dental pulp

DENTAL PULP

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Dr. Madhu Billa I MDSDEPT OF CONSERVATIVE DENTISTRY AND ENDODONTICS SIBAR INSTITUTE OF DENTAL SCIENCES

Dr.MadhuBillaDr.MadhuBilla

CONTENTSCONTENTS Introduction Anatomy Structural organization of pulp Cells of pulp Extra-cellular matrix Circulation & Innervation of pulp Functions of pulp Pulp calcification Age changes Clinical significance

Dr.MadhuBillaDr.MadhuBilla 22

INTRODUCTIONINTRODUCTION

The Pulp is a soft mesenchymal connective The Pulp is a soft mesenchymal connective tissue that occupies pulp cavity in the central tissue that occupies pulp cavity in the central part of the teeth. part of the teeth.

It is a special organ because of its unique It is a special organ because of its unique environmentenvironment


FEATURES OF PULPFEATURES OF PULP

Enclosed within dentinEnclosed within dentin

Resembles embryonic connective tissueResembles embryonic connective tissue

Microcirculatory system with no collateral Microcirculatory system with no collateral systemsystem

Retains ability to form dentin throughout lifeRetains ability to form dentin throughout life


ANATOMY OF PULPANATOMY OF PULP

52 pulp organs – 32 + 2052 pulp organs – 32 + 20

Total pulp volume in permanent teeth is 0.38 Total pulp volume in permanent teeth is 0.38 cc. with mean being 0.02 cc.cc. with mean being 0.02 cc.

The pulp cavity is divided into coronal pulp The pulp cavity is divided into coronal pulp and radicular pulpand radicular pulp


CORONAL PULPCORONAL PULP

It is the pulp occupying the pulp chamber of the It is the pulp occupying the pulp chamber of the crown of the toothcrown of the toothIn young teeth it resembles the shape of the outer In young teeth it resembles the shape of the outer dentindentinIt has six surfaces: occlusal, mesial, distal, buccal, It has six surfaces: occlusal, mesial, distal, buccal, lingual and floorlingual and floor Pulp horns are projections into the cuspPulp horns are projections into the cuspThis pulp constricts at the cervical region where it This pulp constricts at the cervical region where it continues as the radicular pulpcontinues as the radicular pulp


RADICULAR PULPRADICULAR PULP It is the pulp occupying the pulp canals of the root of It is the pulp occupying the pulp canals of the root of the tooththe tooth

In the anterior tooth it is single and in the posterior In the anterior tooth it is single and in the posterior teeth it is multipleteeth it is multiple

It is more fibrous & whitish color, which protects the It is more fibrous & whitish color, which protects the neurovascular bundleneurovascular bundle

As age advances the width of the radicular pulp is As age advances the width of the radicular pulp is reduced, and so is the apical foramenreduced, and so is the apical foramen


APICAL FORAMENAPICAL FORAMEN It forms the portal of entry or exit for the It forms the portal of entry or exit for the contents of the pulpcontents of the pulp

Mean size:Mean size: Maxillary teeth – 0.4 mmMaxillary teeth – 0.4 mm Mandibular teeth – 0.3 mm Mandibular teeth – 0.3 mm

Migration or horizontal pressure causes the apex Migration or horizontal pressure causes the apex to tilt, changing the position of the apical foramento tilt, changing the position of the apical foramen


There may be 2-3 foramina separated by There may be 2-3 foramina separated by cementum or dentin- APICAL DELTA.cementum or dentin- APICAL DELTA.

Largest in palatal root of maxillary teeth and Largest in palatal root of maxillary teeth and distal root of mandibular teeth.distal root of mandibular teeth.

It is usually 0.5-0.75 mm It is usually 0.5-0.75 mm occlusal to the anatomic apex.occlusal to the anatomic apex.


ACCESSORY CANALACCESSORY CANAL Leading laterally from the radicular pulp into the Leading laterally from the radicular pulp into the periodontal tissue.periodontal tissue.

Present in the apical third of the root.Present in the apical third of the root.

Formed due to premature loss of HERS or when Formed due to premature loss of HERS or when developing root encounters a blood vessel.developing root encounters a blood vessel.

May also be present at the furcation region.May also be present at the furcation region.


ACCESSORY CANALSACCESSORY CANALS


CANAL CONFIGURATIONCANAL CONFIGURATION by Weine in 1982by Weine in 1982


VERTUCCI CLASSIFICATIONVERTUCCI CLASSIFICATION


DEVELOPMENTDEVELOPMENT

The primitive oral cavity or The primitive oral cavity or stomodeum, is lined by a stomodeum, is lined by a stratified squamous epithelium stratified squamous epithelium called as called as oral ectodermoral ectoderm..

