Quiz 2: premolars

Question 1

what are the premolar numbers in universal numbering system ?

Answer 1

UR: 4,5
UL: 12, 13
LL: 20, 21
LR: 28,29

Question 2

premolar function

Answer 2

• mastication with molars, and maintain vertical dimension (can still chew if lost molars)
• also help canines shear/cut food.
• support corners of the mouth and prevent cheeks from sagging

Question 3

how many cusps do premolars have

Answer 3

1 facial, and 1 or 2 lingual cusps

Question 4

how many lobes are on premolars?

Answer 4

three on facial surface, one on lingual lobe. exception is mandibular 2nd premolar which may have 2 lingual lobes
(number depends on number of cusps)

Question 5

how is the facial surface similar to canines of premolars?

-how does it differ in maxillary vs mandibular?

Answer 5

facial surface is convex like canines. has buccal ridge (like canines labial ridge)
the buccal ridge is more prominent in the MAXILLARY ARCH!

Question 6

which premolar has less of a horizontal marginal ridge / more vertical instead?

Answer 6

-whiel anterior teeth have vertical marginal ridges, premolars have horizontal marginal ridges!!! they can be viewed from the proximal sides.
EXCEPTION: mandibular first premolar is not as horizontal / more vertical

Question 7

where does the buccal cusp tip sit with respect to the long axis on premolars (general)
and what is the exception

Answer 7

slightly mesial to the long axis

-EXCEPTION– maxilary first premolars buccal cusp tip is slightly to the distal of the long axis!!!

Question 8

which cusp slope is shorter on premolars (general)

Answer 8

mesial is shorter than distal (exception is max first premolars bc cusp tip is slightly distal instead of mesial)

Question 9

where are premolars broadest

Answer 9

at level of contact

Question 10

occlusal view: what are the proportions of the premolars- what is larger FL or MD (general)

Answer 10

-the coronal dimensions: wider faciolingual than mesiodistal

Question 11

what groove features are characteristic of all premolars and whats the exception?

Answer 11

central developmental groove in premolars generally, EXCEPTION is mandibular first premolar which has a pronounced transverse ridge. and not a deep central groove..
-fossae possess suplemental grooves to buccal and lingual for all premolars

Question 12

from an occlusal view, where is the contact of premolars generally? is it buccal or linqual?

Answer 12

either on or slightly buccal to mid-root axis line (buccal half of tooth ish)

Question 13

how does the first and second maxillary premolar differ in terms of the buccal ridge?

Answer 13

maxillary first premolar:

• more prominent buccal ridge
• mesial depression next to buccal ridge (rarely distal depression)

maxillary second premolar:

• buccal ridge is less prominent on second premolars
• distal buccal ridge depression is most common depression

Question 14

interproximal contacts of first and second premolars locations (general and maxillary specific)

Answer 14

first and second both have :
mesial - middle third/near junctino of middle and occlusal thirds
distal- in middle third, more cervical than mesial contact

maxillary :
-mesial contact is more buccal and smaller in size than distal contact

Question 15

compare maxillary roots first/second

Answer 15

maxillary first premolars: usually has two divided roots, buccal and lingual branching from trunk.
can sometimes see lingual root tip from buccal on first premolars
-second premolar root is longer than first root. Root crown ratio is highest for ANY maxillary tooth!!!!!
-apical part of both premolar roots bends to distal. can bend mesial or straight (not as common)
-first premolar has prominent root depressions. distal root depression starts more apically than mesial, and mesial is deeper than the distal one.
-second premolars have a mesial and distal root depression, usually more prominent on distal side.

Question 16

proximal view of maxillary premolars first and second (marginal ridge grooves)?

Answer 16

first:
- have a prominent mesial concavity cervical to the contact area. the mesial root depression is continous with crown depression.
- mesial marginal ridge of first is crossed by groove
- distal marginal ridge groove is less frequently seen

second:
-mesial and distal grooves on second premolars are much less frequently there.

Question 17

describe height of contour from proximal views on premolars (maxillary)

Answer 17

lingual: middle third of the crown
buccal: more cervical at junction of middle and cervical thirds

Question 18

occlusal groove first vs second premolar (maxillary) -occlusal view

slide 40

Answer 18

(central developmental groove)

• first premolar: central groove is longer than second premolar
• mesial and distal pits are closer to marginal ridges on first premolars than second premolars. more supplemental grooves on maxillary second premolars
• second premolar is more symmetrical and less angular from occlusal view (overall shape).
• first premolars have narrower lingual surface than buccal, second premolars have only a slight lingual taper.

