Current controversies in orthodontics sujan /certified fixed orthodontic courses by Indian dental academy


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Current controversies in orthodontics sujan /certified fixed orthodontic courses by Indian dental academy

  1. 1. CONTROVERSIES IN ORTHODONTICS INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. INTRODUCTION Orthodontics, Dentistry‟s first speciality is rich in it‟s history and also in it‟s controversy. Controversies unlike disputes never end. They cannot be settled totally by scientific evidence substantiating any one side of the argument. Lysle E.Johnston – active, honest difference of opinion.
  3. 3. Classification  Diagnosis  Treatment planning  Treatment mechanics  Treatment modalities. controversies Concepts Philosophies
  4. 4. CONTROVERSIES IN ORTHODONTICS Need for orthodontic treatment Timing of treatment Classification of malocclusion Functional appliances Extraction-nonextraction controversy. Bracket design Orthognathic surgery Retention and relapse.
  5. 5. Need for treatment There are 2 aspects to the question of what treatment is needed. Whether treatment is indicated at all and if so, what treatment procedures should be used. Psychosocial indications: Esthetic need for orthodontic treatment: The controversy is that whether we run the risk of denying treatment affecting social and psychological well being or whether we over treat our patients and force upon society standards of appearance that are both unrealistic and unattainable.
  6. 6.  Studies by Dion have shown that the attractiveness of physical appearance is an important determinant of how much even very young children are liked by their peers.  Physically attractive individuals are perceived as possessing a great number of socially desirable traits such as intelligence, friendliness, sensitivity and sincerity.  The theoretical and empirical work on responses to facial attractiveness leads us to at least one obvious generalization: perceived facial attractiveness is a social asset whereas perceived unattractiveness is a social liability.
  7. 7. Functional indications: It is obvious that severe malocclusion must affect function, at least to the extent of making it difficult for the affected individual to breathe, incise, chew, swallow and speak. The reverse also is true: alterations or adaptations in function can be etiologic factors for malocclusion, by influencing the pattern of growth and development. Respiration Jaw function and TMD The decisions about the need for treatment cannot be made on objective assessment of functional or esthetic impairment alone.
  8. 8. TIMING OF TREATMENT Questions about the timing of orthodontic treatment relate almost totally to the question of whether to begin treatment for a child with obvious malocclusion early, during the primary or mixed dentition, or whether to wait for the adolescent growth spurt and the eruption of the permanent teeth. Advantages of early treatment: Rapid change in skeletal and dental structures because of relatively rapid growth The need for complicated surgical and orthodontic procedures eliminated by early orthopedic intervention An abnormality is prevented from occurring – better than wait to manifest itself in it’s fullest form
  9. 9. The argument.. Orthodontists prefer to wait until the permanent teeth have erupted so a more straight forward treatment plan can be done within a predictable duration of time. The question of remaining growth manifesting as relapse does not occur. Some malocclusions like skeletal class III due to prognathic mandible are best treated after all skeletal growth is complete. Patient co operation may be the biggest challenge in early treatment –Graber. Patient turn out due to a long treatment duration may not help the orthodontists cause during a second phase of fixed appliance treatment.
  10. 10. Whether arch expansion procedures are more effective if done during the mixed dentition is debatable-no sufficient data to resolve this is available.
  11. 11. CLASSIFICATION OF MALOCCLUSION Malocclusion presents itself in numerous ways. Classification involves the grouping together of various malocclusions into simpler or smaller groups.. Aim. The classification system followed today is based on Angles classification which was perceived by him almost 100 years ago based on his treatment philosophies, ideals and paradigms of his time. Many orthodontists have developed classification methods, and among them are Kingsley, Angle, Case, Dewey, Anderson, Hellman, Bennett, Simon, Ackerman and Proffit.