During 6th week of the During 6th week of the intrauterine life or two to three intrauterine life or two to three weeks after the rupture of the weeks after the rupture of the buccopharyngeal membrane, buccopharyngeal membrane, basal cells of the oral ectoderm basal cells of the oral ectoderm in certain areas proliferate faster in certain areas proliferate faster than the adjacent cells and forms than the adjacent cells and forms dental laminadental lamina..

Bud stageBud stage

1414Dr.MadhuBillaDr.MadhuBilla

Early cap stage;Early cap stage;

Certain areas along the Certain areas along the dental lamina, dental lamina, ectodermal cells ectodermal cells multiply rapidly and multiply rapidly and forms knob like forms knob like structures called as structures called as enamel organs.enamel organs.

As cell proliferation As cell proliferation continues enamel organ continues enamel organ increases in size and increases in size and resembles a cap in shaperesembles a cap in shape


Late cap stage;Late cap stage;

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On the inside of the On the inside of the cap ectomesenchymal cap ectomesenchymal cells proliferate faster cells proliferate faster than surrounding than surrounding mesenchyme and mesenchyme and forms forms dental papillae.dental papillae.


Bell stageBell stage

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After the inner enamel After the inner enamel epithelium differentiates into epithelium differentiates into ameloblasts, the peripheral ameloblasts, the peripheral connective tissue cells of the connective tissue cells of the dental papillae differentiates dental papillae differentiates into odontoblasts and start into odontoblasts and start producing dentine.producing dentine.

It is at this time, when the It is at this time, when the first layer of dentine has first layer of dentine has formed that dental papillae is formed that dental papillae is the called the the called the dental pulpdental pulp


ZONES OF PULPZONES OF PULP

ODONTOBLAST LAYERODONTOBLAST LAYER

CELL-POOR ZONECELL-POOR ZONE

CELL-RICH ZONECELL-RICH ZONE

PULP PROPERPULP PROPER


ODONTOBLAST LAYERODONTOBLAST LAYER

Present next to predentin with odontoblastic Present next to predentin with odontoblastic process passing through predentin into dentinprocess passing through predentin into dentin

Contains nerve fibers(AContains nerve fibers(Aδδ), capillaries,dendritic ), capillaries,dendritic cellscellsIn the Coronal pulpIn the Coronal pulp– Cells tall columnar, palisadingCells tall columnar, palisading– Layers of 3-4 cellsLayers of 3-4 cells– More odontoblasts per unit areaMore odontoblasts per unit area


Cells in the mid-root region are cuboidal and Cells in the mid-root region are cuboidal and appear flattened at the apical region.appear flattened at the apical region.

No.of odontoblasts per unit area in the No.of odontoblasts per unit area in the radicular pulp is reduced.radicular pulp is reduced.

Neighbouring odontoblasts exhibit junction Neighbouring odontoblasts exhibit junction complexes.complexes.


CELL POOR ZONECELL POOR ZONE Present in coronal pulp next to odontoblast layer, Present in coronal pulp next to odontoblast layer, also called WEIL’S zonealso called WEIL’S zone

40µ wide & relatively free of cells40µ wide & relatively free of cells

Traversed byTraversed byblood vesselsblood vesselsunmyelinated nervesunmyelinated nervescytoplasmic process of fibroblastscytoplasmic process of fibroblasts


Nerve plexus of RashkowNerve plexus of Rashkow

Presence/ absence of this zone depends on the Presence/ absence of this zone depends on the functional statusfunctional status

Relatively diminished inRelatively diminished in

younger pulpyounger pulpolder pulpolder pulp


CELL RICH ZONECELL RICH ZONE

Present in subodontoblastic layerPresent in subodontoblastic layer

Prominent in coronal pulpProminent in coronal pulp

Contains more proportions of fibroblast than pulp Contains more proportions of fibroblast than pulp properproper

Also contains macrophages, dendritic cells and Also contains macrophages, dendritic cells and lymphocytes.lymphocytes.


PULP PROPERPULP PROPER

It is the central mass of the pulpIt is the central mass of the pulp

Contains larger blood vessels and nervesContains larger blood vessels and nerves

Pulpal cells and fibroblasts are also seenPulpal cells and fibroblasts are also seen


STRUCTURAL ORGANIZATION STRUCTURAL ORGANIZATION


Odontoblast cellsOdontoblast process

Dentin Pulp


CELLS OF PULPCELLS OF PULP

ODONTOBLASTSODONTOBLASTS

FIBROBLASTSFIBROBLASTS

UNDIFFERENTIATED CELLSUNDIFFERENTIATED CELLS

IMMUNOCOMPETENT CELLSIMMUNOCOMPETENT CELLS

MAST CELLSMAST CELLS


ODONTOBLASTODONTOBLASTHighly differentiated cells derived from neural crest cellsHighly differentiated cells derived from neural crest cells