Question 19

what are the 2 types of cusp options for mandibular premolars

Answer 19

2 cusps total with 1 lingual cusp , or 3 cusps total with 2 lingual cusps

Question 20

crown shape of mandibular first vs second premolars

Answer 20

• first: crown tapers (converges) to the lingual - its narrower on lingual than buccal side
• second with 2 lingual cusps: on lingual side crown is as wide or wider mesiodistally than the buccal (with 1 lingual cusp, its tapered too)

Question 21

cusp size and shape lingual view of mandibular first vs second premolars

Answer 21

• first premolar: lingual cusp is small and pointed. most of occlusal surface can be seen from lingual side.
• 2nd premolar: w/one lingual cusp– lingual cusp is smaller than buccal. lingual cusp is larger than lingual cusp of first premolar tho!

Question 22

crown shape buccal view of first and second mandibular premolars

Answer 22

pentagon shape

-second buccal cusp is less pointed and cusp slopes are less steep than in mandibular first premolar.

Question 23

cusp ridges from buccal view first and second mandibular premolars

Answer 23

• first mandib premolars: notches often seen on mesiobuccal cusp ridge
• second mandibular premolars: notches often seen on distobuccal cusp ridge

Question 24

how to distinguish mandibular premolars 1 and 2?

Answer 24

• first has a longer crown, shorter root than second

- mandibular first premolar is longer overall than second premolar.

Question 25

marginal ridges of mandibular first premolar - how is it different from other mesial marginal ridges?

Answer 25

its the only tooth in the mouth where the mesial marginal ridge is more apical/cervical than the distal marginal ridge!!!!

Question 26

what is the mesiolingual groove of the mandibular first premolar

Answer 26

frequently seen there
-separates mesial marginal ridge from mesial slope of the small lingual cusp.

(mesial marginal ridge groove on maxillary first premolar)

Question 27

what are the proximal contact areas for first and second premolars? MANDIBULAR

Answer 27

first and second: mesial contact is near junction of occlusal and middle third.

first: distal contact area is in occlusal third and is more occlusal than mesial contact area- this is an EXCEPTION! (other teeth, mesial is more occlusal)
- second premolar: distal contact on second molar is in the middle third (mesial is just occlusal to the occlusal/middle junction)

Question 28

mandibular height of contours from proximal views

Answer 28

first premolar: buccal is in cervical 1/3, lingual is in middle 1/3.

second premolar: buccal is near junction of cervical and middle 1/3. lingual is in middle 1/3.

Question 29

proximal view; mandibular premolar crown shapes?

Answer 29

tilt lingually, but mandibular first premolar tilts more lingually than mandibular second premolar.

Question 30

what is the extra groove that can occur on first premolars occlusal in mandibular???

Answer 30

transverse ridge can be crossed by a shallow central groove extending from mesial to distal fossa (rare tho!)

Question 31

how do first mandibular premolars appear occlusally

Answer 31

• mesial and distal fossas. Both are circular, not triangular. Both possess pits. Distal fossa is usually larger and/or deeper.
• mesial and distal developmental grooves are in a nearly buccolingual direction.

Question 32

what can occlusal fillings of mandibular first premolars be called?

Answer 32

snake eyes. no fissured central groove but pronounced transverse ridge

Question 33

how do second mandibular premolars appear occlusally? (2 cusp type)

Answer 33

-central groove connects mesial and distal pits. no lingual groove.
groove pattern can be U or H shaped.

Question 34

how do second mandibular premolars appear occlusally? (3 cusp type)

Answer 34

• three triangular ridges, none connect and there is no transverse ridge
• only premolar with a central fossa/pit
• central groove may be referred to as mesial and distal grooves joining at central pit. (slide 59)
• lingual groove separates two lingual cusps. the groove completes y shaped occlusal groove pattern.

Question 35

premolars general : what is the typical trinangular ridge -cusp set up and whats the exception

Answer 35

buccal and lingual triangular ridges extend from cusp to central group to form transverse ridges EXCEPT for the three cusped mandibular second premolar which has two lingual cusps no transverse ridge

Question 36

which premolar is the widest of all 8?

Answer 36

maxillary first premolars are the widest!

Question 37

maxillary first vs second premolars; which is longer?

Answer 37

first maxillary premolar is longe rthan second!

Question 38

how does the cusp tip differ on maxillary first vs second premolars? which is more pointed?

Answer 38

the maxillary first premolar is sharper (and longer cusp) than the second premolar.
mesial and distal slopes meet at about 110 degrees on the first and about 130 on the second max premolar

Question 39

maxillary premolars: where is the cusp tip? mesial or distal on each?

Answer 39

first max premolar is slightly to the distal of the mid tooth line. the mesial cusp ridge is longer on first too.

second is to the mesial. (as with both of the mandibular preomlars too!!)

Question 40

where do lingual cusps tilt towards?

Answer 40

always mesial!! so its easy to tell left from right