Dental pulp

SEMINAR
HISTOLOGY OF
NORMAL AND
DISEASED DENTAL
PULP
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

LEARNING OBJECTIVES:-
At the end of the seminar learner should be able to:
Define dental pulp.
Describe the morphology of pulp
Describe the development of pulp
Label the histopathology of pulp
Describe the etiopathogenesis of pulp pathologies
Initiate the examination of pulp pathologies
Describe sequel of pulp pathology.

CONTENTS
 DEFINITION
 MORPHOLOGY OF PULP
 DETAILED HISTOLOGY OF PULP
 BLOOD SUPPLY
 NERVE SUPPLY
 FUNCTIONS OF THE PULP
 AGE CHANGES IN THE PULP
 CLINICAL CONSIDERATIONS
 PULPAL DISEASES
 CONCLUSION
 REFERENCES

Dental Pulp is a richly vascularized
and innervated connective tissue inside
the pulp cavity of a tooth

Development :-
The tooth pulp is initially called the dental papilla.
This tissue is called pulp only after dentin forms
around it.
The young dental papilla is highly vascular, and a
well organised network of vessels appears by the
time dentin formation begins.
After the inner enamel organ cells differentiate into
ameloblasts, the odontoblasts then differentiate
from the peripheral cells of the dental papilla and
dentin production begins.
As this occurs, the tissue is no longer called as
dental papilla but now is designated as the pulp
organ.

Morphlogy
*The coronal pulp: it is present in
the pulp chamber.
*The radicular pulp: it is that part of
the pulp extending from the cervical
region of the crown to the root
apex.
*Apical foramen: The pulp organs
are continuous with the periapical
tissue through the apical foramen.
The average size of the apical
foramen of the maxillary teeth in
the adult is 0.4 mm, while in the
mandibular teeth it is 0.3 mm in
diameter.

Accessory canals:
They are commonly seen to extend from the
radicular pulp laterally through the root dentin
to the periodontal ligament.
They are numerous in the apical third of the
root.
Formation :-
1- it occurs in areas, where the developing root
encounters a large blood vessel, where
dentin will be formed around it, then making
the lateral canal .
2- Early degeneration of the epithelial root
sheath of Hertwig before the differentiation of
the odontoblasts.
3- Lack of complete union of the epithelial
diaphragm at the floor of the pulp chamber.
AccessoryAccessory
canalscanals

Blood vessels,nerves and lymphatics
The dental pulp is formed of specialize loose connective tissue:
intercellular substance
cells fibers
Histological structure of theHistological structure of the
pulppulp

Odontogenic zone:
Location: Adjacent to the predentin with the cell bodies in the
pulp and cell processes in the dentinal tubules.

Cell free zone:
It is present Immediately beneath the
odontoblastic layer .
The cell free zone is the area of mobilization and
replacement of odontoblasts.

Cell rich zone
It is present beneath the cell free zone.
It is composed of fibroblasts and undifferentiated
mesenchymal cells.

Cells of the pulp
1- Synthetic cells (formative cells):
odontoblasts and fibroblasts.
2- Defensive cells:
Macrophages, small lymphocytes,
eosinophil, mast cells and plasma cells.
3- Progenitor cells:
Undifferentiated mesenchymal cells.

Odontoblasts:
Length:
5-7u in the diameter
25-40u in length.
In the early stage of development
odontoblasts consist of a single layer of
columnar cells .
In the later stages of development, the
odontoblastic layer appear pyriform
where the broadest part of the cell
contains the nucleus
They are longer in the crown and then
become cuboidal root wise, at the root
apex, they may be almost flattened.

The cell membranes of adjacent odontoblasts exhibit
junctional complexes.
The clear terminal part of the cell body and the adjacent
intercellular junction is known as terminal bar.

Fibroblasts
These are the most numerous
type of cells.
They are spindle in shape.
They have elongated
processes which are widely
separated and link up with
those of other pulpal
fibroblasts (stellate
appearance).
The nucleus stains deep with
basic dye and the cytoplasm
is highly stained and
homogenous.

