Treatment of Class 2 malocclusions /certified fixed orthodontic courses by Indian dental academy


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Treatment of Class 2 malocclusions /certified fixed orthodontic courses by Indian dental academy

  1. 1. TREATMENT OF CLASS 2 MALOCCLUSION INDIAN DENTAL ACADEMY Leader in continuing dental education
  3. 3. INTRODUCTION Orthodontic specialty deals with various malocclusions . Malocclusion is the study of its cause or causes. Development of normal dentition and occlusion depends on number of interrelated factors that include the dentoalveolar, skeletal and neuromuscular factor.
  4. 4. etiology 1. HERIDITY 2. TRAUMA • Prenatal • Postnatal 1. HABITS • • • • Finger sucking habit Tongue thrusting habit. Mouth breathing habit. Lip biting habit.
  5. 5. 4. DISEASE A. Systemic disease B. Endocrine disease C. Local disease  Gingival or periodontal disease  Tumors  Caries 4. MALNUTRITION 5. UNKNOWN ETIOLOGY
  6. 6. SYNDROMES OCCURRING COMMONLY WITH MALOCCLUSIONS ARE CLASSIFIED AS: (COHEN,PROFFIT,BELL,WHITE ) 1.Malformation syndromes associated with mandibular deficiency. 2.Malformation syndromes associated with mandibular prognathism. 3.Malformation syndromes associated with problems of facial height. 4.Malformation syndromes associated with facial asymmetry.
  7. 7. Malformation syndromes associated with mandibular deficiency:
  8. 8. Pierre Robin syndrome
  9. 9. Treacher Collins syndrome: ( Mandibulo facial dysostosis; Franceschetti syndrome )
  10. 10. •Nager acrofacial dysostosis: •Wilder vanck Smith syndrome: •Mobius syndrome: •Hallermann – Streiff syndrome
  12. 12. ANGLE’S CLASS I • Distal marginal ridge of the upper first permanent molar contacts and occludes with the mesial surface of the mesial marginal ridge of the lower second molar. • The mesio-buccal cusp of the upper first permanent molar falls within the groove between the mesial and middle cusps of the lower first permanent molar. • The mesio-lingual cusp of the upper first molar seats in the central fossa of the lower first molar.
  13. 13. ANGLE’S CLASS II • Mesial marginal ridge of the upper second permanent molar contacts and occludes with the distal surface of the distal marginal ridge of the lower first molar • The distobuccal cusp of the upper 1st permanent molar occludes in the buccal groove of the lower 1st permanent molar. • Angle has sub divided class II malocclusions into two divisions Div. I Div. II
  14. 14. Class II sub division When a class II molar relations exists on one side and a class I relation on the other, it is referred to as Class II subdivision. Based on whether it is a Div. 1 or Divi. 2 it can be called Class II Div. 1 subdivision or Class II Div. II Subdivision.
  15. 15. BALLARD’S CLASSIFICATION Class I : the lower incisal edges occlude with or lie immediately below the cingulum of the upper incisors. Class II : The lower incisal edges lie part to the cingulum platean of the upper incisors.
  16. 16. BALLARD’S CLASSIFICATION various skeletal relationship. SKELETAL CLASS I : The projection of the axis of the lower incisors would pass through the crowns of the upper incisors. SKELETAL CLASS II : The lower apical base is relatively too far back. The lower incisors axis would pass palatal to the upper incisal crown.
  17. 17. CANINE CLASSIFICATION CLASS I - Mesial slope of upper canine Coincides with the distal slope of lower canine CLASS II - Distal slope of upper canine coincides with the mesial slope of the lower canine.
  18. 18. Classification According to Moyers class II can be divided into Six Horizontal types and Five vertical types (AJO-DO 1980 Nov (477-494): Differential diagnosis of Class II malocclusions – Moyers) Horizontal class II Types NORMAL SKELETAL PATTERN:Displays normal relationship of maxilla and mandible to the cranial base and to each other. Upper and lower dentition are within their normal positions over their basal bones
  19. 19. TYPE A or DENTAL CLASS II :A Normal skeletal profile and normal A-P position of jaws. Mandibular dentition is placed normally on its base but Maxillary dentition is protracted, resulting in class II molar relationship and increased incisal overjet and overbite than normal.
