Q6-Developing Posterior Contours

Question 1

The biological contours help to achieve these goals involving the teeth and tissues

Answer 1

stimulate natural, healthy gums
protect supporting tissues
maintain the health of the gingiva and attachments
minimize trauma and irritation to bony tissues

Question 2

Improper contours can result in these issues

Answer 2

often induce early breakdown of supportive structures

result in early loss of teeth

Question 3

The facial and lingual convexities relate to this

Answer 3

crest of curvature = height of contour

Question 4

Where is the greatest convexity (or bulge) of the crown

Answer 4

on the axial surfaces

Question 5

When viewed from the medial or distal, crowns have rather uniform curvatures in which areas

Answer 5

cervical third and in the middle thirs

Question 6

The proper degree of curvature will do what

Answer 6

deflect food over the gingival margin preventing irritation

Question 7

True or False

The proper curvature will allow some stimulation of soft tissue

Answer 7

True; massaging of the gingiva while chewing will help to stimulate the soft tissues

Question 8

What will happen if the proper curvature is absent

Answer 8

the gingival tissue will be drivel apically and this will result in pathological changes

Question 9

What will happen if the proper curvature is too great

Answer 9

The gingiva will be protected too much and lose its gingival tone
food and debris may pack under the area and result in chronic inflammation of the gingiva

Question 10

Where is the facial height of contour

Answer 10

in the cervical third

Question 11

What is the dimension of the facial height of contour

Answer 11

no more than 1/2 mm facially beyond the CEJ

Question 12

Where is the lingual height of contour

Answer 12

in the middle third

Question 13

What is the dimension of the lingual height of contour

Answer 13

no more than 1/2 mm lingually beyond the CEJ

Question 14

What are the exceptions to the lingual height of contour

Answer 14

mandibular second premolars and molars
they extend 3/4 to 1 mm lingual
due to the lingual tilt

Question 15

What is the emergence profile

Answer 15

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

Question 16

What describes the angle of the emergence profile

Answer 16

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

Question 17

Where is the area of the emergence profile

Answer 17

should be flat for 2-3mm above the gingiva

Question 18

Due to the interdental papillae, what does this do for the proximal surfaces

Answer 18

proximal surfaces are ALWAYS flat or slightly concave between the contact area and CEJ to allow room for the papillae

Question 19

What is the contact area of a tooth

Answer 19

the area of the mesial or distal surface of a tooth which touches its neighbors
similar to a ball or ball point contact
can have various locations

Question 20

What are the 4 basic functions of a contact area

Answer 20

aids in proper development of the arches
prevents food from packing between the teeth
allows teeth to be self cleaning
prevents injury to the interproximal tissues

Question 21

True or False

The contact areas become contact points as we age

Answer 21

False; the contact POINTS become contact AREAS as we age

Question 22

What causes the contacts to become more broad

Answer 22

due to wear as the teeth move during function

Question 23

Contact area of all posterior teeth should be where

Answer 23

buccal to the central fossa and in the occlusal third

Question 24

What is the exception to having the contact in the occlusal third

Answer 24

between maxillary molars

in the junction of the occlusal and middle third or middle third

Question 25

What is the exception to having the contact buccal to buccolingual center

Answer 25

between maxillary molars; in the middle third (large lingual)

Question 26

True or False | Mesial contacts are more cervical than distal contacts

Answer 26

False; distal contacts are more cervical than mesial contacts

Question 27

What is the only tooth where the mesial contacts are more cervical

Answer 27

mandibular first premolar

Question 28

Where would you find the axial transitional line angle

Answer 28

between the faciolingual convexities and proximal concavities

Question 29

Improper transitional line angles can present what

Answer 29

a hazard to the supporting tissues

Question 30

True or False | Transitional line angles are straight between the proximal contact point and the CEJ

Answer 30

True

Question 31

This is on the occlusal surfaces of the teeth at the proximal border; a ridge like structures neighbored by two depressions

Answer 31

marginal ridges

Question 32

What forms a marginal ridge

Answer 32

two depressions; occlusal embrasure and proximal fossa | it is concave in shape

Question 33

Marginal ridges have what type of crests, are shaped which ways MD/FL, and the adjacent ridges relate how

Answer 33

rounded elevated crests convex MD concave FL adjacent ridges are at the same height (opposing cusp to contact)

Question 34

What are the exceptions to a normal marginal ridge

Answer 34

premolars and canines

Question 35

Marginal ridges converge from ______ to _______

Answer 35

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

Question 36

In which tooth is it not true that the facial is wider than the lingual

Answer 36

maxillary first molar

Question 37

What is an embrasure space

Answer 37

The "V" shaped space extending outward from the contact area of the teeth also known as a spillway space

Question 38

What are the 2 main functions of the embrasure space

Answer 38

a spillway for the escape of food during function | helps to keep the teeth clean

Question 39

Which embrasure space is always larger, buccal or lingual

Answer 39

lingual space is always larger

Question 40

Cervical curvature/cervical line extends where

Answer 40

it curves occlusally at the proximal and apically at the facial and lingual

Question 41

What does the cervical curvature relate to

Answer 41

the contour of the bony alveolar bone

Question 42

If the cervical margin is within this distance to the alveolar bone, then the bone will begin to recede

Answer 42

1.5-2.0mm

Question 43

An over-contoured crown results from what and causes what

Answer 43

inadequate tooth reduction and it can cause a lack of room for biomaterials

Question 44

What can result if a margin of a restoration is placed subgingival

Answer 44

inflammation and reduction of gingival height

Question 45

When placing a sub gingival margin it is wise to use what material

Answer 45

a metal margin; it is easily tolerated by the tissues

Question 46

True or False | It is important to always establish contours in restorations which are in harmony with the natural tooth structure

Answer 46

True