Host Microbial Interactions to Prolonged Dental Biofilm (Plaque)

Question 1

How is the migration of the JE prevented in healthy tissue?

Answer 1

It is prevented by the healthy underlying connective tissue

Question 2

Describe the migration of the JE in periodontitis

Answer 2

Gingival connective tissue and perio ligament fibres are destroyed - this leaves a space. The JE migrates into the space, moving towards the apex of the tooth.

Question 3

What happens during the breakdown of the PDL in periodontitis?

Answer 3

• Collagen fibres between bone and cementum break down
• Fibroblasts are damaged (reduction in fibres and ground substance)
• Build up of host factors and bacterial factors in connective tissue
• Necrotic cementum ( due to lack of blood vessels in PDL, so no longer being provided nutrients)

Question 4

What are osteoclasts?

Answer 4

They are cells that are responsible for the resorption of bone

Question 5

What damages the alveolar bone in perio disease?

Answer 5

• Bacterial products stimulate release of cytokines, leukotrienes, prostaglandins which activate osteoclasts.
• some bacterial products cause direct damage

Question 6

Which cells secrete inflammatory mediators? (5)

Answer 6

Neutrophils, macrophages, fibroblasts, endothelial cells, osteoblasts

Question 7

How could osteoblasts aid the resorption of alveolar bone?

Answer 7

Osteoblasts produce RANKL (no. 5), which initiates osteoclastogenesis (i.e. make osteoclasts which resorb bone)