These cells have a dual function: They aid in
synthesizing and degradation of fibers and ground
substances in the same cell .
In young pulp, they are :In young pulp, they are :
*large*large
*with large multiple processes*with large multiple processes
*centrally located oval*centrally located oval
nucleus,nucleus,
*numerous mitochondria,*numerous mitochondria,
*well developed Golgi bodies*well developed Golgi bodies
*well developed RER*well developed RER
mitochondriamitochondria
FibroblastFibroblast
(protein secreting cell).(protein secreting cell).

In periods of less activity and aging theseIn periods of less activity and aging these
cells appear smaller and round or spindle-cells appear smaller and round or spindle-
shaped , they are termedshaped , they are termed fibrocytesfibrocytes..
fibrocytefibrocyte
fibroblastfibroblast

Defensive cells:
Histiocyte ( macrophage ):
In light microscope, the cells appear
irregular in shape with short blunt
processes.
The nucleus is small, more rounded and
darker in staining than fibroblast.
Their presence is disclosed by intra-vital
dyes such trypan blue.
These cells are distributed around the
odontoblasts and small blood vessels
and capillaries.

In case of inflammation, *nuclei,
increase in size and exhibit a
prominent nucleolus.
it exhibits granules and vacuoles in
their cytoplasm
Invaginations of plasma membrane
are noted ultastructurally with
aggregation of vesicles or
phagosomes .

Plasma cells:
These cells are seen during inflammation.
The arrangement of chromatin gives the
nucleus a cart wheel appearance.
The mature type exhibits a typical small
eccentric nucleus and more abundant
cytoplasm.
The plasma cells are known to produce
antibodies.

Lymphocytes
They are found in normal pulp
and they increase during
inflammation.

Eosinophils
They are also found inThey are also found in
normal pulp and theynormal pulp and they
increase duringincrease during
inflammation.inflammation.

Mast cells:
They have a round nucleus and their
cytoplasm contains many granules.
They are demonstrated by using
specific stains as toluidine blue.
They produce histamin& heparin.

Progenitor cells:
(The undifferentiated
mesenchymal cells):
They are smaller than
fibroblasts but have a similar
appearance.
They are usually found along
the walls of blood vessels.
These cells have the
potentiality of forming other
types of formative or defensive
connective tissue cells.

Fibers of the pulp
In young pulp the fibers are relatively
sparse and delicate throughout the pulp
and gradually the bundles increase in
size with advancing age.
In older pulp two patterns of collagen
distribution can be seen:
one is a diffuse collagen network with no
definite orientation,
the second is bundles of collagen.
There are no elastic fibers in the pulp
except those present in the walls of the
larger blood vessels.

The ground substance of the pulp:
The ground substance consists of acid
mucopolysaccharides and neutral
glycoprotein.
These substances are the environment that
promotes life of the cells.

Blood vessels
The pulp is highly vascularized.
It is supplied by the inferior and superior
alveolar arteries
As the vessels enter the tooth, their walls
become considerably thinner than those
surrounding the tooth.
Along their course they give numerous
branches in the radicular pulp that pass
peripherally to form a plexus in the
odontogenic region.
The pulpal blood flow is more rapid than
in most areas of the body.
D

Nerve fibers :-
The pulp has an abundant nerve
supply which follows the
distribution of the blood vessels.
Two types of nerve fibers are
present:
The nonmyelinated nerves, are
sympathetic in nature, they control
the contraction of the smooth
muscles of the blood vessels
Myelinated fibers which are sensory
parasympathetic nerves.

The peripheral non mylinated axons
form a network of nerves located
adjacent to the cell-rich zone. This
is termed the " parietal layer of
nerves"or “plexus of Raschkow.”

More nerve endings are found in the pulp
horns than in other peripheral areas of
the coronal or radicular pulp.
Sensory response in the pulp cannot
differentiate between heat, touch,
pressure, chemicals. This is because
the pulp lacks those types of receptors.
So the sensory nerve ending in the pulp
are presumed to function in pain
reception.

