Identification of Individual Teeth

Question 1

General rules of tooth identification (8)

Answer 1

1 - the curvature of the CEJ is usually 1 mm less on the distal side
2 - distal incisor edges are usually more rounded than mesials
3 - tooth roots are not always curved, but if they do, it is usually distally, especially at the apex
4 - Mandibular anterior teeth wear more on the labial edges but maxillary wear more on their lingual edges
5 - the more posterior permanent molars tend to consist of extra grooves and pits etc.
6 - first molars are generally larger in height and cusp size compared to second and third molars
7 - roots of molars tend to get shorter and closer together the more posterior you get
8 - third molars tend to be more wrinkled and unpredictable compared to other molars, can even be missing

Question 2

What are imbrication lines? What are other common names for them?

Answer 2

Developmental depressions, usually not present or very faint. Also called:

• Lines of Perykamata
• Lines of retzius

Question 3

Maxillary incisors

Answer 3

Centrals are wider than laterals, mesioincisal angle is 90 degrees while distoincisal angle is more curved, has a large cingulum, crest of cervical line is often more towards the distal from the labial or lingual view

Question 4

Maxillary lateral incisors

Answer 4

Lesser crown/root ratio, smaller cingulum and the incisal line angles are both more rounded. Smaller than centrals except for same root length. Usually erupt after centrals. Root often curves distally. Common tooth to find diastemas around because it is the most common tooth to have variations in size and shape, with the exception of wisdom teeth

Question 5

Mandibular central incisors

Answer 5

Smallest tooth in the permanent dentition, most symmetrical. Small centred cingulum, subtle lingual fossa and subtle marginal ridges

Question 6

Mandibular lateral incisors

Answer 6

Often larger than the central incisors. Crown is sloped from mesial to distal

Question 7

Both mandibular incisors

Answer 7

Common for collection of supragingival tooth deposits on the lingual side of these teeth, such as biofilm, calculus, and stain. Crown is wider faciolingually than mesiodistally. Roots are oval shaped from the distal side view

Question 8

Mandibular vs maxillary canines

Answer 8

Mandibular lingual surface is more smooth - less defined fossa and marginal ridges compared to maxillary. Mandibular is narrower mesial and distally than maxillary

Question 9

Where is the cusp tip on the maxillary canine?

Answer 9

Centered over the root

Question 10

Maxillary first premolar

Answer 10

Two major cusps, one lingual and one facial about the same size, facial can be slightly longer than lingual. Two roots. Well developed central grooves. Mesial depression on enamel and root

Question 11

Maxillary second premolar

Answer 11

Cusps are approx. same height, single root, shorter central groove. No depressions on the mesial or distal sides. Lingual cusp more mesially. Root slightly distal

Question 12

Main differences between maxillary premolars

Answer 12

• cusps more equal in length on second premolar
• second premolar has only one tooth and one root canal, first premolar has 2 root canals
• first premolar has a depression on the mesial root
• first premolar is bifurcated

Question 13

First mandibular premolar

Answer 13

No central pit, occlusal surface tilted toward the lingual. more cervical curve on the mesial, distal marginal ridge more prominent

Question 14

Second mandibular premolar

Answer 14

More pentagonal shape than the first premolar, no transverse ridge. Has a central pit. May have 2 lingual cusps

Question 15

What are succedaneous teeth?

Answer 15

Teeth that are replaced

Question 16

What are the 3 types of mandibular 2nd molars based on occlusal view?

Answer 16

U type (2 cusps), H type (2 cusps, looks like there’s transverse ridges) and Y type (3 cusps)

Question 17

Maxillary molars

Answer 17

Are usually the first permanent molars to erupt in the maxillary arch, usually has 4 cusps and each molar usually has 3 well separated and well developed roots. 3 roots = trifurcated, 2 roots = bifurcated. Close to sinus and may penetrate the maxillary sinus as a result of accidental trauma or during an extraction

Question 18

Maxillary first molars

Answer 18

Are non-succedaneous, largest tooth in the maxillary arch and the largest crown in the permanent dentition. Strong oblique ridge, 3 roots, palatal root is the largest and longest, buccal groove at midline of crown. Mesiolingual cusp is always much larger than distolingual cusp.

Question 19

Maxillary second molars

Answer 19

Crown is somewhat smaller than the first molar. Usually has 4 cusps and 3 roots, roots are smaller than the first molar’s and the lingual root is still the longest and strongest. Buccal grove is located farther distally. Mesiobuccal cusp is longer than the distobuccal cusp. Smaller oblique ridge than the first molar, roots are closer together

Question 20

Maxillary third molars

Answer 20

Crown is smaller and roots are usually shorter. Roots tend to fuse and result in a single or double tapered root. No oblique ridge, small or missing distolingual cusp. Occlusal has many small grooves. Distofacial cusp is much shorter and smaller than other molars. 3 roots.

Question 21

Mandibular molars

Answer 21

Usually erupt 6 months - 1 year before(?) their corresponding permanent maxillary molars. Usually have 4 or 5 major cusps. All mandibular molars have 2 well developed roots, one mesial and one distal

Question 22

First mandibular molar

Answer 22

3 facial cusps and 2 facial grooves, distofacial cusp is smallest.

Question 23

Second mandibular molars

Answer 23

Non succedaneous, 4 well developed cusps. Mesiobuccal cusp is higher than the distobuccal cusp, occlusal is well defined usually forming a cross or + pattern

Question 24

Third mandibular molars

Answer 24

Can vary greatly and shape and size, smaller than the second molar. 2 roots. May be impacted, meaning they are unable to erupt due to orientation in the bone

Question 25

General tips for maxillary teeth

Answer 25

• mesials 90 degrees; distals rounded
• canines sharper and pointier cusp than mandibular canines
• first premolar bifurcated, second single rooted
• all molars trifurcated (2 buccal and 1 lingual)
• 6’s largest and longest roots

Question 26

General tips mandibular teeth

Answer 26

• Canines less pointed cusp than maxillary
• premolars are short and stubby, single root
• first premolar is 2 cusps, strong transverse ridge
• second premolars are shorter and can be 3 cuspal
• molars are bifurcated