Classification of Maloccvbvvbblusion.pptx

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1. Classification of Malocclusion Dr. Huma Kiani Associate Professor Orthodontics

2. Learning Objectives Define and recognize features of normal and abnormal occlusion Define Andrew’s six keys of occlusion Identify Angle’s malocclusion Identify British Standard of classification

3. OCCLUSION Whe the teeth in the mandibular arch come in contact with those in the maxillary arch in any functional relation, are said to be in occlusion.

4. MALOCCLUSION A condition in which there is a deflection from the normal relation of the teeth to other teeth in the same arch and/or to teeth in the opposing arch

5. Need for classification ? Grouping of orthodontic problems Location of problems to be treated Diagnosis & treatment plan Comparison of different types of malocclusion For self-communication Documentation of problems Epidemiological studies Assessment of treatment effects of orthodontic appliances

6. MALOCCLUSION: QUALITATIVE & QUANTITATIVE METHODS QUALITATIVE METHODS Angle’s classification Modification of angles classification Simon’s classification Bennet’s classification Skeletal classification Ackerman& proffit classification Incisor classification Canine classification QUANTITATIVE METHODS PAR index IOTN index

7. MALOCCLUSION:INTER-ARCH & INTRA-ARCH PROBLEMS Intra-arch problems (individual or groups of teeth) 1.Sagittal problems : Labioversion Linguoversion Distoversion Mesioversion 2. Vertical problems Supraversion Infraversion 3. Rotated teeth 4. Transposition of teeth

8. MALOCCLUSION:INTER-ARCH & INTRA-ARCH PROBLEMS Inter-arch problems 1.Sagittal problems Class II malocclusion Class III malocclusion 2. Transverse problems Crossbite / siccors bite Midline shift 3. Vertical problems Deep bite Open bite

9. Andrew’s six keys of occlusion

10. Molar Interarch Relationship The mesiobucal cusp of the upper first molar should occlude in the groove between the mesial and mesial buccal cusp of the lower first 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. The mesiolingual cusp of the upper first molar should occlude in the central fossa of the lower first molar

11. Mesiodistal crown angulation The gingival part of the long axis of the crown must be distal to the occlusal part of the axis.

12. Labio -lingual Crown Inclination Anterior: The interincisal angle between the crown tangents of the upper and lower incisors is 174 o for normal occlusions (unlike Eastman Standard Value = 131). Posterior: The gingival portions of the teeth are more pronounced buccally than the occlusal portions.

13. 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. Rotated incisors may occupy less space than those correctly aligned. Rotated canines adversely affect esthetics and may lead to occlusal interferences.

14. Tight Proximal Contacts If there are no anomalies in the shape of the teeth, or intermaxillary discrepancies in the mesiodistal tooth size, the contact points should abut in normal occlusion.

15. Flat Occlusal P lane (Curve of Spee ) A normal occlusion has a flat occlusal plane (the mandibular curve of Spee should not be deeper than 1.5mm).

16. Angle’s classification

17. Angle, in 1899, described this classification It was based upon antero -posterior dental relationship Based upon permanent 1st molar relationship Divided into many classes of malocclusions that are designated by Class I, Class II & Class III mal-occlusions

18. Class I Malocclusion ( Neutro -occlusion) The permanent upper & lower 1st molars are in normal relationship, but the rest of the dentition may have deviation from normal occlusion, e.g ; crowding, rotations etc.

19. Class II Malocclusion ( Disto -occlusion) The mesio -buccal cusp of permanent upper molar occludes mesial (anterior) to the lower 1st molar mesio -buccal groove. It is further divided into Class II Div 1 Class II Div 2 Class II subdivision ( Rt or Lt)

20. Class II Div 1 Along with class II molar relationship, the over jet is more than normal i.e. 2-3 mm Molars may be in 1/4th unit, ½ unit or full unit or supra class II relationship

21. Class II Sub-division ( Rt ) Div 1

22. Class II Div 2 Along with class II molar relationship, the overjet is reduced than normal Further divided into; Type A Type B Type C

23. Class III ( Mesio -occlusion) The mesio -buccal cusp of permanent upper 1st molar occludes distal (posterior) to the lower 1st molar mesio -buccal groove Class III sub-division, when one side is in class I & other side in class III (class III side will be Rt or Lt sub-division)

24. Drawbacks of Angle’s classification This is only for dentition & not for skeleton Permanent 1st molars are not fixed points Only depends on AP relationship In case of extracted or missing 1st molars, cannot be classified

25. British Standards Institute Classification

26. Class I — the lower incisor edges occlude with or lie immediately below the cingulum plateau of the upper central incisors

27. Class II — the lower incisor edges lie posterior to the cingulum plateau of the upper incisors. There are two subdivisions of this category: Division 1 — the upper central incisors are proclined or of average inclination and there is an increase in overjet. Division 2 — The upper central incisors are retroclined . The overjet is usually minimal or may be increased.

28. Class III — The lower incisor edges lie anterior to the cingulum plateau of the upper incisors. The overjet is reduced or reversed.