DENTINE HISTOLOGY

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DENTINE HISTOLOGY:

DENTINE HISTOLOGY Dr. Asmat Jameel Assistant Professor B.D.S, F.C.P.S Head Department of Oral Biology

DENTINE 70% Inorganic 20% organic :

DENTINE 70% Inorganic 20% organic Dentinal Tubules (Odontoblastic Processes) Lumen wider near the pulp. More tubules near the pulp

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tissue unique to teeth forms the bulk of each tooth crown & root avascular cellularcontains odontoblast processes is not replaced if damaged some capacity for repair by deposition on its pulpal surface

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vital Sensitive -dentine sensitivity -pain associated with caries -pain associated with exposed & eroded surfaces Dynamic -ion exchange with surrounding environment -dentine composition changes over lifetime -dentine composition also changes as a result of external insult demineralisation↔remineralisation

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Types of dentine Primary dentineforms the bulk of tooth first formed / outer layer is called mantle dentine Secondary dentineslowly laid down along the pulp-dentine border after root formation is complete Tertiary dentineproduced in localised response to noxious stimuli reactive & reparative

DENTINE HISTOLOGY:

DENTINE HISTOLOGY Dentinal tubules. Peritubular dentine. Intertubular dentine. Interglobular dentine. Incremental growth lines. Granular layer of Tomes.

DENTINAL TUBULES:

DENTINAL TUBULES Tapered structure and gives off branches. 2.5 micron meter in diameter near the pulp, 1.2 near the midportion and 900 nanometer near the DEJ.

DENTINAL TUBULES:

DENTINAL TUBULES Contains odontoblast process. Extend through the entire thickness of dentine. Forms a network for the diffusion of nutrients throughout the dentine.

DENTINAL TUBULES:

DENTINAL TUBULES Follow an S-shaped path from the outer surface of dentine to the perimeter of pulp in coronal dentine. Results from crowding of and path followed by odontoblasts as they move towards the centre of the pulp.

DENTINAL TUBULES:

DENTINAL TUBULES In root dentine little or no crowding, tubules runs a straight course. Branches more frequently in root dentine than coronal dentine.

PERITUBULAR DENTINE:

PERITUBULAR DENTINE It encircle the dentinal tubule. Highly calcified matrix. 40% more than intertubular dentine. Less cllagen.

SCLEROTIC DENTINE:

SCLEROTIC DENTINE Dentinal tubules that have become occluded with calcified material. When several tubules are involved dentine appears glassy and translucent. Increases with age.

SCLEROTIC DENTINE:

SCLEROTIC DENTINE Common in apical third of root and in the crown midway between the DEJ and the surface of the pulp. Reduces dentine permeability.

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INTERTUBULAR DENTINE Located between dentinal tubules. Consists of tightly interwoven type I collagen fibrils in which appetite crystals are deposited. Fibrils are arranged randomly roughly at right angle to the dentinal tubules.

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INTERGLOBULAR DENTINE Areas of unmineralized or hypomineralized dentine. Globular zones of mineralization have failed to fuse into a homogenous mass. Vitamin D deficiency or exposure to high level of flouride during dentinogenesis.

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INTERGLOBULAR DENTINE Found in circumpulpal dentine just below the mantle dentine, where the pattern of mineralization is largely globular. No peritubular dentine.

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INCREMENTAL GROWTH LINES Incremental line of von Ebner: Situated 20 micron meter apart. 5-day cycle in which changes in collagen fiber orientation are more exaggerated.

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INCREMENTAL GROWTH LINES Incremental line of von Ebner: Runs at right angle to the dentinal tubules. Marks the normal rhythmic, linear pattern of dentine deposition in an inward and rootward direction.

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INCREMENTAL GROWTH LINES Contour lines of Owen: Secondary curvatures between neighboring dentinal tubules. Deficiencies in mineralization. Neonatal line.

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GRANULAR LAYER OF TOMES Found just below the surface of dentine where the root is covered by cementum. Due to arrangement of collagen and noncollagenous matrix protein at CDJ Increase from CEJ to the apex of the tooth.

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