm Non-extraction : Transverse expansion of premolar segment. Extraction : Any pattern of extraction depending on hard and soft

tissues. Arch length discrepancy > 10mm :Extractionwww.indiandentalacademy.co

Lower lip to E- plane (Caucasians)

Bowman and Johnston AJO DO 2000www.indiandentalacademy.com

Current view point

We find that we have completed the circle and rather than anterior crowding being the principal reason for extraction treatment, facial cosmetics should assume the major diagnostic role in border line cases.

Earlier treatment of maxillo-mandibular basal discrepancies by old and new treatment philosophies and mechanics have produced more stable non-extraction corrections. Better control of Lee-way space and a reduction in caries has helped reduce the amount of lower anterior flaring that was seen in non-extraction cases in the first third of the century. These reasons have moved the specialty of orthodontics to a mixed but more non-extraction oriented approach to treatment.

EARLY VS

LATE TREATMENT

The optimal timing of treatment of children with malocclusion remains controversial.

Determining the relative merits of alternative treatments is complex, not only because of variability in initial conditions and treatment response, also because of differences between orthodontists in treatment beliefs, goals techniques and even skills.

Early treatment

Treatment started either in primary or mixed dentition that is performed to enhance the dental and skeletal development before the eruption of the permanent dentition.

Goals and benefits of phase I treatment

1. Superior facial esthetics2. Greater ability to modify the growth process3. Fewer extractions4. Reduction in the duration and difficulty of subsequent

therapy5. Consistent and predictable elimination of phase II

treatment6. Improvement in patients self concept7. Reduction in the fracture potential of protruding maxillary

incisors8. Greater patient compliance9. Eliminate, if not reduce the need for future jaw surgery10.Greater stability

Iatrogenic damages of early treatment1. Longer overall treatment time2. Loss of compliance3. Greater risk due to prolonged treatment

such as root resorption, whilespot lesion, bone loss caries

4. Increased cost5. Dilacerations of roots6. Impaction of maxillary canines by

premature uprighting of the rootsof lateral incisors

7. Impaction of maxillary second molarswww.indiandentalacademy.co

The procedures in phase I treatment are

1. Growth modification a. Headgears b. Functional appliances c. Face mask d. Chin cap2. Arch length discrepancy a. Serial extraction b. Arch expansion c. Preservation of arch length3. Open bite correction4. Correction of tooth eruption disturbances

Timing of Cl-III treatment

Timing of chin cup treatment for Class III- irrelevant for growth modification & stability.

Semin Orthod 3:224-254;1997.

Face mask treatment for Class III with maxillary deficiency is evidence based.

AJODO 113:333-343;1998.

Semin Orthod 11:112–118 ;2005

Treatment of slow or non-growing patients during late adolescent or adulthood respectively depends upon growth status, esthetics & severity of Malocclusion.

Decide

Camouflage Orthognathic

Surgery

Semin Orthod 11:112–118 ;2005

Timing Of Cl II Treatment

Early intervention for growth modification- Limited skeletal changes reported in long term evaluation.

Slow or non-growing patients during late adolescent or adulthood respectively- Camouflage treatment.

Acceptable results at long term follow up.

AJODO 123:266-278;2003.

Semin Orthod 11:112–118 ;2005

Late adolescence & adults with severe skeletal Class II- Orthognathic surgery

Semin Orthod 11:112–118 ;2005

1. When skeletal change is a goal of Class II malocclusiontreatment by growth modification or surgery, dentalcompensation is a key component to the success oftreatment.

2. The timing of treatment was largely determined by theseverity of the malocclusion and the maturation of thepatient. The era of skeletal correction of malocclusionwith growth modification and innovative surgical

techniquesalso emphasizes dentoalveolar changes are theultimate solution for many Class II malocclusions.

Semin Orthod 11:112–118 ;2005

Melsen (AJO-2003)

She did a long term study on intermaxillary molar displacement. The first time in the year 1978 and then again 7 years later with patients treated with the Kloehn headgear along with cervical traction.

A strong tendency of the molars to return to the class II relationship was demonstrated.

Melsen (AJO-2003) No evidence that a Class I relationship

obtained by extraoral traction was more stable that that obtained by functional or intermaxillary appliances.

It was noted, however, that the variation in the vertical development was related more to each patient’s growth pattern than to the force system applied.

After cessation of the headgear, intramaxillary displacement of the molars was noted, and the total displacement of the molars did not differ from that of the untreated group.

Functional appliances

For 30 years, investigators have noted facial skeletal changes in monkeys as a result of altered oral function.

The potential for changes both as a result of increased mandibular length and also effective mandibular position by means of temporo-mandibular joint remodeling was proposed.

Florida study (AJO DO-1998) Keeling,

Children aged 9 years at the start of treatment were randomly assigned to control, Bionator and Headgear with Biteplates.

There was no significant differences in the final PAR scores when patients who wore their headgear or bionator as a retention appliance between phase 1 and phase 2 treatment were compared with patients who did not wear any appliance during this period

University of North Carolina(AJODO 1997)

PHASE I Randomized

Observation Functional Appliances Headgear

End of Phase I in 15 months

Retention Phase for 1 yearAssigned to four different orthodontists for phase II

It was a prospective long term study.

It had an almost ideal research design.

Conducted by Drs. Camilla Tulloch and William Proffit

All subjects were children with overjet of 7mm

University of North Carolina(AJODO 1997)

University of North Carolina(1997-2004) Results

There was no difference between the groups with regard to ANB angle either at the start or after phase II of treatment.

No difference in the quality of dental occlusion between the children who had early treatment and those who did not.

There was approximately the same distribution of success and failure with and without early treatment.

University of North Carolina(AJODO 1997) Results

Early treatment did not reduce the number of children needing extraction of premolars or other teeth during phase II of treatment.

Early treatment did not reduce the eventual need for orthognathic surgery.

