Premolars

Question 1

buccal ridge

Answer 1

subtle ridge running cervicoocclusally in the middle third of the buccal surface of premolars

Question 2

cusp ridges

Answer 2

A raised part of the occlusal surface of a posterior tooth that runs from a cusp tip toward the central dissectional groove.

Question 3

cusp tip

Answer 3

The highest point of a cusp.

Question 4

central fossae

Answer 4

A shallow depression found approximately in the middle of the occlusal surface of a molar, bordered by the cusp ridges and the occlusal perimeter. Sometimes used to describe the linguo-middle fossa of a lower second bicuspid.

Question 5

triangular fossae

Answer 5

Located adjacent to the marginal ridges on the occlusal surfaces of posterior teeth. Two types of triangular fossae are mesial and distal.

Question 6

furcation

Answer 6

In dentistry, a furcation defect is bone loss, usually a result of periodontal disease, affecting the base of the root trunk of a tooth where two or more roots meet (bifurcation or trifurcation).

Question 7

central grooves

Answer 7

A groove in the occlusal surface of a posterior tooth that runs from the mesial to the distal and dissects the tooth into buccal and lingual parts.

Question 8

marginal grooves

Answer 8

Groove that crosses a marginal ridge

Question 9

triangular grooves

Answer 9

Triangular ridges are convex ridges that are placed from the cusp tip into the central groove of a posterior tooth

Question 10

supplemental grooves

Answer 10

Shallow, linear groove that radiates from the developmental groove. It often gives the tooth surface a wrinkled look.

Question 11

inclined cuspal planes

Answer 11

slopping area between the cusp ridges

Question 12

marginal ridge

Answer 12

are located on the mesial and distal borders of the occlusal surface

Question 13

crowns tipped lingually with respect to the root axis line (proximal view)

Answer 13

mandibular first premolar, mandibular second premolar (two cusp type), mandibular second premolar (three cusp type)

Question 14

pits

Answer 14

Sharp, pinpoint depression where two grooves meet

Question 15

premolar

Answer 15

8 of them in the permanent dentition
maxillary number 4,5,12,13
mandibular number 20,21,28,29

Question 16

root concavity

Answer 16

Linear developmental depression in the root surface; commonly occur on the proximal surfaces of anterior and posterior teeth and the facial and lingual surfaces of molar teeth. In healthy patients, it is covered with alveolar bone and thus help to secure tooth in bone.

Question 17

has the longer central groove

Answer 17

maxillary first premolar

Question 18

has two major cusps almost the same size and length

Answer 18

maxillary second premolar

Question 19

has a central fossa

Answer 19

mandibular second premolar (three cusp type)

Question 20

premolars with only two fossae: both are triangular fossae

Answer 20

maxillary first premolar, maxillary second premolar

Question 21

has a central fossa and two triangular fossae

Answer 21

mandibular second premolar (three cusp type)

Question 22

has a lingual groove

Answer 22

mandibular second premolar (three cusp type)

Question 23

functions of premolars (upper and lower)

Answer 23

masticating food, maintain vertical dimension of face

Question 24

function of first premolars

Answer 24

assist canines in shearing and cutting food morsals

Question 25

function of all premolars

Answer 25

support the corners of mouth and cheeks to keep them from sagging

Question 26

premolar root shape

Answer 26

have convex facial and lingual root surfaces, taper apically, tapers toward the lingual

Question 27

height of contour

Answer 27

from mesial and distal aspects, the facial heights of contour of premolar crowns are in the cervical third

Question 28

contact areas

Answer 28

the proximal contact ares are generally more cervically located and broader than on anterior teeth

Question 29

tooth proportions

Answer 29

are wider faciolingually than mesiodistally

Question 30

buccal ridge prominence

Answer 30

is more prominent on the maxillary first premolar than on the mandibular first premolar

Question 31

crown proportions

Answer 31

maxillary premolars are more oblong or rectangular, mandibular premolars are closer to equal dimension faciolingually as mesiodistally

Question 32

Premolars develop from

Answer 32

Facial lobes (3)
Lingual lobes (1 or 2)

Question 33

roots

Answer 33

of second premolars longer than first

Question 34

maxillary first premolar traits

Answer 34

sharper buccal cusp angle
mesial cusp ridge longest
prominent buccal ridge
two roots or deeply divided single root
almost always mesial marginal ridge groove
crown asymmetrical, more hexagonal
fewer supplemental grooves

Question 35

maxillary second premolar traits

Answer 35

more blunt buccal cusp angle
distal cusp ridge longest
less prominent buccal ridge
narrow more rounded shoulders
distal buccal ridge depression more common
shorter mesial cusp ridge
single root
buccal and lingual cusps similar length
crown symmetrical and more oval
more supplemental grooves