Priya S. Chand MSD

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 n 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 / mm 2 (Coronal)  Intercellular Junctions:  Gap Junctions  Tight Junctions  Adhesion Belts  Desmosome-like

 Devoid of Major Organelles  Occasional Mitochondria (Pre- Dentin)  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 Collagen Functions:

 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 (  150  m)  Afferent & Efferent Vessels  Arterioles, Venules, Lymphatics  Radicular Pulp  Central Location, Larger Lumen  Coronal Pulp  Extensive Vascular Capillary Network

Vasculature of the Pulp Muscular Walls Smaller Lumen Arteriole Thinner Walls Larger Lumen Venule Pulpal Vessels Have Thinner Walls Owing to “Low-Compliance” Environment

Vasculature of the Pulp Nerves Venules Arterioles Lymphatics ? ? ? ?

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  Mostly A  fibers; Larger; Faster  Mediate Sharp, Localized Pain  Non-Myelinated  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 odontoblast- subodontoblast 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

n 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 (protruding into the pulp)  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

YoungerOlder 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

DiseasedNormalDiseased Calcifying Human Dental Pulps

 Seltzer and Bender’s Dental Pulp, by Hargreaves & Goodis 2002  Essentials of Oral Histology and Embryology, by Leslie P Gartner 1999