There was little influence on the time duration that both groups spent wearing fixed appliances.

University of North Carolina(AJODO 1997) Results

Early treatment did reduce severity of class II malocclusion.

Overjet did decrease in the treated groups whether the appliance was a headgear restricting the maxilla or a functional one positioning the mandible forward.

Still doubt whether early treatment is better or not as long as treatment is provided at some point in time.

Studies on Arch length discrepancy (Little AJO 2002). Without treatment a short arch

length will only get worse. Cases that underwent expansion

showed the poorest long-term results Serial extraction followed by routine

treatment yields no greater long-term improvement over premolar extraction in the full dentition.

Two-stage treatment: an outcomes-based assessment Gianelly A.A.1Progress in Orthodontics, Volume 1, Number 1, 1 January 2000, pp. 3-9(7)

Neither self-concept nor the ability to modify growth is improved by stage-one treatment,

There are no skeletodental differences between the results obtained by one-stage and two-stage treatments.

Accordingly, two-stage treatment cannot be endorsed on the basis of providing unique and characteristic psychological or skeletodental benefits.

Assessment of Orthodontic Treatment Outcomes: Early Treatment versus Late Treatment: Tsung-Ju Hsieh, Yuliya Pinskaya, W. Eugene Roberts, The Angle Orthodontist: Vol. 75, No. 2, pp. 162–170

Comparison of the final results between early vs late-treatment groups showed that the early-treatment group had significantly longer treatment time and worse CCA scores than the late-treatment group.

There was no significant difference between early- and late-treatment groups regarding the ABO OGS score.

Current view point There is very little evidence in the

literature to suggest the two phase treatment can significantly modify growth or eliminate the need for protracted phase two treatment nor can it be justified to result is fewer extractions or avoidance of orthognathic surgery.

Early phase one treatment is beneficial in reducing the incidence of incisors trauma and may be useful in correction of eruption disturbances.

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Orthopedics in

Orthodontics fiction or reality?

Duterloo defines orthopedic effect in orthodontics as a change in the position of bones in the skull in relation to each other induced by therapy

According to Isaacson, orthopedic appliances provide a new muscular and functional environment for the facial bones that encourages growth changes of either the mandible or the maxilla.

Class III Orthopedic changes

Stimulation of maxillary growth in all cases, inhibition of mandibular growth as a result of class III therapy was reported in 67% of the studies

Orthopedics in orthodontics: Fiction or reality. A review of the literature—Part II AJO-DO Volume 1996 Dec (667 - 671)

chincup therapy Few studies report on long-term effects

of chincup therapy. The findings of Sugawara et al. indicate that chincup therapy did not necessarily guarantee positive correction of the skeletal profile after complete growth.

Sugawara J, Asano T, Endo N, Mitani H. Long-

term effects of chincap therapy on skeletal profile in mandibular prognathism. Am J Orthod Dentofac Orthop 1990;98:127-33.

Therapeutic maxillary expansion ranging from 0.9 to 3.2mm in 12 weeks to 6 months (short treatment period).

Wertz R, Dreskin M. Minor palatal suture opening: a nonnative study. Am J Orthod 1977;71:367-89.

Maxillary Expansion

Normal Maxillary growth

According to Bolton studies the yearly increase in interjugular width is approximately 1mm, which coincides with Rocky Mountain Standards

Normal Maxillary growth

Savara claims that the maxillary width, expressed as distance between both pterygomaxillary fissures, increased with 0.18mm between 12 and 16 years, because of normal growth.

Savara BS, Singh U. Norms of size and annual increments of seven anatomical measures of maxillae in boys from three to sixteen years of age. Angle Orthod 1968;38:104-68.

Therapeutically induced maxillary expansion is larger than the increase expected because of normal growth, within a short observation period.

As stated by Sarnäs, the net increase out of retention is only 1.6 mm being within anticipated normal growth.

Sarnäs KV, Björk A, Rune B. Long-term effect of rapid

maxillary expansion studied in one patient with the aid of metallic Implants and roentgen stereometry. Eur J Orthod 1992;14:427-32.

No scientific evidence exists so far to indicate that an orthodontist can induce a stable enlargement of maxillary basal bone that exceeds normal growth.

Current view point in Maxillary Expansion

Bite Opening controversy Although the sagittal construction bite

advancement concept generally was accepted by clinicians in Europe (it varied from 3 to 6 mm) depending on the severity of anteroposterior dysplasia and resultant abnormal buccal segment interdigitation, the theory pertaining to the amount of vertical opening and its effects on the muscles produced considerable controversy.

Bite Opening controversy

Anderson and Haupl’s interpretation presupposed freedom for the mandible to assume the physiologic rest position

Slagsvold, later professor of orthodontia at Oslo, reported that his own observations did not substantiate this premise completely. Nevertheless he concurred that forward posturing should not exceed the rest position vertical opening of 2 – 4 mm.

Too wide on opening made compliance more difficult and could produce a depressing force on the teeth, hardly desirable in deep bite, class II malocclusions.

Grude and Frankel strongly support this construction bite limit

The philosophy of Harvold & Woodside has been to exceed the free way space limits, if for no other reasons than to keep the appliance in place at night during sleep or as to maintain a corrective stimulus.

Incremental vs one step advancement

Frankel recommends incremental small advancements of 2 to 3 mm for his appliances rather than the great leap forward of 5 to 7mm. Reactivation of optimal tissue response as well as enhanced patient compliance are factors. This concept encourages daytime wear. The frequency of deglutition is increased and phasic muscle activity is enhanced.

Frankel R: Clinical relevance of step by step mandibular advancement in the treatment of mandibular retrusion using the frankel appliance AJO 1996 333, 1989

Sander and Schmuth also have studied the effect of large protrusion construction bites with tendency to disclude the appliance both during the day and at night reducing the desired effect and jiggling selective teeth.

