The pulp is a soft connective tissue located within the tooth. It has several unique features, including being surrounded by rigid dentin walls and susceptible to changes in pressure. The pulp contains odontoblasts, fibroblasts, undifferentiated cells, and defense cells. It is highly vascularized and innervated. During development, dental papilla forms the pulp through proliferation and differentiation of cells. The pulp cavity is divided into coronal and radicular regions. Nerves and blood vessels enter through the apical foramen, supplying the pulp.

1. Dr. MaDhusuDhan reDDy

2. IntroDuctIon
• The Pulp is a soft mesenchymal connective tissue
that
• Occupies pulp cavity in the central part of the
teeth.
• It is a special organ because of the unique
environment

3. Features oF pulp
• Surrounded by rigid walls (dentin) - unable to
expand in response to injury as a part of the
inflammatory process
• Therefore pulpal tissue is susceptible to change in
pressure affecting the pain threshold
• Pulp is simple connective tissue
• Peripherally layer of specialized cells (odontoblasts)
• Secondary dentin deposited gradually (physiological
process) reduces the blood supply
• Making the tooth resistant to trauma or infection

4.  Total 52 pulp organs; 32: Permanent, 20: Primary
 Total Volume of all permanent teeth pulp organs
is 0.38 cc.
 Mean volume of a single adult human pulp is 0.02
cc.
• Each of these organs has a shape that conforms to
that of the respective tooth.

6. DeVelopMent
• During the 8th week of IUL, there is condensation
of the mesenchmye under the enamel organ-
Dental papilla.
• The enamel organ enlarge and enclose the dental
papilla in their central portion.
• Dental papilla controls the morphology & type of
tooth to be formed.
• Dental papilla shows :
– Extensive proliferation of cells
– High vascularity

7. DeVelopMent
• Following the differentiation of the IEE into
ameloblasts, odontoblast differentiate from the
peripheral cells of dental papilla
• Well organized capillaries are found at beginning
of dentinogenesis
• Capillaries crowd around the odontoblast during
active dentinogenesis
• Root formation is carried out by the proliferation
of cells at the cervical loop.

8. regIons oF the pulp caVIty
• The pulp cavity can be
divided into two main
regions: the coronal pulp is
located within the crown of
the tooth and the radicular
pulp is located within the
root.
A, Coronal pulp; B, Radicular pulp

9. coronal pulp
• Pulp occupying the pulp chamber of the crown of the tooth
• In young teeth it resembles the shape of the outer dentin
• It has six surfaces : occlusal, mesial, distal, buccal, lingual
and floor.
• Pulp horns are projections into the cusp
• This pulp constricts at the cervical region where it
continues as the radicular pulp

10. raDIcular pulp
• Pulp occupying the pulp canals of the root of the
tooth
• In the anterior tooth it is single and in the
posterior teeth it is multiple
• The radicular portions of the pulp is continuous
with the periapical tissues through apical foramen
• As age advances the width of the radicular pulp is
reduced, and so is the apical foramen.

11. apIcal ForaMen
1. Pulp cavity terminates at root apex as small
opening called apical foramen
2. Radicular pulp continuous with connective tissue
of the periodontium through this foramen.
3. Diameter in an adult- maxillary teeth-0.4mm
mandibular teeth-0.3mm
4. Wide open during development of root

12. apIcal ForaMen
5. Sometimes apical opening is found on the lateral
side of the apex
6. There may be 2-3 foramina split by cementum or
dentin- APICAL DELTA
Neurovascular bundle entering
pulp through the foramen

13. accessory canals
• Leading laterally from the radicular pulp into the
periodontal tissue.
• They are numerous in the apical third of the root.
• Formed due to premature loss of HERS or when
developing root encounters a blood vessel.
• Overall occurrence is 33%
• May also be present at the furcation region

15. structural organIzatIon oF
pulp

16. hIstologIcal zones oF pulp
• Odontoblast layer
• Cell-free zone
• Cell-rich zone
• Pulp proper

17. Dentin
Predentin
Odontoblasts layer
Cell free zone
Cell rich zone
Pulp core

18. oDontoBlastIc layer
 Location: Adjacent to the predentin with the cell
bodies in the pulp and cell processes in the
dentinal tubules.
Dentin

19. cell Free zone
• It is also called weil’s zone
• 40 microns wide &relatively free of cells
• Traversed by
– 1. Blood vessels
– 2. Unmyelinated nerves
– 3. Cytoplasmic process of fibroblasts
• This zone is found below the odontoblastic zone

20. cell rIch zone
• Present in subodontoblastic layer
• Contains more proportions of fibroblast and
undifferentiated mesenchymol cells.
• Macrophages, dendritic cells and lymophocytes.
• Zone formed due to migration of cells from pulp
proper
• Mitosis seen when dead odontoblasts are replaced
• Also contain young collagen fibres during early
dentiogenis.