4040μμ length and 5-7 length and 5-7μμ wide wide

During active phase, cells show increase in ER, golgi During active phase, cells show increase in ER, golgi apparatus & secretory vesiclesapparatus & secretory vesicles

After primary dentin formation dentin forming activity After primary dentin formation dentin forming activity slows down with decrease in no.of organellesslows down with decrease in no.of organelles


ODONTOBLASTIC PROCESSODONTOBLASTIC PROCESS

It is a direct extention from cell body into the It is a direct extention from cell body into the dentinal tubuledentinal tubule

Diameter 3-4Diameter 3-4μμ, no cell organelles, no cell organelles

Has well developed cytoskeleton with Has well developed cytoskeleton with microfilaments & microtubules. Mainly microfilaments & microtubules. Mainly composed of protein- tubulin, actin and vimentin.composed of protein- tubulin, actin and vimentin.


JUNCTIONAL COMPLEXJUNCTIONAL COMPLEX

Neighbouring odontoblasts exhibit a series of Neighbouring odontoblasts exhibit a series of junctional complexesjunctional complexes

They promote cell to cell adhesion and play a They promote cell to cell adhesion and play a role in maintaining polarity of odontoblasts.role in maintaining polarity of odontoblasts.


Junctional complexes have been classified by Seltzer Junctional complexes have been classified by Seltzer and Bender as. and Bender as.

Impermeable junctions/ zona occludensImpermeable junctions/ zona occludens- The tight - The tight junction, or zona occludens, is so classified because of junction, or zona occludens, is so classified because of the fusion of adjacent plasma membranes.the fusion of adjacent plasma membranes.

Adhering junctions/ zona adherensAdhering junctions/ zona adherens: where a gap of : where a gap of 200-300A is seen. Under light microscopy, adhering 200-300A is seen. Under light microscopy, adhering junctions were referred to as intercellular bridges. junctions were referred to as intercellular bridges.


Communicating junctions/ gap junctionCommunicating junctions/ gap junction: : where a gap of 10-20A is seen. Communicating where a gap of 10-20A is seen. Communicating junctions, or gap junctions (nexus-type junctions, or gap junctions (nexus-type junctions), are sites of cell-to-cell junctions), are sites of cell-to-cell communication between adjacent odontoblasts communication between adjacent odontoblasts and between odontoblasts and fibroblasts of the and between odontoblasts and fibroblasts of the subodontoblastic layer. subodontoblastic layer.


JUNCTIONAL COMPLEXESJUNCTIONAL COMPLEXES


FUNCTIONS OF FUNCTIONS OF ODONTOBLASTSODONTOBLASTS

Synthesis of organic matrixSynthesis of organic matrix

Synthesis of non collagenous substances like Synthesis of non collagenous substances like sialoprotein, phosphophoryn, osteocalcin, sialoprotein, phosphophoryn, osteocalcin, osteonectin& osteopontinosteonectin& osteopontin

Intracellular accumulation of calciumIntracellular accumulation of calcium

Degradation of organic matrixDegradation of organic matrix


FIBROBLASTSFIBROBLASTSMaximum in number and have the capacity to Maximum in number and have the capacity to synthesise and maintain connective tissue matrix.synthesise and maintain connective tissue matrix.Main functionsMain functions synthesise type I & type III collagensynthesise type I & type III collagen synthesise non-collogenous protein synthesise non-collogenous protein matrix- proteoglycans & GAGsmatrix- proteoglycans & GAGsSynthetic cells have branched cytoplasmic Synthetic cells have branched cytoplasmic extentions with nucleus at one end of the cell. extentions with nucleus at one end of the cell. Common in young pulpCommon in young pulp


Also have the capability of ingesting and Also have the capability of ingesting and degrading the same matrix. Thus these cells degrading the same matrix. Thus these cells have dual function with pathways for both have dual function with pathways for both synthesis and degradation of small size.synthesis and degradation of small size.They play important role in inflammation and They play important role in inflammation and healinghealingThey release inflammatory mediators They release inflammatory mediators cytokines and growth factors cytokines and growth factors


FIBROBLASTFIBROBLAST


UNDIFFERENTIATED UNDIFFERENTIATED MESENCHYMEMESENCHYME

These mesenchymal cells are distributed through These mesenchymal cells are distributed through out the pulp, frequently around the perivascular out the pulp, frequently around the perivascular areaareaThey are stellate shaped with a high nucleus : They are stellate shaped with a high nucleus : cytoplasmic ratiocytoplasmic ratioUnder adequate stimulus they may differentiate Under adequate stimulus they may differentiate into odontoblast or fibroblast.into odontoblast or fibroblast.In older pulp, their number and ability to In older pulp, their number and ability to differentiate comes downdifferentiate comes down


