Tooth Development

Question 1

Morphodifferentitation

Answer 1

refers to the shaping of the tooth, is a continuous process, can be divided into different stages (by its shape), i.e. bud, cap, bell

Question 2

Cytodifferentiation

Answer 2

refers to differentiation of cells into specific cell types giving rise to specific tissues, i.e. ameloblasts giving rise to enamel

Question 3

What generates enamel? dentin? cementum? forms pulp and PDL?

Answer 3

enamel- ameloblasts
dentin- odontoblasts
cementum- cementoblasts
pulp/PDL- fibroblasts

Question 4

What are the 8 stages of tooth development?

Answer 4

Bud Stage-  condensation of oral epithelium
Cap Stage-  early shaping of tooth
Bell Stage
Dentogenesis-  dentin formation
Amelogenesis-  enamel formation
Apposition Stage-  dental tissue matrix
Eruption and Root Development
Functional Stage

Question 5

Bud Stage

Answer 5

outgrowth of oral epithelium which extends into the mesenchymal tissue of the developing gum, connected to oral epithelium by a bridge called the dental lamina

Question 6

Cap Stage

Answer 6

Growth of tooth bud into the enamel organ; mesenchymal cells condense under cap; EO has 3 layers (outer enamel epithelium, stellate reticulum and inner enamel epithelium) which differentiate into preameloblasts. Dental Lamina begin to disintegrate

Question 7

Bell Stage

Answer 7

4 layers:

1) OEE not connected by dental lamina
2) Stellate Reticulum fills enamel organ w/ buffer and nutritive functions
3) Stratum intermedium- 2-3 layers over developing preameloblasts (supports pre.)
4) IEE- single pre. layer

• dental papilla> odontoblasts
• vasculatrization develops in DP
• membranous bone develops

Question 8

Late Bell Stage

Answer 8

odontoblasts secrete predentin, which turns into dentin (w/in 24 hrs); dentin stimulates preameloblasts to differentiate into ameloblasts to secrete enamelin

Question 9

Cytodifferentitation and the establishment of the DEJ:

As predentin is secreted (_________), the odontoblast leaves a long process behind in the predentin- called _________.

Answer 9

dentinogenesis; odontoblast process

Question 10

Tome’s Process

Answer 10

secretory ending of ameleoblast

Question 11

Odontoblast Process

Answer 11

• resides in dentin enclosed in a hollow tube (dentinal tubule)
• OP allows for continual secretion dentin
• allows to sense stimuli from external environment

Question 12

Tight junctions/ ameloblasts

Answer 12

ensures that ameloblasts evenly secretes/ moves