  20. 20. HORIZONTAL TYPE B: Displays mid face prominence with a mandible of normal length. Size of maxilla is increased but mandible is normal Antero posteriorly
  21. 21. HORIZONTAL TYPE C: Displays class II profile though the maxilla and mandible are further back beneath the anterior cranial base than normal the lower incisors are tipped labially, the upper incisors are either upright or tipped off the base labially according to the vertical category.
  22. 22. HORIZONTAL TYPE D: Displays a skeletal profile which is retrognathic because there is a smaller than normal mandible. The mid face is normal or slightly diminished. The mandibular incisors are either upright or lingually inclined, where as maxillary incisors are typically labially positioned. Lip trap can be seen in most of the cases.
  23. 23. HORIZONTAL TYPE E: severe "Class II" profile due to a prominent midface and a normal or even prominent mandible. Bimaxillary protrusion Class II malocclusions are more likely to be horizontal Type E. Both dentitions, in Type E, have a tendency to be forward on their bases and the incisors are often in strong labioversion
  24. 24. HORIZONTAL TYPE F: Combination of maxillary protrusion and Mandibular retrusion with upper and lower anteriors Upright over their basal bones
  25. 25. Vertical class II types: 1.Vertical type 1or High angle case: Features: 1. Anterior facial height >Posterior facial height. 2. Mandibular and functional occlusal planes are steeper than normal. 3. Palatal plane may be tipped downwards while the anterior cranial base tends to be upward. 4. Orthodontists call a "steep mandibular plane" or a "high angle" case and may be what oral surgeons call the "long face syndrome''
  26. 26.
  27. 27.
  28. 28. Vertical type 2: features: 1.Square face. 2.Mandibular plane, functional occlusal plane and palatal planes are more horizontal and often seem parallel. 3.Gonial angle is smaller than normal 4.Anterior cranial base appears horizontal. 5.Skeletal deep bite
  29. 29.
  30. 30. Vertical type 3 Features: 1. Palatal plane tipped upward 2. Decreased upper anterior facial height 3. Predisposition to open bite. 4. Mandibular plane is steeper than normal
  31. 31.
  32. 32.
  33. 33. Vertical type 4: Features: 1. Mandibular plane, functional occlusal plane and palatal planes are tipped downward. 2. Gonial angle is relatively obtuse. 3. Lip line high in the maxillary alveolar process. 4. Upper incisors are tipped labially and lower incisors are tipped lingually. 5. Most rare, severe, and anomalous of the vertical types
  34. 34.
  35. 35.
  36. 36. Vertical type 5: Features: 1.Mandibular and functional occlusal planes are placed normally 2.palatal plane is tipped downward 3.Gonial angle is smaller than normal. 4.Skeletal deep bite may be present 5.lower incisors are labially tipped and upper incisors are lingually tipped.
  37. 37. IDENTIFYING HORIZONTAL TYPES • • • • Dental Class II – Type A Midface prognathic --- Type B and E Mandibular retrognathic --- Type C and D Combination of Mandible And Maxillary extreme skeletal features – Type F
  38. 38. IDENTIFYING VERTICAL TYPES • Type I – shows large values for angles of PM vertical line with Mand. Occl. and palatal plane. • Type II – smaller values for same angles • Type III – Small Pal Plane angle with PM vertical • Type IV – found in association with horizontal Type B • Type V - Large Pal. Plane angles with Pm vertical, normal occlusal and mand plane angles, smaller gonial angles
  39. 39. C SS LA SIO VI DI II 2 N
  40. 40. ClassII Division 2 malocclusions are frequently present in brachyfacial patterns with resulting strong musculature. They generally have moderate to minimum convexity, but occasionally do have a higher convexity with resulting orthopedic problems. The lower facial height and mandibular arc are below normal range.
  41. 41. CLASSIFICATION OF CLASS II DIV-2  Type A Maxillary four permanent incisors can tip palatally without occurrence of crowding  High lip line position  The lips attain a more dorsal position and a “dished in” appearance. BY-VAN DER LINDEN
  42. 42. Type B- The maxillary permanent central incisor will move palatally gradually. The available space in maxillary dental arch is limited.Thus lateral incisors are placed labially. The lower lip will become positioned inferiorly to maxillary lateral incisors and will contribute to the increase of their labial inclination.
