OCB02-1017 Dentinogenesis Flashcards
What is dentineogenesis?
Formation of dentine
Where does dentineogenesis occur?
Dental papilla
What cells perform dentineogenesis?
odontoblasts
When does dentineogenesis occur?
Later bell stage
What do differentiating odontoblasts undergo rapid changes in?
size and polarisation
Where does cytodiffrentiation start?
tip of cusps or incised margins, and travels rootwards
What is the structure of the odontoblast?
Large nucleus at the basal part
Many small cell processes directed towards the basement membrane
Where is the predentine?
In the space between the odontoblast cell body and mental dentine
What colour is the staining of pre dentin?
Pale
What is another term for mineralisation front?
Metadentine
What is the mineralisation front?
It is part of the predentine, directly below mineralised dentine
What do odontoblast processes secrete?
Dentine phosphoprotein
Dentine sialophosphoprotein
Minerals associated with proteoglycans
Where does mineralisation start?
With mantle dentin and moves towards circumpulpal dentin
What occurs when the odontoblast secretes mantle dentin?
It buds off matrix vesicles which are 30-200nm in diameter
What is the purpose of alkaline phosphatase in the vesicles of mineralisation?
They increase PO43- concentration to develop crystals
Where are crystalline structures only present in?
Mantle dentine
What is controlled to control odontoblasts?
Controlling influx of Ca2+ ions
Controlling secretion and metabolism of matrix proteins
How does mineralisation of circcumpulpal dentine occur?
By Ca2+ nucleation at spaces present with bundles of collagen
What controls mineralisation of circumpulpal dentine?
DPP
Dentine phosphoprotein
What does it mean by circupulpal dentine having a linear mineralisation front?
The calcification of dentine appears uniform
What are the properties of DPP?
Highly acidic so binds to Ca2+
Can change shape to bind Ca2+ ions to allow crystal growth
What are the functions of DPP?
Transports Ca2+ to mineralisation front
Stabilisation of formed crystals
Inhibits crystal formation in high concentration
What are the proteins of odontoblasts?
Osteonectin
Osteopontin
Boe Sialoprotein
Proteoglycans
What does osteonectin do?
Inhibits growth of hydroxyapatite and promotes Ca2+ and Po4 3- binding to collagen
What does osteopontin do?
Promotes mineralisation
Where is bone sialoprotein found?
Early mineralising dentine, predentine and peritubular dentine
What are circular areas of mineralisation called?
Calcospherites
What are areas where calcospherites fail to fuse called?
Interglobular dentine
When does the peritubular dentine layer form?
Same time as interlobular dentine
What is root dentine initiated by?
The formation of HERS
How does the rate of formation of root dentine differ to coronal dentine?
Root dentine forms slower than coronal dentine
What is mineralisation like in multicoated teeth?
They have isolated areas of mineralisation
What are the properties of root dentin (hyaline layer)?
No dentinal tubules
Non-collageous fibrillar matrix
What signalling molecules are in tertiary dentine formation?
TGF-B
