9th Class

Question 1

Andrews’ Six Keys to normal (optimal) occlusion are a widely quoted set of static
occlusal goals for teeth relationships in the inter-cuspal position:

Answer 1

1. Correct inter-arch relationships (Classification).
2. Correct crown angulation (Tip).
3. Correct crown inclination (Torque).
4. No rotations.
5. Tight contact points.
6. Flat curve of Spee (0.0 - 2.5 mm).

Question 2

The mesio-buccal cusp of the upper first permanent molar falls where?

Answer 2

within the groove between the mesial and middle cusps of the lower
first permanent molar.

Question 3

The distal surface of the distal marginal ridge of the upper first
permanent molar contacts and occludes where?

Answer 3

with the mesial surface of

the mesial marginal ridge of the lower second molar.

Question 4

The mesio-lingual cusp of the upper first molar seats where?

Answer 4

in the central

fossa of the lower first molar.

Question 5

The premolars enjoy a ________ relationship buccally,

and a ________ relationship lingually.

Answer 5

cusp-embrasure; cusp fossa

Question 6

Maxillary Canine has a ______ relationship with

Mandibular Canine & 1st Premolar.

Answer 6

cusp-embrasure

Question 7

T/F: Crown angulation refers to angulation (Tip) of the long axis of the
crown, not to angulation of the long axis of the entire tooth.

Answer 7

True

Question 8

• Facial axis of the clinical crown (FACC) best viewed from the labial or buccal perspective.
• For all teeth except molars, is located at the mid-developmental ridge that runs
vertically and is the most prominent portion in the central area of the labial or buccal
surface.
• The facial axis of molar crowns is identified by the dominant vertical groove on the
buccal surface.

Answer 8

Crown Angulation (Tip)

Question 9

Crown Angulation (Tip)
A “\_\_ reading" when the gingival portion of the FACC is distal to the incisal portion.

Answer 9

+ reading

Question 10

Crown Angulation (Tip)
A “ \_\_ reading" when the gingival portion of the FACC is mesial to the incisal portion.

Answer 10

• reading

Question 11

Each normal model had a _____ inclination of the gingival portion of each
crown, It varied with each tooth type, but within each type the tip pattern was
consistent from individual to individual.

Answer 11

distal inclincation

Question 12

______ is formed by a line which bears 90° to the occlusal plane and FACC. (as viewed from the mesial or distal).

Answer 12

Crown inclination angle

Question 13

(crown inclination)

A ___ reading is given if the gingival portion of the tangent line of the crown is lingual to the incisal portion.

Answer 13

+ reading

Question 14

(crown inclination)

A __ reading is recorded when the gingival portion of the tangent line of the crown is labial to the incisal portion.

Answer 14

• reading

Question 15

ANTERIOR CROWN INCLINATION:

• In upper incisors __ crown inclination.

Answer 15

+ inclination

Question 16

ANTERIOR CROWN INCLINATION:

• In lower incisors __ crown inclination.

Answer 16

• inclination

Question 17

Properly inclined ______ crowns contribute to normal overbite and posterior occlusion.

Answer 17

anterior

Question 18

A ____ crown inclination for each crown from the U canine through the U-
2nd PM.

Answer 18

minus inclincation for upper canine thru upper 2nd PMs

Question 19

Are the upper molars or pms more negative in terms of crown inclincation?

Answer 19

Molars

Question 20

A progressively greater _____ crown inclination existed from the lower
canines through the lower 2nd molars.

Answer 20

“minus”

Question 21

As you move from the lower canine posteriorly in the mandible, how do the crown inclinations change?

Answer 21

Progressive get more (-)

Question 22

T/F: Teeth should be free of undesirable rotations.

Answer 22

True

Question 23

Rotated molar, would occupy
____ space than normal, creating a situation unreceptive to normal
occlusion.

Answer 23

More space

Question 24

T/F: Contact points should be tight (no spaces).

Answer 24

True

Question 25

There is a natural tendency for the curve of Spee to ____ with time.

Answer 25

deepen

Question 26

A ____ plane of curve of spee should be a treatment goal.

Answer 26

flat

Question 27

Lower jaw’s growth downward and forward sometimes is ______ and continues longer than that of the upper jaw.

Answer 27

faster

Question 28

Lower jaw’s growth downward and forward sometimes is faster and continues longer than that of the upper jaw.
his causes the Lower Anterior teeth to be: (what 4 things happen)

Answer 28

• Forced back and up.
• Crowded lower anterior.
• A deeper overbite.
• Deeper curve of Spee.

Question 29

The lower teeth need to be ______ mesio-distally compared to the
upper teeth.

Answer 29

smaller

Question 30

T/F: When the lower teeth are not smaller, it becomes impossible for all
the lower teeth to fit inside the upper arch.

Answer 30

True

Question 31

•This analysis helps in determining the differences in size between the maxillary and mandibular teeth and ideal relationship within the inter-arch.
•The Analysis or Ratio is a useful measurement tool that determines the relative M-D tooth size of upper and lower teeth.
•This Analysis has been identified for both the entire arch and for the anterior teeth.
➢These ratios were developed because there is generally more variability in the anterior tooth size than posterior tooth size.

Answer 31

Bolton analysis