Functions of the pulp:Functions of the pulp:
1- Inductive:
Dental papilla induces the enamel organ formation and
also determines the morphology of the tooth.
2- Formative :
Pulp organ produces dentin. Odontoblasts develop the
organic matrix and functions in its calcification.
3- Nutritive :
The pulp nourishes the dentin. Nutrition is mediated
through the odontoblasts and their processes.

4- Protective:
The sensory nerves in the tooth respond with pain to all
stimuli, Pain sensation is a useful alarm system of the
pulp.
5- Defensive or reparative:
The pulp responds to irritation by producing reparative
dentin and mineralizing any affected dentinal tubules.
These reparative reactions are an attempt to wall off
the pulp from the source of irritation.
The presence of macrophages, lymphocytes and
leucocytes aid in the process of repair of the pulp.

Age changes in the pulp
The size of the pulp chamber
The size of the apical foramen
The cellular elements
The bl. vessels & nerves
The Vitality
Reticular atrophy: The total affect is the production of a lessened vitality of
the pulp tissue and a lessened response to stimulation.
decreased

Pulp calcification
localizedlocalized
((pulp stonespulp stones )
diffusediffuse
False denticleFalse denticleTrue denticleTrue denticle

True denticles
They consist of irregular dentin
containing traces of dentinal
tubules and few odontoblasts.
True denticles are rare to occur,
they are small in size and
commonly found in the root canal
near the apical foramen.
odontoblastodontoblast
dentinaldentinal
tubulestubules

False denticles
They are evidence of dystrophic
calcification of the pulp tissue .
They contain no dential tubules.
They are formed of degenerated cells or
areas of hemorrhage which act as a
central nidus for calcification.
Overdoses of vit. D, may favor the
formation of numerous denticles.

Pulp stones are classified according to
their location into: free, attached and
embedded.
they continue to increase in size and in
certain cases they fill up the pulp
chamber completely.
If pulp stones come close enough to a
nerve bundle pain may be elicited.
The close proximity of pulp stones to
blood vessels may cause atrophy of it.
freefree
attachedattached

Diffuse pulp calcification
Commonly occurs on top of hyaline
degeneration in the root canal and
not common in the pulp chamber.
They are irregular calcific
deposition in the pulp tissue
following the course of blood vessels
or collagenous bundle.
Advancing age favors their
development.

Microscopic zones in pulp:-www.indiandentalacademy.com

Histological section of pulp:-www.indiandentalacademy.com

 For all operative procedures, the shape of pulp chamber and
its extensions into the cusps, the pulpal horns, is important to
remember.
 Pulp stones lying at the opening of the root canal may cause
considerable difficulty when attempting to locate the canal.
 When accessary canals are located near the coronal part of
the root or in the bifurcation area, a deep periodontal pocket
may cause inflammation of the dental pulp. Thus periodontal
disease can have a profound influence on pulpal integrity.
 Conversely, a necrotic pulp can cause spread of disease to
the periodontium through an accessary canal.
Clinical considerations:-www.indiandentalacademy.com

The pulp is highly responsive to stimuli.
Even a slight stimulus will cause
inflammatory cell infiltration.
A severe reaction is characterised by
increased inflammatory cell infiltration
adjacent to cavity site, hyperaemia, or
localised abscesses.

PULPITIS
Pulpitis is an
inflammation of pulp
tissue, a response to
surrounding environment
The vitality of the tooth
depends on defence
response of pulp dentine
complex by:
- sclerotic dentin
- tertiary dentin
- Calcified bridge of
dentinal tubules

ETIOLOGY
1. MECHANICAL: Trauma, iatrogenic damage
and barometric changes.
2. THERMAL: uninsulated metallic restorations
and dental procedures like cavity preparation,
exothermic chemical reactions of dental
materials etc.
3. CHEMICAL: Irritation from certain dental
materials or from erosion.
4. BACTERIAL: Through toxins or from direct
extension of caries

