DENTIN

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Presentation by:
Garima singh
1st yr PG
Dentin
1

• Primary dentin Vs
permanent dentin
• Infected dentin Vs affected
dentin
• Smear layer
• Dentin bonding system
• Conclusi...

• Dentin is a
mineralized, elastic, yellowish-
white, avascular tissue enclosing the
central pulp chamber.
• Dentin is cha...

• Inorganic material 70%
– Consist of hydroxyapatite in form of small plates
• Organic material 20%
– It is about 90% coll...

• It is a two phase sequence
– collagen matrix formation
– Mineralization
• Outlines are
– Differentiation of odontoblast
...

• Differentiation of odontoblast is brought about by
the expression of signaling molecule and growth
factors in cells of I...

• The first sign of dentin formation is the
appearance of distinct, large-diameter collagen
fibrils (0.1-0.2 mm in dia) ca...

• Throughout dentinogenesis, mineralization is
achieved by continuous deposition of mineral,
initially in the matrix vesic...

• Two pattern:
1) Globular mineralization
Deposiotion of crystals in
several discrete areas of matrix
by heterogenous capt...

• Dentin formation begins at the
bell stage of tooth development in
tissue adjacent to concave tip of
the folded inner ena...

• Many genes are implicated in dentinogenesis, the
newer ones being
– MAP1B for odontoblast differentiation, and
– PHEX fo...

• Color :
Pale yellow in deciduous teeth ,Yellow in permanent
dentition.
Light passes through thin, highly mineralized
e...

• Hardness:
Dentin is softer than enamel but more hard than
bone or cementum.
Hardness of dentin is one fifth (1/5th ) t...

• Modulus of elasticity of dentin is 1.67x 10⁶ PSI.
• Tensile strength of dentin is approx. 40MPa
, which is less than cor...

• Extend through entire thickness
of dentin from DEJ to pulp.
• ‘S’-shaped path from the outer
surface of the dentin to th...

• Diameter of dentinal tubules :
– Larger in diameter near pulp - 3 to 4µm, and
smaller at the DEJ- 1µm.
• Number of Denti...

• The dentin that immediately surrounds the dentinal
tubules is termed peritubular dentin.
• This dentin forms the walls o...

• The main body of dentin is
composed of intertubular
dentin.
• It is located between the
dental tubules more
specifically...

• It is term used to describe areas
of unmineralized or hypo
mineralized dentin where
globular zones of mineralization
(ca...

• When root dentin is viewed under
transmitted light in ground
section , a granular- appearing
area, the granular layer of...

• Incremental lines of von Ebner appear as fine lines or
striationsion.
• A that reflect rhythmic dentin deposition are mo...

Dentinoenamel junction:
• Unique bond between two very
dissimilar materials.
• It is scalloped or pitted or wavy
in outlin...

Dentino-cemental
junction:
• There is a smooth line junction
between the dentin and
cementum in permanent teeth.
• The cem...

• In human teeth three types of dentin can be
recognized–
– Primary dentin
– Secondary dentin
– Tertiary dentin
Types of d...

Primary Dentin-
• Formed prior to the eruption of the teeth and root
completion.
• Major bulk of dentin.
• It is composed ...

Mantle Dentin-
• The first-formed dentin in the crown underlying the
DEJ.
• Large collagen fibrils perpendicular to DEJ (0...

Secondary dentin-
• Formed after completion of root formation.
• Continuing, but much slower deposition of dentin.
• Narro...

• Greater deposition of secondary dentin on the roof
and floor of the pulp chamber leads to an asymmetric
reduction in siz...

Tertiary dentin-
• Tertiary dentin is also known as Reactive,
Reparative or Irregular secondary dentin.
• It is the dentin...

• Usually appears as a localized dentin deposit on the
wall of the pulp cavity immediately subjacent to the
area on the to...

Reactionary dentin:
• When the original odontoblasts that made secondary
dentin are responsible for focal tertiary dentin
...

Reparative dentin:
• If the provoking stimulus causes destruction of the
original odontoblasts, the newly differentiated
o...

• Nerve fibers were shown to accompany 30-70%
odontoblastic process, and these are reffered to as
intratubular nerves.
• N...

• 3 basic theories of pain conduction through
dentin are:
• Direct neural stimulation: by which the nerve in
dentin get st...

• Hydrodynamic theory: various
stimuli affect fluid movement in
dentinal tubule.
• This fluid movement , either
inward/ ou...

• Dead tracts and blind tract:
• When dentin is damaged,
odontoblastic processes die or
retract leaving empty dentinal
tub...

• Longitudinal ground section of
permanent teeth dentin showed
DT following an ‚S‛-shaped
curve, where as in primary DT
fo...

• Primary tooth showing incremental lines at an
angle to the dentinal tubules, whereas permanent
tooth showing incremental...

• Infected dentin: Superficial layer which is
soft and leathery in consistency and dark
brown in color.
– It has a high co...

• Whenever dentin has been cut or abraded, a thin
altered layer is created on the surface.
• Composed of denatured collage...

• The fundamental principle of adhesion to tooth
substrate is based upon an exchange process by
which inorganic tooth mate...

42
Clinical implications:
• Dental caries
• Dentin hypersentivity
• Dentinogenesis imperfecta
• Dentin dysplasia

• Dentin is a living tissue. It is covered by enamel in
crown portion and by cementum in root portion.
• It will become se...

• Chowdhary N ,Subba Reddy VV. Dentin comparison in primary
and permanent molars under transmitted and polarised light
mic...

• Gallagher R, Balooch M, Balooch G, Wilson R, Marshall S,
Marshall G. Coupled nanomechanical and Raman
microspectroscopic...

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