Molars

Question 1

What is the shape of the upper first molar?

Answer 1

• Diamond shaped: with the longer diagonal extending from the mesio-buccal to the disto-palatal cusp and emphasised by the presence of a strong ridge of enamel (oblique ridge)

Question 2

Which cusp is the largest in the upper first molar?

Answer 2

The mesio-lingual cusp

Question 3

Which cusp is the smallest in the upper first molar?

Answer 3

disto-lingual

Question 4

What is there on each side of the ridge of an upper first molar?

Answer 4

A fissure: these 2 fissures are connected by a shallow fissure completing the H-shaped pattern

Question 5

What is the distal fissure on an upper first molar like?

Answer 5

• Runs parallel to the oblique ridges and continues on to the palatal surface

Question 6

What is the mesial fissure on an upper first molar like?

Answer 6

• Has a right angles bend
• One arm runs towards the mesial surface, but does not continue on to it, the other run towards, and on to, the buccal surface

Question 7

On which tooth can a tubercle of Carabelli be present?

Answer 7

The upper first molar

Question 8

On which cusp can a tubercle of Carabelli be present on an upper first molar?

Answer 8

Mesio-palatal cusp

Question 9

Roughly what percentage of upper first molars have a tubercle of Carabelli present?

Answer 9

Around 60%

Question 10

What are the proximal surfaces of the upper first molar like?

Answer 10

• Convex, with the distal more curved than the mesial

Question 11

How many roots does the upper first molar have?

Answer 11

3 roots

- 2 buccal and 1 palatal - diverging from a common root stalk

Question 12

Which root is the palatal root of an upper, first molar on the same plane as?

Answer 12

The disto-buccal root

Question 13

What is the palatal root of the upper first molar like?

Answer 13

• Is the longest and strongest of the 3 roots of the tooth

- Is slightly compressed bucco-lingually

Question 14

What is the general shape of the upper second premolar?

Answer 14

More triangular shape

Question 15

How many roots dies an upper second molar have?

Answer 15

3 however the palatal root is often partially fused with either of the buccal roots

Question 16

What is the crown of the upper third molar like?

Answer 16

• Smallest of the three upper molars. Usually only 3 cusps but various forms

Question 17

What are the roots of the upper third molar like?

Answer 17

• Usually fused together into one common, bulky root grooved in the positions where separate roots would be divided

Question 18

How many cusps does a lower first molar have?

Answer 18

Five cusps: 3 buccal and 2 lingual

Question 19

What is the transverse fissure of the lower first molar?

Answer 19

• Groove starting on buccal surface deepens into transverse fissure across occlusal surface and ends as groove on lingual surface
• In the centre of the crown, it deepens further to form a pit

Question 20

Where is the mesio-distal fissure of the lower first molar?

Answer 20

• It starts near the mesial marginal ridge, crosses the central pit and divides into 2 branches which pass on each side of the small distal cusps

Question 21

Which surface of the lower first molar is bigger?

Answer 21

• The buccal surface is larger than the lingual surface

- The buccal surface is lingually inclined

Question 22

What are the proximal surfaces of the lower first molar like?

Answer 22

• Convex, with the distal much rounder because of the distal cusp

Question 23

How many roots does the lower first molar have and how are they shaped?

Answer 23

2 roots: 1 mesial and 1 distal

• Both strongly compressed mesio-distally and may show distal curvature. These features are most pronounced on the mesial root
• The distal root is therefore not visible from the mesial aspect. The mesial root is usually curved, grooved and broader than the distal root

Question 24

What does the lower first molar have which can increase the risk of caries?

Answer 24

The buccal surface usually has a pit which is at increased risk of caries

Question 25

Which root of the lower second molar is broader?

Answer 25

The mesial root

Question 26

Which root of the lower second molar is longer?

Answer 26

The distal root

Question 27

What is the occlusal surface of the lower second molar like?

Answer 27

• More symmetrical and smaller than lower first molar
• Usually only four cusps of similar size
• The occlusal surface is almost square
• The fissure pattern is + shaped

Question 28

Which cusps of the lower second molar are the highest?

Answer 28

The lingual cusps are the highest

Question 29

Which cusp of the lower second molar is the biggest?

Answer 29

The mesio-buccal cusp

Question 30

What are the roots of a lower second molar like compared to a lower first molar?

Answer 30

Roots less divergent than those of lower first molar, and may be fused

Question 31

What is the crown of a lower third molar like?

Answer 31

Very variable in shape and size

• 50% five cusps
• 40% four cusps
• 10% three or > five cusps

Question 32

What are the roots of the lower third molar like?

Answer 32

Often fused