Tooth Morphology

Question 1

difference in natal and neonatal teeth

Answer 1

natal = formed and present at birth
neonatal = formed in the first few days of life

Question 2

what are natal and neonatal teeth

Answer 2

usually primary lower central incisors which have been in an ectopic position and erupt early

Question 3

calcification of crowns at birth

Answer 3

1/2 central incisors
1/3 lateral incisors
tip of primary canines
1/2 FPM
1/3 SPM
tips of cusps of first permanent molars

Question 4

general rule of primary tooth eruption

Answer 4

lowers before uppers with exception of lateral incisors

Question 5

pattern of primary tooth eruption

Answer 5

A B D C E

Question 6

what age is primary dentition expected to be completed by

Answer 6

2 1/2 - 3 yrs

Question 7

primary v permanent crowns

Answer 7

• primary incisors are smaller in crown and root proportions
• primary molars wider mesiodistally then permanent
• primary crowns more bulbous
• primary teeth whiter

Question 8

upper right / left first primary molar (54/64/D)

Answer 8

prominent mesiobuccal tubercle

Question 9

lower right / left first primary molar (74/84/D)

Answer 9

prominent mesiobuccal tubercle
rectangle shape

Question 10

upper right / left second primary molar (55/65/E)

Answer 10

prominent transverse ridge that runs across tooth

Question 11

lower right / left second primary molar (75/85/E)

Answer 11

3 buccal cusps

Question 12

primary v permanent roots

Answer 12

primary roots narrower
primary roots longer and more slender
primary roots flare apically to allow room for developing permanent crowns

Question 13

primary v permanent pulp

Answer 13

• primary pulp chamber larger in proportion to crown surrounding them
• primary pulp horns extend higher occlusally

Question 14

primary v permanent root canals

Answer 14

primary tend to be ribbon shaped with multiple interconnecting accessory canals

Question 15

primary v permanent hard tissue

Answer 15

• coronal dentine thinner than permanent teeth
• enamel is relatively thin with a consistent depth unlike permanent

Question 16

anthropoid / primate spacing

Answer 16

spacing mesial to upper deciduous canine
spacing distal to lower deciduous canine

Question 17

leeway space

Answer 17

extra mesiodistal space occupied by primary molars which are wider than the premolars that replace them 1.5mm per side upper arch / 2.5mm per side lower arch

Question 18

mixed dentition

Answer 18

begins from eruption of first permanent tooth until the exfoliation of the last primary tooth

Question 19

upper arch eruption sequence

Answer 19

6 1 2 4 5 3 7 8

Question 20

lower arch eruption sequence

Answer 20

6 1 2 3 4 5 7 8