tooth development Flashcards
what is the 3 primary embryonic layers?
ectoderm, mesoderm, endoderm
which primary embryonic layer is enamel derived from?
ectoderm layer
which primary embryonic layer is our teeth (other than enamel) derived from?
ectomesenchyme layer
where is neural crest cell located?
between ectoderm and neural tube
what cell type is nerual crest cell/tissue?
ectomesenchyme
what is the 5 stages in tooth development?
initiation, morphogenesis, cytodifferentiation, matrix secretion, root formation
what happens in initiation?
primary epithelial band develops at approx 6 weeks, and appears as thickening in epithelium of embryonic mouth (stomodaeum). primary epithelial band divide into 2 parts at about week 7: vestibular lamina (buccal sulcus) and dental lamina (enamal organ).
what is the 2 stage in morphogenesis?
bud and cap stage
when does bud stage happens?
approx 8-10 weeks
what is found in bud stage?
dental lamina thickens into bud stage enamel organs. ectomesenchymal condensation appears which is the dental papilla.
what happens in cap stage?
enamel organ form a cup over dental papilla. enamel organ consist of external enamel epithelium and internal enamel epithelium.
when is cap stage
abt 11 weeks
where does external enamel epithelium and internal enamel epithlium meet?
at the cervical loop
what happens in cytodifferentiation?
bell stage of enamel organ form
when is bell stage?
abt 14 weeks
what happens in bell stage?
more cell layers are differentiated and tooth shape is being defined.
which 4 cell layers is found in bell stage enamel organ?
stratum intermedium, stellate reticulum, internal enamel epithelium, external enamel epithelium
what shape cell is stratum intermedium?
spindle shape cell
what happens in 12th for tooth development?
extension appears on lingual side of dental lamina. that is the dental lamina for the permanent successor
when does the 1st permanent molar germ develops?
about 16th weeks
what happen in late bell stage?
crown shape is well defined
Apposition of enamel and dentine begin
when is the late bell shage of enamel organ?
about 18 week IUL
what does enamel knot do?
number and location of enamel knot is the number and location of the cusp
It give the shape of tooth
what cell differentiate into odontoblast?
dental papilla cell adjecent to IEE
what does odontoblast produce?
dentine matix
what cell differentiate into ameloblast?
internal enamel epithelium
when does IEE cell differenciate into ameloblast?
after dentine formation begun (by odontoblast differentiated from dental pipilla cell)
what does ameloblast produce?
enamel
