Development and morphology of the primary teeth

Question 1

What are the life cycles of the tooth?

Answer 1

bud –> cap –> bell –> apposition –> calcification
bud = initiation
cap = proliferation
bell = histo + morphodifferentiation

A&M p.90

Question 2

what happens to the tooth if each of the life cycles of the tooth is distrubed?

Answer 2

• Bud/initiation = congenital abseence of a tooth is the result of a lack of initiation
• Cap/proliferation = fewer than the normal # of teeth (failure of the tooth germ to develop)
• bell/histo-morpho = abnormal forms and sizes of teeth, resulting in conditions such as peg lateral, microdontia and macrodontia
• apposition = enamel hypoplasia (interruption in matrix apposition by ameloblasts)
• calcification/mineralization = hypomineralization

A&M p.90, 91

Question 3

Morphology: what are the characteristics of Mx CI (central incisor)?

Answer 3

mesiodistal width of the crown is greater than cervico-incisal length

A&M p.92

Question 4

Morphology: what are the characteristics of Mx LI (lateral incisor)?

Answer 4

opposite of Mx CI and cervico-incisal length is greater than the mesiodistal width

A&M p.92

Question 5

• What develops into ameloblasts?
• What develops into odontoblasts

Answer 5

• ameloblasts develops from IEE (inner enamel epithelium)
• odontoblasts develops from dental papillae (DP)

A&M p.91

Question 6

What happens to the pulp chambers of primary teeth?

Answer 6

they decrease in size as age increases and under the influence of both function and abrasion of the occlusal and incisal surfaces of the teeth

A&M p.95

Question 7

What is the difference between primary vs permanent in terms of enamel rod direction?

Answer 7

primary teeth enamel rod directon in the cervical area is angled occlusally compared with the apical direction in permanent teeth

A&M p.95

Question 8

What are crown color difference in primary vs. permanet teeth

Answer 8

the crown color of the primary teeth is whiter and lighter shade than permanent teeth

Question 9

Morphology:
- which teeth is bigger (Md CI vs LI) for primary teeth?
- what is the difference between Md CI vs. LI?

Answer 9

• Md LI is somewhat larger in all dimensions except labiolingually.
• Md LI’s incisal edge slopes toward the distal aspect of the tooth

A&M p.93