Derived from the dental
papilla like the dentin

FUNCTIONS OF THE
DENTAL PULP

Contains nerves, arterioles,
venules, capillaries, lymph
channels, connective tissue
cells, intercellular substance,
odontoblasts, fibroblasts,
macrophages, collagen
and fine
fibers

*function of pulp*
production of primary and secondary
dentin by odontoblasts

*function of pulp*
supplies nutrients and
moisture
to dentin
through the blood vascular
supply to the
odontoblasts and their
processes

*function of pulp*
various stimuli elicit only pain
as a response, does not
differentiate between heat,
touch, pressure and
chemicals; control of
circulation
in the pulp

*function of pulp*
✓ response to irritation by
mechanical, thermal,
chemical or bacterial
stimuli

*function of pulp*
deposition of reparative
dentin
- protective barrier
against caries and various
other
irritating factors

*function of pulp*
In cases of severe irritation,
inflammation may
become irreversible; since it is
confined in dentin,
dentin limits the inflammatory
response

protective barrier
against caries and various
other
irritating factors

convenient source of
multipotent
stem cells

Soft connective tissue that
supports the dentin

Principal cells of dental pulp

4 ZONES OF THE PULP

ZONE OF THE PULP
(pulp periphery)

ZONE
high cell density (which again
is seen easily in the coronal pulp adjacent to the cell-free zone)

zone
major vessels and nerves
(which is characterized by
the
major vessels and nerves of
the
pulp)

ZONE OF THE PULP
beneath the odontoblasts
(which is prominent in the
coronal pulp)

Form and maintain the
dentin

Form a layer lining the periphery
of the pulp and have the
odontoblastic process extend
into dentin

Most distinctive cells of the
pulp

odontoblast
Midportion of pulp

Crown of fully developed tooth:
cell bodies are columnar and
measure approximately
50 µm
in height

odontoblast
Apical part

reflects their functional activity
and
ranges from an active
synthetic
phase to a quiescent phase

begins at the neck of the cells
where it begins to narrow as
it
enters the predentin

Odontoblasts in the crown
is
larger than odontoblasts in
the
root

Soft connective tissue that
supports the dentin

when differentiated, they
cannot
undergo further cell division

give dentin its viability and
ability to respond to various
stimuli

2 DIVISION OF
PULP CAVITY

convenient source of multi-potent
stem cells

The space PULP occupies

radicular portion

coronal portion

terminates at the apical foramen,
where the pulp and the
periodontal ligament meet and the main nerves and vessels enter and
leave the tooth

control of circulation in the
pulp

LOCATION OF LARGER
ODONTOBLASTS

Most abundant cells in the
pulp

When dentin is exposed due to caries, cavity preparation, gingival recession or attrition

Represent pool from which pulp
connective tissue cells are
derived

cell bodies are columnar and
measure approximately
50 µm in height,

Forms and maintains pulp
matrix

abundant cytoplasm and
peripheral cytoplasmic
extensions

THEORIES OF DENTIN HYPERSENSITIVITY

MECHANISM OF DENTIN HYPERSENSITIVITY
The tubular nature of dentin permits fluid movement to occur within the tubule when a
stimulus is applied, a movement registered by pulpal free nerve endings close to the
odontoblasts *

Numerous in the coronal portion
(cell-rich zone)

Concentric layers of mineralized tissue formed by surface accretion around blood thombi, dying/ dead cells or collagen fibers

Can be free or unattached to the outer pulpal wall or can be attached to dentin

found throughout the cell-rich
area and the pulp core

the means by which the pulp
and mineralised tissues
surrounding the dentine (enamel and cementum) communicate.

consists of collagen and
ground
substance

MECHANSIM OF DENTIN
The dentin contains nerve endings that respond when it is stimulated

Mesenchymal cells that have self-renewal capability

Have the capacity to give rise to osteoblasts and may therefore be a promising tool for bone regeneration

Similar function to the Langerhans’ cells of the epithelium

Consists of collagen fibers and ground substance that make up the extracellular matrix of the pulp

MECHANISM OF DENTIN
odontoblasts serves as receptors and are coupled to nerves in the pulp

