Dental Pulp: A centralized soft connective tissue within a tooth surrounded by dentin.
Coronal Pulp (Pulp Chamber): Located within the crown.
Radicular Pulp (Pulp Canals): Located in the root, communicates with outer tissues via the apical foramen.
Development
Originates from Dental Papilla.
During tooth development:
Inner enamel epithelial cells differentiate into ameloblasts.
Ameloblasts signal dental papilla cells to become odontoblasts.
Odontoblasts deposit dentin, with unmineralized papilla forming dental pulp.
Histological Zones of Dental Pulp
1. Odontoblastic Zone
Location: Periphery of the pulp, adjacent to dentin.
Cells: Contains odontoblasts; columnar in coronal pulp, cuboidal in root mid-portion, spindle-shaped in apical part.
Functions: Secrete dentin, have odontoblastic processes.
Cell Junctions: Desmosomes, Tight junctions, Gap junctions.
2. Cell-Free Zone (Zone of Weil)
Location: Beneath odontoblastic zone, only in coronal pulp.
Characteristics: No cells present.
3. Cell-Rich Zone
Location: Next to cell-free zone.
Cell Types:
Fibroblasts: Most numerous, produce extracellular fibers.
Undifferentiated Mesenchymal Cells: Pluripotential, can differentiate into odontoblasts, fibroblasts, macrophages.
4. Pulp Core
Location: Central area of pulp chamber and canals.
Characteristics: Less densely packed cells, contains fibroblasts, undifferentiated mesenchymal cells, and defense cells (macrophages, dendritic cells, mast cells, etc.).
Vasculature and Innervation: Extensive capillary network, heavily innervated with non-myelinated nerves forming the plexus of Raschkow.
Functional Aspects
Cell Differentiation: Mechanisms for differentiation of mesenchymal cells in absence of ameloblasts is still unclear.
Innervation and Sensitivity: The plexus of Raschkow plays a role in dentin sensitivity, according to the Hydrodynamic theory.
Conclusion
The dental pulp is a complex tissue crucial for tooth development and function, with distinct zones each playing specific roles in maintaining pulp vitality and responding to external stimuli.