a brief description of various classifictaion system of malooclusion. normal occlusion and malooclusion

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2. Classification and Etiology
Of
Malocclusion
Dr .Kapil Saroha
BDS, MDS
ORTHODONTICS AND DENTOFACIAL ORTHOPAEDICS
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3. Contents
• Introduction
• Normal occlusion - A brief overview
• What is Malocclusion?
• Classification of Malocclusion
• Etiology
• Development of Malocclusion
• Conclusion
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5. Andrews six keys to Normal
Occlusion
Key I : Molar Relationship

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6. Key II : Crown Angulation (Tip)
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8. Key III : Crown Inclination

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9. Key IV : Absence of Rotations

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10. Key V : Tight Contacts

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11. Key VI : Occlusal Plane
Flat to slight curve of Spee

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12. Key VII : Correct tooth size
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13.  
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14. Any deviation from ideal occlusion scheme described by Angle
Definitions:-
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17. Introduced in 1899(Dental Cosmos)
Based on A-P relationship of the dental arches.
Upper first permanent molar – Key to occlusion
Constant position relative to Key Ridge
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18. Molar relation :
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19. Angle’s classification has 4 groups :-
o Normal occlusion
o Class I Malocclusion
o Class II Malocclusion – Division 1
- Division 2
o Class III Malocclusion
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20. Normal occlusion :
Normal molar relation
Line of occlusion-smooth
catenary curve
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21. Class I Malocclusion :
Line of occlusion - irregular
Normal molar relationship
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22. Includes variations such as :
 Open bite
 Deep bite
 Crossbite
 Bimaxillary protusion
Combinations – Deep bite+Bimaxillary protusion
- Open bite+Bimaxillary protusion
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23. Class II Division 1
1. Proclined U anteriors
2. ‘V’ shaped maxillary arch.
3. Supraversion of the lower
anteriors.
4. Abnormal muscle activity.
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24. Class II Division 2
1. Retroclined upper centrals &
labially tipped upper laterals
2. Wide maxillary arch.
3. Supraversion of lower incisors.
4. Exaggerated curve of spee.
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25. Class II Div 1 / 2 Subdivision:
Cl II molar on one side , Cl I molar on other side.
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26. Class III
Mesiocclusion / Prenormal
Occlusion
Lower dental arch mesial to
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27. Class IV ??
Class II molar on one side & Class III on the other side
Cl III subdivision : Cl III on one side, Cl I on one side.
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28. Plus points of Angle’s classification
1)Simple & universally acceptable.
2)In original article, described each contacting
cuspal incline, emphasis on first molar in
subsequent revision.
Angle’s prototype
ideal occlusion
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29. Limitations of Angle’s system of classification :
1)Skeletal malocclusion not considered.
2) Only A-P discrepancy
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30. 3) Position of the first molar not always stable.
a. Relation not stable to cranial base
b. Mesial migration , rotations , diff stages of development
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32. 4) Severity of MO ?
5) Etiology ?
6) Missing first molars ??
7) Individual tooth malpositions not considered
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33. 8) Deciduous / Mixed dentition.
Angle classification revisited -AJO 1992 ; Sep By Morton Katz
Modified Class I
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34. If not First molar ……then what ???
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35. Skeletal malrelation :
• Skeletal 1
• Skeletal 2
• Skeletal 3
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36. British Standard Classification :
r classification – based on relation of L incisor edges to U central
cingulum p
d & Wayman (1964)
ied by Williams & Stephens (1992) – improve inter-examiner reliability
Cl I Cl II div 1 Cl II div 2 Cl II
intermediate
Cl III
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37. Class I malocclusion
Dental : Normal molar relationship.
Skeletal : Normal antero-posterior relationship
between the maxilla and the mandible.
Extra oral : Orthognathic profile
Soft tissue : Normal muscle function.
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38. Bimaxillary protrusion
Entire dentition forward wrt facial profile
3 Criteria for Bimaxillary protusion : (Proffit)
1. Excessive separation of lips at rest(not >
4mm)
2. Excessive effort to bring the lips into
closure
3. Prominence of lips in profile view
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39. Open bite
Abnormal perioral muscle function
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40. Class II MO
Mn in distal relation with maxilla
Class II Div 1
Extra oral findings :
Profile – Convex
Retrognathic Mn
Acute Nasolabial angle
Retruded chin
Lip trap maybe present
Abn perioral muscle function
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41. Class II MO
Division 1
Intra oral findings:
1.Class II molar relation.
2.Proclined upper incisors.
3. ‘V’ shaped maxillary arch.
4.Supraversion of the lower anteriors.
5.Exaggerated curve of Spee.
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42. Class II Div 2
Extra oral findings:
•Pleasing profile
•Perioral muscle function
within normal limits
 Depth of mentolabial
sulcus
 Redundancy of L lip
•Chin projection prominent-
tends to mask Mn deficiency.
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43. Cl II Div 2
Intra oral findings :
Retroclined U centrals ,
Laterals in labioversion
Types of incisor patterns in Cl II Div 2
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44. Intra oral findings
•Minimal overjet
•Mx arch may be wider - Squarish
arch
•Mn labial gingivae traumatised
•Mn incisors crowded +
supraversion
•Deep bite

