Amelogenesis Flashcards
dentine, cementum and the alveolar bone are all mineralised connective tissue, what is enamel?
mineralised epithelial product
Does enamel contain collagen?
No
1-2% of enamel is organ matrix, what is this made up of?
enamel proteins (amelogenesis, enamelins and tuftelin)
enzymes
when does enamel form in relation to dentine?
starts to form after dentine mineralises
Enamel prism shape is governed by what?
tomes process and direction of migration of the ameloblast
What is the final cue for onset of amelogenesis?
dentine formation
breakdown of the basal lamina
Regions formed without a tomes process are aprimastic, where are these regions?
the 1st formed - innermost
last formed - outermost
what are the roles of enamel proteins?
- aid nucleation of hydroxyapatite
- orientate and stabilise crystal growth
what happens to enamel protiens during maturation?
they are broken down and lost
Maturation of crystals requires what?
mineral ions in and enamel matrix out
what viscosity is amelogenenin?
thixotropic
what happens to amelogenin?
enzymes break down amelogenins and the bulk of break down products are removed
what matrix proteins flows out and what matrix remains?
flows out = amelogenins
matrix that remains = enamelin
once most of the enamel thickness is laid down, what is lost?
tomes process
- last formed enamel is aprismatic
What is the final ameloblast secretion called?
the enamel cuticle
