Pathogenesis of Periodontal Disease Quiz (ODS Learning Outcomes)

Chronic Periodontitis: Histopathology

• Host Response:
  • Innate: Rapid, non-specific response to infection.
  • Adaptive: Requires antigen presentation to lymphocytes.
    • Type 1 (Cell-mediated): Involves:
      • Cytokines (e.g., signaling molecules)
      • Macrophages (immune cells)
      • Endogenous antigens (from within the body)
    • Type 2 (Humoral): Involves:
      • Cytokines
      • B cells (immune cells producing antibodies)
      • Basophils (immune cells)
      • Mast cells (immune cells)
      • Exogenous antigens (from outside the body)
  • Cytokine Production:
    • Regulates inflammation and cell signaling.
    • Promotes systemic inflammation.
    • Examples: IL-1 (bone resorption, inhibits bone formation); IL-6 (bone resorption, stimulates T cells); IL-8 (inflammation, activates neutrophils).
  • Prostaglandins: Affect platelets, endothelium, and mast cells.
  • MMPs: Matrix metalloproteinases (enzymes involved in tissue breakdown).

Chronic Periodontitis: Microbiology

• Virulence Factors:

  • Endotoxin
  • Cytotoxin
  • Leukotoxin
  • Immunosuppressive factors
  • Chemotaxis inhibitors
  • Protease
  • Collagenase
  • Adhesins (molecules enabling bacteria to attach)

• Mechanism of Pathogenicity:

  • Colonization:
    • Growth requirements: Oxygen, pH 7-8.5, temperature 35.5°C.
    • Adhesion to surfaces.
    • Co-aggregation (e.g., Fusobacterium nucleatum as a bridging organism).
    • Nutrient supply (e.g., gingival crevicular fluid).
    • Competition with other microorganisms.
    • Evasion of the host defense system:
      • Capsule
      • Slime layer
      • Killing of leukocytes (white blood cells)
      • Degradation of antibodies and blood proteins.
      • Dysregulation of cytokines.
  • Production of Factors Damaging the Host:
    • Direct Tissue Damage:
      • Protease
      • Collagenase
      • Metabolic products increasing mucosal permeability.
      • Lipopolysaccharides
    • Indirect Tissue Damage:
      • Macrophages
      • T cells
      • Cytokines
      • Antibodies
      • Inflammatory cells attacking surrounding tissue.

Explore the histopathology of chronic periodontitis, focusing on host responses including innate and adaptive immunity. Understand the roles of cytokines and immune cells such as macrophages, B cells, and mast cells in the inflammatory process. This quiz covers critical concepts in the pathogenesis of periodontal disease.