  43. 43. Type C- There is a marked shortage of available space in the maxillary dental arch. Centals and Laterals are palatally tipped, and canines, emerges buccally and labially tipped position.
  44. 44. TYPE A TYPE B TYPE C
  45. 45. THERAPEUTIC CLASSIFICATION. Class II malocclusions can be classified Therapeutically as: 1.Skeletal class II. 2.Dentoalveolar class II. 3.Functional class II
  46. 46. Skeletal class II Antero posterior disproportion of jaws in size and position result in skeletal class II. Skeletal class II Pattern can result due to: 1. Increased size of Maxilla. 2. Decreased size of Mandible 3.Combination of Increased Maxilla and Decreased Mandible size
  47. 47. CEPHALOMETRIC FINDINGS INDICATING CLASS II DUE TO MANDIBULAR DEFICIENCY: Variant 1: 1. Downward and back ward rotation of mandible caused by small size of ramus and body of mandible. 2. Decreased posterior facial height. 3. Steep mandibular plane angle. 4. Increased ANB angle. 5. Increased angle of convexity.
  48. 48. 6. Increased over jet. 7. Greater positive value of wits appraisal. 8. Posterior position of point B in relation to Na perpendicular. 9. Normal position of point A in relation to Na perpendicular. 10.Dental compensation of protruded mandibular incisors
  49. 49.
  50. 50. Variant 2: features: 1. Convex profile. 2. Normal or an increased ramus length. 3. Flat mandibular plane angle. 4. Normal or increased posterior facial height. 5. Excessive bony chin masking the mandibular deficiency but still have lack of support for lower lip.
  51. 51. 6. Short anterior facial height. 7. Hyperactive mentalis muscle. 8. Deep anterior overbite 9. Maxillary incisors are lingually inclined masking the anteroposterior dental discrepancy.. 10. Accentuated curve of spee.
  52. 52.
  53. 53. MANDIBULAR DEFICIENCY: Variant 3:Due to retruded position: Features: 1. Normal or decreased size of mandible. 2. Cranial base angle is more obtuse. 3. Glenoid fossa is more posteriorly positioned.
  54. 54. FUNCTIONAL CLASS II :(FORCED BITE MALOCCLUSION) Based on different types of movement of mandible from rest position to occlusion class II malocclusions can be divided into 3 functional types. 1.Functional True class II malocclusion. 2.Functional class II with posterior sliding movement 3.Functional class II with anterior sliding movement
  55. 55. CLASS II DIV.1: A MALOCCLUSION IS CHARACTERIZED BY •PROCLINED : Upper incisors with resultant increase in overjet • A deep incisor OVER BITE can occur in the ant region. •A characteristic feature of this malocclusions is the presence of abnormal muscle activity. •The upper lip is usually hypotonic, short and fails to form a lip seal. •The lower lip cushions the palatal aspect of the upper teeth, a feature typical of a class II Div 1 referred to as “lip trap”.
  56. 56. • The Tongue occupies a lower position thereby failing to counter act the buccinator activity. • The unrestrained Buccinator activity results in narrowing of the upper arch at the premolar and canine regions thereby producing a “V” shaped upper arch. • hyper active mentalis activity. The "three M's": Muscles, Malformation and Malocclusion - Graber: AJO-DO 1963 Jun (418450)
  57. 57. FEATURES OF CLASS II DIVISION-2 Features: 1.Mandibular molars assume a posterior position with respect to maxillary 1st molars and maxillary arch. 2.Mandibular arch may or may not show any individual irregularities but usually has exaggerated curve of spee. 3.Supraversion of mandibular incisors. 4.Mandibular labial gingival tissue is often traumatized
  58. 58. 5.Maxillary arch is wider than normal in inter canine region. 6.Remarkable and constant distinguishing feature is lingual inclination of maxillary centrals and labial inclination of lateral incisors. 7.Excess overbite (closed bite)
  59. 59. 8.Abnormal path of closure due to combination of lingual inclination of maxillary incisors and infraocclusion of posteriors result in mandible to be forced into retruded tooth guidance with condylar movement posteriorly and superiorly in articular fossa creating a displacement. 9.Electromyographic research shows with dominance of the posterior fibers of both temporalis and masseter muscles
  60. 60. Features Class II division 1 Class II division 2 Profile Convex Straight to mild convexity Lips • upper Short • lower everted • competency incompetent Normal Normal Competent Mentalis muscle Hyperactive - Lower facial height Normal or increased Decreased Arch form “V” shaped Square, “U” shaped Mentolabial sulcus Deep Deep or normal
  61. 61. Palate Deep Normal Incisors Proclined Centrals are retroclined Overjet Increased Decreased Overbite Deep overbite Closed bite Crown root Normal angulation Axis of crown and root are bent and is referred to as collum angle Path of closure Normal Backward Interocclusal clearance increased Normal/increased/ decreased
  62. 62. Why to correct class II? 1.Esthetics. 2. Function. 3.Trauma. 4.TMJ problems. 5.Periodontal problems.