Milestones in the development and practical application

of functional appliances AJO 1984: 48, 1983

Also histological evidence support periodic incremental advancement because of the periodically enhanced condylar and fossa response with each adjustment

With single 6 to 7 mm the condylar and fossa growth stimulus is of shorter duration, daytime wear becomes more difficult and adverse labial proclination of mandibular incisors may be greater.

Day time vs Night time wear

Selmer Olsen believed that the muscles could not actually be stimulated during sleep. Nature had designed them to rest at night and swallowing occurred only 4 to 8 times any hour

Komposch and Hackenjos, Sander, Schmuth, Herren corroborated the finding that activator does not activate muscles during sleep.

Harvold and Woodside, Ricketts recommend nighttime wear of appliance for maximum effect.

Day time vs Night time wear

Effect of head posture during sleep

Mandibular rest position depends on the head and body posture, thereby the restriction of muscle movement required to create the desired mandibular position change, without the activator in place, varies constantly involving different muscle groups and creating different force vectors on the activator.

Variation in head posture during sleep alters the magnitude and direction of force.

The phase of sleep, intraoral air pressure, dream cycle, state of mind are additional conditioning factors all uncontrolled by clinician.

Only the mandibular position and the potential effect on glenoid fossa are controlled.

Effect of head posture during sleep

What happens with the use of functional appliances?

In spite of considerable research and debate the precise mode of action of functional appliance remains obscure

Dentoalveolar changes: Harvold and others have stressed the importance of a vertical manipulation of the functional occlusal plane in achieving class II corrections with removable functional appliances.

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Dentoalveolar changes

Prevention of the eruption of maxillary buccal segments which is normally in downward and mesial direction

Removable functional appliance do not distalize the upper dentition unless Headgear is used

Midface restriction Effect on Mandibular growth: is

again a controversy

What happens with the use of functional appliances?

Can we grow smaller Mandibles?

Much of the work demonstrating the ability of functional appliances to stimulate mandibular, growth as based on animal experimentation.

Animal studies Cartilage proliferation by increased mitotic activity in pre-

chondroblastic zone growth increments of condyle. Petrovic A, Stutzmann J, Oudet CL. Control processes in the

postnatal growth of the condylar cartilage of the mandible. In: McNamara Jr JA, ed. Determants of mandibular form and growth. Monograph 4, Craniofacial Growth Series. Ann Arbor: Center for Human Growth and Development, University of Michigan, 1975.

Increase in effective length of mandible

McNamara Jr JA, Bryan FA. Long-term mandibular adaptations to protrusive function: an experimental study in Macaca mulatta. Am J Orthod Dentofac Orthop 1987;92:98-108.

Therapeutic remodeling of glenoid fossa

Woodside DG, Metaxas A, Altuna G. The influence of functional appliance therapy on glenoid fossa remodeling. Am J Orthod 1987;92:181-98.

Catch-up growth after treatment independent of direction of therapeutic force.

Elder JR, Tuenge RH. Cephalometric and histologic changes produced by extraoral high-pull traction to the maxilla in Macaca mulatta. Am J Orthod 1974;66:599-644.

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Several investigators showed dramatic changes in mid-face of monkeys after headgear treatment.

Henry HL, Cleall JF. Radiographic cephalometric method of assessment of craniofacial growth in monkeys. J Dent Res 1974;53:369-74.

Joho JP. The effects of extraoral low-pull traction to the mandibular dentition of Macaca mulatta. Am J Orthod 1973;64:555-77.

Meldrum RJ. Alterations in the upper facial growth of Macaca mulatta resulting from high-pull headgear. Am J Orthod 1975;67:393-411.

Animal studies

The same story holds true for maxillary protraction studies on monkeys.

Kambara T. Dentofacial changes produced by extraoral forward force in the Macaca irus. Am J Orthod 1977;71:249-77.

Experiments on mandibular retrusion in rats show histological and some macroscopic decrease of mandibular length.

Charlier et al (1969),Petrovic et al (1975),Janzon and Bluher (1965),Ajano (1986)

Animal studies

Whether these findings on animal models are applicable to human beings during routine clinical treatment is debatable.

Discrepancies between animal and human studies are expected since animal experimentation frequently involves the use of continuous forces.

These types of forces usually are impractical and often undesirable in most clinical situations therefore treatment results can be expected to be less dramatic and more variable

Long-term Effect After Activator, Headgear-Activator, Herbst Appliance and Headgear Treatment

The orthopedic effect induced by an appliance is one point of interest, but more interesting is long-term behaviour

Panchez et al published many reports on long-term effects on Herbst appliance.

Only temporary effect on existing skeleto-facial growth pattern.

After orthopedic intervention – maxillary and mandibular growth seemed to strive to catch up with early pattern.

Pancherz H, Anchus-Pancherz M. The headgear effect of the Herbst appliance: a cephalometric long-term study Am J Orthod Dentofac Orthop 1993;103:510-20.

Basal maxillary changes are relatively stable 6 years after retention. The growth pattern of the maxilla was changed in a more posterior-inferior direction

Wieslander L, Buck DL. Physiologic recovery after cervical traction therapy. Am J Orthod 1974;66:294-301.

Long-term Effect After Activator, Headgear-Activator, Herbst Appliance and Headgear Treatment

Recently, DeVincenzo investigated changes in mandibular length before, during, and after successful orthopedic correction of Class II malocclusions. The increase in mandibular length during the functional appliance phase was pronounced and the rate of increase is dramatic.

DeVicenzo JP. Changes in mandibular length before, during, and after successful orthopedic correction of Class II malocclusions using a functional appliance. Am J Orthod Dentofac Orthop 1991;99:241-51.

J Orofac Orthop. 2001 Nov;62(6):436-50. Clinical application and effects of the Forsus spring. A study of a new Herbst hybrid.Heinig N, Goz G.

