Ideal occlusion

Question 1

Angle’s classification refers to…? (2)

Answer 1

Just anterior-posterior relation of 1st perm molars

*does NOT analyze the vertical or transversal

Question 2

Angle: Class I molar occlusion?

Answer 2

1st U Molar mesiobuccal cusp OCCLUDES 1st L Molar buccal groove

Question 3

Angle: Class II molar relation?

Answer 3

LOWER 1st molar buccal groove occludes DISTAL to mesiobuccal cusp

(lower jaw is “pushed” back)

Question 4

Angle: Class III molar relation?

Answer 4

LOWER 1st molar buccal groove occludes MESIAL to mesiobuccal cusp

(lower jaw is “pushed” forward)

Question 5

Angle: Canine class I?

Answer 5

U canine cusp occludes BETWEEN distal aspect of L canine & mesial aspect of 1st premolar

Question 6

Angle: Canine class II?

Answer 6

Distal of L canine occludes DISTAL to cusp of U canine

Question 7

Angle: Canine class III?

Answer 7

Distal of L canine occludes MESIAL to cusp of U canine

Question 8

Ideal overjet?

Answer 8

2mm

Question 9

Ideal overbite?

Answer 9

1/3 of lower covered

Question 10

optimum arch shape?

Answer 10

• oval

- upper wider anterior-posteriorly and trasnversly

Question 11

Teeth angulation frontally? (2)

Answer 11

• U posterior: buccal

- L posterior: lingual

Question 12

Functional tooth contacts for lower molars?

Answer 12

Buccal cusp of L contact dentral fossa of U

Question 13

Functional tooth contacts for upper molars?

Answer 13

Palatine cusps contact central fossa of L

Question 14

Each tooth occludes with ____

teeth of the opposite arch except for …? (3)

Answer 14

• two
• 3rd molars
• lower incisors

Question 15

Lower incisors incisal edge contacts…?

Answer 15

palatine aspect of U incisors

Question 16

Andrew’s 6 keys?

Answer 16

1. Molar relationship
2. Crown tip (mesio-distal)
3. Crown torque (buccal-lingual)
4. Rotations
5. Tooth tight contacts
6. Oclusal plane (Curve of Spee)

Question 17

Whats andrew’s plane?

Answer 17

Divides dental crowns in two parts: incisal and

gingival portion: EM point

Question 18

Andrews molar relationship?

Answer 18

U 1st molar DISTAL surface of DISTOBUCCAL cusp occludes with MESIAL surface of MESIOBUCCAL cusp of L SECOND molar

Question 19

Andrews crown angulation? (2)

Answer 19

gingival long axes of crown more distal than the incisal portion (positive value)

(therefore all teeth are mesially angulated)

Question 20

Andrew’s crown torque inclination?

Answer 20

• labiolingual / buccolingual inclination

- positive reading: gingival portion of tangent line/crown is LINGUAL to incisal

Question 21

How do we measure Andrew’s crown torque?

Answer 21

• Agnle formed by a line which is 90 degree to the occlusal plane AND a tangent line to the bracket side (middle of labial/buccal long axis of clinical crow viewed mesially/distally)

Question 22

Andrew’s rotation?

Answer 22

• teeth should be free of undesirable rotations

- rotated teeth occupy more space than normal = not normal occlusion

Question 23

Andrew’s tight contacts?

Answer 23

-no spaces

Question 24

Andrew’s curve of spee?

Answer 24

on nonorthodontic models ranged from flat to slight curves