  63. 63. TREATMENT PLANNING OF CLASS II: Treatment planning of class II depends mainly on 3 criteria: 1. Nature of malocclusion. 1.Skeletal. 2.Dentoalveolar. 3.Functional. 4.Combination. 2.Severity of malocclusion. 1.Mild. 2.Moderate. 3.Severe. 3.Age. 2.After growth
  64. 64. General strategies for class II correction 1.Differential restraint and control of skeletal growth 1.Extra oral traction. 2.Differential promotion of skeletal Growth: 1.Functional appliances. 3.Guidance of eruption and alveolar development:
  65. 65. 4.Movement of teeth and alveolar process (Camouflage treatment). 1.Extraction treatment. 2.Non Extraction treatment. 5.Training of muscles: 1. Functional appliances. 6.Surgical Translation of parts after growth in severe cases: 1.Orthognathic surgery
  66. 66. ATMENT T RE
  68. 68. Types of Head gears 1. High pull H.G(parietal) 2. Medium pull H.G(occipital) 3. Low pull H.G(cervical) 4. Combee pull H.G 5. Reverse pull H.G
  69. 69. Center of resistance (CR) Maxillary first molar Entire maxilla Entire maxillary teeth
  70. 70. Clinical location of the Cres: (Stanley Braun angle 1999;69: 81 - 84) • An amalgam plugger or similar instrument in the maxillary vestibule when the teeth are in occlusion and the soft tissues and lips are relaxed. The amalgam plugger is positioned half the distance from the functional occlusal plane to the lower border of the orbit corresponding to the distal contact of the maxillary first molar. The instrument is then palpated externally and a mark is made on the skin surface corresponding to it.
  72. 72. CERVICAL H.G • Extrusion of teeth and steepening of O.PCervical H.G with outer bow low • Extrusion of teeth and flatenning of O.PCervical H.G with outer bow very high
  73. 73. OCCIPITAL H.G • Intrusion of teeth and steepening of O.POccipital H.G with outer bow post to C.O.R • Intrusion of teeth and flatenning of O.POccipital H.G with outer bow ant to C.O.R
  74. 74. COMBEE PULL H.G • Distal force and flatenning of O.P Combee pull H.G with outerbow above C.R • Distal force and steepening of O.P- Combeepull H.G with outer bow below C.R • Distal force with no change in O.P- Combeepull H.G with outer bow through C.R
  75. 75. Timing of cervical headgear treatment Kopecky and Fishman : AJO-DO 1993 Aug (162-169) The most optimum treatment time is between maturational stages SMI 4 to 7, a very high velocity period of growth. The next most desirable time to treat is during the accelerating velocity period between stages SMI 1 to 3, and The least desirable time is during the decelerating velocity period between maturational stages SMI 8 to 11.
  77. 77. INCREASED ACTIVITY OF L.P.M Increased growth CLASS II ELASTICS NEW MANDIBULAR POSITION Increased activity activity of the of the retrodiscal condylar cartilage pads and lengthening of the mandible FORWARD MOVEMENT OF LOWER DENTAL ARCH GPR page 45
  79. 79. Functional appliances are designed to change the patients •Pattern of function, •Alter the jaw relationships, •Reprogram the neuromusculature, thus altering the functional matrix of the face.
  80. 80. Criteria for functional appliances selection Indications for functional appliances: •Patient in growth phase. •Skeletal Class II malocclusions due decreased size of mandible are good indicators for functional appliances •Horizontal growth pattern.
  81. 81. Contraindications: 1.Patient in post growth phase. 2.Skeletal Class II malocclusions due to prognathic maxilla. 3.Skeletal class II due to normal sized and retrusive positioned mandible(unfavorable prognosis). 4.Gross irregularities in individual tooth positions(crowding and rotations). 5.Proclined lower anterior teeth. 6.Vertical growth pattern.