Appear larger than fibroblasts and are Appear larger than fibroblasts and are polyhedral in shapepolyhedral in shapeFound along the pulp vessels in cell rich zone Found along the pulp vessels in cell rich zone and scattered throught out the central pulpand scattered throught out the central pulpThese are mainly totipotent cells and and when These are mainly totipotent cells and and when need arises they may become need arises they may become odontoblasts ,fibroblasts or macrophages odontoblasts ,fibroblasts or macrophages


IMMUNOCOMPETENT CELLSIMMUNOCOMPETENT CELLS

They play a major role local inflammation and They play a major role local inflammation and immunity.immunity.They are recruited from blood stream & remain as They are recruited from blood stream & remain as transient inhabitants in pulptransient inhabitants in pulpThese cells areThese cells areLymhpocytesLymhpocytesMacrophagesMacrophagesDendritic cellsDendritic cellsMast cellsMast cells


LYMPHOCYTES IN PULPLYMPHOCYTES IN PULP

Present along the walls of blood vesselsPresent along the walls of blood vessels

CD8+ T lymphocytes > CD4+ T lymphocytes, CD8+ T lymphocytes > CD4+ T lymphocytes, B lymphocytes are very rare.B lymphocytes are very rare.

Involved in initial immunodefenseInvolved in initial immunodefense

Plasma cells may be present in coronal pulpPlasma cells may be present in coronal pulp


MACROPHAGES IN PULPMACROPHAGES IN PULP

Described as histiocytesDescribed as histiocytes

Located close to blood vesselLocated close to blood vessel

Have several phenotypesHave several phenotypes

They express varying combinations of several They express varying combinations of several macrophage associated antigens and so help in T macrophage associated antigens and so help in T lymphocyte activationlymphocyte activation


MACROPHAGES MACROPHAGES

Dark staining nucleus with cytoplasmic Dark staining nucleus with cytoplasmic granulesgranules


DENDRITIC CELLSDENDRITIC CELLS

Discrete populations of hematopoetically derived Discrete populations of hematopoetically derived leucocytesleucocytesCharacterised by Characterised by ▪ ▪ peculiar dendritic morphologypeculiar dendritic morphology ▪ ▪ expression of high amount of expression of high amount of class II MHC class II MHC moleculesmolecules ▪ ▪ high motilityhigh motility ▪ ▪ capacity of antigen presentation capacity of antigen presentation to T to T lymphocyteslymphocytes


MAST CELLSMAST CELLS

Occur in small groups in relation to blood Occur in small groups in relation to blood vesselsvessels

Present only during pulpal inflammationPresent only during pulpal inflammation

Cytoplasmic granules of these cells containCytoplasmic granules of these cells contain▪▪Heparin- anticoagulantHeparin- anticoagulant▪▪Histamine- inflammatory mediatorHistamine- inflammatory mediator


EXTRACELLULAR MATRIXEXTRACELLULAR MATRIX

Connective tissue fibersConnective tissue fibers▪ ▪ CollagenCollagen▪ ▪ ElastinElastin▪ ▪ FibronectinFibronectinGround substanceGround substance▪ ▪ ProteoglycansProteoglycans▪ ▪ GlycosaminoglycansGlycosaminoglycansBasement membraneBasement membrane


COLLAGENCOLLAGENExtra cellular structural protein, major constituent of Extra cellular structural protein, major constituent of connective tissueconnective tissue

It has a triple helical domain, formed by 3 It has a triple helical domain, formed by 3 polypeptide chains(polypeptide chains(ααchains) bound by hydrogen chains) bound by hydrogen bonds & hydrophobic interactionbonds & hydrophobic interaction

Fibrils display characteristic striation at intervals of Fibrils display characteristic striation at intervals of 64nm. Hallmark for identification of collagen fibrils.64nm. Hallmark for identification of collagen fibrils.


COLLEGEN FIBRECOLLEGEN FIBRE


Type I:▪present as thick striated fibrils ▪responsible for pulp architectureType III:▪thinner fibrils, mainly distributed in cell free & cell rich zones▪contributes to the elasticity of pulpType IV:▪present along the basement membrane of blood vesselsType V & VI:▪seen to form dense meshwork of thin micro fibrils through out the stroma


COLLAGEN FIBRESCOLLAGEN FIBRES

Seen in relation with fibroblastsSeen in relation with fibroblastsDr.MadhuBillaDr.MadhuBilla 5050

Collagen turnover is maintained by pulp fibroblasts

During bacterial infection & inflammation, collagenolytic activity is accelerated following collagenase produced by bacteria, PMN & fibroblasts

Collagen synthesis is accelerated during reparative dentin formation.Dr.MadhuBillaDr.MadhuBilla 5151

ELASTIC FIBERELASTIC FIBER

Elastin molecules form the unit structure of Elastin molecules form the unit structure of Elastic fibersElastic fibersThese elastin molecules join to form a random These elastin molecules join to form a random coil structurecoil structureThis has the ability to expand and contract like This has the ability to expand and contract like a rubber band.a rubber band.


