Maxillary First Premolar

Question 1

For the maxillary first premolar, how many developmental lobes are seen?

Answer 1

4; 3 bucal and 1 lingual

Question 2

For the maxillary first premolar, when is the expected age of eruption?

Answer 2

10-11 years

Question 3

For the maxillary first premolar, universal teeth #s?

Answer 3

5 & 12

Question 4

For all premolars, what is longer the occlusocervical crown length or the mesiodistal crown length?

Answer 4

Occlusocervical crown length. All premolars are taller than they are wide.

Question 5

For the maxillary first premolar, what is the crown shape from the buccal/lingual view?

Answer 5

Trapezoid or pentagon. Also described as being ovoid in the occlusal 1/3.

Question 6

For the maxillary first premolar, how do the mesial and distal outlines compare from the facial/lingual view?

Answer 6

Mesial Outline: Convex with a concavity below the height of contour. Mesial cusp ridge is LONGER than the distal cusp ridge (NOT the case in canines)
Distal Outline: Convex. Again the distal cup ridge is shorter than the mesial cusp ridge.

Question 7

For the maxillary first premolar, what are the mesial and distal heights of contour (occlusogingival contact points)?

Answer 7

Mesial: Middle 1/3; just below occlusal and middle 1/3s junction
Distal: Middle 1/3; cervical to mesial height of contour

Question 8

For the maxillary first premolar, the buccal surface has a well developed facial ridge (middle lobe) and often mesial and distal depressions are found on either side. Is this feature also found on the lingual surface? If not, what is?

Answer 8

No, the lingual surface is much smaller M-D and O-G than buccal surface. The lingual surface of the maxillary premolars tapers to the mesial.

Question 9

How many roots do the maxillary first premolars have? Name(s)? Which way does the apex curve?

Answer 9

2. Buccal and lingual roots. Both dilacerate to the distal, although the buccal root is more likely to do this.

Question 10

For the maxillary first premolar, what is the crown shape from the occlusal view?

Answer 10

Hexagon.

Question 11

For the maxillary first premolar, what 6 ridges make up the occlusal table?

Answer 11

Two marginal ridges and four M-D cusp ridges.

Question 12

For the maxillary first premolar, is the B-L or the M-D dimension longer?

Answer 12

The B-L dimension is longer than the M-D (opposite of anterior teeth)

Question 13

For the maxillary first premolar, what is the more prominent triangular ridge, the buccal or lingual triangular ridge?

Answer 13

The buccal triangular ridge is more prominent. The lingual triangular ridge is seldom prominent and is a flatter surface.

Question 14

The buccal and lingual triangular ridges meet, forming what ridge?

Answer 14

A transverse ridge.

Question 15

For the maxillary first premolar, what are the two depressions on the occlusal surface?

Answer 15

The mesial and distal fossae.

Question 16

For the maxillary first premolar, what is the major distinguishing factor that distinguishes it from all other teeth?

Answer 16

The mesial marginal ridge groove. The mesial extension of the central fossa groove onto the mesial surface of the maxillary first premolar.

Question 17

For the maxillary first premolar, describe the facial and lingual outlines from the occlusal view.

Answer 17

The facial outline is convex with a prominent middle lobe

The Lingual outline is convex.

Question 18

For the maxillary first premolar, what is the crown shape from the proximal view?

Answer 18

Trapezoid, tooth tapers at occlusal surface.

Question 19

For the maxillary first premolar, describe the facial and lingual outlines as seen from the mesial/distal view.

Answer 19

Facial outline: Convex

Lingual outline: Convex; lingual cusp shorter than facial cusp by about 1mm, more blunt cusp

Question 20

For the maxillary first premolar, is the occlusal table centered over the root trunk?

Answer 20

Yes

Question 21

For the maxillary first premolar, what are the buccal and lingual heights of contour?

Answer 21

Buccal: Middle 1/3
Lingual: Middle 1/3

Question 22

For the maxillary first premolar, what is the buccolingual contact location for the mesial and distal surfaces?

Answer 22

Mesial: buccal to the buccal-lingual center line
Distal: buccal to the buccal-lingual center line; distal contact is MORE buccal than mesial contact

Question 23

For the maxillary first premolar, which side, mesial or distal, has a cervical developmental depression that runs along the side of the tooth continuing apically into the root depression (present on both sides)?

Answer 23

The mesial crown surface has a cervical development depression.

Question 24

For the maxillary first premolar, how many pulpal canals are present? Shape in cross section?

Answer 24

2 pulpal canals that are kidney or figure 8 in shape.

Question 25

For the maxillary first premolar, which root is shorter?

Answer 25

The lingual root.