21. pulp core
• It is central region of the pulp
• Contains major blood vessels and nerves of the
pulp
• Pulpal cells and fibroblasts are also seen

22. CELLS OF PULP
• Odontoblasts
• Fibroblasts
• Undifferentiated Cells
• Defense Cells

23. ODONTOBLASTS
• A Peripheral area of the pulp where the
odontoblasts reside is termed odontogenic zone.
• Arranged in Palisading pattern cells are tall
columnar forming a layer of 3 to 5 cells in depth.
• Shape may vary
– Cornal pulp- columnar
– Midportion - cuboidal
– Apical region - Flattened

24. ODONTOBLASTS
• These cells have large process extending into
dentin
• The no of odontoblasts corresponds to the number
of dentinal tubules
• Average no of odontoblasts estimated to 45,000
per Sq.mm of odontogenic zone.
• Odontoblasts in the crown are larger than in the
root.

25. ODONTOBLASTS
• Shape of the odontoblasts also reflect the
functional activity of the cell.
• During active phase, cells show increase in
endoplasmic reticulum golgi appartus and
secretory vesicles.
• Resting (or) Non active phase cells are flattened
little cytoplasm condensed chromatin and
decrease no of ER

26. JUNCTiONAL COmPLEx
• Numerous junctions such as gap junctions tight
junction and desmosomes are found between
odontoblasts.
• Indicating exchange of ions and small molecules.
• They promote cell to cell adhension and play a
role in maintaining polarity of odontoblasts

27. Gap junction
desmosome

28. ODONTOGENiC PROCESS
• Odontoblasts give off a single process that extends
into dentin and housed within dentinal tubules
• These process devoid of major organelles
• They contain abundance of microtubular
filaments and coated vesicles

29. FUNCTiONS OF ODONTOBLASTS
• Synthesis of organic matrix
• Synthesis of non collagenous substances like
sialoprotein, phosphophoryn, osteocalcin,
ostenoectin & osteopontin
• Intracellular accumulation of calcium
• Degradation of organic matrix

30. FiBROBALSTS
• Cells that occur in greatest number in the pulp
• Function is to form, maintain the matrix that
consists of collagen fibers and ground substance
throughout the pulp
• They are spindle in shape.
• The fibroblasts are stellate shaped cells having
extensive process.

31.  The nucleus stains deep with basic dye and the
cytoplasm is highly stained and homogenous.
H&E stain
Immunohistoc
hemical
method

32.  These cells have a dual function: synthesize and
degradation of fibers and ground substances in the same
cell .
• In young pulp:In young pulp:
• large cells with largelarge cells with large multiple processesmultiple processes centrally locatedcentrally located
oval nucleusoval nucleus, numerous, numerous mitochondriamitochondria, well developed, well developed
golgi bodiesgolgi bodies well developedwell developed RERRER
FibroblastFibroblast
(protein secreting cell).(protein secreting cell).

33. In periods of less activity and aging these cells
appear smaller and round or spindle-shaped with
few organelles , they are termed fibrocytes.

34. UNDiFFERENTiATED mESENCHYmE
• These mesenchymal cells are distributed through out the
pulp, frequently around the perivascular area - believed
to be toti potent cell
• They are Polyhedral shaped with peripheral processes
and large oval nuclei
• Difficult to differentiate from fibroblast under light
microscopy
• Under adequate stimilus they may differentiate into
odontoblast or fibroblast or macrophages.
• In older pulp, their number and ability to differentiate
comes down

35. DEFENCE CELLS
• They play a major role local inflammation and
immunity.
• They are recruited from blood stream and remain
as transient inhabitants in pulp
• These cells are
1. Macrophages
2. Mast cells
3. Plasma cells
4.Lympocytes, Neutrophils, Eosinophils, basophils
and manocytes.