•Exaggerated curve of Spee
•Forced retrusion
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45. Class II MO
DentalSkeletal
•Maxillary dental protrusion
•Mesial drift of upper 1st
molars
•Mn deficiency
•Mx excess
•Both
Skeletal Cl II
Usually assoc with dental Cl II MO
Dental compensations seen - Protrusive Mn
Insicors
- Retrusive Mx
incisors
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46. N nasolabial angle (102 ± 8˚)
Protrusion of U anteriors
Deficiency of chin
L lip everted/redundant
Deep mentolabial sulcus
Lip incompetence
L inc supreerupt- deep bite
Facial appearance
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47. Small sized Mandible
Both body & ramus small
Clockwise rotation of Mn
 Post facial height
Steeper Mn plane
Normal SNA
ANB, SNB
 angle of convexity
 A-B diff –WITS
True horiz- ‘A’ – normal
‘B’ – posterior
 Mn inc – Mn plane angle
- N-B line
Mn inc – Occlusal plane
- FH
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48. Mn body small but ramus normal or  length
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49. Mn body small,
Normal or  ramus
N / post facial height
Mn plane flatter
Bony chin projection +++
Unit length of Mn maybe N
lower ant facial height

lips everted at rest
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50. Normal size –Retruded positio
ANB , Normal SNA, SNB
A-B diff on occlusal – WITS
Cranial base angle – obtuse
Glenoid fossa -posterior posit
 Normal size, A-P unit length
lower ant facial height
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51. Maxillary Excess
1. Vertical maxillary excess
2. A-P maxillary excess (midface protrusion)
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53. Facial appearance :
•Long narrow nose,prominenet dorsum, narrow alar bases
 Lower facial height
 Display of Mx inc wrt to upper lip @ rest
•Excessive gingival exposure on smiling
•N /obtuse nasolabial angle
•Relative chin retrusion –clockwise rotation of Mn
•Relative Mx inc protusion (A-P discrepancy)
• ++ Lip incompetence
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54. A-P plane
ANB, normal SNA
SNB
Angle of convexity
A-B diff wrt occusal
Occusal-steep, diff 
True horiz- ‘A’ – normal
‘B’ – posterior
‘A’ anterior to ‘N’
Unit length of Mn
maybe normal wrt Mx
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55. Vertical plane
11  Lower Anterior facial ht
2. Steeper Mn plane
3. Molars ± Incisors position
inferior to palatal plane
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56. A-P maxillary excess
Mid face protrusion
Facial features :
Entire midface protrusion
vs dentoalv protrusion
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58. A-P maxillary excess
ANB,SNA,
normal SNB
A-B diff on occlusal
on True horiz
Angle of convexity
A-P Mx length
Mn length normal
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59. Maxillary excess & Mn deficiency
Most often both
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60. Dental Class II
Normal relation of Skeletal bases
Mx molars moved forward
Causes
Mx dental protusion
Mesial drift of upper 1st
molar
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61. Maxillary dental protusion
Diff from A-P Mx excess
Extra oral:
•Only lip protruded
•Convex profile
Intra oral:
•Overjet
•Gen Mx spacing & protuding U incisors
•Mn dentition normal
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62. Normal A-P&
vertical skeletal
r/lships
LA of U inc wrt
NA
SN
FH
Maxillary dental protrusion
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63. Mesial drift of first perm molar
Causes :
1) Congenital absence/premature loss of E
2) Ectopic molar eruption
3) Congenital absence of Mx 2nd
PM
4) Displacement / Impacted 2nd
PM
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64. Class III MO
Mn in mesial relation with Maxilla
Growth & size of Mn - heredity
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65. Intra oral findings:
Mandibular incisors –
Cross bite, inclined lingually.
Maxillary arch constricted.
Extra oral findings:
Concave profile
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66. Cl III MO
Skeletal Dental
True Pseudo
Maxillary
Deficiency
Mandibular
Excess
Combination
of both
Flattening
of infra
orbital rim
& area adj
to nose
Chin protruded ?
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67. Class III molar & overjet
Functional assessment
True Cl III Pseudo Class III Compensated
Cl III
Negative overjet Positive overjet/
End-to-end incisal
Eliminate CO CR shift
Cl I MO Cl III MO
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68. Sunday Bite
Scissors Bite
Brodie Bite
X- occlusion
Dual bite
Other terms :
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