Elastic fibers are first formed in bundles of thin micro filaments called Oxytalan fibers

Elastin is then deposited inbetween oytalan fibers to form elastic fibers.

Always associated with larger blood vessels


FIBRONECTINFIBRONECTINIt is a multifunctional stromal glycoprotein that exists asIt is a multifunctional stromal glycoprotein that exists as

• • a circulatory plasma proteina circulatory plasma protein • • a protein that attaches to cellsa protein that attaches to cells • • insoluble fibrils forming a part of the extra cellular insoluble fibrils forming a part of the extra cellular

matrix matrix It plays a role in cell-cell & cell-matrix adhesion It plays a role in cell-cell & cell-matrix adhesion Has a major effect on the proliferation, differentiation & Has a major effect on the proliferation, differentiation & organization of cellsorganization of cells


GROUND SUBSTANCEGROUND SUBSTANCE

It is a structureless mass, gel-like consistency, makes It is a structureless mass, gel-like consistency, makes up the bulk of the pulpup the bulk of the pulp

Consists complexes of proteins, carbohydrate and Consists complexes of proteins, carbohydrate and water.water.

Broadly classified asBroadly classified asGlycoaminoglycansGlycoaminoglycansProteoglycansProteoglycans


GLYCOSAMINOGLYCANSGLYCOSAMINOGLYCANSGAG are branched polymers of glucosamine & galactoseamine, GAG are branched polymers of glucosamine & galactoseamine, along with ester sulfate groups, uronic acid & carboxyl groupalong with ester sulfate groups, uronic acid & carboxyl group4 main types:4 main types:Chondroitin sulphate/dermatan sulphateChondroitin sulphate/dermatan sulphateKeratin sulphateKeratin sulphateHeparin sulphateHeparin sulphateHyaluronic acid (non-sulphated)Hyaluronic acid (non-sulphated)GAG found in pulp is mainly chondroitin sulphate, dermatan GAG found in pulp is mainly chondroitin sulphate, dermatan sulphate & hyaluronic acidsulphate & hyaluronic acid


PROTEOGLYCANSPROTEOGLYCANS

Proteoglycans consists of a central protein core with Proteoglycans consists of a central protein core with side chains of GAGsside chains of GAGs

Due to presence of various structural groups of GAG, Due to presence of various structural groups of GAG, proteoglycans are hydrophilic & act as polyanionsproteoglycans are hydrophilic & act as polyanions

Thus proteoglycans carry high –ve charge that prevent Thus proteoglycans carry high –ve charge that prevent diffusion of larger molecules but attract cationic diffusion of larger molecules but attract cationic material.material.


ROLE IN PULPROLE IN PULP

During dentinogenesis, the ground substance show During dentinogenesis, the ground substance show affinity for collagen and influence fibrinogenesisaffinity for collagen and influence fibrinogenesis

Chondroitin sulfate has strong capacity to bind with Chondroitin sulfate has strong capacity to bind with calcium and help in mineralisationcalcium and help in mineralisation

Decorin is suggested to be synthesized by Decorin is suggested to be synthesized by odontoblasts and may play a role in mineral odontoblasts and may play a role in mineral nucleationnucleation


BASEMENT MEMBRANEBASEMENT MEMBRANE

It is a sheet like arrangement of extra cellular It is a sheet like arrangement of extra cellular protein matrix at the epithelial-mesenchymal protein matrix at the epithelial-mesenchymal interfaceinterfaceComposed of 2 layersComposed of 2 layers

lamina densa - electron denselamina densa - electron dense lamina lucida - electrolucentlamina lucida - electrolucent

Basement membrane is a product of Basement membrane is a product of connective tissue and epitheliumconnective tissue and epithelium


1-4µm wide, relatively cell free1-4µm wide, relatively cell freeUltrastructurally it is also called as basal lamina, Ultrastructurally it is also called as basal lamina, but it is not just a membrane but but a basal but it is not just a membrane but but a basal complex consisting of lamina and fibrescomplex consisting of lamina and fibresLamina densa contains type IV collagen coated Lamina densa contains type IV collagen coated with heparin sulphate and appears as chicken wire with heparin sulphate and appears as chicken wire configurationconfigurationAnchoring fibrils which contain type VII collagen Anchoring fibrils which contain type VII collagen are inserted into lamina densaare inserted into lamina densa


