tooth development

Question 1

how is the lip developed

Answer 1

• invagination of oral epithelium into mesenchyme
  
  • creates cleft
    
    • separation forms gap between lip and jaw

Question 2

when is the primary epithelial band formed?

Answer 2

week 6

Question 3

what are the 3 stages of tooth development - in order

Answer 3

1. bud
2. cap
3. bell

Question 4

what happens in the bud stage

Answer 4

• dental lamina extends further into mesenchyme
• condensation of mesenchyme around the bud
  
  • ( increased density of mesenchymal cells )

Question 5

what properties do the dental lamina have which allows it to extend into the mesenchyme?

Answer 5

• growth requires lots of energy
  
  • high mRNA content
    
    • actively produces signalling components
  • lower glycogen content
• mitochondria of active cells produce ATP
  
  • (increased oxidative activity)

Question 6

what do the mesenchymal cells go on to form?

Answer 6

dental papilla

Question 7

what does the dental papilla go onto form?

Answer 7

tooth dentine

& contributes to other periodontal tissues

Question 8

epithelial cells of the dental lamina go onto form …

Answer 8

enamel organ

Question 9

what occurs in early cap stage?

Answer 9

• morphology changes
  
  • bud flattens
• cells histo-differentiate
  
  • epithelial cells which make up enamel organ become more cuboidal
  • formation of different layers in enamel organ
• ectromesenchymal cells condense more to form dental papilla

Question 10

what occurs in late cap stage?

Answer 10

• enamel organ grows bigger
• further condensation of ectomesenchymal cells at edges of papilla
  
  • ectomesenchymal cells encapsulate enamel organ in sac called dental follicle
• formation of tooth germ

Question 11

what does the tooth germ consist of?

Answer 11

• enamel organ
• dental papill
• dental follicle

Question 12

the enamel organ goes onto form..

Answer 12

enamel

Question 13

the dental papilla goes on to form…

Answer 13

dentine & pulp

Question 14

the dental follicle goes on to form

Answer 14

PDL

cementum

Question 15

when does enamel knot formation take place?

Answer 15

transition between late cap and early bell stage

Question 16

when are you able to see the distinct layers, such as IEE,OEE,SI,SR

Answer 16

late cap stage

early bell stage

Question 17

what is the enamel knot

Answer 17

a cluster of non-divided epithelial cells

around cusp tip

Question 18

role of enamel knot

Answer 18

• signals to epithelial cells to proliferate further around papilla
• signals for further differentiation