Classification of malocclusion in orthodontics


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Classification of malocclusion in orthodontics

  1. 1. Classification of malocclusion ABDULLAH KARAMAT FINAL YEAR BDS FMHCM&D , LAHORE
  2. 2. Before going to malocclusion or abnormal occlusion lets ask first , what is normal occlusion ??!!
  3. 3. Andrew’s six keys to normal occlusion : 1- Molar inter-arch relationship : -The mesiobuccal cusp of the upper first molar should within the groove between the mesial and middle buccal cusps of the lower first permanent molar -The crown of the upper first molar must be angulated so that its distal marginal ridge occludes with the mesial marginal ridge of the lower second molar.
  4. 4. - The mesio-lingual cusp of the upper first molar should occlude in the central fossa of the lower first molar.
  5. 5. 2- Mesio-distal crown angulation : The gingival part of the long axis of the clinical crown must be distal to the occlusal part of line passing through long axis of tooth.
  6. 6. 3- Labiolingual crown inclination : • When viewed from mesial or lingual side if gingival area of crown is more lingually placed than the occlusal position , it is referred to as positive crown Inclination and vice versa. • The maxillary incisors exhibit a positive crown inclination , mandibular incisors show a slightly negative crown inclination
  7. 7. • The maxillary and mandible posterior teeth both have negative crown inclinations.
  8. 8. 4- Rotations : • In order to achieve correct occlusion, none of the teeth should be rotated. • Rotated molars and premolars occupy more space in the dental arch than normal. • Rotated incisors may occupy less space than those correctly aligned.
  9. 9. • Rotated canines adversely affect esthetics and may lead to occlusal interferences
  10. 10. 5- Tight contacts : To consider an occlusion normal , there should be tight contact between adjacent teeth
  11. 11. 6-Curve of Spee : A normal occlusion has a flat occlusal plane (the mandibular curve of Spee should not be deeper than 1.5mm).
  12. 12. Malocclusion : -Intra arch -Inter arch: Saggital plane Vertical plane Transverse plane
  13. 13. 1- Intra arch malocclusions : Distal inclination or tipping Mesial inclination Lingual inclination Buccal inclination Mesial displacement Distal displacement Lingual displacement Buccal displacement
  14. 14. infraversion suparversion rotations Mesiolingual or distbuccal Distolingual or mesiobuccal Transposition
  15. 15. 2- Inter arch : A- Saggital plane : Edward Angle created a classification of different malocclusions based on the relative antero-posterior (A-P) position of the maxillary first molar regarding the mandibular first molar which may be perceived in a sagittal plane.
  16. 16. Class I : When the mesio-buccal cusp of the upper first molar occludes in the mesio-buccal groove of the lower first molar, but there are problems like spacing or crowding.
  17. 17. Class II : The upper molars are in a Class II position, which is anterior to the mesiobuccal groove of the lower first molar. There are two subtypes: division 1 division 2
  18. 18. Class II Division 1: The molar relationships are like that of Class II and the upper anterior teeth are protruded/proclined resulting in an increased overjet.
  19. 19. Class II Division 2: The molar relationships are Class II, but the central are retroclined (inclined towards the palate) and the lateral or canine teeth are proclined (inclined towards the lip). A deep bite is commonly found.
  20. 20. Class III : In this case the upper molars are placed posteriorly to the mesiobuccal groove . It can be related to a decreased or reversed overjet. When there is a reversed overjet the lower anterior teeth are found ahead of the upper anterior teeth. The normal occlusion involves the upper teeth overlapping the lower.
  21. 21. B- vertical plane : 1. Deep bite or overbite : It is a condition in which there is excessive vertical overlap between upper and lower anteriors
  22. 22. 2-Open bite : it is a condition where there is no vertical overlap between upper and lower teeth
  23. 23. C- Transverse plane : The transverse arch malocclusions include various types of cross bites
  24. 24. Incisor classification :
  25. 25. Canine classification :