FUNCTIONS:FUNCTIONS:▪ ▪ Act as sieve between epithelium & Act as sieve between epithelium & connective tissueconnective tissue▪ ▪ Helps in organisation & differentiation by Helps in organisation & differentiation by enabling interactions between extracellular enabling interactions between extracellular molecules & cell surface receptorsmolecules & cell surface receptors


CIRCULATION OF THE PULPCIRCULATION OF THE PULP

Pulp organ is extensively vascularised with blood Pulp organ is extensively vascularised with blood vessels arising from superior & inferior alveolar vessels arising from superior & inferior alveolar arteries.arteries.

Pulp has a micro circulatory system which lacks Pulp has a micro circulatory system which lacks true arteries & veins.true arteries & veins.

The largest vessels are arterioles & venules which The largest vessels are arterioles & venules which regulate the local interstitial environment.regulate the local interstitial environment.


PULP VASCULATUREPULP VASCULATURE


Pulpal blood flow is more rapid than in most Pulpal blood flow is more rapid than in most areas of bodythis is perhaps attributable to the areas of bodythis is perhaps attributable to the fact that pulpal pressure is highest of body fact that pulpal pressure is highest of body tissuestissuesFlow of blood in arterioles- 0.3-1mm/sec in Flow of blood in arterioles- 0.3-1mm/sec in venules 0.15mm/sec and in capillaries venules 0.15mm/sec and in capillaries 0.08mm/sec0.08mm/sec


Vessles consists of 3 layersVessles consists of 3 layers• tunica intima: consists of squamous or cuboidal tunica intima: consists of squamous or cuboidal endothelial cellsendothelial cells•Tunica media: 5µ thick consists of smooth muscle Tunica media: 5µ thick consists of smooth muscle cells, ocassionally the endothelial cell wall is in cells, ocassionally the endothelial cell wall is in contact with muscle cells which is termed contact with muscle cells which is termed myoendothelial junctionmyoendothelial junction•Tunica adventitia: made of collagen fibres forming Tunica adventitia: made of collagen fibres forming a loose network around larger arteriesa loose network around larger arteries


CAPILLARIES:•Function as exchange vessels regulating the transport or diffusion of substances between blood and local interstitial tissue elements• They consists of single layer of endothelium surrounded by basement membrane• Capillary pressure: 35 mmHg• Capillary wall is 0.5μ thick & acts as semi permeable membrane


VENULES:

• Collecting venules receive pulpal blood flow

from the capillaries & transfer it to the venules

• Arterio-venous anastomosis permits direct

shunting from arterioles to venules

• Venular pressure-19mmHg


LYMPHATICSLYMPHATICSLymphatic vessels are formed from a fine meshwork of small, thin walled lymph capillaries

They start as blind openings near Weil’s zone & odontoblastic layer

The larger lymphatic vessels run along the blood vessels & nerves


More numerous in in central part of pulp than More numerous in in central part of pulp than in peripheral areasin peripheral areasThose draining the anterior teeth pass to Those draining the anterior teeth pass to submental lymphnodes and those draining the submental lymphnodes and those draining the posterior teeth pass to submandibular and deep posterior teeth pass to submandibular and deep cervical lymphnodes.cervical lymphnodes.


INNERVATIONINNERVATION

Principle role is to help in conscious recognition of irritants to the pulp,

Dental pulp contains sensory and motor fibers to fulfill the vasomotor and defense function

Sensory afferent fibers are branches of maxillary & mandibular divisions of trigeminal nerve.


After entering the foramen, they arborize. Larger fibers are present in the central zone. They divide as they proceed peripherally and coronally.

Subjacent to the cell rich zone, the nerves branch extensively forming a parietal layer of nerves- NERVE PLEXUS OF RASHKOW. This layer contains both Aδ and C fibers

.In the cell free zone, they form a rich network responsible for pain.


TYPES OF NERVE FIBRESTYPES OF NERVE FIBRES


NERVE FIBERSNERVE FIBERSA-fibers C-fibers

•Myelinated •Unmyelinated•20% •80%

•Diameter – 2-5µm •0.3-1.2µm

•Conduction velocity 6-30m/sec

• 0.4-2m/sec

•Distributed in odontoblastic & subodontoblastic zones & associated with Dental pain.

•Distributed throughout the pulp tissue & associated with pain due to pulp damage.

•Impulses are intercepted as sharp & prickling pain.

•Conduct throbbing & aching pain.

