Lecture 4

Question 1

Biological contours

Answer 1

stimulate natural, healthy teeth. Protect the supporting tissues.
maintain the health of gingiva + periodontum
minimize trauma and irritation to bony tissues.

Question 2

Improper contours

Answer 2

often induce early breakdown of supportive structures.

result in early loss of teeth.

Question 3

Crest of Curvature

Answer 3

Height of Contour - facial and lingual convexities

Question 4

Mesial and distal HOC

Answer 4

contact

Question 5

The proper degree of curvature will deflect

Answer 5

food over the gingival margin preventing irritation.

Question 6

The proper curvature allows stimulation

Answer 6

of soft tissue

Question 7

If the curvature is absent, the

Answer 7

gingival tissue will be driven apically and this will result in pathological changes.

Question 8

If the curvature is too great, the gingiva is protected too much and loses

Answer 8

gingival tone. Food and debris may pack under this area and result in chronic inflammation of the gingiva.

Question 9

*No more than 1/2 mm. facially

Answer 9

beyond the CEJ.

Question 10

Exception: mandibular second premolar and molars

Answer 10

3/4 to 1 mm. lingual

Question 11

Teeth move in place, rubbing

Answer 11

increases contact size over time

Question 12

Lingual embrasures are always larger than buccal embrasures except

Answer 12

maxillary first molar (where the facial embrasure is wider) and between the mandibular centrals (where the facial and lingual embrasures may be the same size).

Question 13

Emergence Profile

Answer 13

Tooth surface that is gingival to height of contour and above the gingival crest

The profile of the gingival third of a restoration as it emerges from the gingival crevice.

It should be flat for 2-3 mm above the
gingiva.

Question 14

PROXIMAL SURFACES ARE ALWAYS FLAT OR SLIGHTLY CONCAVE BETWEEN THE

Answer 14

CONTACT AREA AND THE CEJ TO ALLOW ROOM FOR THE PAPILLAE

Question 15

Contact area

Answer 15

The area of the mesial or distal surface of a tooth which touches it’s neighbors. It is similar to a ball to ball point contact. It can have various locations.

Question 16

Basic Functions of Contact Area:

Answer 16

1. Aids in proper development of the arches.
2. Prevents food from packing between the teeth.
3. Allows the teeth to be self- cleaning (to some extent).
4. Prevents injury to the interproximal tissues.

Question 17

Contact Areas

Answer 17

Contact areas of all posterior teeth should be buccal to the central fossa and in the occlusal third

Question 18

In occlusal 1/3 - contact

Answer 18

Exception - between max molars (junction of middle and occlusal

Question 19

Buccal to buccolingual center - contact exception

Answer 19

Max molars are in center 3rd.

Question 20


Marginal ridges converge from


Answer 20

buccal to lingual (facial 1/2 is wider than lingual 1/2)

Question 21

Marginal ridges converge from —– except!

Answer 21

Mandibular 2nd premolar 3 cusp type and Maxillary first molar

Question 22

functions of Embrasures

Answer 22

1. It is a spillway for the escape of food during function.

2. It help maintain the tooth clean

Question 23

Cervical Curvature

Answer 23

Margins of restoration often end at the cervical line or CEJ. This line curve occlusally at the proximal and apically at the facial and lingual. The curvature relates to the contour of the bony alveolar area.

Question 24

“BIOLOGIC WIDTH”

Answer 24

1.5 to 2 mm from margin to bone.

Question 25

An over-contoured crown results directly from inadequate

Answer 25

tooth reduction and causes a lack of room for biomaterials.

Question 26

Placing the margins of restorations subgingival

Answer 26

can cause inflammation and

reduction of gingival height.

Question 27

For subgingival margins it is wise to consider using a

Answer 27

consider using a metal margin, which is easily tolerated by the tissues. If esthetics
is a concern zirconia crowns are very compatible with tissues.