3rd Molars

Question 1

Which molar is the smallest?

Answer 1

The third molar is the smallest molar, with 1st > 2nd > 3rd in size (for both maxillary and mandibular molars).

Question 2

Describe the occlusal table and surface of third molars.

Answer 2

The occlusal table of third molars is small due to closely positioned cusps, and the surface is the most wrinkled among molars.

Question 3

What is unique about the root-to-crown ratio of third molars?

Answer 3

Third molars have the smallest root-to-crown ratio, with shorter roots and longer crowns compared to 1st and 2nd molars.

Question 4

How are the roots of third molars typically shaped?

Answer 4

The roots are usually fused, pointed, and crooked, often curved distally but sometimes mesially.

Question 5

What is the occlusal height characteristic of maxillary third molars?

Answer 5

Maxillary third molars are the shortest teeth occluso-cervically among permanent molars.

Question 6

What is the occlusal height characteristic of mandibular third molars?

Answer 6

Mandibular third molars are the shortest teeth occluso-cervically among mandibular teeth.

Question 7

Which teeth are most likely to be impacted?

Answer 7

Third molars are the most likely teeth to be impacted.

Question 8

Which teeth are most commonly congenitally missing?

Answer 8

Third molars are the most commonly congenitally missing teeth.

Question 9

What is the second most commonly congenitally missing tooth?

Answer 9

The maxillary lateral incisor.

Question 10

What is the third most commonly congenitally missing tooth?

Answer 10

The mandibular second premolar.

Question 11

What cusp variations are present in maxillary third molars?

Answer 11

They can have 3, 4, or 5 cusps, with the fifth being the cusp of Carabelli.

Question 12

What is unique about the oblique ridge in maxillary third molars?

Answer 12

It can be well-developed, poorly developed, or completely absent in tricuspid molars.

Question 13

Describe the roots of maxillary third molars.

Answer 13

Maxillary third molars have three roots (mesiobuccal, distobuccal, palatal) that are often fused and indistinct.

Question 14

What is the nature of developmental grooves in maxillary third molars?

Answer 14

They can be either clear or indistinguishable.

Question 15

What is the nature of supplemental grooves in maxillary third molars?

Answer 15

They are always clear, contributing to a wrinkled surface.

Question 16

How many cusps can mandibular third molars have?

Answer 16

They can have 4 cusps (like the second molar) or 5 cusps (like the first molar).

Question 17

Describe the roots of mandibular third molars.

Answer 17

They typically have two roots (mesial and distal) that are undersized, malformed, and often crooked.

Question 18

How does the root trunk length of third molars compare to other molars?

Answer 18

The root trunk of third molars is longer, meaning the furcation is more apical.

Question 19

What is the overall size comparison of third molars?

Answer 19

They are more bulbous with a smaller occlusal table and a more rounded appearance than other molars.