CLASSIFICATION
 INFLAMMATORY DISEASES OF THE DENTAL PULP:-
a)Reversible pulpitis
- symptomatic (acute)
- asymptomatic (chronic)
b) Irreversible pulpitis
- Acute
abnormally responsive to cold
abnormally responsive to heat
-chronic
asymptomatic with pulp exposure
hyperplastic pulpitis
internal resorption
 PULP DEGENERATION
 Calcific
 Others
 NECROSIS

ACUTE REVERSIBLE
PULPITIS
(Focal reversible pulpitis, Pulp hyperaemia)

Acute reversible
inflammation of
pulp tissue is
characterized by
vascular dilatation
ETIOLOGY: -
 Any mild irritants

CLINICAL FEATURES: -
Signs and symptoms: painful
Duration: 10-15 minutes, severe and short
Precipitating factors of pain: hot and cold
agents
Nature of pain:
Throbbing, continuous and radiating.
Pain stops when precipitating factors are
removed

The pain depends on -
The size of exposed pulp (size of
dental caries)
Severity of pulp inflammation
Age of patient
Nature of covering dentine

HISTOLOGICAL
FEATURES: -
Inflamed or
hyperaemic pulp
tissue contains
dilated blood vessels
of various sizes and
are lined by
endothelial cells
Presence of
reparative
dentin,extravasation
of edema fluid
Presence of normal
odontoblasts indicate
vitality of the pulp
tissue.

PROGNOSIS-:
It is a reversible condition.
If it is treated , pulp will return back to
its normal status.
If it is left untreated , it will not return
back to its normal status but it will
enter the next phase....

ACUTE PROGRESSIVE
PULPITIS

CLINICAL FEATURES: -
Duration : - more than 10-15 minutes,
severe and continuous, especially at night
Precipitating factors of pain : -
spontaneous, as well as hot and cold
agents
Nature of pain : -
Throbbing continuous and radiating pain
The pain does not stop even when
precipitating factors are removed.

PROGNOSIS: -
If it is left untreated, it will change
to chronic irreversible pulpitis or
pulp necrosis

CHRONIC IRREVERSIBLE
PULPITIS

It is a chronic
inflammation of pulp
tissue characterized
by specific clinical
features.
CLINICAL
FEATURES: -
Signs and symptoms:
- painful
Duration: - long
duration (few days to
months).

Precipitating factors of pain: -
hot, cold agents and during
mastication.
Nature of pain: -
Mild and intermittent pain
The pain stops when
precipitating factors are relieved
and when the tooth is treated

The pain depends on: -
The size of exposed pulp (size of
dental caries)
Severity of pulp inflammation
Age of patient
Nature of covering dentin

HISTOPATHOLOGICAL FEATURES:
-
The pulp tissue
contains dilated
blood vessels
with varying
sizes.
Degenerated
odontoblasts are
seen.
Areas of chronic
inflammatory
cells and fibrosis
can be seen
around inflamed
areas

PROGNOSIS: -
 It is dependant on the success of
pulp capping.

CHRONIC HYPERPLASTIC
PULPITIS
( Pulp Polyp )

 It is a chronic inflammation ofIt is a chronic inflammation of
pulp tissue characterized bypulp tissue characterized by
hyperplasia of connective tissuehyperplasia of connective tissue
of pulp in the form of polypoidof pulp in the form of polypoid
mass which originates frommass which originates from
exposed pulp chamberexposed pulp chamber

CLINICAL FEATURESCLINICAL FEATURES ::
--
Site:Site:
 A grossly cariousA grossly carious
molar(permanent/decimolar(permanent/deci
duous) where pulpduous) where pulp
chambers are wide,chambers are wide,
having multiple rootshaving multiple roots
with highly vascularwith highly vascular
pulp tissuepulp tissue
Shape :Shape : nodularnodular
fungated mass fills thefungated mass fills the
pulp chamberpulp chamber

Size :Size : variablevariable
Colour :Colour : reddish, bleeds readilyreddish, bleeds readily
Covering surface :Covering surface : intact orintact or
ulceratedulcerated
Symptoms:Symptoms: it is symptomless,
except during mastication, when
pressure of the food bolus may
cause discomfort.

