histology of pulp Flashcards
What is the origin of pulp?
ectomesenchymal cells of dental papilla
what are the classifications of pulp
coronal - found in pulp horns
radicular - found in pulp canals
what are the functions of pulp?
- formative - has mesenchymal cells that ultimately form dentin
- nutritive - nourishes the avascular dentin
- sensory - free nerve endings provide pain sensation
- protective - produces reparative dentin as needed.
What are the zones from outer to inner?
odontoblastic –>
cell-free zone of weil –>
cell-rich zone –>
pulp core
what is in the odontoblastic zone?
a single layer of odontoblasts lining the pulp chamber
what is in the cell-free zone of weil?
devoid of cells (except during dentinogenesis). Contains the parietal plexus of nerves (Raschkow’s Plexus) and a plexus of blood vessels (including arteriovenous anastomoses).
what is in the cell-rich zone?
fibroblasts and undifferentiated cells
what is in the pulp core?
contains fibroblasts, macrophages, leukocytes, blood and lymph vessels, myelinated (mostly Adelta) and unmyelinated (c) sympatheitc nerve fibers, collagen type I and III, and ground substance. There are no elastic fibers.
what are denticles?
pulp stones = concentric layers of mineralized tissue
What are the effects of aging on pulp?
increased collagen fibers and calcification.
decreased pulp chamber volume (due to continued dentin deposition), apical foramen size, cellularity, vascularity, and sensitivity.
odontoblast
characteristic cells of the pulp; synthesize the matrix and control the mineralization of dentin; devoid of major organelles; occasional mitochondria; microtubules & filaments
fibroblast
most common cell type and increased numbers in the coronal pulp; cell-rich zone; form pulp matrix - produce and maintain pulp matrix (capable of synthesizing, ingesting, and degrading collagen)
macrophage
tendency to central localization function: scavenge dead cells presence implies fibroblast turnover class II MHC positive large, oval or spindle-shaped nucleus, dark-staining nucleus, clear cytoplasmic areas
cells of the pulp
odontoblast fibroblast macrophage dendritic cells lymphocytic cells undifferentiated cells
dendritic cells
most prominant immune cells in the pulp
location: below OB zone (cell processes between odontoblasts)
function: immunosurveillance, recognize, capture foreign Ag, non-phagocytic
increased in carious teeth
class II MHC positive
lymphocytic cells
T lymphocytes are present in normal pulp
B lymphocytes are present in inflamed pulp
influence of internal dental epithelium
the enamel epithelium induces the differentiation of odontoblast, and odontoblasts and dentin induce the formation of enamel
intracellular junctions
cell bodies of the odontoblasts are joined by variety of membrane junctions, which have specific functions
gap junctions
communication between cells
tight junctions
control permeability of the layer
desmosome
mechanically link cells
odontoblast process
devoid of major organelles, occasional mitochondria (pre-dentin), microtubules and filaments
apical foramen area
arterioles, venules, lymphatics
radicular pulp
central location, larger lumen
coronal pulp
extensive vascular capillary network
pulp stones significance
decrease overall number of pulp cells
decrease reparative potential
not a cause of pain
interference with RCT
age changes in the pulp
protection of pulp –> intra-tubular mineralization (sclerosis) –> reduced thermal sensitivity, impaired bacterial penetration