  12. 12. CLASSIFICATION OF MALOCCLUSION  What we today call normal occlusion was described as early as the eighteenth century by John Hunter.  Carabelli, in the mid-nineteenth century, was probably the first to describe in any systematic way abnormal relationships of the upper and lower dental arches. The terms edge-to-edge bite and overbite are actually derived from Carabelli's system of classification  Edward angle introduced a system of classifying malocclusion in the year 1899. Edward H. Angle contributed the concept that if the mesiobuccal cusp of the maxillary first molar rests ill the buccal groove of the mandibular first molar, and if the rest of the teeth in the arch are aligned, ideal occlusion will result. (this is not the Class I as Angle actually saw it) Angle described three basic types, what he termed malocclusion, all of which represented deviations in an anteroposterior dimension.
  13. 13.  It merely described the relationship of the teeth and did not include a diagnosis.  It does not deal with any malocclusion in it’s entirety. This gives rise to the issue of Analogous and homologous malocclusions  The Angle system does not take into account the possibility of arch-length problems. The reintroduction of extraction into orthodontic therapy has made it necessary for orthodontists to add arch-length analysis as an additional step in classification.  The classification does not indicate the complexity of the problem.
  14. 14.  Angle described in minute detail each contacting cusp incline, to prove his point, in ideal occlusion, every tooth (except the lower centrals and upper third molars) should have two antagonists.  Angle emphasized the importance of each premolar and canine contacting two occluding teeth.
  15. 15. The original classification by Angle, had Class II as a full premolar- width distoclusion and Class III as a full premolar-width mesioclusion. Assuming an average premolar width of 7.5 mm, then Class I ranged from 7 mm mesioclusion to 7 mm distoclusion, for a total range of Class I of 14 mm. This range was far too broad, and so in 1907, Angle revised his definition, making Class II more than half of a cusp distoclusion and Class III more than half of a cusp mesioclusion. Angle's modification reduced the range from 14 mm to a 7 mm range. However, 7 mm is still too broad a range to act as a treatment goal if an orthodontist is to treat with precision.
  16. 16. Canine relation classification: Classification was based on the sagittal relation of the maxillary canine to the mandibular canine. Maxillary canines are among the most stable of dental units because they are the longest rooted of all teeth and therefore very well anchored to the alveolar bone. The canine is the "keystone" tooth in the dental arch, and like the keystone of a stone archway, it provides a buttressing support for the incisors, as well as the posterior teeth. Also, canines provide a vital protective function in lateral excursive movements.
  17. 17. Premolar classification:  The premolar classification was put forth by Morton Katz as a modification to the Angle’s classification  premolars usually present a sharply defined cusp tip, which is centered on the central axis of the premolar crown and which fits precisely into the opposing embrasure. Also, the cuspal inclines are steeper and deeper than molar cusps, which makes a more positive fit.  From the negative perspective, orthodontists traditionally have not had high regard for premolars as functional dental units and have selected premolars most often of all tooth types for sacrifice in an extraction treatment. Also, premolars may have anomalous tooth size or shape.
  18. 18. 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.
  19. 19. Functional appliances The use and mode of action of functional appliance is shrouded in controversy. The reason behind this is because of the different philosophies and basis on which each designer constructed his appliance. There may not be a specific modus operandi behind all functional appliances. Quote from Brite Melson‟s The controversies herein relates to the Growth changes with functional appliances.
  20. 20.  Functional appliances evolved from different concepts of the interrelationship between the orofacial musculature , dentition and plasticity of growth. Each led to a working hypothesis expressed as an appliance design.  By 1980‟s though clinical success with functional appliances was witnessed by practitioners, questions whether they could really stimulate mandibular growth remained. Growth stimulation can be defined in two ways:  1. as the attainment of a final size larger than would have occurred without treatment or  2. as the occurrence of more growth during a given period than would have been expected without treatment.
  21. 21. The randomized clinical trials of the 1990’s: the data showed that, on average, children treated with either headgear or a functional appliance had a small but significant improvement in their jaw relationship, while the untreated children did not.  Does it really modify growth?  Does early treatment really make any difference in the long run, compared with treatment during adolescence? Advantage of early treatment: reduction in number of patients requiring extractions or surgery.