•Low threshold of excitability. •High threshold of excitability.7373Dr.MadhuBillaDr.MadhuBilla

FUNCTIONS OF DENTAL FUNCTIONS OF DENTAL PULPPULP

INDUCTIVE

FORMATIVE

NUTRITIVE

PROTECTIVE

DEFENSE


INDUCTIVEINDUCTIVE

It induces epithelial differentiation into dental lamina & enamel organ

It also induces the enamel organ to become a particular type of tooth


FORMATIVEFORMATIVE

Pulp induces dentin formation that surrounds & protects the pulp

This involves formation of primary & secondary dentin

The primary dentin is tubular & regularly arranged. Formed before root closure


NUTRITIVENUTRITIVE

Dental pulp maintains the vitality of dentin by providing O2 & nutrients to the odontoblasts

Also provides continuing source of dentinal fluid

Nutrition made possible by rich peripheral capillary network


PROTECTIVEPROTECTIVE

Pulp helps in recognition of stimuli like heat, cold, pressure, chemicals by way of sensory nerve fibres

Vasomotor innervation controls the muscular wall of blood vessels. This regulates the blood volume & rate of blood flow & hence the intrapulpal pressure


DEFENSEDEFENSE

When irritated or injured the pulp will respond by

1. Dentinal pain

2. Smear layer formation

3. Tubular sclerosis

4. Irritation dentin formation

5. Inflammation of subjacent connective tissue


REGRESSIVE CHANGESREGRESSIVE CHANGES(AGING)(AGING)


Cell changesCell changes-in addition to appearance of fewer cells in the in addition to appearance of fewer cells in the aging pulp the cells are characterized by decrease aging pulp the cells are characterized by decrease in size and number of cytoplasmic organellesin size and number of cytoplasmic organellesFibrosis:In aging pulp accumulation of both diffuse fibrillary components and bundles of collagen fibres usually appear


PULP CALCIFICATIONSPULP CALCIFICATIONSIt is a common occurrence with incidence of 50% It is a common occurrence with incidence of 50% of all teethof all teethSize may range from microscopic particle to Size may range from microscopic particle to stones that may occlude the pulp chamberstones that may occlude the pulp chamberComposed of carbonated hydroxyapitite crystalsComposed of carbonated hydroxyapitite crystalsPulp calcification may bePulp calcification may bePulp stonesPulp stonesDiffuse calcificationsDiffuse calcificationsCalcific MetamorphosisCalcific Metamorphosis


Pulp denticles, are classified as - Pulp denticles, are classified as -

According to structure:According to structure:1)True denticles1)True denticles2)False denticles2)False denticles3)Diffuse calcifications3)Diffuse calcificationsAccording to location:According to location:1)Free- entirely surrounded by pulp 1)Free- entirely surrounded by pulp 2)Attached-partially fused with dentine.2)Attached-partially fused with dentine.3)Embeded- entirely surrounded by dentine 3)Embeded- entirely surrounded by dentine

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Goga, R., Chandler, N. P. and Oginni, A. O. (2008), Pulp stones: a review. International Endodontic Journal, 41: 457–468


TRUE DENTICLESTRUE DENTICLESRound or ovoid with smooth surfaces and concentric Round or ovoid with smooth surfaces and concentric lamellae.lamellae.

Appear to grow by addition of collagen on their Appear to grow by addition of collagen on their surfacesurface

Believed to be formed around HERSBelieved to be formed around HERS

They contain dentinal tubules, and are frequently They contain dentinal tubules, and are frequently found near root apex.found near root apex.


FALSE DENTICLESFALSE DENTICLES

They have a rough surface no particular shape & laminations

Grow due to mineralization of preformed collagen fibers

Cause of such calcification may be, degenerating cells, blood thrombi or collagen fibrils all of which form a nidi for calcification

Usually present in the pulp chamber.Dr.MadhuBillaDr.MadhuBilla 8585

True denticles are not dystrophic structures, since they True denticles are not dystrophic structures, since they are composed of dentin and formed by detached are composed of dentin and formed by detached dentinoblasts or fragments of Hertwig's sheath, which dentinoblasts or fragments of Hertwig's sheath, which may stimulate undifferentiated cells to assume may stimulate undifferentiated cells to assume dentinoblastic activity. dentinoblastic activity.

False denticles are formed when a degenerating tissue False denticles are formed when a degenerating tissue structure serves as a nidus for deposition of concentric structure serves as a nidus for deposition of concentric layers of calcified tissue. layers of calcified tissue.

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CalcificationsCalcifications

These are found in both healthy and aging These are found in both healthy and aging pulps, although their incidence increases with agepulps, although their incidence increases with age


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Dystrophic calcification is a deposition of calcium salts in

dead or degenerating tissue. It may be due to local

alkalinity of the destroyed tissue that attracts the salts.

