The dental pulp is the soft tissue contained within the pulp chamber and root canals of teeth. It is composed of loose connective tissue and nerves that provide sensation and nourishment to the tooth. The pulp contains cells such as odontoblasts, fibroblasts, macrophages, and stem cells embedded within an extracellular matrix. Odontoblasts are responsible for dentin formation and maintenance. With age, the pulp undergoes regressive changes like fibrosis, calcification in the form of pulp stones, and decreased cellularity. Diseases like caries, trauma, and chemical irritation can lead to inflammation of the pulp tissue.

1. Pulp
Dr.Smitha Rao

2. Pulp
 Mesenchyme connective tissue
that occupies pulp cavity in the
central part of the teeth
 Surrounded by dentin on all sides
except at the apical foramen &
accessory canal openings

4. Pulp tissue removed during
endodontic therapy by a size 20
broach file

5. Pulp
 32 (permanent) + 20 (primary) =
52 Pulp organs
 Total volumes of perm. teeth pulp organs =
0.38 cc
 Mean volume of a single adult human pulp =
0.02 cc
 Molar pulps are 3-4 times larger than
incisor pulps

6. DEVELOPMENT
 Formed by dental papilla.
 Odontoblasts – neural crest origin (ectodermal).
 Other pulpal cells - mesenchymal origin.
 Immature dendritic cells appear in and around the
odontoblastic layer at early stage.
 First layer of dentin deposited- dental papilla
becomes dental pulp.
 Numerous fibroblasts-remain closely packed, are
stellate shaped with large nucleus and little
cytoplasm and lay down fine collagen fibres.

7. DEVELOPMENT
 Developing pulp has high GAG content.
 Chondroitin sulphate is higher with little hyaluronan,
while opposite is true for mature pulp.
 Enamel organ extends as HERS and determines final
morphology of the space (pulp chamber and root canals).
 Once full length of roots is established, the developmental
stage of dental pulp can be considered complete.

8. Anatomy:
pulp
Coronal pulp Radicular pulp

9. Coronal pulp
 Has 6 surfaces
 Has pulp horns which are protrusions
that extend into the cusps of each crown
 Number depends on the cuspal number
 Pulp becomes smaller with age

11. Radicular pulp
 Extends from the cervical region of the
crown to the root apex
 Anterior teeth-single
 Posterior teeth-multiple
 Continuous with the periapical
connective tissues through the
apical foramen

12. Histology
4 zones:
 Odontoblastic zone
 Cell free zone of weil
 Cell-rich zone
 Pulp Core

14. Structure of pulp:
Intercellular
substance
Pulp
Cells

15. Structure of pulp:
Cells
Odontoblasts
Fibroblasts
Immunocompetent
cells
Macrophages
Undifferentiated
ectomesenchymal cells

16. Odontoblasts:
 Second most prominent cells of pulp
 palisade pattern of arrangement in the
crown of the mature tooth
 Constant location adjacent to the
predentin-odontogenic zone of the
pulp
 Cell body in pulp & cell processes in the
dentinal tubules
 Tall columnar in crown, cuboidal in
middle of root & flat spindle shaped near
the apex of tooth

18. Microvasculature of dental pulp:

20. Odontoblasts:
Diameter -5-7micronm
Length-25-40micronm
Pulp-dentine interface-59,000-76,000 per
square millimeter in coronaldentin with less in
root
Active cell-elongated ,basally placed nucleus &
a basophilic cytoplasm
Resting cell-stubby,little cytoplasm &
haematoxyphilic nucleus
Transitional stage-intermediate beteen active
& resting stage

21. Odontoblasts:
 Undergo apoptotic cell death –shown by
marker bcl-2
 Release interleukin -8
 Nitric oxide synthetase have been
identified in odontoblasts

22. Fibroblasts:
 Cells occurring in greatest numbers
in the pulp
 More in number in the coronal
portion of pulp where they form the
cell-rich zone
 Form &maintain the pulp matrix,
which consists of collagen & ground
substance

23. Fibroblasts:
 They function in collagen fiber
formation
 In young pulp the cells divide & are
active in protein synthesis
 In older pulp they appear rounded
or spindle shaped with short
processes & exhibit fewer
intracellular organelles –fibrocytes

