TEETH! - Development

Question 1

What is the initiator of tooth development?

Answer 1

Dental lamina

Question 2

What of the tooth bud is neural crest origin?

Answer 2

Dental papilla

Question 3

What is the role of the stellate reticulum?

Answer 3

support and protect ameloblasts

Question 4

Tell me about hertwig’s epithelial root sheath

Answer 4

• Composed of IEE and OEE
• Breaks apart once the 1st layer of dentin is laid down, if there are remnants they persist as rests of malassez
• if it remains attached to dentin it can differentiate into ameloblasts causing enamel pearls

Question 5

Timing of dental lamina formation? tooth bud formation?

Answer 5

7 weeks dental lamina forms

8 weeks tooth bud forms for primary teeth

Question 6

Problems with proliferation can lead to?

Answer 6

Lead to anomalies of size, proportion, numbers, twinning

Question 7

Problems with HISTOdifferentiation can lead to?

Answer 7

Differentiation of odontoblasts is before ameloblast differentiation. Therefore problems with histo, can lead to anomalies of enamel/dentin
- AI I and IV, Dentinogenesis imperfecta

Question 8

Describe what problems with MORPHOdifferentiation can lead to?

• List deficient morphodifferentiation?
• List excessive morphodiff?

Answer 8

Morphing means to change shape. So problems are with shape, basic form, and relative to size/shape

• Deficient morpho: peg lateral, mulberry molars, hutchinson incisors, microdontia
• Excessive morpho: dilaceration, tuberculated cusps, carabelli, gemination, macrodontia, tauradonts, fusion, dens in dente, dens evaginatus, concresence

Question 9

Problems with apposition-

• Ex of deficient?
• Ex of excessive?

Answer 9

• Deficient apposition: Enamel hypoplasia, dentin dysplasia,
• Excessive apposition: hypercementosis, enamel pearls

Question 10

Problems with mineralization

• Ex of deficient?
• Ex of excessive?

Answer 10

• Deficient mineralization: AI II, III, and IV, fluorosis, localized hypomineralized and interglobular dentin
• Excessive mineralization: sclerotic dentin

Question 11

Relate the embyrologic timing of the primary dentition to the permanent dentition

Answer 11

• At 20 weeks, just after 2nd primary molar is calcified (it is the last primary tooth to calcify), the permanent central, lateral, canine, 1PM, and 1stM are INITIATED.

Question 12

Which teeth are initiated post partum and when?

Answer 12

the 2nd PM-10 months pp
2nd M - 12 mo post partum
3rd M - 5 years post partum

Question 13

Time to completion of the root in a primary tooth? permanent tooth?
- Time to complete occlusion for a permanent tooth?

Answer 13

Primary: 18 months post eruption
Permanent: 3 years
5 years until in full occlusion after crown completion

Question 14

Calcification times for the permanent teeth

Answer 14

3-4 months: central, cuspid
10 months: lateral**
1.5 years: 1st PM
2 years: 2nd PM
2.5 years: 2nd M
8 years : 3rd M

**remember the lateral takes less time to cook than the cuspid, it starts later