Evaluation of the lateral cephalograms showed that dental effects accounted for 66% of the sagittal correction. The sagittal occlusal relations were improved by approximately 3/4 of a cusp width to the mesial on both the right and left side as a result of distal movement of the upper molars and mesial movement of the lower molars. Retrusion of the upper and protrusion of the lower incisors reduced the overjet. Intrusion and protrusion of the lower incisors reduced the overbite. The occlusal plane was rotated in clockwise direction as a result of intruding the lower incisors and the upper molars. The maxillary and mandibular arches were expanded at the front and rear during treatment.

Controversies

in Pre Adjusted

Appliancewww.indiandentalacademy.co

Torque in the Base vsTorque in the Face

By 1988, about 30 % of all American orthodontists were using the straight wire appliance, another 50% were using Partly programmed edgewise appliances

Patent restrictions allowed them to reproduce no more than four of the eight vital features that appear in fully programmed brackets

( David webb, “A” company)

The Torque In the base allows the slot of the fully programmed bracket target correctly on the crown’s mid transverse plane

Torque in the face causes occluso gingival variation in the placement of slot point over mid transverse plane

Hence the Torque in base was an important issue with the first and second generation PEA brackets because Level slot line up was not possible with brackets designed for Torque in Face.

Modern Bracket systems like MBT system, have been developed using CAD-CAM system

The computer is first able to locate the precise location for the bracket slot, relative to in – out distance and torque position for each teeth. Once this position is established, it can be build up the in – fill areas to optimize all requirements of the brackets

018 vs 022 Slot: Steiner introduced the 0.457 mm × 0.711

mm (0.018-inch × 0.028-inch) slot for stainless steel wires in lieu of the 0.559 mm × 0.711 mm (0.022-inch × 0.028-inch slot for gold alloy wires.

Original intention of 022 slot was not meant for sliding mechanics, (as it is ideally suited) but it is for Torque movement control when 22 X 28 gold wires were used

With the advent of stainless steel wires, edgewise brackets were redesigned from 022 to 018 slot.

022 slot however was superior when sliding of teeth is necessary by the use of undersized stiffer wires, but is inferior to 018 slot in Effective torque expression due to limited springiness and range of stiffer wires used in wider slot.

018 vs 022 Slot:

Role of Titanium arch wires became evident in alignment and torque control in wider 022 slot by the characteristics like higher range and resistance to permanent deformation.

Even undersized stiffer wires are the alternate solution

018 vs 022 Slot:

Bracket prescription

SystemSystem

U1 U2 U3 U4 U5 L1 L2 L3 L4 L5

Tp Tq Tp Tq Tp Tq Tp Tq Tp Tq Tp Tq Tp Tq Tp Tq Tp Tq Tp Tq

Andrews 5/7 9/3 11/-7 0/-7 0/-7 0/-1 0/-1 5/-11 0/-17 0/-22

Roth 5/12 9/8 11/0 0/7 0/7 0/-7 0/-7 5/-11 0/-17 0/-22

Alexander 5/14 9/8 11/0 0/-7 0/-7 0/-5 0/-5 6/-7 0/-11 0/-17

Hilgers 5/22 9/14 11/7 0/-7 0/-7 0/-1 0/-1 5/7 0/-11 0/-17

Level Anchorage 5/14 9/8 6/0 0/-7 0/-7 0/-1 0/-1 6/0 4/-11 6/-11

Ricketts 5/22 8/14 5/7 0/0 0/0 0/-1 0/-1 5/7 0/0 0/-11

MBT 4/17 8/10 8/0 0/-7 0/-7 0/-6 0/-6 3/0 2/-12 2/-17

Sondhi 5/22 9/14 10/3 0/-7 0/-7 0/-1 0/-1 6/-7 0/-11 0/-17

In Andrew’s Original System:

Concerning the 1st order information: There is no antirotation system on any tooth, except a 10° distal offset on upper molars.

Concerning the 2nd order information: Teeth of the buccal segments all present a positive angulation, meaning that they all have a mesial crown tip, mostly for the 1st and 2nd upper molars.

Concerning the 3rd order information: On the upper arch: - The upper incisor only has a 7° torque - The upper canine has a negative torque of –7, equal to the torque of the biscuspids.- The torque if slightly greater on molars.

On the Lower arch:- The torque on the buccal segments is progressive from the canines to the 2nd molars.

A torque of 7° on central incisors was soon found to be insufficient, since the play between archwire and bracket slot, which wasn’t taken into account, creates important loss of information during retraction stages and hence the amount torque necessary to compensate for the unwanted lingual tipping was clearly greater than 7°

Andrew’s system soon got the reputation of being an “anchorage burning appliance” - - -

Increased tip in anterior brackets to compensate for wagonwheel effect

In 1974, Ronold Roth:

Based on anticipation of relapse during and

after treatment came up with his fully

programmed universal appliance. Thus he

systematically included the information for

over correction in all three planes of space.

Concerning the 1st order information: All teeth in the buccal segment – anti rotation system. Upper molars reinforce distal offset from 10° to 14° and lower molars 4°

anti-rotation

Concerning the 2nd order information : Canine angulation increased to 11° to 13° Maxillary buccal segment lose their mesial tip and are in more anchorage situation. www.indiandentalacademy.co

Concerning 3rd order information: The torque

on the upper incisors is increased by 5°

- Torque on the upper canines decreased by 5°- Torque is markedly greater on molars. (-14°

instead of -9°)

On the lower arch :

- Torque on the buccal segments stays identical to Andrew’s except for a decrease from 35° to 30° on the second molar which decreases the “rolling effect” (lingual tip) sometimes noticed with Andrews’ torque.

Vari Simplex Discipline

The most important angulation of the is the -6 degrees angulation of the lower 1st

molars. The mandibular first molars have this tip

back built in to promote leveling and to gain arch length.

The preservation of anchorage achieved using this technique is in keeping with the original Tweed principles

Vari Simplex Discipline In other systems, torque was

developed based on averages obtained by measuring the dentition of untreated ideal occlusions.

The Vari-Simplex approach, however, was to measure torque found in rectangular archwires used to finish well treated orthodontic cases.

Vari Simplex Discipline The 5º torque in mandibular incisor

brackets helps to move the incisal edge of the mandibular incisors lingually (less than 0.5 mm) and the root apices of these tooth labially (approximately 1mm).

Hilgers prescription

- Upper incisors have a considerably increased torque. 22° for the central incisor, 14 ° for the lateral incisor.

- Upper canine has a 7 ° torque, this creates a transverse differential of 14 ° between canine and biscuspid.

Ricketts Bioprogressive therapy

Bioprogressive therapy started initially with placing torque in the upper anteriors only.

This so called automatic torquing of the upper incisor was a graduation of multiples of 7 degrees with the

cuspid at 7º, lateral at 14º and central at 22º (may be it should have been 21º).

The “Full Torque Bioprogressive appliance” had built in torque for the lower posterior brackets too.

The same graduation for 7º, 14º and 22º was incorporated here, too.

Ricketts finally developed the “Triple Control Bioprogressive appliance” which also had second molar tubes with 32º of torque.

MBT prescription

Combination of Andrew’s and Roth with few changes

Anti rotation system was removed, all the excessive mesial tip has been removed.

Upper incisors have markedly increased torque of 17 ° and 10 ° and upper canine -7 ° torque.

The torque on the lower incisors increase to - 6 °

CONTROVERSIES IN ORTHOGNATHIC SURGERY

THE USE OF RIGID INTERNAL FIXATION The most universally used method for

stabilisation of ractures and osteotomies ha been the use of intermaxillary fixation (IMF).

Common methods of IMF include the use of arch bars , Ivy loops, cast splints or simply the use of the orthodontic appliance.

The introduction of rigid fixation has reduced the time required for IMF which would otherwise be 3 to 8 weeks of immobilisation.

ORTHOGNATHIC SURGERY

THE USE OF RIGID INTERNAL FIXATION Controversies in the use of Rigid

internal fixation include: Does RIF improve bony healing and post

operative osteotomy strength? Does it improve long term stability? Is there a greater chance of developing

TMD post operatively with RIF?www.indiandentalacademy.co

ORTHOGNATHIC SURGERY THE USE OF RIGID INTERNAL

FIXATION It was Spiessl who first described

the use of bone screws for fixation of a sagittal osteotomy in 1974.

The various RIF systems include: Lag screws Bone plating Pin systems

ORTHOGNATHIC SURGERY Advantages of rigid fixation:

Reduction or elimination of IMF Period of IMF can vary from 2to three weeks or

the suregon may choose not to use IMF at all. Increased post operative safety More rapid bone healing Ability to check the post operative occlusion

in cases where segments have been displaced.

Ability to stabilize osteotomies that would otherwise be difficult to stabilise

Better control of bony segments

ORTHOGNATHIC SURGERY Advantages of rigid fixation:

Increased stability More rapid reduction of oedema Improved condition of the TMJ and muscles of

mastication post operatively DISADVANTAGES:

Technical difficulties Increased expense Increased risk of infection Need for plate and screw removal Neurosensory disturbances Tooth devitalisation TMJ symptoms

ORTHOGNATHIC SURGERY TMJ

considerations in the use of RIF

ORTHOGNATHIC SURGERY

Kundert compared condylar displacement in patients treated with sagittal osteotomies of the mandible with screw fixation and wire fixation. The authors noted condylar distraction in both groups with the magnitude slightly greater in the screw fixation group.

J. Oral Surgery. 35: 881; 1977.

A computed tomography study showed some medial rotation of the condylar segment. Varying inter condylar distances were also seen. However, screw fixation apparently caused no major positioning problems of the condylar bearing segments.

J. Maxillo face Surg. 12: 139; 1984.

-Timmis et al compared 28 patients with rigid fixation Timmis et al compared 28 patients with rigid fixation 14 patients treated with wire fixation . The wire 14 patients treated with wire fixation . The wire osteosynthesis group showed no statistical change in osteosynthesis group showed no statistical change in facial pain, TMJ pain or clinical signs after surgery. The facial pain, TMJ pain or clinical signs after surgery. The rigid fixation group however showed significant rigid fixation group however showed significant decrease in TMJ noise, facial pain, and TMJ pain.decrease in TMJ noise, facial pain, and TMJ pain.

Oral surg. 62: 119; Oral surg. 62: 119; 1986.1986.

Carter et al studied the effects of various fixation methods for mandibular advancement surgery, they concluded that:

After sagittal split osteotomies of the mandibular rami, horizontal rotation of the condyle usually occurs, regardless of the type of fixation or the position of the distal segment.

2. There were statistically significant changes (p < 0.001) in the intercondylar angles with all three types of fixation when the distal segments were measured in the anterior and posterior positions. However, the clinical significance of these changes was not proved.

3. In the three methods of fixation, the only statistically significant difference (p = 0.005) was between screw and wire osteosynthesis when the distal segments were in the forward position.

4. There were no consistent differences in horizontal rotation between the condyles that were fixed first and those that were fixed second, for either the left or right side.

5. The size of the original intercondylar angle did not affect the magnitude of change in the postoperative intercondylar angle, regardless of the position of the distal segment or the type of fixation used.

Less Rigid Wire Cause the teeth

are no longer used as handles to the bone (IMF), the extra strength & rigidity are unnecessary.

More Rigid Wire During surgery

patients are still placed in IMF before screw or plate placement.

Flexible orthodontic appliance may lead to erroneous segment positioning & difficult finishing

ROOT RESORPTION

related to ORTHODONTIC

TREATMENT

Bates (1856) – 1st to discuss root resorption of permanent teeth.

