Max. 1 PM_O Asp.

Question 1

What is the shape of the crown outline of the maxillary first premolar?

Answer 1

The crown outline is hexagonal or rounded, depending on the reference.

Question 2

Which dimension is greater in the maxillary first premolar, buccolingual or mesiodistal?

Answer 2

The buccolingual dimension is greater than the mesiodistal dimension.

Question 3

What does the lingual convergence of the crown refer to?

Answer 3

The mesiodistal width of the facial (buccal) aspect is slightly greater than the lingual aspect, reflecting the lingual convergence of the crown.

Question 4

How can you identify the mesial aspect of the occlusal surface?

Answer 4

By the presence of the mesial marginal developmental groove, which passes through the mesial marginal ridge.

Question 5

Describe the mesiofacial and distofacial angles of the maxillary first premolar.

Answer 5

The mesiofacial angle is almost 90 degrees, while the distofacial angle is also sharp.

Question 6

What is the characteristic of the mesial proximal contact?

Answer 6

The mesial proximal contact is located facial to the faciolingual center.

Question 7

Compare the distal and mesial proximal contacts.

Answer 7

The distal proximal contact is similar to the mesial but located slightly more facial than the mesial contact.

Question 8

What is the shape of the lingual outline?

Answer 8

The lingual outline is spheroidal.

Question 9

What is the occlusal table?

Answer 9

An imaginary line connecting the marginal ridge, cusp ridge, buccal, and lingual aspects of the tooth.

Question 10

Which cusp ridge is more facial, distal or mesial?

Answer 10

The distal cusp ridge is slightly more facial than the mesial cusp ridge.

Question 11

Describe the lingual cusp ridges of the maxillary first premolar.

Answer 11

The lingual cusp ridges are semicircular.

Question 12

What are the two triangular ridges of the maxillary first premolar?

Answer 12

1. Buccal triangular ridge (formed by mesial and distal inclines meeting at a 120-degree angle). 2. Lingual triangular ridge, which is seldom prominent.

Question 13

What are the mesial and distal triangular fossae?

Answer 13

Triangular depressions found on the occlusal surface.

Question 14

What is a transverse ridge?

Answer 14

The area where both the buccal and lingual triangular ridges meet or fuse.

Question 15

How many main developmental grooves are on the occlusal surface, and what are they?

Answer 15

Four main developmental grooves: 1. Central developmental groove (3 mm wide, extends to the mesial marginal ridge, forming the mesial marginal developmental groove). 2. Mesiobuccal groove (towards buccal aspect). 3. Distobuccal groove (towards buccal and distal). 4. Supplemental groove (less distinct, sometimes absent).

Question 16

How does the mesial marginal ridge compare to the distal marginal ridge?

Answer 16

The mesial marginal ridge is shorter than the distal marginal ridge.

Question 17

What is the buccal triangular ridge composed of?

Answer 17

It is composed of mesial and distal inclines meeting at an obtuse angle of 120 degrees.

Question 18

What is the function of the transverse ridge?

Answer 18

It facilitates the fusion of buccal and lingual triangular ridges, enhancing structural support.

Question 19

What is a unique feature of the maxillary first premolar’s central developmental groove?

Answer 19

It extends approximately 3 mm mesiodistally and connects with the mesial marginal developmental groove.

Question 20

What is a supplemental groove, and is it always present?

Answer 20

It is a less distinct groove that may be absent or present as additional grooves beyond the main developmental grooves.

Question 21

Why is the mesial marginal ridge shorter than the distal marginal ridge?

Answer 21

This reflects the asymmetry of the occlusal surface, enhancing functionality.