This mineralization thus may occur in minute areas of

young pulp tissue affected by minor circulatory

disturbance.

Diffuse calcifications are generally observed in the root

canal but may also be seen in the pulp chamber.

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AGE CHANGESAGE CHANGES

Formation of secondary dentin through out life, Formation of secondary dentin through out life, reduces the size of the pulp chamber & root canalsreduces the size of the pulp chamber & root canals

Decrease in cellularityDecrease in cellularity

Odontoblast decrease in size & number, & may Odontoblast decrease in size & number, & may disappear in certain areas. Especially on pulpal disappear in certain areas. Especially on pulpal floor over bifurcation & trifurcationfloor over bifurcation & trifurcation


Increase in number & thickness in collagen Increase in number & thickness in collagen fibers particularly in radicular pulp fibers particularly in radicular pulp Reduction in the nerve fibers & blood vesselsReduction in the nerve fibers & blood vesselsIncrease resistance of pulp against action of Increase resistance of pulp against action of enzymesenzymesIn dentin, In dentin,

Increase in peritubular dentinIncrease in peritubular dentinDentinal sclerosis, reduces permeability Dentinal sclerosis, reduces permeability

Increase in dead tractsIncrease in dead tracts


CLINICAL CONSIDERATIONSCLINICAL CONSIDERATIONS

Anatomic considerationsAnatomic considerations

Effect of dental materials on pulpEffect of dental materials on pulp

Effect of Operative Procedures Effect of Operative Procedures

Effects subsequent to restorationEffects subsequent to restoration


ANATOMIC ANATOMIC CONSIDERATIONSCONSIDERATIONS

Dimensions of tooth preparation are dictated Dimensions of tooth preparation are dictated by pulpal morphologyby pulpal morphology Young permanent teeth have wider pulp Young permanent teeth have wider pulp chamber and so do deciduous teethchamber and so do deciduous teeth Cervical horns present in maxillary molars Cervical horns present in maxillary molars complicate class V restoration and endodontic complicate class V restoration and endodontic treatmenttreatment developmental disturbances and advanced agedevelopmental disturbances and advanced age


ANATOMIC ANATOMIC CONSIDERATIONSCONSIDERATIONS


EFFECT OF DENTAL EFFECT OF DENTAL MATERIALS ON PULPMATERIALS ON PULP

Amalgam corrosion products inhibit cell growthhigh thermal conductivity Glass ionomerswell tolerated by pulpRMGI used for direct pulp capping Zinc Oxide Eugenolhas an anti-bacterial and anodyne effecthigher concentrations leads to chronic inflammation & thrombosis of vessels


Zinc Phosphatestrong to moderate cyto-toxic reactions is due to leeching of zinc ions and low pH Resin adhesive systemsThe formation of hybrid layer secures the enamel-resin interface with a continuous seal which acts as a biometric barrier Dentin bonding agents monomer molecules reaching the pulp can irritate the pulp causing inflammation


EFFECTIVE DEPTHEFFECTIVE DEPTH

The effective depth is the area of minimum The effective depth is the area of minimum thickness of sound dentin separating the pulpal thickness of sound dentin separating the pulpal tissue from the carious lesiontissue from the carious lesion

2mm or more, healthy reparative reaction2mm or more, healthy reparative reaction 0.8 – 2mm, unhealthy reparative reation0.8 – 2mm, unhealthy reparative reation 0.3 – 0.8mm, pulpal destructon0.3 – 0.8mm, pulpal destructon (Marzouk, 2006)(Marzouk, 2006)


CONCLUSIONCONCLUSION

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Pulp to the tooth is like heart to the body, providing constant source of nutrition to maintain the vitality of the tooth. Every precaution should be taken to preserve the vitality of the tooth.

The preservation of the healthy pulp during operating procedure and successful management in cases of diseases are two most important challenge to the clinicians


REFERENCESREFERENCES

GROSSMANS ENDODONTIC PRACTICEGROSSMANS ENDODONTIC PRACTICE S.COHENS PATHWAYS OF PULP-9S.COHENS PATHWAYS OF PULP-9THTH EDITION EDITION ORBANS ORAL HISTOLOGYORBANS ORAL HISTOLOGY TEN CATES ORAL HISTOLOGYTEN CATES ORAL HISTOLOGY SELZERS AND BENDERS THE DENTAL PULPSELZERS AND BENDERS THE DENTAL PULP R. INOKIS DYNAMIC ASPECTS OF DENTAL PULPR. INOKIS DYNAMIC ASPECTS OF DENTAL PULP FRANKLIN S. WEINE – 5FRANKLIN S. WEINE – 5THTH EDITION EDITION


THANK YOU….THANK YOU….


dental pulp

Health & Medicine