24. Fibroblasts:
Immature pulp - cellular elements
predominate
Mature pulp - fibrous components
predominate
Dual function; In addition to
forming the pulp matrix, capable of
ingesting &degrading the same
matrix

25. Fibroblasts….
 Secrete angiogenic factors like FGF-2
& VEGF
 Secrete colony stimulating factor
 In cell culture on stimulation form
mineralized tissue

27. Macrophages
 Oval or spindle shaped
 Macrophages are present in the normal
dental pulp & are more dense around the
blood vessels of the inner pulp & around
the odontoblast layer

28. Dendritic cells:
 Bone marrow- derived, antigen
presenting dendrite cells are found
in & around the odontoblast layer in
nonerupted teeth & in erupted teeth
beneath the odontoblast layer
 Function is similar to Langerhans
cells in that they capture & present
foreign antigen to the T cells

29. Dendritic cells:
 Participate in immunosurveillance
& increase in number in carious
teeth
 Dendritic cells & macrophages
constitute some 8% of the total
cell population, with dendritic
cells exceeding macrophages

30. Undifferentiated
ectomesenchymal cells
 Totipotent cell
 Depending upon the stimulus these
cells may give rise to odontoblasts ,
fibroblasts or macrophages.
 Represent the pool from which
connective tissue cells of the pulp are
derived

31. Matrix & ground substance
 Collagen-typeI & typeIII
 Ground substance composed of
glycosaminoglycans, glycoproteins & water
 Ground substance lend support to the cells of
the pulp& also serve as transport medium of
nutrients from the blood vessels to the cells &
transport of metabolites from cells to blood
vessels

32. Pulpal stem cells
 Migrate to the site of injured
odontoblasts & produce dentin
 TGF beta 1 & BMP-2 involved in the
migration of stem cells
 Pluripotent-adipocytes & neural cells

33. Pulpal stem cells
 Produce dentinogenesis &
osteogenesis
 Dentin sialoprotein present
 Dentonin stimulate dental pulp stem
cell
 Pulp tisue of 3rd molars - viable after
cryopreservation

34. Functions of pulp
1. Inductive: interact with oral
epithelial cells leading to
differentiation of dental lamina &
enamel organ formation
2. Formative: formation of dentin
3. Sensory: sensation of tooth is felt
through the nerves of the pulp

35. Functions of pulp
4. Nutritive: supplies nutrition to the
dentin through blood vessels &
odontoblastic processes & maintain the
vitality of tooth
5. Defensive or reparative: protects it
self & vitality of the tooth by producing
reparative dentin

36. Blood vessels of the dental pulp:
 Supply oxygen & nutrients where they are
most needed during dentinogenesis
 Pulpal blood flow-
1.in arterioles-0.3to1mm/sec
2.In venules-approx.0.15mm/sec
3.In capillaries-approx.0.08mm/sec
 Arise from inferior or superior alveolar
artery

37. Blood vessels of the dental pulp
Vessels possess 3 layers:
1. Tunica intima-squamous or cuboid
cells
2. Tunica media-5microm thick&consists
of one to three layers of smooth muscle
cells
3. Tunica adventitia-made up of few
collagen fibres

38. Blood vessels of the dental pulp:
 Pericyte lies on the surface of vessels
 Arterio-venous shunts regulate blood flow
 Blood capillaries – 8-10microm in
diameter
 Fenestrated capillaries-rapid transport of
metabolites during dentinogenesis

41. Nerves of the dental pulp
 Nerves enter pulp through apical
foramen, along with afferent blood
vessels & together form the “neuro-
vascular bundle”
 Nerve bundles that enter the pulp
consists principally of sensory afferents of
the trigeminal nerve & sympathetic
branches from the superior cervical
ganglion

42. Nerves of the dental pulp
 In the crown there is a pronounced
plexus of nerves beneath the
odontoblasts, known as the plexus of
Raschkow – occupy the cell-
free zone of weil & can be demonstrated
in silver stained sections under light
microscope or by immunocytochemical
techniques
 In the root-no corresponding plexus

