Permanent Premolars/Bicuspids

Question 1

Are premolars always referred to as bicuspids?

Answer 1

No, the mandibular 2nd premolars can sometimes have 3 cusps

Question 2

How many lobes form the premolars?

Answer 2

Most form from 4 lobes (3 buccal and 1 lingual) and have 2 cusps, except for the mandibular 2nd premolar which sometimes forms from 5 lobes (3 buccal, 2 lingual) and will have 3 cusps

Question 3

Are premolars wider M/D or B/L?

Answer 3

Buccal/Lingual

Question 4

Describe the buccal ridge of the maxillary premolars

Answer 4

Runs vertically down the midline w/ developmental depressions on either side

Question 5

Describe the marginal ridges of the maxillary premolars

Answer 5

On the occlusal surface

Create a boundary that separates the occlusal surface from the peripheral surfaces (MMR, DMR)

Question 6

Where are the triangular ridges of the maxillary premolars?

Answer 6

Occlusal surface of the cusps, runs buccal to lingual (BTR, LTR)

Question 7

Describe the central groove of the maxillary 1st premolar

Answer 7

Spans mesial pit to distal pit

Question 8

What forms the triangular fossa?

Answer 8

Area where the mesial/distal pits meet the triangular grooves and the M/D and B/L grooves

Question 9

On which tooth do we see the marginal groove?

Answer 9

Only on the maxillary 1st premolar only.

Acts as a spillway

Question 10

What are the triangular grooves and what do they form?

Answer 10

MBG/MLG and DBG/DLG

Terminate at and form the triangular fossa

Question 11

Where are developmental grooves usually found?

Answer 11

Usually found on the occlusal surface of the maxillary 2nd premolars

Give surface a wrinkled appearance

Question 12

Where is the height of contour on the mesial/distal aspects of the max 1st premolars?

Answer 12

Occlusal 1/3

Question 13

Where is the height of contour on the buccal aspect of the max 1st premolar?

Answer 13

Cervical 1/3

Question 14

Where is the height of contour on the lingual aspect of the max 1st premolars?

Answer 14

Middle 1/3

Question 15

What is the function of the 1st premolars?

Answer 15

Tearing, supplements the function of the canines

Question 16

Which tooth does the maxillary 1st premolar resemble?

Answer 16

Canine buccal aspect but is 1.5-2mm shorter

Root is also shorter

Question 17

How curved is the CEJ of the maxillary 1st premolars?

Answer 17

Not as curved M/D as the canines

Question 18

Which ridge on the maxillary 1st premolars is longer, the DBCR or the MBCR?

Answer 18

DBCR

Question 19

Describe the mesial marginal groove of the maxillary 1st premolar

Answer 19

Extends from the occlusal table to the mesial surface and is very prominent

Question 20

Describe the root depression on the max 1st premolar

Answer 20

Very prominent on the M/D

Question 21

Where does the bifurcation occur on the root of the max 1st premolar?

Answer 21

Apical 1/3, buccal root is usually longer

Question 22

How many roots do max 1st premolars have?

Answer 22

Usually 2. May have 1 but still 2 pulp canals. Can also be trifurcated w/ 3 pulp canals

2 buccal, 1 palatal

Question 23

What is the function of the 2nd premolars?

Answer 23

Grinding. Supplementing the function of the molars

Question 24

What is the size and shape of the maxillary 2nd premolars? Height difference between the cusps?

Answer 24

Slightly smaller than the 1st premolars and more rounded

Cusps are almost equal in height

Question 25

Do the max 2nd premolars have a MMG?

Answer 25

No

Question 26

What is the shape/contour of the buccal cusp ridge on the max 2nd premolars?

Answer 26

More curved

Question 27

Do the max 2nd premolars have a central groove?

Answer 27

Sometimes. It will be shorter or not there at all with just a pit w/ supplemental grooves on the occlusal surface

Question 28

How many roots do the max 2nd premolars have?

Answer 28

Usually a single root w/ one pulp canal but will occasionally have 2 pulp canals and may bifurcate

Question 29

Of the two maxillary premolars, which has the longer root?

Answer 29

2nd, has a mesial root depression

Question 30

What is the height of contour on the mesial/distal aspects of the mandibular 1st premolars?

Answer 30

Middle 1/3

Question 31

What is the height of contour on the buccal aspect of the mand 1st premolars?

Answer 31

Between the cervical and middle 1/3's

Question 32

What is the height of contour on the lingual aspect of the mand 1st premolars?

Answer 32

Middle 1/3, near cusp tip

Question 33

What is the difference in the cusp tips between the max/mand 1st premolars?

Answer 33

Cusps are more blunt on the mandibular

Question 34

Describe the CEJ on the mand 1st premolars

Answer 34

Fairly straight w/ a slight curve toward the occlusal

Question 35

Describe the crown form of the mand 1st premolar

Answer 35

Cusp tip sits over the root and occlused with the max fossa

Question 36

What can you see from the lingual aspect of the mand 1st premolars?

Answer 36

Lingual cusp is in line with the BTR forming a True Transverse Ridge MLG is visible and prominent

Question 37

What is the shape of the occlusal table on the mand 1st premolar?

Answer 37

Triangular

Question 38

Describe the mesial triangular fossa (MTF) on the mand 1st premolars

Answer 38

Smaller w/ a pit that the MLG courses from

Question 39

Describe the distal triangular fossa (DTF)

Answer 39

Larger w/ a pit

Question 40

Describe the roots of the mand 1st premolar

Answer 40

May have a mesial root depression One root with one pulp canal- may have 1 root with 2 pulp canals and may also bifurcate

Question 41

Describe the shape of the mandibular 2nd premolars

Answer 41

Shaped more like a molar w/ well developed lingual cusps

Question 42

Describe the buccal aspect of the mand 2nd premolars

Answer 42

Smoother, usually with no developmental depressions and lass prominent BCR

Question 43

Describe the occlusal shape on the mand 2nd premolars

Answer 43

Round or squared and very symmetrical

Question 44

What are the two cusp types of mand 2nd premolars?

Answer 44

3 cusp type | 2 cusp type

Question 45

How many lobes form the 3 cusp type mand 2nd premolars?

Answer 45

5 lobes- 3 buccal (1 cusp), 2 lingual (2 cusps) Mesiolingual cusp is larger than the distal lingual cusp Lingual groove is only present on the 3 cusp type

Question 46

How many lobes form the 2 cusp type mand 2nd premolars?

Answer 46

4 lobes- 3 buccal, 1 lingual

Question 47

What are the 3 variations of occlusal patters in mand 2nd premolars?

Answer 47

U, H and Y

Question 48

How many cusps/fossa on the U-shaped and H-shaped occlusal patterns?

Answer 48

2 cusps | 3 fossa

Question 49

How many cusps/fossa in the Y-shaped occlusal pattern of the mand 2nd premolars?

Answer 49

3 cusps | 3 fossa

Question 50

Describe the root of the mand 2nd premolars

Answer 50

Single root with 1 or 2 pulp canals Larger and longer than the mand 1st premolar May bifurcate with a deep developmental groove on the mesial