Maxillary first premolars

Question 1

Buccolingually or mesodistally, which is wider? What is the shape of the occlusal outline?

Answer 1

Wider buccolingually and has an oval shape occlusal outline

Question 2

Typically, how many cusps on this tooth? What are they?

Answer 2

2 cusps; buccal and lingual

Question 3

What are the depressions on the buccal surface called that divide the tooth into lobes? How many lobes are there? And which lobes has a specific characteristic, what is it?

Answer 3

There are 2 developmental depressions; distobuccal and mesiobuccal that divide the buccal surface into 3 lobes. The central lobe has a buccal ridge that extends from the cusp apex to the root

Question 4

The mesiobuccal line angle is rounded. True or False?

Answer 4

False, the mesiobuccal line angle is sharp. The distobuccal line angle is rounded.

Question 5

Which cusp is taller?

Answer 5

buccal cusp

Question 6

What structure connects the buccal and lingual cusps?

Answer 6

Mesial and distal marginal ridges

Question 7

What crosses over the mesial marginal ridge and extends on to the mesial surface?

Answer 7

Mesial marginal groove

Question 8

Describe the mesial concavity or mesial developmental depression

Answer 8

On the mesial surface is a concavity that extends from the HOC to the root and its a good way to distinguish first from second maxillary premolars.

Question 9

Mesial and Distal HOC on all posterior teeth

Answer 9

Between middle and occlusal third (distal HOC closer to cervical line than mesial)

Question 10

Buccal HOC on this tooth

Answer 10

Between middle and occlusal third (same as maxillary second premolars)

Question 11

lingual HOC on this tooth

Answer 11

in the middle third (same as maxillary second premolars)

Question 12

Typically, how many roots?

Answer 12

1 or 2 roots can be presents (buccal and lingual roots)

Question 13

Describe the displacement of the lingual cusp.

Answer 13

The lingual cusp is displaced slightly towards the mesial

Question 14

What structures mark the boundaries of the occlusal table?

Answer 14

Distobuccal cusp ridge, distal marginal ridge, distolingual cusp ridge, mesiolingual cusp ridge, mesial marginal ridge and mesiobuccal cusp ridge.

Question 15

The mesial and distal pits are connect by what?

Answer 15

Central groove

Question 16

What strcutures emanate from the pits?

Answer 16

The mesiobuccal and mesiolingual grooves from the mesial pit and distobuccal and distolingual grooves from the distal pit

Question 17

The buccal cusp ridge (random fact)

Answer 17

It is straight and not parallel to the central groove

Question 18

What are the ridges that are present on the occlusal table that give a triangular appearance in cross section?

Answer 18

Buccal and lingual triangular ridges

Question 19

The triangular ridges separate the occulusal surface into what

Answer 19

The mesial and distal triangular fossa