Periodontal Ligament: Support, Sensory, Nutritive, And Homeostatic Roles

Periodontal Ligament: Support, Sensory, Nutritive, And Homeostatic Roles

Describe the histology and functions of PDL.
Answer:

Functions of PDL:

1. Supportive:

• When a tooth is moved in its socket due to the force of mastication or orthodontic force, part of the periodontal space is narrowed while the other is widened.
• The periodontal ligament in the narrow periodontal space is compressed.
• The collagen fibers in this area act as a cushion for the displaced tooth.

2. Sensory:

• When teeth move in their sockets, they distort receptors in the PDL and trigger a response.
• PDL carries tactile sensation from teeth and hence helps in the localization of pain.
• PDL contributes to the sensation of touch and pressure.

3. Nutritive:

• The blood vessel within the PDL provides nutrition to the centrocytes of the PDL and osteocytes of the alveolar bone.
• The blood vessel also helps in the removal of the catabolites from the cells.

4. Homeostatic:

• The cells of the PDL have the capability to synthesize and resorb the extracellular substance of the connective tissue of the ligament.
• If the balance between synthesis and resorption is disturbed, the quality of the tissue is changed.
• This gradually leads to loss of attachment which results in tooth loss.
• In all areas of PDL, there is continual cell death which is replaced by new cells produced by the division of progenitor cells.

5. Eruptive:

• PDL components enable teeth to adjust their position.
• PDL provides space and acts as a medium for cellular remodeling and hence continued eruption occurs.

6. Physical:

• PDL protects vessels and nerves from mechanical forces.
• It offers resistance to impact from occlusal forces.
• Acts as a shock absorber to transmit occlusal forces to the bone.

7. Pormative/Resorptive:

• Cementoblast and osteoblast form cementum and bone respectively.
• Cementoclast and osteoclast resorb cementum and bone respectively.