  22. 22. Can mandibular growth be modified beyond it’s true genetic potential?  The answer seems to be elusive. As is shown by the use of the Milwakee braces. However the Milwaukee braces phenomenon also shows us the remarkable rebound capacity of the hard tissue system and the dominance of inherent growth potential.  While Angle strongly believed that the mandible could be made to grow Case disagreed. As Case states.. “Malrelations of this character point directly to heredity. The claim and recently repeated inference that the mandible can be made to grow by artificial stimuli beyond its inherent size is not in accord with any law of organic development." Baring future chemical or genetic manipulation, this still appears to be a valid principle, although there are others who strongly believe otherwise.
  23. 23. Gianelly through various studies has shown that the mean growth modification of 2mm can be achieved by functional appliance treatment. Thus when compared to a 6mm correction of class II relation to a class I the effects of functional appliances may not be clinically significant. Harvold found significantly higher increments in mandibular length during treatment than after treatment. But however when he compared the results with untreated controls matched for age and growth status he found that the changes can only be ascribed to normal age related changes. Studies by McNamara on the Frankl appliance and Herbst appliance effects on the mandible and the dentition have shown both appliances had influenced the growth of the craniofacial complex in treated persons. Significant skeletal changes were noted in both treatment groups, with both groups showing an increase in mandibular length and in lower facial height, as compared with controls.
  24. 24. McNamara and Bryan studied the Long-term mandibular adaptations to protrusive function on 11 experimental animals.. At the end of the 14-week experimental period, the mandibles of the treated animals were 5 to 6 mm longer than those of the control animals. They concluded that the results of this study do not support the hypothesis that the mandible has a genetically predetermined length
  25. 25. □ Limitations of current clinical and animal research: □ A double blind study is not possible in testing functional appliances and thus bias cannot be eliminated. The orthodontist is well aware of the type of appliance he is using and probable treatment effects it can produce. □ Growth versus treatment changes should always be compared with untreated controls matched for age, sex and growth status. Even though so much criteria may be taken the experimental samples and control samples may not be totally matched because the growth potential of two people may not be the same unless they are monozygotic twins. And if monozygotic twins were even used it would be unethical to treat one sibling while leaving the other untreated.
  26. 26. Functional appliances and two phase treatment A multicenter, randomized controlled trial of 174 children to study the dental, skeletal and psychosocial effects of Twin Block have shown that all changes produced were purely dentoalveolar and skeletal changes were actually so minimal as to be considered clinically significant. However results did show that early Twin Block use did result in an increase in self concept and a reduction of negative social experiences.
  27. 27. EXTRACTION-NONEXTRACTION CONTROVERSY The controversy was between the Angle‟s school of thought and it‟s followers like Martin Dewey and Calvin Case. 1902 - Angle Rousseau concepts He believed that all humans were created to have a full complement of natural teeth which would go hand in hand with an ideal occlusion and a harmonious face. He idealized an occlusion thus which contained a full compliment of well aligned teeth, which occluded along his line of occlusion. Second: proper function of dentition would be the key to maintaining teeth in their correct position.
  28. 28. It is first of all evident from the statements of Angle that his philosophic basis was creationist dogma rather than ideals backed by strong scientific basis. "The Extraction Debate of 1911.“ Calvin Case - "The Question of Extraction in Orthodontia," . To substantiate the case further he presented a patient whose dental protrusion would have worsened had a non extraction treatment had been done. Thus emphasizing that all cases cannot be treated non extraction to achieve a harmonious face.
  29. 29. Charles Tweed Raymond Begg With the development of the Tweed edgewise philosophy and the Begg appliance came a period in orthodontics where premolars were indiscriminately extracted for correction of malocclusion. This lead to unfavorable facial appearances. Present day status – decline in extractions?
  30. 30. Wick Alexander now claims only 10% of his cases are treated with extraction and the rest being treated non extraction. Norman Cetlin treats 95% cases with extraction and only 10% with non extraction. The current dogma Stability of distalised upper molars? Expanded arches Lower canine width cannot be increased. Long term retention is necessary for stability.
  31. 31.
  32. 32. The option to treat either extraction or non extraction should be made objectively for each case based on strong evidence rather on some ones opinion „that it woks.‟
  33. 33. Camouflage vs Surgery Beyond the adolescent growth spurt, even though some facial growth continues, too little remains to correct skeletal problems. The possibilities for treatment are  displacement of the teeth, to compensate for the underlying skeletal discrepancy  by surgical repositioning of jaws.
  34. 34. Characteristics of patient who would be a good candidate for camouflage treatment are:  Too old for successful growth modification  Mild to moderate skeletal class II or mild skeletal class III.  Reasonable good alignment of teeth  Good vertical facial proportions – neither extreme long face nor extreme short face
  35. 35. Camouflage should be avoided in:  Severe class II, moderate or severe class III, and vertical skeletal discrepancies.  Patients with severe crowding or protrusion of incisors, in whom the entire extraction space will be required to achieve proper alignment of the incisors.  Patients with excellent remaining growth potential or non-growing adults with more than mild discrepancies.
  36. 36. BRACKET DESIGN Brackets are of basically two types – ribbon arch brackets and edgewise brackets. The ribbon arch brackets were first designed by Angle for his Ribbon arch appliance. The bracket was modified by inverting it by 180 degree and used by Raymond Begg for his light arch wire appliance..
  37. 37. Angle- single wing bracket Swain – twin brackets Ivan Lee – preangulated Jarabak – preangulated and pretorqued Andrews – fully programmed controversies : 0.018 slot or the 0.022 slot
  38. 38. BRACKET DESIGN E.H. Angle was the first to design the Edgewise type of bracket for his edgewise appliance. He used the 0.022 slot for his appliance. As the edgewise appliance originated before the discovery of stainless steel, Angle was forced to use gold alloy wires for making arch wires. Gold alloy wires had a low modulus of elasticity and therefore to increase the stiffness of the wire in bending and torsion and to increase the rigidity, Angle had no other choice but to increase the dimensions of the wire and therefore had to use the 0.022 slot.
  39. 39. BRACKET DESIGN  It was Steiner who first proposed the 0.018 slot (0.018 x 0.028) and used it for the ‘Steiner’ brackets which were single width brackets with rotation wings.  Swain later adopted the 0.018 slot for his Siamese brackets to improve wire characteristics due to the decreased inter bracket span.  With the advent of stainless steel which is 50% stiffer than spring tempered gold it became essential to decrease wire dimensions to reduce force levels.  The 0.022 slot today prevails over the 0.018 slot because of the development of newer orthodontic alloys such as TMA and NiTi. It was the discovery of TMA with it’s stiffness characteristics similar to gold that brought back the 0.022 slot back into the market.
  40. 40. BRACKET DESIGN ADVANTAGES OF 0.018 SLOT Decreased wire inventory Decreased treatment time Increased wire flexibility due to smaller dimension of wires. DISADVANTAGES OF 0.018 SLOT Desired third order M/F ratios may not be produced by newer orthodontic alloys.
  41. 41. BRACKET DESIGN DISADVANTAGES OF 0.022 SLOT Increased wire inventory Inability to attain third order control until last stages of treatment Increased treatment time. ADVANTAGES OF 0.022 SLOT Recommended for Orthognathic cases Can use newer orthodontic alloys with minimum patient discomfort
  42. 42. BRACKET DESIGN Are the 0.018 and 0.022 slots truly 0.018 and 0.022 …….?  Kusy and Whitley measured 24 brackets from eight manufacturers microscopically to 0.0001 inch .  Three brackets were under sized whereas the rest were oversized.  The largest 0.018 slot measured 0.0209 whereas the largest 0.022 slot measured 0.0237.
