Mental Dental Perio - Video 6

Immune Cells in Periodontal Response

• Neutrophils are the first line of defense and play a crucial role in controlling bacterial challenges and destroying periodontal tissue.
• They migrate from blood vessels to the periodontal pocket via chemotaxis and form a barrier to protect the body from pathogenic bacteria.
• Neutrophils internalize bacteria via phagocytosis and kill them using biologic bleach, which is a mix of nasty chemicals, including myeloperoxide and oxygen radicals.
• Neutrophil gelatinase (MMP-8) is involved in the destruction of periodontal tissues and is inhibited by the antibiotic tetracycline.

Neutrophil Abnormalities

• Defective neutrophil chemotaxis can lead to aggressive periodontitis.
• Abnormalities in neutrophil function can result in a "lose-lose" situation, where too much neutrophil activity leads to tissue destruction, and too little activity leads to unchecked bacterial growth.

Macrophages

• Macrophages are antigen-presenting cells that regulate the immune response by releasing cytokines like IL-8.
• They also include monocytes and dendritic cells.

Mast Cells

• Mast cells are involved in vascular permeability and dilation of blood vessels.
• They produce IgE, which is an antibody famously produced by mast cells.

Lymphocytes

• Lymphocytes are a category of immune cells involved in the periodontal response.
• B cells become plasma cells and make antibodies.
• T helper cells (CD4 cells) help with communication between immune cells.
• T cytotoxic cells (CD8 cells) directly kill intracellular antigens.
• Natural killer cells (NK cells) recognize and kill tumor and virally infected cells.

Pro-Inflammatory Mediators

• Pro-inflammatory mediators, such as MMPs, favor the destructive nature of periodontal disease.
• MMPs are matrix metalloproteinases that destroy collagen, the most common protein in the human body, leading to localized tissue damage.

Anti-Inflammatory Mediators

• Anti-inflammatory mediators oppose tissue destruction and are involved in a constant balance with pro-inflammatory mediators.

Stages of Gingivitis

• The initial lesion (2-4 days) involves neutrophil infiltration.
• The early lesion (4-7 days) involves T lymphocyte infiltration.
• The established lesion (14-21 days) involves B cell infiltration and maturation into plasma cells.
• The advanced lesion (stage 4) involves transition to irreversible tissue damage, characterized by bone loss and clinical changes in color, contour, and consistency.