Post on 04-Apr-2018
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DENTINOGENESIS
Dr. Asmat Jameel
Assistant Professor
B.D.S, F.C.P.SHead Department of Oral Biology
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Begins at bell stage.Odontoblast differentiated from
ectomesenchymal cells of dental papilla
after receiving stimulus from IDE.
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DIFFERENTIATION
Dental papilla cells are small andundifferentiated with central nucleus andfew organelles.
Seperated from IDE by an acellular zonet at conta ns some ne co agen r s.
When cells of IDE reverse polarity,
c anges a so occurs n a acen en apapilla.
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DIFFERENTIATION
Cells enlarge ----preodontoblast---odontoblast as their cytoplasm increasesin volume to contain increase amount of
protein synthesizing organelles. ce uar zone s e mnate y
odontoblast.
on o as are g y po arze wnucleus located away from IDE.
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DENTINE
First collagen synthesized is deposited inthe ground substance of dental papilla.
VON KORFFS FIBERS: large diameter
0.1-0.2 micron meter collagen fibrilstype .
Originate deep among the odontoblast
ex en owar an an ou n estructureless ground substance
.
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DENTINE
Odontoblast continue to increase in size,produce smaller type I collagen thatorient themselves parallel to future DEJ .
Plasma membrane of odontoblasta acent to exten s stu yprocesses into the forming extracellular
.
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DENTINE
Budds off small matrix vesicles which liesuperficially near the basementmembrane.
Mineral phase first appears within thematrx ves c es as s nge crysta s.
Crystal grow and rupture and fuse with
a acen crys a s o orm a con nuouslayer of mineralized matrix.
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At mantle dentine formation capillariesfound in the subodontoblast layer.
As circumpulpal dentinogenesis is
initiated these capillaries migrateetween t e o onto ast.
After dentinogenesis retreat from the
o on o as .
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MINERALIZATION
Globular Linear.
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Mantle dentine region.Deposition of crystals in several discrete
areas o matrx.
Continued crystal growth, globular
enlarge and eventually fused to form asingle calcified mass.
Size depends upon rate of deposition ofdentine.
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Circumpulpal.When rate of formation ro ress slowl ,
mineralization front appears more
uniform.
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DENTINE
Hertwigs root sheath initiate thedifferentiation of odontoblast that formroot dentine.
Collagen fibers align parallel to basalamna n mante entne.
Degree of mineralization is less.
Rate of deposition is slower.
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DENTINOGENESIS
Demarcation line present betweenprimary and secondary dentine onhistological sections.
Less regular organization of dentinaltu ues or may e a sent.
Crowding or death of odontoblast.