dental development 2

Question 1

how are dentine and enamel formed from the bell stage?

Answer 1

cytodifferentiation

IEE differentiates into odontoblasts to secrete dentine.

they then differentiate into ameloblasts to begin secreting the enamel crown.

Question 2

enamel is formed in two stages during cytodifferentiation, what are these?

Answer 2

1- protein matrix is deposited - which is partially mineralised

2- organic component removed and mineralisation complete.

Question 3

what are the 7 stages of ameloblast differentiation?

Answer 3

morphogenic
histodifferentiation
secretory - initial
secretory - tomes process
maturative - ruffle-ended
maturative - smooth
protective

Question 4

what occurs during morphogenic / histodifferentiation of ameloblasts?

Answer 4

IEE cells differentiate into ameloblasts.

cells elongate to become columnar

nucleus migrates to the basal end of cell

Question 5

what occurs in the secretory phase of AmeloBlastDifferentiation? (ABD)

Answer 5

become secretory cells

synth and secrete enamel matrix proteins

Question 6

what occurs in the maturation phase of ABD

Answer 6

majority of matrix proteins then removed

mineral content increased

Question 7

what occurs in the protection phase of ABD?

Answer 7

ameloblasts regress to form protective layer - reduced enamel epithelium

involved in eruption and formation of epithelial attachment

Question 8

what condition can cause teeth that are: unusually small, discoloured, pitted or grooved, and prone to rapid wear and breakage

Answer 8

amelogenesis imperfecta

Question 9

what disorder can cause tooth discolouration and translucency?

Answer 9

dentinogeneis imperfecta

Question 10

how is the root formed from the enamel organ?

Answer 10

cervical loop migrates apically to form shape of crown and the root

Question 11

how does the cementum and root dentine get laid down?

Answer 11

migrated cervical loop (hertwigs epithelial sheath)

• induces the formation of root dentine then breaks down as no enamel needed
• Sharpey’s fibres embedded in cementum

follicle cells differentiate into cementoblasts