Anatomy and Physiology of Dental

Pulp

Jarin PaphangkorakitDepartment of Oral Biology

Faculty of DentistryKhon Kaen University

jarin@kku.ac.th

551 201 Oral Anatomy and Physiology I

References:Nanci A. Dentin-Pulp Complex. In: Ten Cate's Oral Histology: Development, Structure, and Function. St. Louis: Mosby, 2003. Garant PR. Oral Cells and Tissues. Chicago:Quintessence, 2003.

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Objectives

• Formation of dentine (dentinogenesis)• Sensation (pain only?)• First line of defense to injuries and

infection of dentine• Tertiary dentine• Immuno-competent• Clearance of toxic substances

Functions of dental pulp

Components of d entalpulp

Cells + (extracellular) Matrix

Fiber Ground substance

• Collagen

• Elastin

Structural Adhesive

• Fibronectin

• Laminin

• HS

• DS

• CS

GAG Proteoglycan

• Decorin

• Versican

Components of dental pulp CELLS (odontoblast, fibroblast,

undifferentiated cell, macrophage, dendritic cell)

FIBERS AND GLYCOPROTEIN (collagen type I, III, no elastic fiber, fibronectin)

GROUND SUBSTANCES (glycosaminoglycans, chondroitin sulfate proteoglycan)

BLOOD VESSELS, NERVES, LYMPH VESSELS

• Maintain tissue’s physical properties and integrity

• Control of growth and development and repairs

• Control of cell migration

• Control of diffusion of macromolecules

Functions of pulpal extracellular matrix

Collagen in dental pulp

• Concentration varies from species to speci es, 3 2 % in human pulp.

• Higher content in the middle and apical pulp.

• Total collagen decreases with age.

• Interestingly high level of collagen type III. 43( %) : vascular content, tissue extensibility (cf.

Elastin)

• ii iiiii( . . ) .

Adhesive glycoproteins in dentalpulp

• Fibronectin found in predentine NOT mature

dentine.

• Fibronectin present in pulp and dental papilla.

• Fibroblasts synthesize pulpalfibronectin.

• Fibronectin is expressed during reparative dentinogenesi

s.

Immunoreactive fibronectin molecules detected along the border of predentine and between odontoblast (Yoshiba et al., 1994)

Glycosaminoglycans in dental pulp

• Chondroitinsulfate, der mat an sul f at e, hyal ur oni c aci d pr esent

• Amount of uronic acid decreases withage

• Total GAG decreases with reduced dent i nogeni c act i vi t y

• Decorin may involve in mineral nucl eat i on at t he mi ner al i zat i on f ront

Organization of cells in the pulp

tight junction

nerve terminals

Pulp vasculature

Pulp tissue is highly vascularized.

40-50 ml/min/100g

(Kim, 1985)

Dental pulp interstitial fluid (ISF) and exchange of substances between plasma and ISF. (* values from Tonder and Kvinnsland, 1983; Ciucchi

et al., 1995)

(5.5-10.3 mmHg*)

(43 mm Hg)

(20 mm Hg)

(35 mm Hg)

Hydrostatic pressure in dental

pulp

Approx. 1800 non myelinated +400 myelinated

Intradentinal nerves are mostly found in pulpal horns.

A-delta fibers - 230Conduction velocity

m/s iiiii iiiiiiiii ii iiiii iiiii iiii, iiiiiiiiii ii

hydr odynami c st i mul i Sensitive to ischemia Sharp pain

C fibers - 02Conduction velocity m/s iiiiii iiiiiiiii ii iiii i iiii iiii, iiii iiiiii ii iiiiii iiii

iii iii Sensitive to anesthetics iiii iiii

Types and properties of pulpal sensory nerve fibers

A-beta fibers Conduction velocity 30-70 m/s Very low threshold, non-noxious

sensation 50% of myelinated fibers in pulp Functions not fully known

Non-myelinated sympathetic fibers

iiiiiiiiii iiiiiiii 0-2 m/s Post-ganglionic fibers of

superior cervical ganglion Vasoconstriction

Possible mechanisms of dentine sensitivity

Hydrodynamic mechanism(Gysi, 1900; Brannstrom, 1963)

Pulp venules

STIMULATION

Increased pulp interstitial fluid

Increased pulp pressure

Increased tubular fluid flow

Release of inflammatory agents?

Increased blood viscosity and rbc

congestion in capillary bed

Increased A-V shunt blood flow

Outward dentinal fluid flow and aspiration of odontoblasts

CNS, Pain, Reflexes

Vasodilation, Increased permeability

Pulpal axonal reflex due to dentine stimulation

Without infection, Vascular changes couldbe resolved.

Without infection, Vascular changes couldbe resolved.

Axon reflex

SP, CGRP

Dentine

References Nanci A. Dentin-Pulp Complex. In: Ten

Cate's Oral Histology: Development, Structure, and Function. St. Louis: Mosby, 2003.

Garant PR. Oral Cells and Tissues. Chicago:Quintessence, 2003.

Synthesis of collagen and its assembly into fibrils and fiber

Some types (of 15) of known collagen

Type Molecular Tissue distribution

Fibril-forming I [1(I)]2 2(I) bone, skin, tendon, ligaments

(90%) of body collagen

II [1(II)]3 cartilage, intervertebral disc,

notochord, vitreous humor of eye

III [1(III)]3 skin, blood vessels, internal organs

V [1(V]2 2(V) as type I

XI [1(XI] 2(XI) 3(XI) as type II

Fibril-associated IX [1(IX] 2(IX) 3(IX) cartilage (with type II)

XII [1(XII)]3 tendon, ligaments (with some type I)

Network-forming IV [1(IV)]2 2(IV) basal laminae

VII [1(VII)]3 anchoring fibrils beneath stratified

squmous epithelia

RGD = - cell binding domain

The structure of a fibronectin dimer.

Structure of a GAG

Structure of proteoglycans

Aggrecan mechani calsuppor t(cartilage)

Betaglycan -binds TGF beta (cell surface*, matrix)

Decorin binds type I and (CNT) -TGF beta

Perlecan basal l ami nae (basal laminae)

-Syndecan 1 binds FGF (cell surface*)

iiiiiiii i ii iiiii iiiiiiiiiiii* =

Some k nown proteoglycans: