tooth development Flashcards
how is the lip developed
- invagination of oral epithelium into mesenchyme
- creates cleft
- separation forms gap between lip and jaw
- creates cleft
when is the primary epithelial band formed?
week 6
what are the 3 stages of tooth development - in order
- bud
- cap
- bell
what happens in the bud stage
- dental lamina extends further into mesenchyme
- condensation of mesenchyme around the bud
- ( increased density of mesenchymal cells )
what properties do the dental lamina have which allows it to extend into the mesenchyme?
- growth requires lots of energy
- high mRNA content
- actively produces signalling components
- lower glycogen content
- high mRNA content
- mitochondria of active cells produce ATP
- (increased oxidative activity)
what do the mesenchymal cells go on to form?
dental papilla
what does the dental papilla go onto form?
tooth dentine
& contributes to other periodontal tissues
epithelial cells of the dental lamina go onto form …
enamel organ
what occurs in early cap stage?
- 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
what occurs in late cap stage?
- 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
what does the tooth germ consist of?
- enamel organ
- dental papill
- dental follicle
the enamel organ goes onto form..
enamel
the dental papilla goes on to form…
dentine & pulp
the dental follicle goes on to form
PDL
cementum
when does enamel knot formation take place?
transition between late cap and early bell stage
when are you able to see the distinct layers, such as IEE,OEE,SI,SR
late cap stage
early bell stage
what is the enamel knot
a cluster of non-divided epithelial cells
around cusp tip
role of enamel knot
- signals to epithelial cells to proliferate further around papilla
- signals for further differentiation