Maxillary 2nd Pre-Molar

Question 1

First Calcification

Answer 1

2-2.25 years

Question 2

Enamel completion

Answer 2

6-7 years

Question 3

eruption

Answer 3

10-12 year

Question 4

root completion

Answer 4

12-14 years

Question 5

Measurements

Answer 5

Facial-Lingual width is greater than mesial-distal width

Root is longer than crown

Will have two CUSPS

Question 6

Pulp Canals

Answer 6

1 canal/1 foramen 75%

2 canals/2 formane 24%

Question 7

Functions

Answer 7

Similar to that of the maxillary 1st premolar, resemble each other well

Question 8

Maxillary 2nd Premolar vs Maxillary 1st Premolar

Answer 8

• Less angular, more rounded crown from all aspect
• Single ROOT

Root is as long as or longer than the 1st premolar

Lots of variation in the size of the maxillary 2nd premolar can be seen in crown- noticeable smaller crevico-occlusally and mesiodistally, but can be larger too.

Question 9

Max 2nd Premolar- Buccal Aspect

Answer 9

Buccal cusp of 2nd is not as long as the 1st, and it is also more blunt than pointed.

The mesiobuccal cusp ridge is shorter than the distobuccal cusp ridge– THIS IS OPPOSITE OF THE MAX 1st Premolar- but normal as compared with the MAX CANINES.

Buccal ridge is not as prominent as on the maxillary 1st premolar.

Question 10

Max 2nd Premolar- lingual outline

Answer 10

Lingual cusp is usually longer than the lingual cusp of the 1st, making the crown on the lingual side longer.

Question 11

Max 2nd Premolar- mesial outline

Answer 11

Cusps are SHORTER than 1st Premolar

Cusps are closer in length, but buccal cusp is still longer.

Greater distance between the cusp tips widens the occlusal surface buccolingually.

CUSPS are shorter in length but further apart, transitions into distance similar to molars

A shallow development depression can be seen on the root surface but does not extend beyond CEJ

Question 12

Is there a developmental depression existing on the mesial surface of the crown like on the 1st premolar?

Answer 12

NO

Question 13

Is there a deep mesial marginal developmental groove?

Answer 13

No

Question 14

What is the significant difference on the mesial aspect?

Answer 14

SINGLE ROOT

Question 15

Is the distal root depression deeper than on the mesial depression on same tooth?

Answer 15

YES- opposite of maxillary 1st premolar

But does NOT cross into the CROWN

Question 16

Can understanding these depressions help understand periodontal disease?

Answer 16

YES

Question 17

Occlusal Aspect of Max 2nd Premolar

Answer 17

Crown is more rounded than 1st

Central developmental groove is shorter and irregular

LOTS OF supplementary grooves

Surface is pretty wrinkly

Buccal cusp is slightly mesial to the bisecting line while on the MAX 1st premolar it lies distal– THIS IS THE NORMAL

Question 18

Max 1st vs Max 2nd Cusp Tip

Answer 18

Max 1st buccal cusp tip is distal

Max 2nd buccal cusp tip is mesial

Question 19

Max 1st vs Max 2nd Mesiobuccal Cusp Ridges

Answer 19

The Max 1st Mesiobuccal cusp ridge is longer and straighter

The Max 2nd Mesiobuccal cusp ridge is shorter

Question 20

Max 1st vs Max 2nd Buccal Cusp Angles

Answer 20

Max 2nd Premolar has a greater angle at the cusp tip

Question 21

Lingual aspect comparing the two

Answer 21

Lingual cusp is shifted towards the MESIAL and is shorter than the BUCCAL CUSP

Question 22

Mesial aspect comparing the two

Answer 22

1st premolar has a bifurcated roots and a distinct mesial depression existing into the crown- ending at the cervical contact area

2nd premolar displays a single root and smaller depression on the mesial side

Question 23

Occlusal view comparing the two

Answer 23

Max 1st premolar is hexagonal

Max 2nd premolar is Oval