HISTOLOGICALHISTOLOGICAL
FEATURESFEATURES : -: - Mass consists of proliferation of granulationMass consists of proliferation of granulation
tissue with newly formed, dilated bloodtissue with newly formed, dilated blood
vessels of varying sizes, chronicvessels of varying sizes, chronic
inflammatory cells and fibrosisinflammatory cells and fibrosis
 Surface of pulp polyp is usually covered bySurface of pulp polyp is usually covered by
stratified squamous epithelium.stratified squamous epithelium.
 Presence of generalized degeneratedPresence of generalized degenerated
odontoblasts also called “Wheat Sheaving”odontoblasts also called “Wheat Sheaving”
of Odontoblasts .of Odontoblasts .
 Source of epithelial cells are from saliva orSource of epithelial cells are from saliva or
desquamated mucosa of cheek or gingiva .desquamated mucosa of cheek or gingiva .
 Nerve fibers may be found in epithelialNerve fibers may be found in epithelial
layer.layer.

INTERNAL RESORPTION
 It is an ediopathic slow or fast
progressive resorptive process
occurring in the dentin of the pulp
chamber or root canals of the teeth.
 CAUSE- The cause is not known, but
such patients often have a history of
trauma.
 SYMPTOMS- Internal resorption in
the root of a tooth is asymptomatic, if
in the crown of the tooth then may be
manifested as a reddish area called
“ pink spot” .
 The radiograph usually shows a
change in the appearance of the wall
in the root canal or pulp chamber, with
a round or ovoid radiolucent area

HISTOLOGICAL FEATURES
Unlike caries, the internal
resorption is a result of
osteoclastic activity.
The resorptive process is
characterised by lacunae,
which may be filled in by
osteoid tissue.
Multinucleated giant cell
or dentinoclasts may be
seen.
The pulp is usually
chronically infammed.

TREATMENT- Extirpation of pulp stops the
internal resorptive process.
PROGNOSIS- it is best before perforation
of the root or crown occurs.

PULP NECROSIS

It is an irreversible condition
of pulp tissue
characterized by dead pulp
tissue and degeneration
( necrosis )
ETIOLOGY : -Severely
irritant agents.
CLINICAL FEATURES : -
Signs and symptoms : no
painful symptoms.
Discoloration of tooth is
seen.

HISTOLOGICAL FEATURES
In a necrotic pulp , cellular
debris , microorganisms
may be seen.
The periapical tissue may
be normal ,or a slight
evidence of inflammation
of apical periodontal
ligament may be present .

CONCLUSION
The preservation of healthy pulp during operative
procedures and successful management in cases of disease
are two of the most important challenges to the Dentist.
 The resistance of pulp depends upon the cellular activity,
nutritional supply , age, and other metabolic and physiologic
parameters.
 This variability has led to the remark that “ some pulps will
die if you look crossly at them, while others can’t be killed
with an axe.”
If pulpitis is left untreated , the infection will enter the
periapical region, causing further damage.
 The value of the pulp as an integral part of the tooth, both
anatomic and functional, should be recognised and every
effort should be made to conserve it.

BIBLIOGRAPHYBIBLIOGRAPHY
 Orban's , textbook of oral histology andOrban's , textbook of oral histology and
embryology, 11embryology, 11thth
editionedition
 Shafer WG, Hine MK, Levy BM. A textShafer WG, Hine MK, Levy BM. A text
book of oral pathology. 5book of oral pathology. 5thth
editionedition
 Neville BW, Damm DD, Allen CM, BouquotNeville BW, Damm DD, Allen CM, Bouquot
JE. Textbook of Oral and maxillofacialJE. Textbook of Oral and maxillofacial
pathology. 2pathology. 2ndnd
edition.edition.
 Grossman’s Endodontic Practice. 12Grossman’s Endodontic Practice. 12thth
editionedition

THANK YOU!!

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