36. i- 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 distrbuted around the odontoblasts and small
blood vessels and capillaries.
 Engulfment and digestion of foreign material
 Constitute 8-9% of total pulpal populations

37.  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 .

38. ii- mAST CELLS:
• They have a round nucleus and their cytoplasm
contains many dark staining granules.
• They are demonstrated by using specific stains as
toluidine blue.
• They produce histamin & heparin.
• Occur in small groups in relation to blood vessels
• Present only during pulpal inflammation

39. iii- 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.

40. iV- LYmPHOCYTES
• Usually found extravascularly in the normal pulp
• During inflammation they increase in number.
• Lymphocyte present along the walls of blood vessels
• Usually they are not found in uninflamed pulp
• They phagocyte foreign material .

41. V- EOSiNOPHiLS
They are found in normal pulp and they increaseThey are found in normal pulp and they increase
during inflammation.during inflammation.

42. ExTRA CELLULAR mATRix
• Connective tissue fibers
– Collagen
– Elastin
– Fibronectin
• Ground substance
– Proteoglycans
– Glycosaminoglycans
• Basement membrane

43. FIBRES (COLLAGEN FIBRES)
• Extra cellular structural protein, major
constituent of connective tissue
• Collagen fibers appear throughout the pulp
• Young fine fibers ranging in diameter from 10-
12mm.
• Pulp collagen fibers do not contribute to dentin
matrix production.

44. • After root completion pulp matures and bundles
of collagen fibers increase in number
• They scattered throughout the coronal or
radicular pulp, or they appear in bundles. These
are termed diffuse or bundle collagen
• Most prevalent in root canals, especially near
apical region.

45. • Type I:
 Present as thick striated fibrils
 Responsible for pulp architecture
• Type III:
 Thinner fibrils, mainly distributed in cell free
and cell rich zones
 Contributes to the elasticity of pulp
• Type IV:
 Present along the basement membrane of
blood vessels
• Type V and VI:
 Seen to form dense meshwork of thin
microfibrils through out the stroma

46. • Collagen turnover is maintained by fibroblasts
• During bacterial infection & inflammation,
collagenolytic activity is accelerated following
collagenase produced by bacteria, PMN &
fibroblats
• Collagen synthesis is accelerated during
reparative dentin formation

47. ELASTIC FIBER
• 1. This has the ability to expand and contract like
a rubber band
• 2. Elastic fibers are first formed in bundles of thin
micro filaments called Oxytalan fibers
• 3. Elastin is then deposited in between oxytalan
fibers.
• 4. Always associated with larger blood vessels

48. FIBRONECTIN
• It plays a role in cell-cell & cell-matrix adhesion
• Has a major effect on the proliferation,
differentiation & organization of cells.
• Seen around the blood vessels
• Also found in odontoblast layer with fibers passing
into predentin

49. • Fibrinoectin helps to maintain cell morphology
and provide a tight seal at this site.
• Fibronectin may be involved in cell migration and
anchorage in the wound healing process of the
connective tissue of pulp.
• It regulates the migration and differentiation of
secondary odontoblasts

50. GROuNd SuBSTANCE
• It is a structure less mass, makes up the bulk of
the pulp
• Consists of complexes of proteins, carbohydrate
and water.
• Broadly classified as
– Glycoaminoglycans
– Proteoglycans
• These substances are the environment that
promotes life of the cells

51. GLYCOSAMINOGLYCANS
• GAG found in pulp is mainly chondroitin
sulphate, dermatan sulphate & hyaluronic acid
• Proteoglycans - provide protection against
compression.
• During dentinogenesis, the ground substance show
affinity for collagen and influence fibrinogenesis
• They have capacity to bind with calcium and help
in mineralisation

52. BASEMENT MEMBRANE
• It is a sheet like arrangement of extra cellular protein
matrix at the epithelial-mesenchymal interface
• Composed of 2 layers
– lamina densa- electron dense
– lamina lucida- electro lucent
• Basement membrane is a product of connective tissue and
epithelium
• It is composed of
– Collagen type IV
– Laminin-adhesive glycoprotein
– Fibronectin
– Heparin sulfate

53. FuNCTIONS
• Act as sieve between epithelium and connective
tissue
• Helps in organisation and differentiation by
enabling interactions between extra cellular
molecules and cell surface receptors
– Eg: Odontoblasts during tooth development

54. BLOOd SuppLY TO ThE puLpBLOOd SuppLY TO ThE puLp
 The pulp organ is extensively vascular with vessels
arising from the external carotids to the superior
or inferior alveolar arteries. It drain by the same
vein.
 The walls of the pulpal vessels become very thin as
their enter the pulp.
 The blood vessels gain entry into the pulp through
the apical foramen and at times through accessory
foramen.

