The document provides a detailed overview of dental pulp anatomy, including the composition of pulp cells such as odontoblasts and fibroblasts, their functions, and the structure of the pulp cavity. It distinguishes between various types of canals within the root and discusses the ultrastructure and functions of odontoblasts and defense cells like macrophages and lymphocytes. Additionally, it describes the extracellular matrix components and their roles in the dental pulp environment.

1. Dental Pulp
Mariam Khardziani DDM, TSU

2. PULP CAVITY

3. Pulp horns

4. Root canal
The root canal begins as a funnel-shaped canal
orifice, generally at or just apical to the cervical
line, and ends at the apical foramen (AF)
Root canal orifice
Apical foramen

5. Accesory canals
Furcation (chamber) canal
Lateral canal
Apical delta Δ
Apical third – 74%
Middle third – 11%
Cervical third – 15%

6. Accessory canals
According to the glossary of American Association of Endodontists,
lateral and accessory canals are differentiated as
 Lateral canal is a canal that is located at approximately at right
angles to main root canal
 Accessory canal is the one that branches off from main root canal,
usually in the apical region of the root.
 Apical deltas are multiple accessory canals that branch out from the
main canal at or near the root apex

7. Composition of the pulp
Cells
Odontoblasts
Fibroblasts
Mesenchymal stem cells
Defense cells
Antigen presenting cells
Macrophages
Lymphocytes
Extracellular matrix (ECM)
Fibers
Ground substance
Blood vessels
nerves

9. Pulp-dentin complex
• Pulp and dentin function as a unit
• The odontoblasts are located in the
periphery of the pulp tissue, with
extensions into the inner part of dentin.
• Dentin would not exist unless produced
by odontoblasts, and the dental pulp is
dependent upon the protection provided
by the dentin and enamel

10. Odontoblasts
 Outermost stratum of cells of the
pulp
 Odontoblasts are polarized: nuclei
towards the pulp, mitochondria
rich area towards the predentin
 They have cytoplasmic projection
– odontoblastic process
 Odontoblastic process continue
within the dentinal tubules

11. Ultrastructure of odontoblasts
 A large nucleus that may contain up to
four nucleoli
 The nucleus is situated at the basal end
of the cell
 Well-developed Golgi complex, centrally
located in the supranuclear cytoplasm
 Numerous mitochondria and ribosomes
 Prominent RER (rough endoplasmic
reticulum)

12. What does the odontoblasts synthesize?
• Type I collagen
• Type V collagen
• Proteoglycans
• Dentin sialoprotein
• Phosphophoryn (involved in mineralization)
• Alkaline phosphatase (involved in mineralization)
• Acid phosphatase (lysosomal enzyme, which is involved in digesting
the proteins from predentin)

14. Odontoblast process

15. Odontoblasts layers
Coronal pulp
Radicular pulp

16. Cell-poor zone
 Immediately subjacent to the odontoblast layer in the coronal pulp
 Approximately 40 μm in width
 So called cell-free layer of Weil
 Contains blood capillaries, unmyelinated nerve fibers, and the
slender cytoplasmic processes of fibroblasts

17. Cell-rich zone
 This stratum contains a relatively high proportion of fibroblasts
compared with the more central region of the pulp
 It is much more prominent in the coronal pulp than in the radicular
pulp
 Besides fibroblasts, the cell-rich zone contains a variable number of
immune cells like macrophages and dendritic cells but also
undifferentiated mesenchymal stem cells

18. Pulp proper
 central mass of the pulp
 loose connective tissue
 larger blood vessels
 nerves
 fibroblasts

19. Fibroblasts
 Most numerous cells of the pulp
 They are tissue specific
 Fibroblasts synthesize collagen type I and III, as well as proteoglycans and GAGs
 This cells also phagocytose and digest collagen

20. Defense cells

21. Macrophage
They are monocytes that have left the
bloodstream, entered the tissues, and
differentiated into various
subpopulations
A major subpopulation of
macrophages is active in endocytosis
and phagocytosis
 Functions of macrophages:
 Act as a scavengers
 Present the antigens to memory T
cells
 Produce signaling molecules: IL1, TNF,
growth factors…

22. Dendritic cells
• Accessory cells of immune system
• Similar cells to Langerhans cells in the epidermis and mucous
membrane
• They are antigen presenting cells
• In the normal pulp they are mostly
• Located in the periphery of the coronal pulp close to the predentin

23. Lymphocytes
In normal pulp T cells are
found, mostly T8 lymphocytes
(suppresors)
B lymphocytes are scarcely
found uninflamed pulp
Mast cells
 Mast cells are seldom found in the normal
pulp tissue
 They are routinely found in chronically
inflamed pulps.
 The granules of mast cells contain heparin,
an anticoagulant, and histamine

24. Pulpal interstitium (ECM)
 Interstitial fluid
 Interstitial matrix
• Major structural component – collagen
• The other components are proteoglycans, hyaluronan and elastic
fibers
Interstitium
Glycosaminoglycans (GAGs)

25. Extracellular matrix (ECM) = Ground
substance
In the pulp, the principal proteoglycans include:
 hyaluronic acid (strong affinity for water)
 dermatan sulfate
 heparan sulfate
 chondroitin sulfate (active during dentinogenesis)
 Ground substance also acts as a molecular sieve in that it excludes large
proteins
 Cell metabolites, nutrients, and wastes pass through the ground
substance between cells and blood vessels

26. Mariam.khardziani@tsu.ge