  43. 43. BRACKET DESIGN □ Are the 0.018 and 0.022 slots truly 0.018 and 0.022 …….? Factors contributing to this variability…. Lack of verification standards Varying manufacturer tolerances United states versus European tooling For example Europeans use metric tooling i.e mm, cm , m. Their target value for machining a bracket which would be 0.018 slot in the United states would be 0.5mm which is actually 0.0197 inches.
  44. 44. BRACKET DESIGN The 0.020 slot. Rubin, peck and Kusy have proposed the use of an 0.020 slot (0.5 mm) This would reduce the burden on inventories of users of both 0.018 and 0.022 slots and reduce manufacturer costs.
  45. 45. Though both the 0.018 and 0.022 slot may still be used based on personal preferences, a uniform slot size and tooling units may be necessary for standardization and to know that we really use the slot size we wanted irrespective of where the manufacturer is based.
  46. 46. ORTHOGNATHIC SURGERY  For patients whose orthodontic problems are so severe that neither growth modification nor camouflage offers a solution, surgical realignment is the only possible treatment.  It is possible to semiquantitate about the limits of the orthodontic treatment, in the context of producing normal occlusion
  47. 47. Envelop of discrepancy
  48. 48. The borderline patient: camouflage or surgery? For the patient whose deformity is within the envelop, the decision must be made in the context of esthetic impact of the two forms of treatment. Acceptable results likely in  Average or short facial pattern  Mild anteroposterior jaw discrepancy  Crowding <4-6mm  Normal soft tissue features  No transverse skeletal problems
  49. 49. Poor results likely  Long vertical facial pattern  Moderate to severe anteroposterior jaw discrepancy  Crowding >4-6mm  Exaggerated features  Transverse skeletal component of problem
  50. 50. RETENTION AND RELAPSE For many years clinicians did not agree about the need for retention. Different philosophies or schools of thought have developed and present day concepts generally combine several of these theories.  The occlusion School: Kingsley stated that, “ The occlusion of the teeth is the most potent factor in determining the stability in a new position”. Proper occlusion is of primary importance in retention.  The apical Base school: It was Axel Lundstrom who suggested that the apical base was an important factor in maintaining correct occlusion  The mandibular incisor school: Grieve and Tweed suggested that the mandibular incisor must be kept upright over the basal bone.  The musculature school: Rogers emphasized the need for establishing proper muscle balance for maintenance of occlusion.
  51. 51. RETENTION AND RELAPSE Relapse in lower anterior region: Many hypotheses have been put forward to explain the incidence of lower incisor crowding after treatment.  Relationship of third molars : the mesial eruptive force of the third molars give rise to lower anterior crowding. This led to therapeutic extractions and removal of impacted third molars. Ades et al compared four groups of patients 10 years out of retention. The groups included- third molars erupted, third molar agenesis, third molar impaction, and third molar extraction cases. He found no difference in the mandibular incisor crowding, inter canine width between these groups.  Mesial component of force and physiological mesial migration.  Late mandibular growth and maximum intercanine width: continued mandibular growth even after maturation of inter canine width can lead to incisor crowding. A retention protocol untill completion of skeletal growth may be
  52. 52. RETENTION AND RELAPSE Duration of retention: At the moment there is no agreement as to a specific duration of retention for patients. There is no clinical evidence as to whether a longer duration of retention has better post treatment stability than one of shorter duration.
  53. 53. Orthodontics may be the only specialty which has “philosophies”. It was based on these philosophies that most work in Orthodontics was done. However treatment philosophies may not be enough in today's world. We need more scientific basis to back our treatment protocols. We need to follow „evidence based Orthodontics‟ more than „opinion based orthodontics‟. The only way this can be done is to improve our clinical research.
  54. 54. Thank you For more details please visit