Odontoblastic Layer Explained: Cells, Functions, And Pulp Zones

Odontoblastic Layer Explained: Cells, Functions, And Pulp Zones

Enumerate structures in the pulp. Write in detail about the odontoblastic layer and its function.
Answer:

Structure of pulp:

• It consists of

1. Intercellular substance.
2. Fibroblasts
3. Fibers
4. Undifferential mesenchymal cells.
5. Odontoblasts.
6. Defense cells.
7. Blood vessels
8. Lymph vessels.
9. Nerves and nerve ending.

Odontogenic layer:

• Histologically four distinct zones are recognized they are.
• They are.

1. Odontogenic layer
2. Cell-free zone
3. Cell-rich zone
4. Pulp core

Odontogenic layer:

• It occurs adjacent to the prevention
• It consists of odontoblasts which are the second most prominent cell in the pulp after fibroblasts.
• These cells line the periphery of the pulp with their long axis at right angles to the pulp surface.
• The odontoblastic process extends into the dentinal tubules.

Number:

• The number of odontoblasts corresponds to the number of dentinal tubules.
• It ranges from 59,000 to 76,000 per square millimeter in coronal dentin to lesser in root dentin.

Shape:

• Odontoblasts in the crown are also larger than odontoblasts in the root.
• In the crown, they appear columnar, whereas in the midportion on the pulp, they are more cuboid, and in the apical part more flattened.

Nucleus:

• It is situated basally towards the pulpal side.
• It is oval in shape.

Cell organelles:

• Odontoblast has a prominent Golgi apparatus, abundant mitochondria, numerous vesicles, much endoplasmic reticulum, and numerous mitochondria scattered throughout the cell.
• The odontoblastic process contains no endoplasmic reticulum but during the active phase contains occasional mitochondria and vesicles.

Variation:

• The morphology of odontoblasts varies with their functional activity.

1. Active cell:
   • Appear elongated
   • The nucleus is basally located
   • Possess basophilic cytoplasm and prominent Golgi apparatus.
2. Resting cell:
   • It is stubby.
   • Posses little cytoplasm.
   • The nucleus is more hematoxyphilic.

Functions:

• Odontoblasts function primarily as secretory cells.
• They also secrete ground substances.
• They release inflammatory chemokine IL-8, chemotactic for neutrophils.
• Odontoblasts contain nitric oxide synthetase which plays an important role in vasodilation and blood pressure regulation.