class ii division 2 malocclusion

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class ii division 2 malocclusion

  1. 1. Class II division 2 malocclusion
  2. 2. Introduction  A Class II Div.2 relationship is defined by the British Standards classification when the lower incisor edges occlude posterior to the cingulum plateau of the upper incisors with retroclination of the upper central incisors The overjet is usually minimal, but may be increased .The prevalence of this malocclusion in a Caucasian population 10%.
  3. 3. Cont.  According to Angle's classification, in a Class II Division 2 malocclusion where the mesiobuccal cusp of the upper 1st permenent molar should be at least half cusp anterior to the mesio buccal developmental groove on lower 1st permenent molar, and the upper central incisors should be retroclined ,The upper lateral incisors may be similarly retroclined although in other cases, Particularly in the presence of crowding, they may be proclined.
  4. 4. Class II div. 2
  5. 5. Types of cl ii div 2  Three types of cl ii div 2 can be distinguished based on diffrences in the spatial conditions in the maxillary arch: Type A:- the four maxillary permanent incisors are tipped palatally, without the occurrence of crowding.
  6. 6. Cont.  Type B: the maxillary central incisors  are tipped palatally and the maxillary  laterals are tipped labially.  Type C: the four maxillary permanent incisors are tipped palatally with the  canine labial positioned. 
  7. 7. Main features of class ii div 2  1-retroclination of the upper incisors.  2-excessive incisal overbite (deep bite).  3-a low gonial angle.  4-square facial profile.  5-the lips have sufficient vertical dimension to be able to meet in the rest position.  6-lips meet in front of the upper central incisors.  7-There is commonly a pronounced labiomental groove beneath the lower lip.
  8. 8. A etiology Skeletal pattern Soft tissues Dental factors Aetiology
  9. 9. Skeletal pattern  Class II division 2 malocclusion is commonly associated with a mild Class ll skeletal pattern, but may also occur in association with a Class 1 dental base relationship.
  10. 10. Skeletal pattern
  11. 11. Soft tissue The influence of the soft tissues mediated by the skeletal pattern… lower facial height is reduced the lower lip line will effectively be higher incisors relative to the crown of the upper (more than 1/3 of crown A high lower lip line will tend to retrocline the upper incisors Class II division 2 incisor relationships may also result from bimaxillary retroclination caused by active muscular
  12. 12. High lip line cause retroclination to incisors
  13. 13. Patient with bimaxillary retroclination due to lip action
  14. 14. Soft tissue  in some cases the upper lateral incisors, which have a shorter crown length, will escape the action of the lower lip and therefore lie at an average inclination, whereas the central incisors are retroclined
  15. 15. Dental factor  As with other malocclusions, crowding is commonly seen in conjunction with a Class II division 2 incisor relationship In the upper labial segment this usually manifests in a lack of space for the upper lateral incisors which are crowded and are typically rotated mesiolabially out of the arch  In the same manner lower arch crowding is often exacerbated by retroclination of the lower labial segment. This can occur because the lower labial segment becomes 'trapped' lingually to the upper labial segment by an increased overbite
  16. 16. Cont.  the upper central incisors exhibit a more acute crown - root angulation. this crown-root angulation could itself be due to the action of a high lower lip line causing deflection of the crown of the tooth relative to the root after eruption.  reduced or absent palatal cingulum on the upper incisors. This can be another factor contributing to the excessive overbite.
  17. 17. Traumatic deep bite  The lower incisors may cause ulceration of the palatal tissues due to deep bite
  18. 18. Traumatic deep bite  retroclination of the upper incisors leads to stripping of the labial gingivae of the lower incisors.
  19. 19. lingual cross bite  lingual cross bite of 1st and 2nd premolars the owing to the relative positions and widths of the arches, and possibly to trapping of the lower labial segment within a retroclined upper labial segment
  20. 20. Differences between cl ii div 1 and cl ii div 2 feature Div 1 Div 2 profile convex Convexity/ straight lips incompetent competent Lower facial height Increase/normal decrease Arch form V-shape Square/ U-shape incisors proclined CI LI Overjet overbite Increase deep Decrease deep Path of closure normal backward retroclined proclined
  21. 21. Treatment aims  1-To improve the aesthetics of the teeth and the function of the teeth and jaws.  2-To relieve crowding and produce alignment of the teeth within the arches  3-Where the overbite is excessive, to reduce it.  4-If the overjet is increased, reduce it
  22. 22. Treatment options  1-no treatment  2-extraction only  3-removable appliance  4-single fixed arch appliance  5-full upper and lower fixed appliance  6-functional appliance  7-orthognathic surgery
  23. 23. Treatment options  No treatment:-In milder Class II Division 2 malocclusions in which the typical facial appearance is acceptable, as is the overbite, and the incisors are neither too retroclined nor too crowded, advising no active treatment can be a very reasonable approach to management  Extractions only:-This is rarely an acceptable treatment approach in this type of malocclusion .However , where buccal crowding is severe with a tendency for the premolars to be excluded from the arch this may be an option to consider.
  24. 24. Treatment options  Removable appliances:- 1-In these types of malocclusion an upper removable appliance is most frequently used to assist in the reduction of the deep overbite during the early stages of a fixed appliance treatment (adjunctive support).
  25. 25. Treatment options 2-In a very limited number of cases a definitive simple removable treatment alone may be appropriate. An example might be where a labial spring is used to bring back a single proclined lateral incisor into the arch This movement would be performed after an 'en masse' appliance had been used to move the teeth of the buccal segments distally. 3-The use of an isolated removable appliance, particularly in combination with a premolar extraction pattern, is rarely prescribed in Class II Division 2 malocclusion.
  26. 26. Treatment options  Single fixed arch appliance:- overbite and upper central incisor inclination is largely acceptable.  Extra-oral traction might then be applied to the upper first molars. When sufficient space has been achieved by this means or by a second premolar extraction, an upper appliance may be fixed to the teeth to align and derotate the upper lateral incisors.  Some limited torquing of incisor apices palatally may be possible.
  27. 27. Treatment options  Upper and lower fixed appliance:-The most common way to treat class ii div.2 .  Extraction pattern:-The first option, which should always be considered, is whether this malocclusion may be corrected on the basis of 'no extractions' or Extraction of permanent second molars.
  28. 28. Treatment options  1- no extraction:-where the incisors are retroclined, torquing the root apices palatally will increase the arch length and gain sufficient space to both align the dental arches and reduce the overbite. In such a situation a high level of patient compliance is essential since the end result depends on the extra oral traction (headgear) being worn by the patient for long periods to supplement the anchorage.
  29. 29. Treatment options  2-with extraction:- we need extraction to gain space In the following situations:*the incisors require more torque to achieve an acceptable inter incisal angle. *there is a deeper initial overbite. *The crowding is more severe. so premolar extractions might be considered (usually four second premolars).
  30. 30. Treatment options  Overbite:-One of the chief reasons for employing a twin arch fixed appliance is to correct the overbite to a stable result. This is achieved by active intrusion of the lower incisors to flatten the curve of Spee.  Interincisal angle:-the interincisal angle is obtuse at the start of treatment. Obtaining a stable overbite correction is dependent on torquing the incisor root apices palatally to achieve a more acute (reduced) interincisal angle.
  31. 31. Treatment options  Functional appliances:- some functional appliances      are most effective in cases where the lower facial height is reduced. The upper incisors are firstly proclined to create a Class II Division 1 malocclusion then treat it with functional appliance. Types of functional appliances used in Cl ii div.2 :-Andresen appliance. -The Harvold appliance. -The Frankel appliance. -Clark's Twin-Block appliance.
  32. 32. Treatment options Clark's Twin-Block appliance The Frankel appliance These appliances are designed to move the mandible in a forward position Andresen appliance.
  33. 33. Treatment options  Orthognathic surgery:- In the more severe forms of this malocclusion, where the facial profile is poor and the overbite is very deep (and traumatic), a combination of orthodontics and jaw surgery is the best approach.  initial pre surgical phase of fixed appliance orthodontics, the upper incisors are proclined to create an overjet The mandible is then advanced by surgery to reduce this overjet and correct the facial profile.
  34. 34. Post-treatment stability  Lateral incisor alignment:- There is a very strong tendency for the lateral incisors to return towards their original position. This is particularly true if they were rotated. Where possible the position of these teeth should be overcorrected during treatment. Or prolonged retention but it is not yet clear whether retention beyond six months does improve stability or it merely postpones the relapse.  Overbites:- relapse of overbite reduction will occur unless palatal movement of the incisor apices has reduced the interincisor angle.
  35. 35. Thanks…………

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