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DENTAL PULPDEPARTMENT OF PAEDODONTICS AND PREVENTIVE DENTISTRYC.K.S TEJA INSTITUTE OF DENTAL SCIENCES,TIRUPATIPREPARED BY : L. MAHESHWAR REDDY 1ST YEAR M.D.S

CONTENTS Introduction Embryology Anatomy Structural organization of pulp Cells of pulp Extra-cellular matrix Circulation of pulp Metabolism of pulp

Innervation of pulp

Functions of pulp

Pulp of deciduous teeth

Age changes

Clinical considerations

Recent advances

Conclusion

References

INTRODUCTION

DEFINITION: According to Cohen - the pulp is a soft tissue of mesenchymal origin residing within the pulp chamber and root canal of teeth.

SALIENT FEATURES

Maxillary (Cubic Centimeter)Mandibular (Cubic Centimeter)Central Incisor0.0120.006Lateral Incisor0.0110.007Canine0.0150.014First Premolar0.0180.015Second Premolar 0.0170.015First Molar 0.0680.053Second Molar0.0440.032Third Molar0.0230.031

DEVELOPMENT

ANATOMY OF PULPCORONAL PULPIt is the pulp occupying the pulp chamber of the crown of the tooth

RADICULAR PULPIt is the pulp occupying the pulp canals of the root of the tooth

APICAL FORAMEN

ACCESSORY CANAL

Structural Organization of pulp

DentinPredentinOdontoblasts layerCell free zoneCell rich zonePulp core

Histology of pulp Morphologic zones of pulp-

ODONTOBLAST LAYER

CELL-POOR ZONE

CELL-RICH ZONE

PULP PROPER

Odontoblastic layer

CELL FREE ZONECELL RICH ZONE

PULP COREThe pulp proper is the central mass of the pulp

It contains the larger blood vessels and nerves.

The connective tissue cells in this zone are fibroblasts, or pulpal cells.

Histological Structures of the PulpThe dental pulp is formed of specialize loose connective tissue contain : 1) Cellular elements : a. Formative cells : Odontoblast, Fibroblast . b. Progenitor cells : Undifferentiated mesenchymal cells c. Defensive cells : Macrophages, neutrophils, eosinophils, basophils, mast cells , plasma cells and Lymphocytes.

2) Fibrillar elements : a. collagen bundles b. fine collagen fiber3) Ground substance: Act as a medium to transport nutrients to cells and metabolites of the cell to the blood vessels. 4) Neurovascular elements : Blood vessels, nerves, lymph vessels

ODONTOBLASTSecond most common cells in the pulp.

Dentin

Pulp

Odontoblast processOdontoblast cells

ODONTOBLASTIC PROCESS

JUNCTIONAL COMPLEXES

b- Fibroblasts

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UNDIFFERENTIATED MESENCHYME

IMMUNOCOMPETENT CELLSThey play a major role in local inflammation and immunity.

They are recruited from blood stream & remain as transient inhabitants in pulp

These cells are -Lymhpocytes -Macrophages -Dendritic cells -Mast cells

A- Histiocyte ( macrophage ) :

B-Plasma cells:

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LYMPHOCYTES IN PULP

DENDRITIC CELLS

Eosinophils

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MAST CELLS

EXTRA CELLULAR MATRIX

FIBREGROUND SUBSTANCE

COLLAGEN ELASTINFIBRONECTINLAMILIN

GAGPR OTEOGLYCAN

Collagen fibers

Von kroff fibresCollagen has been described as having a unique arrangement in the peripheral pulp, these bundles of collagen are called Von kroff bundles.

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GROUND SUBSTANCEIt is a structureless mass, gel-like consistency, makes up the bulk of the pulp

Consists complexes of proteins, carbohydrate and water.

Broadly classified as a.Proteoglycans-

Functions of GAG- 1.Water retention 2. Ion binding & electrolyte distribution during mineralization (Bowness 1968). b. Glycoproteins Water- 90%

Maintain tissues physical properties and integrity Control of growth and development and repairs Control of cell migration Control of diffusion of macromoleculesFUNCTIONS OF PULPAL EXTRACELLULAR MATRIX

CIRCULATION OF THE PULPSystemic circulation:-

Pulp organ is extensively vascularised with blood vessels arising from internal maxillary artery

Internal maxillary artery Mandibuar artery pterygoid artery Pteygo-palatine artery

Inferior alveolar artery infraorbital artery posterior superior alveolar arteryDental incisive mental anterior superior alveolar branch artery artery molars, incisors lower lip incisors, bicuspids molars, bicuspidspremolars

Microcirculation:

Arterioles(50 diameter)Terminal arteriolesPrecapillariesMetarteriolesCapillaries (8)

SEM shows extensive arborization of capillaries from the metarterioles

CAPILLARIES:

Venules

LYMPHATICS

REGULATION OF PULPAL BLOOD FLOW

Neuronal regulationa. Sympathetic fibersb. Parasympathetic fibersc. Peptidergic afferent fibers

Endocrine & paracrine regulation

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INNERVATIONPrinciple role is to help in conscious recognition of irritants to the pulp, which gives the opportunity to have the problem corrected before irreversible effects can occur

Nerve fibers, mylinated & unmyelinated , enter the tooth through the apical foramen

Dental pulp

Sensory afferent fibers Motor nerves

Branches of maxillary & mandibular divisions of trigeminal nerve.Sympathetic division of autonomic nervous system

Plexus of Rashkow

Sympathetic Innervation

Sympathetic nerve fibers forming plexus around arterioles

Neuropeptides

They are proteins that have been associated with central & peripheral nervous system.Following are the neuropeptides demonstrated in nerves of dental pulp:Substance p 5 hydroxy tryptamineVasoactive intestinal peptideProstraglandinSomatostationAcetylcholineNorepiepheine

Nerve Plexus of Raschkow Sensory nerve fibers that originate from inferior and superior alveolar nerves innervate the odontoblastic layer of the pulp cavity. These nerves enter the tooth through the apical foramen as myelinated nerve bundles. They branch to form the subodontoblastic nerve plexus of Raschkow which is separated from the odontoblasts by a cell-free zone of Weil. In addition to the sensory nerves, sympathetic nerve bundles also enter the tooth to innervate blood vessels.

A, Odontoblasts; B, Cell-free zone of Weil; C, Nerve plexus of Raschkow

A-delta fibersConduction velocity 2-30 m/sLower thresholdInvolved in fast, sharp painStimulated by hydrodynamic stimuliSensitive to ischemiaSharp painC fibersConduction velocity 0-2 m/sHigher thresholdInvolved in slow, dull painStimulated by direct pulp damageSensitive to anestheticsDull painA-beta fibersConduction velocity 30-70 m/sVery low threshold, non-noxious sensation40% of myelinated fibers in pulpFunctions not fully known

Non-myelinated sympathetic fibersConduction velocity 0-2 m/sPost-ganglionic fibers of superior cervical ganglionVasoconstriction & Vasodilation.

Nerves in pulp

Dentin pulp complexDentin the most voluminous at mineralized connective tissue of the tooth forms the hard tissue portion of the dentin pulp complex where as dental pulp is a living soft connective tissue maintains the vitality of the dentin (Linde and Goldberg 1993, Torneck 1994)

Dentin contains multiple closely packed dentinal tubules in which the dentnal fluid and the cytoplasmic process of the cells that have formed the dentin, the odontblast are located(Torneck 1994)

The unity of dentin and pulp is responsible for formation and protection of the tooth

FUNCTIONS OF DENTAL PULPINDUCTIVEFORMATIVENUTRITIVEPROTECTIVEDEFENSE

PULP OF DECIDUOUS TEETH Anatomical differences-

DimensionsPulp chamberPulp horns Cervical constrictionsRoot canalsAccesory canalsApical foramen Histological differences-

Degree of cellularityVascularityInnervation

AGE CHANGESVarious age changes in pulp are- - Dimensional changes

- Cellular changes

- Pulpal fibrosis

- Calcifications

- Changes in vascularity

Age changes in the pulp The size of the pulp The apical foramen The cellular elements The bl. vessels & n. Vitality

Reticular atrophy: The total affect is the production of a lessened vitality of the pulp tissue and a lessened response to stimulation.

decreased

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Pulpal fibrosis

PULP CALCIFICATIONSIt is a common occurrence with incidence of 50% of all teeth

Size may range from microscopic particle to stones that may occlude the pulp chamber

Composed of carbonated hydroxyapitite crystals

Pulp calcification may be- -Pulp stones True pulp stones false pulp stones -Diffuse calcifications -Calcific Metamorphosis

Sundell Schematic Presentation

Local Metabolic Dysfunction

Trauma

Hyalinization of injured cell

Vascular Damage

Thrombosis Vessel Wall Damage

Fibrosis

MineralizationGrowthPulp Stones

Denticles True denticle- False denticle-

attached

free

Attached denticleFree denticle

Diffuse Calcification

Calcific MetamorphosisLuxation of teeth as a result of trauma may result in calcific metamorphosis

Usually results in partial or complete radiographic obliteration of the pup chamber

Resembles cementum or bone on dentinal walls

Teeth may present with a yellowish hue

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Decrease in quality of blood vessels

Blood vessels:-

Aging has an adverse effect on the number & quality of blood vessels supplying the dental pulp (Benefit 1965)

The arterioles in the older pulp exhibited hyperplasia of the intima & dystrophic changes in the media & adventitia.

CLINICAL CONSIDERATIONS Anatomical considerations

Effect of dental materials on pulp

Effect of Operative Procedures

EFFECT OF DENTAL MATERIALS ON PULPAmalgam 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 effect The sedative effects are due to eugenol ability to block / reduce the nerve impulse activityhigher concentrations leads to chronic inflammation, thrombosis of vessels

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Formocresol High degree of diffusion causes a chronic inflammation of the pulp .Mutagenic and carcinogenic Calcium hydroxideinduces dentin bridge formation when used for direct pulp capping

Mineral trioxide aggregateSuperior to calcium hydroxide as a direct pulp capping agent

Zinc PhosphateStrong to moderate cyto-toxic reactions is due to leeching of zinc ions and low Ph Resin adhesive systems The formation of hybrid layer secures the enamel-resin interface with a continuous seal which acts as a biometic barrier Dentin bonding agents Monomer molecules reaching the pulp can irritate the pulp causing inflammation

Acid etching Etching apparently increases the pulpal inflammation because it removes the debris that accumulate over the dentinal tubules when they are cut thereby facilitating the penetration of irritants into dentinal tubules

EFFECT OF OPERATIVE PROCEDURES Effects of tooth preparationPressure and Frictional heat DesiccationExposure of dentinal tubulesDirect damage to odontoblast process

CAVITY DEPTH 1mm Shields Pulp 0.5- 0.25mm Tertiary Reactive Dentin 0.25mm> ~ Odontoblasts die & Reperative dentin is formed very fast.

CAVITY DRYING61

PULPAL PATHOLOGIESReversible pulpitisIrreversible pulpitisChorinic hyperplastic pulpitisInternal resorptionExternal resorption

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Irreversible pulpitisChorinic hyperplastic pulpitis

External Resorption

Internal resorption-

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Recent advancesPulpal regeneration-

This exciting new era was found by Urist with the introduction of bone morphogenic protein

In pulpal regeneration the tissue would be isolated from noxious restorative material in the chamber, thereby diminishing the chances of resorption.

BMPs are osteogenic proteins implicated in cell differentiation, tissue morphogenesis, regeneration and repair.

Stem cellsDental pulp stem cells are multipotent stem cells that have a potential to differntiate into a variety of cell types.

Historically, dental stem cells were first isolated by Gronthos and co-workers from the dental pulp.

Animal studies have shown the great potential of DPSCs for repair and regeneration of various tissues, such as, heart, muscles, and teeth

Clinically a bio- teeth made from autogenous DPSC,s should be the best choice for clinical tooth reconstruction

There are two widely used methods for the isolation of dental pulp stem cells: the explant method (DPSC-OG) and the enzymatic digestion method of the pulp tissue (DPSC-EZ) .

It has been demonstrated that the outgrowth method allows DPSCs to differentiate into skeletal muscle fibres. Markers expressed by DPSCs are CD29 and CD44,CD34 as well as CD73 and CD105 and CD 117. This population has great self-expansion and osteogenic differentiation capabilities and produces a living autologous fibrous bone (LAB) tissue in vitro and bone tissue when implanted in mice.

Conclusion we, as dental physicians, provide the highest level of technical and scientific accuracy and artistic flair in the holistic well being of the tooth organ and in turn fulfill the aspiration of those individuals who place in us their unwavering trust - our patients.

Refences Dental pulp; Seltzer and bender; 3rd editiony;Oral Histology; Tencate; 5th Edn Oral Histology & Embryology; Orban 11th Edn Pathways of Pulp; Cohen; 8th Edn Endodontics; Ingle; 5th EdnTextbook Of pedodontics; Shobha Tandon

ANCA VIALARIU1), IRINA-DRAGA CRUNTU2) Department of Oral Rehabilitation, Faculty of Dentistry, Gr. T. Popa University of Medicine and Pharmacy, Iassy 2) Department of Oral Biology, Faculty of Dentistry, Gr. T. Popa University of Medicine and Pharmacy, Iassy-2005Review ofDental pulp stem cells: State of the art and suggestions for a true translation of research into therapy Marcella La Noce a , Francesca Paino a , Anna Spina a , Pasqualina Naddeo a , Roberta Montella a , Vincenzo Desiderio a , Alfredo De Rosa b , Gianpaolo Papaccio a, *, Virginia Tirino a, *, Luigi Laino c-2014

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