  82. 82. Activator: Indication: Mild to moderate class II malocclusions with deep bite and horizontal growth pattern. Contraindication: 1.Crowding cases. 2.Proclined lower anteriors. 3.In vertical growers.
  83. 83. EFFECTS: Antero-posterior effects: 1) A forward displacement of the lower arch. 2) A distal movement of maxillary arch. 3). An inhibition of the forward growth of the maxilla. 4) A stimulation of condylar growth. 5) A remodelling of the mandibular fossa. 6) An elimination of interferences which guide the mandible distally during closure.
  84. 84. The vertical effects: Successful overbite reduction found to be accompanied by: 1) Inhibition of lower incisor eruption. 2) Facilitation of molar eruption. 3) Encouragement of forward mandibular rotation. 4) An increase in lower face height.
  85. 85. Bionator (Balters appliance): AFFECTS OF BIONATOR: • Change in tongue position. • Keeps away buccal musculature. • Lip seal. • Mandibular protrusion.
  86. 86. Effects of Bionator : (AO, 1995:423 - 430: Changes in soft tissue profile following treatment with the bionator: D. William Lange, Varun Kalra, B.) 1) Decreased skeletal convexity. 2) reduced overjet and overbite. 3) Decreased facial convexity. 4) Increase in mentolabial angle.
  87. 87. Frankel functional regulator Indications : Class II cases with abnormal perioral muscle function Mechanism of action: This appliance is used as oral gymnastic appliance to help in overcoming abnormal perioral muscle activity and rehabilitates the muscles and to establish proper lip seal. FR-2
  88. 88. FUNCTIONAL REGULATOR FR 1 : Treatment of class I and class II div 1. FR1a : Class I with minor to moderate crowding and in deep bite cases. FR1b : Class II div 1 where overjet does not exceed 5 mm. FR1c : Class II div 1 where overjet is more than 7 mm. FR2 : Treatment of class II div 1 and div 2. FR3 : Treatment of class III. FR4 : Open bite and bimaxillary protrusion. FR5 : Can incorporate head gear, indicated in patient with high mandibular plane angle and vertical maxillary excess.
  89. 89. Twin block appliance: Indications: 1.In class II malocclusion to modify occlusal inclined plane in disto occlusion that have a distal component of force that is unfavorable for normal forward mandibular development. 2.In patients with poor tolerance to other functional appliances Mechanism of action: Forces of occlusion are used as functional mechanism to correct malocclusion.
  90. 90. Management of Class II / Div. 2 Malocclusion. • using the sagittal twin block appliance. screws are put in the palate for arch development in antero posterior direction. They act by 75-80% advancement of anteriors and 20-25% distalization of posteriors. In cases where transverse expansion is required a third screw may be put transversely in the midline.
  91. 91. One-phase versus two-phase treatment: GIANELLY: AJO-DO 1995 Nov (556-559) 90% of all growing patients can be treated successfully in only one phase by starting treatment in the late mixed dentition. 1. Utilizing leeway space for crowding correction 2. 1 mm of intercanine expansion produces a 0.73 mm increase in arch perimeter, whereas a 1 mm expansion of the molars produces only a 0.27 mm increase. (Germane N, et al. AM J 1991;100: 421-7). DENTOFAC ORTHOP
  92. 92. 3. Molar distalizing: molars can be moved distally 1 to 2 mm per month during late mixed dentition period. (Armstrong MM. AM J ORTHOD 1971;59:217-43). 4. In patients with mandibular retrognathism, use of functional appliances intent to stimulate mandibular growth. Less than 10.5 years - 3.2 mm/year mandibular growth and greater than 10.5 years - 4.0 mm/year (McNamara JA Jr, et al. AM J ORTHOD 1985;88:91109).
  93. 93. FIXED FUNCTIONAL APPLIANCES Indications: 1. Indicated in correction of class II malocclusions due to retrognathic mandible in growing patients. 2. In preadolescent patients to utilize residual growth left. 3. Uncooperative patients.