Ottolengui (1914) – related root resorption to orthodontic treatment

Root resorption after treatment Part 2 – Brezniak and Wasserstein AJO-DO Volume 1993 Feb (138 - 146)

Etiology (Phillips, Reitan and Shafer et al)

Physiologic tooth movement. Adjacent impacted tooth pressure. Periapical or periodontal inflammation. Tooth implantation / replantation. Continuous occlusal trauma. Tumors/cysts. Metabolic / systemic disturbances Local functional / behavioral problems.

Nail –biting. Tongue thrust with open bite. Dilacerations.

Orthodontic treatment Individual susceptibility.

Types of Root resorption (Andresen) Surface resorption Inflammatory resorption 1. Transient 2. Progressive Replacement resorption

Root resorption after orthodontic treatment is surface / transient inflammatory resorption

Controversies in factors influencing root

resorption

Alveolar bone density

Becks,Tager,Reitan found Root resorption is greater in dense bone.

Wainwright – Density affects tooth movement rate, but no relation to extent of root resorption.

Fixed vs removable

The use of fixed appliances is more damaging to the roots

Ketcham claimed that normal function is disturbed by the splinting effect of orthodontic fixed appliances over a long period that can cause root resorption.

- Linge BO, Linge L. Apical root resorption in upper anterior teeth.

Eur J Orthod 1983;5:173-83.

Begg V/s edgewise It is often stated that the light wire Begg

technique causes less root resorption than edgewise

Although maxillary incisor root resorption during the Begg third stage has been documented

- Remmelnick HJ. The effect of anteroposterior incisor repositioning on the root and cortical plate: a follow-up study. J Clin Orthod 1984;18:42-9.

There is no difference between these techniques, but found that the frequency of root resorption was significantly higher (48%) in traumatized maxillary incisors when intruded by the Begg technique compared with edgewise technique (43%).

Root resorption after orthodontic treatment of traumatized teeth. Malmgren et al AM J ORTHOD 1982;82:487-91.

Begg V/s edgewise

Type of Orthodontic movement

The stress distribution along the roots during bodily movement is less than the stress concentration at the apex resulting from tipping. Therefore risk of root resorption that is due to bodily movement should be less than that of tipping.

Reitan K. Biomechanical principles and reactions. In: Graber TM, Swain BF. Orthodontics current principles and techniques. St. Louis: CV Mosby, 1985:101-92.

Degree of Orthodontic force

Harry and Sims found the distribution of resorbed lacunae was directly related to the amount of stress on the root surface. They concluded that higher stress causes more root resorption.

According to Schwartz, applied force exceeding the optimal level of 20 to 26 gm/cm2 causes periodontal ischemia, which can lead to root resorption.

Continuous vsintermittent forces

The pause in treatment with intermittent forces allows the resorbed cementum to heal and prevents further resorption.

- Oppenheim A. Human tissue response to orthodontic intervention of short and long duration. Am J Orthod 1942;28:263-301.

On the other hand, intermittent forces have been linked in their damaging effects to jiggling forces.

Hall A. Upper incisor root resorption during Stage II of the Begg technique. Br J Orthod 1978;5:47-50

Continuous vsintermittent forces

Orthodontic treatment timing

Orthodontic treatment should begin as early as possible since there is less root resorption in developing roots and young patients show better muscular adaptation to occlusal changes.

-Rosenberg HN. An evaluation of the incidence and amount of apical root resorption and dilaceration occurring in orthodontically treated teeth, having incompletely formed roots at the beginning of Begg treatment. AM J ORTHOD 1972;61:524-5.

Orthodontic treatment

and temporomandibula

r disorders

The attention of the orthodontic community regarding TMD however was heightened in the late 1980s after litigation involving the allegations that orthodontic treatment was the proximal cause of TMD in orthodontic patients.

In the 1980’s articles in various journals and trade magazines suggested that orthodontic treatment might play a role in initiating temperomandibular disorder.

On the other hand it was also claimed that orthodontic treatment might be effective in alleviating the signs and symptoms of TMD. www.indiandentalacademy.co

The benefits of orthodontic treatment in the management of Temperomandibular Disorder is questionable, since the occlusion is considered as having a limited role in the cause of TMD.

But the potential detrimental effects of orthodontic treatment on TMJ has captured the attention of orthodontic community.

Some of the examples of Orthodontic treatment which can lead to Temperomandibular Disorders are :

- William E. Wyatt. Preventing adverse - William E. Wyatt. Preventing adverse effects on TMJ through orthodontic effects on TMJ through orthodontic treatment . AJO 1987; 91: 493 treatment . AJO 1987; 91: 493 ––499499

1) Effect of headgear and/or class II elastics in correction of Class II malocclusions with deep interlocking cusps.

By the headgear force, as the maxillary dentition is moved backward the muscles of mastication will attempt to retract the mandible when the patient closes into maximum intercuspation.

This compensating movement by the mandible can put distal pressure on the condyles and conceivably cause an anterior dislocation of the disk.

The cross elastics have a little effect on TMJ. As the jaw is pulled to one side, distal pressure is put only on one condyle and chances of anterior dislocation of disc. If it creates a TMJ problem then elastics should be worn only during waking hours so that the muscles can help to hold the mandible forward because of muscle tension.

2) Effect of Cross elastics to correct the

midline

3) Effect of Reverse Headgear or Class III Elastics for Correction of Class III malocclusion :

This again can put distal pressure on the mandible. If there is a developing problem, treatment is limited to waking hours as muscle tension or tone, positions the mandible forward.

Since at night, the muscles are relaxed and there is more distal pressure on condyle since compensating muscle activity is not in play.

4) Effect of Lower Expansion and Upper Contraction :

In most cases, the crowded lower anterior teeth are in contact with the lingual of the upper anterior teeth. There is a spacing in upper anterior. The common request that the patient makes is to close the spaces in the upper anterior teeth. If a orthodontist tries to close down the anterior (upper) spaces without opening the bite, it may create a premature contact with the lower anterior teeth and exert distal pressure on the mandible that may result in TMJ pain. www.indiandentalacademy.co

The majority of orthodontically treated cases mostly have dental deep bite at the beginning.

