Dentinogenesis
Dentinogenesis
Dentinogenesis
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<strong>Dentinogenesis</strong><br />
Professor Dr Maha M.F Mounir
Dentin & Pulp<br />
Odontoblasts<br />
are an integral<br />
part of both<br />
dentin & pulp
Dentin is a vital tissue containing cell<br />
processes of odontoblasts & neurons.<br />
Odontoblasts form dentin matrix, &<br />
neurons convey sensory information
<strong>Dentinogenesis</strong> occurs prior to<br />
amelogenesis<br />
• Soon after the deposition of<br />
the first layer of dentin (mantle<br />
dentin), odontoblasts express<br />
MMPs to digest the basement<br />
membrane to allow E & D<br />
matrices & their respective<br />
mineral phases to come onto direct contact<br />
a strong mechanical bond is<br />
formed between E & D
Bell stage-establishing coronal<br />
form<br />
• Secretion & mineralization<br />
of dentin & enamel matrices<br />
begins only after the shape<br />
of crown has been determined<br />
in soft tissue<br />
Secretion & mineralization<br />
of dentin precedes enamel<br />
formation
<strong>Dentinogenesis</strong>
<strong>Dentinogenesis</strong><br />
• Preodontoblast elongates & forms the<br />
odontoblastic process. The nuclei<br />
occupies the basal portion of the cell &<br />
organelles are located at apical end,Polarity
ODONTOBLATS<br />
• Consists of a cell body + an odontoblastic<br />
process ( that branches laterally & terminally)<br />
• Function: secretion, distribution & removal of matrix<br />
components+ mineralization of dentin
Mantle Dentin<br />
• First formed layer of dentin. It contains<br />
thick collagen fibers that lie perpendicular<br />
to the ADJ ( fibers of circumpulpal dentin<br />
are parallel approximately to ADJ & are<br />
finer)
Von Korff’s Fibers<br />
• Are the first secreted collagen fibers<br />
(dentin matrix protein) that may pass<br />
between differentiating odontoblasts &<br />
extend towards basal lamina where they<br />
end in a fan shaped arrangement<br />
(argyrophilic= take silver stain)<br />
• Consists of type I + type III collagen
Predentin<br />
• Is the un-mineralized dentin matrix
Predentin
Dentin Matrix proteins<br />
• Are secreted externally via transport<br />
vesicles
incremental deposition of<br />
enamel & dentin
Forming dentin in crown area
Dentine mineralization<br />
• Small mineral crystals in:1.Matrix vesicles<br />
2.nucleated in spaced within collagen fibrils<br />
( globular & linear mineralization)
Incremental deposition of dentin<br />
• Incremental lines of Von Ebner<br />
• Neo-natal line
Thank you
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