  94. 94. SAGITTAL CHANGES: • Restraint of maxillary growth: headgear like effect • Stimulation of mandibular growth • Proclination of lower incisors • Posterior movement of upper molars: headgear like effect. VERTICAL CHANGES: • Eruption of lower molars; intrusion of lower incisors: reduction of overbite • Proclination of lower incisors contributing to overbite reduction
  95. 95. A. Rigid 1. Herbst appliance 2. Mandibular anterior repositioning appliance (MARA) 3. Mandibular protraction appliance (MPA) 4. Eureka spring 5. Universal bite jumper 6. Mandibular corrector 7. Biopedic 8. Mandibular Advancing Repositioning Splint(MARS)
  96. 96. B. Flexible • Jasper Jumper • Churro Jumper • Adjustable bite corrector • Klapper Super Spring Corrector • Forsus
  97. 97. C-II CORRECTION : a likely scenario (Graber & Vanarsdall - pg 481) Skeletal effects: •Condylar growth amount during treatment (1-3 mm). •Fossa displacement, growth, & adaptation (3-5 mm). (BUSCHANG P H et al AJO 113;437, 1998) •Elimination of functional retrusion (0.5-1.5 mm) (upward and backward path of closure reduced).
  98. 98. • More favorable growth direction- trabecular orientation (0.5-1.5 mm). • Withholding of downward & forward maxillary growth (1-1.5 mm). • Differential upward & forward eruption of buccal segments. (1.5-2.5 mm). • Headgear effect (0.5-0.0 mm).
  99. 99. AJO-DO 1989 Mar (250-258): REVIEW ARTICLE - Bishara and Ziaja Regardless of the type of functional appliance used (1) optimizing mandibular growth, (2) redirection of maxillary growth, (3) lingual tipping of the maxillary incisors, (4) labial tipping of the mandibular incisors, (5) mesial and vertical eruption of mandibular molars, and (6) inhibition of mesial movement of the maxillary molars. A combination of orthodontic (60% to 70%) and orthopedic (30% to 40%) movements provides the correction necessary for successful treatment.
  100. 100.
  101. 101. Indications for Molar distalization • Lack of space for eruption of premolars due to mesial migration of permanent first molars • End on molar relationship with mild to moderate space requirement • Cases with less than a full cusp class II molar relationship • Good soft tissue profile • Borderline cases • Mild to moderate space discrepancy with missing 3rd molars/2nd molars not yet erupted
  102. 102.  Headgears  Wilson Bimetric arch  Modified Nance Lingual appliance  Molar distalization with magnets  Use of Super elastic NiTi  NiTi Double Loop system  Jones Jig
  103. 103.  The Pendulum appliance  Fixed piston appliance  The K-loop appliance  The distal jet  Lokar Molar Distalizing Appliance  Franzulum appliance
  104. 104. u o m a C e g la f
  105. 105. Treatment of malocclusion with underlying mild or moderate jaw discrepancies, which can achieve a good dental occlusion, through extraction of certain teeth, to mask skeletal problem.
  106. 106. IDEAL CASE
  107. 107. oMild to moderate skeletal Class II Jaw oReasonably good alignment ( so that Xn spaces can be used for retraction and not to relieve crowding) oGood vertical facial proportions, neither extreme short face (skeletal deep bite)
  108. 108. NOOOO……..
  109. 109. oSevere class II, oModerate or severe Class III, oVertical Skeletal Discrepancies. oPatients with severe crowding or protrusion of incisors in whom extraction spaces would be required to align remaining
  111. 111. Inner envelope Orthodontic tooth movement alone Middle envelope Orthodontic tooth movt.+ Growth modification Outer envelope Orthognathic surgery
  112. 112. Envelope of discrepancy for Maxilla
  113. 113. Envelope of discrepancy for mandible
  114. 114.
  115. 115. SURGICAL CORRECTION OF CLASS II Surgical option should be choosen in following cases: 1.Severe skeletal discrepancy or extremely severe dento alveolar problem. 2.Adult patients 3.Young patients with extremely severe or progressive deformity. 4.Good general health status of patient.
  116. 116. Cephalometric Assessment Useful ratios: 1) SN: Maxilla: Mandible = 20:14:21 2) Corpus:Ramus = 7:5 3) Middle face : Lower face = 45 % : 55% 4) Postr:Antr face height(Jarabak)=62– 64% 5) Nasal : Labial = 1:4( Nasolabial angle )
  117. 117. Cephalometric Assessment Useful ratios: 20 14 5 1 4 7 21
  118. 118. Surgical & orthodontic phases of treatment. 3 phase 1. pre surgical orthodontic phase. 2. surgical phase. 3. post surgical orthodontic phase.