If the deep bite is treated by extrusion of the posteriors, there will be increase in the vertical dimension of the lower face.

In most of the cases vertical dimension of the lower face will largely tend to revert to its original height.

5) The Retentive Phase :

As the bite deepens post treatment four possible adverse effects can be seen.

Spacing in upper anterior teeth. Crowding in lower anterior teeth. Tends to move maxillary dentition

forward. Drives the mandible distally

Since most of the orthodontists give a 3 to 3 fixed retainer on both upper and lower anterior teeth after the active treatment. These retainers prevent

Firstly, lower anterior teeth from crowding or collapsing.

Secondly, prevent the upper anterior teeth from rotating, separating or moving forward. www.indiandentalacademy.co

But at the same time the retainer cannot prevent other two adverse effects i.e. forward movement of maxillary dentition and distal movement of mandible, which can again lead to TMJ problems.

Numerous epidemiologic studies have shown a significant prevalence, with an average of 32% reporting at least one symptom of TMD and an average of 55% demonstrating at least one clinical sign.

Several investigators have noted that signs and symptoms of TMD generally increase in frequency and severity in the second decade of life.

1) What is the prevalence of signs and symptoms of TMD in orthodontically untreated population ?

-Williamson EH. Temporomandibular dysfunction in pretreatment adolescent patients. AM J ORTHOD 1977;72:429-33.www.indiandentalacademy.co

Two of the first major investigations sponsored by the National Institute of Health revealed no statistically significant differences between the treated and untreated groups & the assumption made by some authors that orthodontic treatment can prevent symptoms of mandibular dysfunction is disproven.

2) Does orthodontic treatment lead

to a greater incidence of TMD ?

-Sadowsky C, BeGole EA. Long-term status of temporomandibular joint function and functional occlusion after orthodontic treatment. AM J ORTHOD 1980;78:201-12.

-Sadowsky C, Polson AM. Temporomandibular disorders and functional occlusion after orthodontic treatment: results of two long-term studies. AM J ORTHOD 1984;86:386-90.

Another study of the long term effects of orthodontic treatment stated that comprehensive orthodontic treatment can be under taken without fear of creating TMD problems.

- Larsson E, Ronnerman A. Mandibular dysfunction symptoms in orthodontically treated patients ten years after the completion of treatment. Eur J Orthod 1981;3:89-94.

In the major longitudinal study conducted by Dibbets et al consisting of 171 patients, 75 of whom were treated by Begg mechanotherapy, 65 were treated by activator and 30 patients were treated with chin cups, revealed that at the end of treatment, fixed appliance group had a higher percentage of objective symptoms than did the functional group, but no differences existed at the 20 year follow up evaluation.

3)Does the type of appliance (e.g. fixed functional or orthodontic vs orthopedic) make a difference ?

4) Does the removal of teeth as part of an orthodontic protocol lead to a greater incidence of TMD ?

View point articles and tests have strongly associated the extraction of premolars with the occurrence of TMD in orthodontic patients.

But clinical studies that have dealt with this issue have not shown relationship between premolar extraction and TMD.

Sadowsky etal studiedSadowsky etal studied 160 patients and reported that joint sounds were evident before and after treatment in 87 extraction patients and 73 non extraction orthodontic patients. They reported there is no increase in the risk of development of joint sounds regardless of whether teeth were removed .

Sadowsky C, BeGole EA. Long-term status of temporomandibular joint function Sadowsky C, BeGole EA. Long-term status of temporomandibular joint function and functional occlusion after orthodontic treatment. and functional occlusion after orthodontic treatment. AM J ORTHOD 1980;78:201-12.AM J ORTHOD 1980;78:201-12.

5) Can orthodontic treatment lead to a posterior displacement of the mandibular condyle?

A number of viewpoint articles have asserted that a wide variety of traditional orthodontic procedures e.g. premolar extraction, extraoral traction, retraction of maxillary anterior teeth cause TMD signs and symptoms by producing a distal displacement of condyle .

Gianelly et al did the study collecting the tomograms to evaluate condylar position. They took the tomograms before orthodontic treatment in 37 consecutive patients aged 10 to 18 years and compared them with tomograms from 30 consecutively treated patients with fixed mechanotherapy and removal of four premolars. No differences in condylar position were noted between groups .

- Longitudinal evaluation of condylar position : Gianelly, Anderson, and Boffa 1991 AJO DO Nov 416 - 420

Another study conducted by Luecke and Johnston evaluated the pretreatment and post treatment cephalograms of 42 patients treated with fixed appliances in conjunction with the removal of two upper premolars.

The result of the study indicated that the majority of patients about 70% undergo a forward mandibular displacement and a slight opening rotation of mandible. The remainder of the sample had distal movement of the condyle.

- Premolar extraction and mandibular position Luecke and Johnston Jan AJODO 1992

Thus researchers concluded that posterior condyle position was not a result of orthodontic treatment.

6) Should the occlusion of orthodontic patients be treated to specific gnathologic standards ?

Several view point articles including those by Roth et al and Williamson have maintained that TMDs may result from a failure to treat orthodontic patients to gnathologic standards that include the establishment of a “mutually protected occlusion” and proper seating of the mandibular condyle within the glenoid fossa.

-Roth RH, Gordon WW. Functional occlusion for the orthodontist.

Part IV. J Clin Orthod 1981;15:246-54,259-65.www.indiandentalacademy.com

In contrast Pullinger et al reported that small occlusal slides less then 1 mm are common in asymptomatic subjects as well as patients with TMD.

-Occlusal TMJ orthopedic relationships: Pullinger, Solberg, Hollender, and Petersson,AJO DO1987 Mar 200 - 206

The establishment of an occlusion that meets gnathologic ideals probably is unnecessary particularly in adolescent patients and sometimes impossible to attain in some adult patients .

