Permanent Premolars

Question 1

What is the geometry of premolars from the buccal surface ?

Answer 1

Trapezoidal shape

Question 2

What is the geometry of premolars from the interstitial surface ?

Answer 2

Maxillary - trapezoidal shape
Mandibular - rhomboidal shape

Question 3

Which is the only premolar with 2 roots ?

Answer 3

Permanent maxillary first premolar

Question 4

What are the characteristics of the permanent maxillary first premolar ?

Answer 4

• 2 roots
• bicuspid
• canine fossa
• buccal cusp is slightly bigger than the palatal cusp

Question 5

How is the permanent maxillary first premolar sided ?

Answer 5

• The mesial dimension of the buccal cusp is slightly greater than the distal dimension
• The fissure on the occlusal surface crosses the mesial marginal ridge but not the distal marginal ridge

Question 6

What are the characteristics of the permanent maxillary second premolar ?

Answer 6

• buccal cusp and palatal cusp are more or less equal in size
• single rooted
• no canine fossa
• fissure doesn’t cross the marginal ridge (transverse fissure)

Question 7

How is the permanent maxillary second premolar sided ?

Answer 7

From the palatal view - the distal slope is greater than the mesial slope
- the tip of the cusp appears to point mesially

Question 8

What are the characteristics of the permanent mandibular first premolar ?

Answer 8

• single rooted
• 2 cusps (buccal and lingual)
• lingual cusp is very small so occlusal surface slopes obliquely downwards

Question 9

What are the characteristics of the permanent mandibular second premolar ?

Answer 9

• bicuspid but can look tricuspid
• large buccal cusp
• lingual cusp can be split into two
• mesial lingual cusp is more prominent than distal