  119. 119. Pre surgical orthodontics • Main aim is to position the teeth in the arches ,so that the dental arches become compatible,facilitating their proper placement during surgery. • Main tooth movements commonly required include intrusion,levelling,derotation,closure of spaces,correction of anterior / posterior crossbites &co-ordination of the arches.
  120. 120. Extraction patterns Extraction of upper second premolars and lower first premolars Basically – the desired final post surgical position of the incisors should be achieved presurgically
  121. 121. Leveling the mandibular arch. • Accentuated curve of spee can be corrected by two methods 1. Intrusion of incisors. 2. Extrusion of premolars
  122. 122. • If the incisors are elongated & face height is normal / excessive they must be intruded to prevent problems in controlling face height at surgery. • Face is short & distance from lower incisal edge of the chin is normal leveling by extrusion of posterior teeth is indicated.
  123. 123. MIDFACE SURGERIES  Le Fort I maxillary osteotomy – Posterior repositioning – Superior repositioning  Maxillary anterior segmental osteotomy: – Dentoalveolar proclination. – Bimaxillary protrusion.  Interdental corticotomy : In class II div I cases with maxillary prognathism and anterior spacing
  124. 124. MANDIBULAR SURGERIES Mandibular deficiency can be corrected surgically by  Bilateral Saggital split osteotomy (Treatment of choice).  C osteotomy.  L osteotomy.  Vertical osteotomy
  126. 126. A process of new bone formationbetween the surfaces of bone segments gradually separated by incremental traction It was introduced by Ilizarov in 1951. In 1989, McCarthy was the first to clinically apply an external fixation device for mandibular lengthening.
  127. 127. Distraction appliances of the maxillofacial region can be divided into: •Extra-oral appliances •Unidirectional devices •Bi-directional devices •Multidirectional devices •Intra-oral devices •Tooth-borne devices •Tissue-borne devices •Hybrid (tooth and tissue borne) devices
  128. 128. Uni-Directional Distractor Bi-Directional Distractor Multi-Directional Distractor
  129. 129. MERITS OF DISTRACTION • Potential for greater movements • Potential for less relapse • No donor site morbidity
  130. 130. DISADVANTAGES • • • • • • Patient compliance Socially acceptability Intensive post-op monitoring Lengthy treatment time Mechanical failures Procedure to remove distractors
  131. 131. Retention and Stability
  132. 132. Retention and stability: A r eview of the liter ature - Blake and Bibby (A m J Or thod Dentofacial Orthop 1998;114:299-306) Expansion is thought to be better tolerated in Class II Division 2 cases than Class I and Class II Division 1. Adequate interincisal contact angle may prevent overbite relapse and good posterior intercuspation prevents relapse of both crossbite and AP correction.
  133. 133. Overbite relapse tends to occur in the first 2 years posttreatment and maintenance of intercanine width is thought to increase stability.(30% to 50% of the correction is retained) Growth may aid in the correction of orthodontic problems but may also cause relapse of treated cases. Improved occlusion in the mixed dentition provides better long-term stability (Dugoni SA et al Angle Orthod 1995;65:311-20).
  134. 134. RELAPSE REVISITED (James L. Vaden et al AJO DO 1997; 111: 543-53) • Expansion in maxilla is retained whereas expansion in mandible is lost. • 78% of incisor overbite correction is lost in 15 years of treatment. • 58 % of mandibular incisor irregularity correction maintained. • 96% of maxillary irregularity correction maintained.
  135. 135. Relapse and Stability
  136. 136. CONCLUSION The choice of appliance should be based on the proper diagnosis. Clinicians should be thoroughly familiar with the appliances they are using, including their potential benefits and limitations. Clinicians also should be aware of the effects of these appliances on the dentofacial structures when formulating a treatment plan for each individual patient.
  137. 137. REFERENCES • • • • • Proffit WR: Contemporary Orthodontics Mosby Moyers RE: Handbook of Orthodontics Fonseca – Oral and Maxillofacial Surgery Graber, Vanarsdall : current principles and technique. Graber , Rakosi, Petrovic : dentofacial orthopedics with functional appliances.
  138. 138. Leader in continuing dental education