Ortho

1. D R Z A F A R U L I S L A M
A S S O C I A T E P R O F E S S O R O R T H O D O N T I C S
ANDREW’S SIX KEYS OF
OCCLUSION

2. SIX KEYS OF OCCLUSION
1. MOLAR
RELATIONSHIP
2. ROTATIONS OF
TEETH
3. SPACING OF TEETH
4. TOOTH
INCLINATION
5. TOOTH ANGULATION
6. CURVE OF SPEE

3. MOLAR RELATION
 Molars in class I relation
 The mesiobuccal cusp of
maxillary first
permanent molar should
occlude in the buccal
groove of mandibular
first permanent molar

4. Rotations of teeth
 Their should be no
rotations of teeth

5. Spacing of Teeth
 There should be no
spacing in the teeth

6. Tooth Inclinations
 Also called torque of
teeth
 The teeth should be
ideally inclinated
buccolingually/palatally
 12, 8, -1, -7, -7, -14, -14
 -1, -1, -11, -17, -22, -30, -
30

7. Teeth Angulations
 Also called TIP
 The teeth should be
ideally angulated
mesiodistally
 5, 9, 13, 0, 0, 0, 0
 0, 0, 7, 0, 0, 0, 0

8. Curve of Spee
 A curve passing along the
buccal cusps of posterior
teeth and incisal edges of
anterior teeth
 Curve of spee should be
flat or slightly concave

9. 7TH KEY OF OCCLUSSION
 Bennet and Mc Laughlin
 There should be no
Bolton discrepancy

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