Homeostasis and Turnover in the Periodontium

Question 1

What is the periodontium?

Answer 1

• those structures/tissues supporting and investing the tooth, comprises root cementum, PDL, alveolar bone and dento-gingival junction

Question 2

What is homeostasis?

Answer 2

Homeostasis: the ability of an organism to maintain the internal environment of the body within limits that allow it to survive

• self-regulating process that return critical systems of the body to a set point within a narrow range of operation, consistent with survival of organism
• highly developed in warm blooded animals living on land, which must maintain body temperature, fluid balance, blood pH and oxygen tension within narrow limits, while at the same time obtaining nutrition to provide the energy to maintain homeostasis

Question 3

Why do we need to keep a healthy PDL?

Name some of the cells it contains:

Answer 3

PDL needs to respond to masticatory forces to return to normal

• must keep same width at all times
• mainly collagen fibres running between bone and cementum
• main cell type is fibroblasts
• some epithelial, osteoblasts, cementoblasts and mesenchymal cells

Question 4

How is collagen turnover in the PDL carried out?

Answer 4

Collagen usually broken down by production of collagenases, but instead in PDL internalises collagen fibrils it wants to break down, leading to much better control of which and where collagen is broken down