Odontogenic Embryology Flashcards
what does odontogenesis mean
tooth development
when does odontogenesis start? how long can it take
- starts 6th week in utero and can take up to 20+ years
what are the 5 stages of odontogenesis
1) dental lamina
2) bud
3) cap
4) bell
5) root formation and eruption
what two processes occur during the bell stage
amelogenesis
dentinogenesis
what are the locations of odontogenesis
maxillary and mandibular prominences
what impacts the shape of the face
the expansion of the paranasal sinuses and the growth of the mandible and maxilla to *accommodate the teeth
where does the dental lamina arise from
epithelial- mesenchymal interaction between overlying oral epithelium and underlying mesenchyme derived from neural crest cells
what occurs at 6 weeks during
basal layer of the epithelial lining forms a C shaped structure called the dental lamina along the length of the upper and lower jaws
what does the lamina give rise to?
*10 dental buds in each jaw forming the primordia of the ectodermal components of the teeth
what are buds surrounded by
ectomesenchymal cells
when does the cap stage occur
approx. 10 weeks
how does the bud first look
morphs into a cap-shaped *enamel organ
what are the 3 structures of the bud (while cap-shaped)
1) outer enamel epithelium (OEE)
2) inner enamel epithelium (IEE)
3) stellate reticulum (SR)
what does the IEE develop into
the ameloblasts
what occurs with the SR
cells secrete GAGs, which draws water into the organ and causes it to swell, the cells are interconnected with desmosomes and they become star shaped
what happens after the bud appears
mesenchymal components from the neural crest start to enclose the cap and fill the indentation
what are the 2 components of the cap once mesenchymal components start to enclose it?
1) Dental papilla (DP)*
2) Dental sac (DS) or dental follicle
describe the details of the DP
- protuberance at the underside of the cap
- *odontoblasts eventually develop into dentin
- remaining cells develop into the *pulp (nerve and blood supply)
describe the details of the DS
beginning to form by mesenchymal cells surrounding the cap
- stays with tooth until eruption, can cause pathology
what is the last step of the cap stage
enamel knot forms