Dentin

pattern of mineralization Root dentin formation

Physiologic 1ry ,2ry and 3ry dentin

Ahmed Emam

Dentinogenesis

acellular zone separates ameloblasts from dental papilla

Dentinogenesis - Secretory Stage

Odontoblasts and process

Odontoblast cellsOdontoblast process

Dentin Pulp

Note: collagen fibers & odontoblastic processes in tubules

Dentinogenesis

First sign of dentin formation.

arrows show von Korff’s fibers

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Note: mineralization foci forming mantle dentin

Odontoblasts produce organic matrix & crystals.

Matrix

vesicleRupture of th

e

MV and begin of

mineralizationMineralize

d

MD

MANTLE DENTIN

CIRCUMPULPAL DENTIN

Maturation of dentin

Matrix vesicle

Rupture of the MV and begin of mineralization

Maturation of dentin

Begin of Crystallization

Crystal lodgment

Types of dentin: globular/interglobular

Inter-globular dentin

Inter-globulerdentin

Interglobular Dentin

Inter-globulerdentin

DentinalTubules

DentinoEnamelJunction

Odontoblast processes

Hard Tissue Formation Bell Stage

Proliferation of c

ells fro

m

“cervi

cal lo

op”

Formation of Hertwig’s epithelial root sheath.

Sheath grows around dental papilla/future pulp.

Pulp

Incremental layering of cementum.

Alveolar bone

The Completed Root

Dentin

Cementum

Granular layer of Tom

Hyaline layer

• The lamellar appearance of the cellular cementum is apparent, as are the cemento cytes. A hyaline layer (green arrow) lies between the cementum and dentin, and contains proteins secreted by the root sheath that are related to the enamelins produced by the ameloblasts. In addition, the collagen fibers of primary acellular cementum are oriented perpendicularly to the fibers of the dentin into which they insert. This provides for the very strong bonding of cementum to dentin, and thus aids in the attachment of the tooth to alveolar bone via the periodontal ligament fibers. The tubular structure of dentin is clearly visible, and the granular layer of Tomes (black arrow) can be seen subjacent to the cementum

• This micrograph also demonstrates the highly branched structure of the odontoblastic processes in root dentin, which is thought to be responsible for the granular layer of Tomes. The arrow and bracket indicate the region of the hyaline layer.

DENTIN CLASSIFICATION

Types of dentin:

Primaryphysiologicaldentin

Secondaryphysiologicaldentin

Primaryphysiologicaldentin

Secondaryphysiologicaldentin

Tertiarydentin

Primaryphysiologicaldentin

Secondaryphysiologicaldentin

Tertiarydentin

Dead tracts

THE END

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