55. • Pulpal blood flow is more rapid than in most area
of the body
• So pulpal pressure is highest of body tissues
• The flow of blood in
– arterioles - 0.3 to 1mm/sec
– Venules – 0.15mm/sec
– Capilaries – 0.08mm/sec

56. ARTERIAL OF TEETh

57. VENOuS dRAINAGE OF TEETh

58. LYMphATIC dRAINAGE OF TEETh

59. NERVE SuppLY TO ThE puLpNERVE SuppLY TO ThE puLp
• Nerves : Several large nerves enter the apical
canal of each Molar and Premolar and single ones
enter the anterior teeth. This trunks transverse the
radicular pulp, proceed to the coronal area and
branch peripherally.

60. • Structure of Tooth
A - crown
B - enamel
C - dentine
D - gum
E - tooth pulp
F - cement
H - nerves & blood
vessels

62. Nerve Plexus of Raschkow
• Nerves enter the tooth through the apical foramen
as myelinated nerve bundles. They branch to form
the subodontoblastic nerve plexus of Raschkow
which is separated from the odontoblasts by a cell-
free zone of Weil.

63. A, Odontoblasts; B, Cell-free zone of Weil; C, Nerve plexus of Raschkow

64. Nerves in pulpNerves in pulp

65. Dental PulpDental Pulp
Nerve Blood vessel

66. Clinically Importance features of the Dental PulpClinically Importance features of the Dental Pulp
With age the pulp becomes less cellular. The
number of cells in the dental pulp decreases as
cell death occurs with age.
The volume of the pulp chamber decreases with
continued deposition of secondary dentine. In
older teeth, the pulp chamber decreases in size;
in some cases the pulp chamber can be
obliterated.
An increase in calcification in the pulp occurs
with age.

67. Age changes in the pulpAge changes in the pulp
The size of the pulp
The apical foramen
The cellular elements
The bl. vessels & n.
Vitality
decreased

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

69. True denticles
They consist of irregular dentin
containing traces of dentinal
tubules and few odontoblasts.
Remnants of the epithelial root
sheath invade the pulp tissues
causing UMC of the pulp to form
this irregular type of dentin.
odontoblastodontoblast
dentinaldentinal
tubulestubules
True denticles areTrue denticles are rarerare &&
smallsmall in size&in size&
found near thefound near the apical foramenapical foramen..

70. False denticles
*They are evidence of dystrophic
calcification of the pulp tissue .
*They contain no dentinal 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.

71. *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.
*The close proximity of pulp stones
to blood vessels may cause
atrophy of it. freefree
attachedattached

72. 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.

73. Free True
Denticle

75. Odontoblast
Predentin
Dentinal
Tubules

76. A, True pulp stone; B, Pulp
cavity; C, Dentin

77. False pulp stone
A, False pulp stone; B, Pulp cavity

78. Functions of the pulpFunctions 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 function in its
calcification.

79. 3-Reparative: through the formation of highly
mineralized reparative dentin at the site of
injury to seal off the pulp from the source of
irritation . Also the pulp may mineralize the
affected dentinal tubules by forming
sclerotic dentin .
4-Defensive : pulp inflammation represents
other aspect of its response to irritation. In
this condition, the defensive cells of the
pulp
will be increased and activated to repair
and heal the inflamed pulp and
phagocytoses the invading bacteria and
their toxin .

80. 5- Protective: : any environmental irritating
stimuli always elicit pain as a response .
6- Nutritive : the extensive pulp vasculature
ensures an excellent nourishment to the
odontoblasts for the continuously forming
secondary dentin . This is provided through the
capillaries found in the odontogenic zone .