anatomy and physiology of dental pulp
TRANSCRIPT
Anatomy and Physiology of Dental
Pulp
Jarin PaphangkorakitDepartment of Oral Biology
Faculty of DentistryKhon Kaen University
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: