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Priya S. Chand MSD [email protected] What does an Endodontist care about pulp histology ? Origin of the Pulp Condensed Ectomesenchyme Dental Papilla Influence of Internal Dental Epithelium Dentin Effects Enamel Formation Pulp Chamber Pulp Horn Orifice Coronal Apical Apical Foramen and Constriction Pulp Horns Apical Foramen Cemento-Dentinal Junction Lateral and Accessory Canals Pulp Function : – Production of Dentin – Maintenance of Dentin Dentin Predentin Odontoblasts Subodontoblastic plexus of Raschkow Cell free zone Cell rich zone Pulp proper Pulp Organization – Odontoblastic Zone – Cell-Free Zone (Weil) – Cell-Rich Zone – Pulp Core Endodontics, Ingle’s, 2002 Odontoblast Fibroblast Undifferentiated mesenchymal Cell Macrophage Dendritic Cell Lymphocyte Most Distinctive Cell Location: Size Gradient: 59K to 76K / mm2 (Coronal) Intercellular Junctions: Gap Junctions Tight Junctions Adhesion Belts Desmosome-like Devoid of Major Organelles Occasional Mitochondria (PreDentin) OB- Equipped for Exo/Endocytosis Most Common Cell Cell-Rich Zone Pulp Core Histology- Active vs. Resting Functions: Form Pulp Matrix Maintain Pulp Matrix Capable of Synthesizing, Ingesting & Degrading CollagenFunctions: Polymorphic and highly motile. Tendency to Central Location Function: Scavenge Dead Cells Presence Implies FB Turnover Class II MHC Positive Histology: Large, Oval or Spindle-Shaped Nucleus Dark-Staining Nucleus Clear Cytoplasmic Areas Location: Below OB Zone Cell Processes between odontoblasts Function: Immunosurveillance Recognize, Capture Foreign Ag Non-Phagocytic Increased in Carious Teeth Class II MHC Positive T- Lymphocytes Present in Normal Pulp B- Lymphocytes Present in Inflamed Pulp Fibers Type I collagen (predominant in dentin) produced by odontoblasts Type I & III (in pulp, ratio 55:45) produced by pulp fibroblasts Type V, small amount in pulp Reticular fibers Aging, increase in collagen Apical portion has more collagen then coronal. Ground substance Similar to other soft connective tissue Glycosaminoglycans, glycoproteins, Water in the form of sol-gel. Apical Foramen Area Arteriolar Size ( 150m) Afferent & Efferent Vessels Arterioles, Venules, Lymphatics Radicular Pulp Central Location, Larger Lumen Coronal Pulp Extensive Vascular Capillary Network Vasculature of the Pulp Arteriole Venule Pulpal Vessels Have Thinner Walls Owing to “Low-Compliance” Environment Muscular Walls Thinner Walls Smaller Lumen Larger Lumen Vasculature of the Pulp Arterioles Lymphatics ? Nerves ? ? Venules ? P & P Endodontics, 2002 Endodontics, Ingle’s, 2002 Sensory axons myelinated A (1-6 m), predominant A (6-12 m), small percentage unmyelinated A and A after branching off C fibers (< 1 m), mainly in pulp core Branching of nerve bundles as they approach the subodontoblastic region (plexus of Raschkow) Endodontics, Ingle’s, 2002 Sensory Afferents of CN V Transmit Pulpal Sensation Effectors on Arterioles, Capillaries, Veins CGRP Vasodilation Substance P Plasma Extravasation Sympathetic Superior Cervical Ganglion Control Arteriolar Smooth Muscle Myelinated Non-Myelinated Mostly A fibers; Larger; Faster Mediate Sharp, Localized Pain C fibers; Smaller; Slower Myelin Sheath Reduction Coronally Sensory Afferents of CN V Transmit Pulpal Sensation Effectors on Arterioles, Capillaries, Veins CGRP Vasodilation Substance P Plasma Extravasation Sympathetic Superior Cervical Ganglion Control Arteriolar Smooth Muscle Suda et al, 1997 Lymph Drainage and Lymphatic Vessels P & P Endodontics, 2002 Lymphatic capillary arising and collecting from within the odontoblastsubodontoblast region Endodontics, Ingle’s, 2002 Hard tissue apposition in pulp space Endodontics, Ingle’s, 2002 Significance: Overall # of Pulp Cells Reparative Potential NOT a Cause of Pain Interference with RCT Uninflamed pulp. Typical pattern of calcifications Endodontics, Ingle’s, 2002 Pulp Stone Endodontics, Ingle’s, 2002 Protection of Pulp – Intra-Tubular Mineralization (sclerosis) – Reduced Thermal Sensitivity – Impaired Bacterial Penetration Free denticles located free in the pulp Attached denticles attached to the wall of pulp chamber into the pulp) (protruding Interstitial denticles wholly within wall of pulp chamber True denticles (formed by odontoblasts) rare and when present, located in radicular pulp False denticles Do not posess odontoblasts. Age Changes Affect Response Stimulated “Age Changes” in Myelinated & Unmyelinated Nn Age-Related in Sensitivity Dystrophic Calcification If Large, “False” Pulp Stone Contributes to Reduced Vascularity “Diffuse” Calcification Younger Older Vascularity “R” Us Collagen, Flow Accelerated Dentin Deposition Calcified Canals Age Changes More Fibrous, Less Cellular Endodontics, Ingle’s, 2002 Age Changes In Blood Vessels Endodontics, Ingle’s, 2002 Calcifying Human Dental Pulps Normal Diseased Diseased Seltzer and Bender’s Dental Pulp, by Hargreaves & Goodis 2002 Essentials of Oral Histology and Embryology, by Leslie P Gartner 1999