A trend toward decreased prevalence of TMD signs and symptoms in treated patients also was noted by Sadowsky , Polson and Dahl et al.

British Dental Journal 202, E2 (JAN 2007)TMD and occlusion part I. Damned if we do? Occlusion: the interface of dentistry and orthodontics

Evidence is lacking to suggest static occlusal factors cause TMD.

British Dental Journal 202, E3 (JAN 2007)TMD and occlusion part II. Damned if we don't? Functional occlusal problems: TMD epidemiology in a wider context

Evidence is lacking to suggest functional occlusal factors cause TMD. Investigation of other aetiological factors has been relatively neglected.

Conclusion

Controversies go hand in hand with any science especially with Orthodontics. The only way to resolve these controversies is by moving on from traditional “Opinion based Orthodontics” to “Evidence based Orthodontics”

Thank youwww.indiandentalacademy.co

References Proffit “Contemporary orthodontics”. Birte Melson “Current controversies in

orthodontics” Samir E. Bishara “Third molars: A dilemma!

Or is it?” Am J Orthod Dentofacial Orthop 1999; 115: 628-33.

Margaret E. Richardson “The role of the third molars in the cause of late lower arch crowding: A review.” Am J Orthod Dentofac Orthop 1989; 95 : 79-83.

Naphtali Brezniak, Atalia Wasserstein “Root resorption after orthodontic treatment: Part 1 and Part 2 – Literature review.” Am J Orthod Dentofac Orthop 1993; 103(1) : 62-66 and 138-146.

James A. McNamara, Donald A. Seligman and Jeffrey P. Okeson “Occlusion, Orthodontic treatment and temporomandibular disorders – A review.” Journal Orofacial Pain 1995; 9 : 73-90.

L.R. Dermaut, C.M.F. Aelbers “Orthopedics in orthodontics: Fiction or reality. A review of literature Part I and Part II.” Am J Orthod Dentofac Orthop 1996; 110 : 513-519 and 667-671.

Donald G. Woodside “Do functional appliances have an orthopedic effect?” Am J Orthod Dentofac Orthop 1998; 113(1) : 11-14.

William E. Wyatt. Preventing adverse effects on TMJ through orthodontic treatment . AJO 1987; 91: 493 –499

Reint M. Reynders Orthodontics and temporomandibular disorders: A review of the literature (1966-1988) AJO 1990; 97: 463-471

Sadowsky C, BeGole EA. Long-term status of temporomandibular joint function and functional occlusion after orthodontic treatment. AM J ORTHOD 1980;78:201-12.

James A.McNamara,Jr., Orthodontic treatment and temperomandibular disorders.OOO 1997;83 : 107-117

Burton H.Goldstein . Temperomandibular disorders .OOO 1999 ;88:379-383

Ambiguities of Angle’s classification : 1989 No. 4, 295 - 298Donald J. Rinchuse, Daniel J. Rinchuse

Diagnostic value of plaster models in Contemporary Orthodontics: Chad Callahan, P. Lionel Sadowsky and Andre Ferreira. Seminar in Orthodontics 3rd issue 2005.

Rheude B, Sadowsky Pl, Ferriera A, Jacabson A. An evaluation of the use of digital study models in orthodontic diagnosis and treatment planning Angle Ortghod 75: 292-296, 2005

Han U. Consistency of orthodontic treatment decisions relative to diagnostic recordsAJO DO 1991, 100: 212-219

Reliability of Digital vs Conventional cephalometric Radiology: A comparative evaluation of landmark identification error. Scott R. Mclure etal Seminar in Orthodontics 3rd Issue 2005.

- The Extraction debate of 1911 by case, Dewey and cryer. Discussion of case: The question of e traction in orthodontia. AJO 50: 751,1964

The effects of buccal corridor spaces and arch form on smile estheticsRoden-Johson D., Gallerano R, English J AJODFO 2005, 127: 343-50

Mandibular third molars and post retention crowding Kaplan R. AJO DO 1974 ;66:411-430

Root resorption after treatment Part 2 – Brezniak and Wasserstein AJO-DO Volume 1993 Feb (138 - 146)

Linge BO, Linge L. Apical root resorption in upper anterior teeth.

Eur J Orthod 1983;5:173-83.

Remmelnick HJ. The effect of anteroposterior incisor repositioning on the root and cortical plate: a follow-up study. J Clin Orthod 1984;18:42-9.

Root resorption after orthodontic treatment of traumatized teeth. Malmgren et al AM J ORTHOD 1982;82:487-91.

Reitan K. Biomechanical principles and reactions. In: Graber TM, Swain BF. Orthodontics current principles and techniques. St. Louis: CV Mosby, 1985:101-92.

Oppenheim A. Human tissue response to orthodontic intervention of short and long duration. Am J Orthod 1942;28:263-301.

Hall A. Upper incisor root resorption during Stage II of the Begg technique. Br J Orthod 1978;5:47-50

Rosenberg HN. An evaluation of the incidence and amount of apical root resorption and dilaceration occurring in orthodontically treated teeth, having incompletely formed roots at the beginning of Begg treatment. AM J ORTHOD 1972;61:524-5

Pancherz H, Anchus-Pancherz M. The headgear effect of the Herbst appliance: a cephalometric long-term study Am J Orthod Dentofac Orthop 1993;103:510-20.

Wieslander L, Buck DL. Physiologic recovery after cervical traction therapy. Am J Orthod 1974;66:294-301.

DeVicenzo JP. Changes in mandibular length before, during, and after successful orthopedic correction of Class II malocclusions using a functional appliance. Am J Orthod Dentofac Orthop 1991;99:241-51.

Assessment of Orthodontic Treatment Outcomes: Early Treatment versus Late Treatment: Tsung-Ju Hsieh, Yuliya Pinskaya, W. Eugene Roberts, he Angle Orthodontist: Vol. 75, No. 2, pp. 162–170

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