44. Nerves of the dental pulp
 Each bundle contains myelinated &
unmyelinated axons
 Myelinated axons loose myelin-as the
nerve ascend coronally
 Substance-P, 5-hydroxy tryptamine,
vasoactive peptide, somatostatin &
prostaglandins as well as acetycholine
& nor epinephrine –found throughout
pulp

45. Nerves of the dental pulp :
 Neuropeptides-- Calcitonin gene related
peptide (CGRP) & Substance-P→
potent vasodilators
 Nor-epinephrine & neuropeptide Y →
vasoconstrictors
 Substance-P → non receptive transmitter
 Somatostatin → act against it
 Pulp organs lack receptors for heat,
touch, pressure or chemicals

47. Regressive changes (aging)
 Fibrosis
• Accumulation of both diffuse fibrillar
components & bundles of collagen
fibers
• External trauma such as dental caries or
deep restorations causes localized
fibrosis or scarring effect
• Atherosclerotic plaques may appear in
pulpal vessels
• Calcifications are found that surround
vessels

48. Regressive changes (aging)
 Pulp stones (denticles):
• Nodular, calcified masses appearing in
either or both the coronal & root
portions of the pulp organ
• Asymptomatic, unless they impinge on
nerves or blood vessels
• Seen in functional as well as embedded
unerupted teeth

50. Regressive changes (aging)
Pulp stones
(denticles):
True
denticles
False
denticles

51. Pulp stones:
True denticles:
• Similar in structure to dentin
• Are rare, located close to the apical foramen
• Development is caused by the inclusion of
remnants of the epithelial root sheath within
the pulp
• These epithelial remnants induce the cells of
the pulp to differentiate into odontoblasts,
which then form the dentin masses called
true pulp stones

52. Pulp stones:
False denticles:
• Do not exhibit dentinal tubules
• Concentric layers of calcified tissue
• Some cases calcification sites appear
within a bundle of collagen fibers
• Phleboliths-serve as nidi for false
denticles
• All denticles begin as small nodules
but increase in size by incremental
growth on their surface

53. Pulp stones:

54. Pulp stones
(depending on their
relation to the
dentin of tooth)
Free
Attached
Embedded

56. Pulp stones:
 Free denticles:
entirely surrounded by pulp tissue
 Attached denticles:
partly fused with the dentin
 Embedded denticles:
entirely surrounded by dentin

57. Pulp stones:
 Incidence –
 66%of teeth-10-3oyears
 80% of teeth-30 & 50 years
 90%-over 50 years of ageFree
denticles:

58. Diffuse calcifications
 Irregular calcified deposits
following collagen fibre bundles or
blood vessels
 Found more in the root canal &
less in coronal area
 Surround blood vessels-dystrophic
calcification

59. Diffuse calcifications

60. Clinical considerations:
 Wide pulp chamber in the tooth of a
young person will make a deep cavity
preparation hazardous
 Dehydration cause pulpal damage
 Associated with trauma, the pulp
becomes transformed into granulation
tissue and the dentine commences to be
resorbed internally at the pulp-dentine
surface

61. Diseases of dental pulp
Etiology –
1. Dental caries
2. Tooth fracture – trauma
cracked tooth syndrome
3. Anachorectic pulpitis
- anachoresis – phenomenon by which blood borne
bacteria, dyes, pigments, metallic substances, foreign
products & other materials are attracted towards the
site of inflammation
- probable cause – increased capillary permeability in
particular area

62. 4. Chemical irritation – erosion
acidic restorative material
5. Thermal changes – polishing procedures
cavity preparation
tooth restored with
exothermic
restorative
material.
6. Galvanic currents
7. Periapical tissue – accessory canals
8. Aerodontalgia

63. Classification of
pulpitis
•Acute
•Chronic
•Both acute and chronic –
Partial or focal pulpitis
Total or generalised
•Closed pulpitis
•Open pulpitis

64. References
 Orban’s oral histology &embryology-12th
edition
 Ten Cate’s oral histology-7th edition
 Oral anatomy, histology and embryology;
Berkovitz, 3rd edition
 Essentials of oral histology &
embryology, 2rd edition, James k . avery

65. Thank you
Thank you