CFD 17 - odontogenesis 3b Flashcards
When does the alveolar bone start to form?
as teeth develop, the bone extends around the tooth germ
- tooth germ needs to start making alveolar bone to sit in
Where does the alveolar bone come from?
the outer layer of condensed mesenchyme
Why is there not much difference between composition of alveolar bone and cementum?
HERS cells cause osteogenic differentiation - form bone cells
What are Gubernacular canals?
area between apex of deciduous and permanent tooth germ
- connective tissue through the alveolus bone
- eruption canal for the permanent tooth
What are the main cell type found in the PDL?
spindle-shaped fibroblasts
- these cells appear to be (functionally) distinct from fibroblasts found in gingival tissues
What does the PDL produce masses of?
collagen fibres
(also hyaluronan, growth factors such as TGFbeta1 and EGT, MMP’s (matrixmetalloproteinases)
What are the types of collagen fibres found around the tooth?
- horizontal
- alveolar crest
- circumferential
- dentino-gingival
- trans-septal
- alevolo-gingival
- inter-radicular
- oblique
- apical
What is in control of the number of roots forming?
the dental papilla interacting with the HERS
What pathway is really important in root development?
Sonic Hedgehog
During root development, what receptor does Shh bind to?
PTCH1
During root development, what happens if you block the Wnt pathway?
less mineralisation
- Wnt3 pathway very important in the mineralisation of the dental follicle cells in response to HERS
During root formation, what does HERS form?
the hyaline layer
During root formation, what does HERS interact with?
dental papilla
During root formation, what does the Hyaline layer interact with?
dental follicle
What does the dental papilla form?
odontoblasts —> dentine
