Occurs in about 10 of children In milder forms they may be acceptable functionally and the facial appearance can be pleasing In severe cases the over bite is very deep associated with periodontal ID: 1020320
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1. Class II, Division 2 MalocclusionsOccurs in about 10% of childrenIn milder forms they may be acceptable functionally, and the facial appearance can be pleasing.In severe cases the over bite is very deep, associated with periodontal trauma palatal to upper, and labial to the lower incisors.
2. Div 1Div 2
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5. Occlusal Features:Class II incisor relationship with retroclination of the upper central incisors.The upper lateral incisors may also be retroclined, but typically they are proclined, mesially inclined and mesio-labially rotatedThe overbite is deep and over jet is average.The anterioposterior buccal segment relationship is usually mild class II.Transversely, there may be buccal crossbite
6. Skeletal Relationships:The skeletal pattern may be Class I, but is generally mild Class II, and the chin is well developed so that the facial profile is good.The lower anterior face height is often smaller than average and characteristically the maxillary-mandibular planes angle is low, with a well-developed mandibular angle.
7. Class II, Div. 2 incisor relationship is generally the result of dento-alveolar compensation for a class II skeletal pattern by retroclination of the upper central incisors.
8. Class 11 division 2 malocclusion
9. Facial GrowthIn many class II, Div.2 patients, facial growth is favourable, and there is an anterior mandibular rotation, as might be expected from the diminished anterior face height and the form of the chin.
10. Soft Tissues The lips are almost always of adequate length to meet without strain.Frequently the lip line is high relative to the upper incisor crown, and the higher the lip line the more retroclined the upper incisors are liable to be. There is often a well-developed labiomental fold.
11. Traumatic overbite
12. TREATMENT OPTIONSGrowth modificationOrthodontic camouflageOrthognathic surgery
13. GROWTH MODIFICATIONAim for Growth modificationSome mandibular growthSome restraint of maxillary growthForwards mandibular rotationBut after alignment of anterior teeth
14. HOW TO MODIFY GROWTHHeadgears (high pull & cervical pull)Functional appliances
15. HEADGEARSIn class ii malocclusion, HG has 2 functions:restrain maxillary AP growth so allows mandible to catch upto control the vertical position of the maxilla and maxillary posterior teeth as downward movement of either the jaw or the teeth will project mandibular growth more verticallyMolar distalisation
16. SELECTION of HG TYPEHigh pull HG: superior and distal force on teeth and maixllaCervical pull: inferior and distal forceThe more signs of a vertically excessive growth pattern are present, the higher the direction of pull and vice versa
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18. Center of resistance of the molar is in the midroot region, force vector above this point should result in distal root movement and vectors below this point should cause distal crown tippingThe length and position of the outer HG bow and the form of anchorage ( head cap or neckstrap) determine the vector of forceCenter of resistance of maxilla is above premolar root
19. ORTHODONTIC CAMOUFLAGEAim of treatment Relieve crowdingLevel and align archesDecrease OBDecrease OJ
20. Considerations :to reduce OB with anterior bite planeaid correction of buccal segment with EOTconvert class II div 2 patients to class II div 1Xtn 5s rather than 4s to minimize lingual movement of LLS
21. If lower arch accepted, upper arch mildly crowded with at most half unit class molar relationship,Consider moving the upper buccal segment distally with headgear (which may require the removal of 7 7 ), followed by the canine retraction just sufficient for labial segment alignment. Extraction of 5 5 and fixed appliance therapy is an alternative where cooperation with headgear is unlikely. If buccal segment relationship is a full unit class 11 or extraction of 5 5 is required for the relief of crowding, removal of 4 4 is usually indicated.
22. ORTHOGNATHIC SURGERYCorrection of functional and aesthetic consequences of severe dentofacial deformity through combination of orthodontic, surgical and, possibly, restorative dentistry.
23. IndicationsOrthodontic problems are so severe that neither growth modifications nor camouflage affects a solution.
24. Le Fort I, II & IIISARPE
25. pretreatment
26. After functional followed by fixed appliance therapy
27. STABILITYRelapase mostly occurs 6-8 wks post op Proffit et al., 1996Late relapse >1yr post op in 2.5-8% of pts depends on direction of movement, fixation, technique used. Proffit et al., 1996Similar relapse with BSSO and VSS, approximately 10% ( Proffit et al 1996)Mandibular advancement – stable if no vert face height change
28. Post treatment stabilityAlignment of 2 2 and overbite reduction are prone to replace. Bonded retention is advisable for 2 2 .Flat anterior bite plane on URA retainer is recommended until growth is complete to promote overbite stability.