Reduces the overall number of cells within the pulp

A THEORY WHERE odontoblasts act as a receptor

the need for synthesis diminishes
and the fibroblasts appear as
flattened spindle-shaped
cells with dense nuclei

PRIMARY FUNCTION
OF
FIBROBLAST

Macrophages appear as large oval or sometimes elongated cells with dark-stained nucleus microscopically

FIBROBLAST
actively synthesizing matrix and
therefore have a plump
cytoplasm and extensive
amount of organelles

Stimulated directly or indirectly by fluid movement

Endodontic therapy

may contain tubules and be surrounded by cells resembling odontoblasts

ACTS AS Denticles

have the capability of ingesting
and degrading collagen when
appropriately stimulated

Depending on the stimulus,
may give rise to odontoblasts
or
fibroblasts

A THEORY WHERE Dentin is innervated directly

Can be a problem during endodontic therapy

promising tool for bone regeneration

These cells participate in immunosurveillance and increase in number in carious teeth, where
they infiltrate the odontoblast layer and can protect their processes into the tubules.

T lymphocytes are found HERE

B lymphocytes are scarce HERE

bone-marrow derived, antigen presentingdendritic cells are found in and around the

Can differentiate into odontoblasts, chondrocytes, adipocytes and neurons

Discrete calcified masses that have calciumphosphorus ratios comparable to dentin

Overall collagen content increases with age of the pulp

Decreased volume of the pulp chamber and root canal due to continued dentin deposition

Greatest concentration of collagen generally occurs in the most apical portion of the pulp

Ground substance resembles other tissues: glycosaminoglycans, glycoprotein and water

gradual reduction of the tubule diameter; closure of the tubule

Blood vessels enter and exit the dental pulp by way of the apical and accessory foramina

inceased brittleness and decreased permeability

Fibers are principally type I and type III collagen

extensive plexus of nerves in the cell-free zone of Weil just below the cell bodies of the odontoblasts in the crown portion of the tooth

Nerves enter the pulp through the apical foramen along with the afferent blood vessels and together form the neurovascular bundle

what age when the cell density has decreased by about half

Circulation establishes the tissue fluid pressure found in the extracellular compartment of the pulp

Sensory afferent nerves of CN V (trigeminal nerve) and sympathetic branches of the superior cervical ganglion;

One or sometimes two vessels of arteriolar size enter the apical foramen with the

They arise as small, blind, thin-walled vessels in the coronal region of the pulp

reduction in the vascular supply to the pulp

cells gradually decrease in number

Age changes render the pulp more resistant to environmental injury

produce more sclerotic dentin, deposit secondary dentin at an increased rate

gradual reduction of the tubule diameter; closure of the tubule

Occurrence of irregular areas of dystrophic calcifications

Reparative dentin also contributes to the reducing sensitivity

More severe stimulus

Appearance of fibrous bundles due to change in collagen fibril distribution

age lessens the ability of the dentin-pulp complex to repair itself

decreased potential for differentiation of new odontoblasts from the mesenchymal cells of the pulp and the formation of reparative dentin

narrowing of dentinal tubule diameter, deposition of peritubular dentin

have a much more favorable prognosis for surviving pulpal inflammation

Stimuli are not transmitted as rapidly
Complete obliteration of older tubules with mineralization
Pulp horns recede
Pulp becomes more fibrotic

band of epithelium that gives
rise to two subdivisions which ingrow into the
underlying mesenchyme colonized by neural crest
cells

which forms afterwards and is
positioned just in front of dental lamina

Largest portion of the tooth structure,
extending almost the full length of the tooth

covered by the enamel in the crown and
cementum in the roots

forms the walls of the pulp cavity – pulp
chamber and pulp canal

Both dentin and pulp are derived from the

Provides elasticity and strength to
the tooth;

enables it to withstand
loading forces by mastication and
trauma

Protects and preserves the
integrity of the pulp tissue

• More radiolucent than enamel
but more radiopaque than the
pulp

Protects and preserves the
integrity of the pulp tissue

composition Mature dentin:

TRUE OR FALSE
Dentinal crystallites are smaller than enamel
crystallites

Dentinal crystallites size in bone and
cementum

Provides greater yield to
the pressure of a sharp
explorer tine (tends to catch
and hold in dentin)