Histopathology of Disease

• What are gingivitis and periodontitis classified as?

  Destructive inflammatory disorders
• What is gingivitis confined to?

  The marginal gingiva
• What does periodontitis involve?

  Destruction of the connective tissue attachment and loss of alveolar bone
• What is the pathogenesis of chronic periodontal disease?

  • Balanced host-parasite relationship
  • Tipping of the balance may lead to disease
  • Re-establishment of the balance arrests the disease, becoming static
  • Healing may occur

  
• What is the appearance of normal marginal gingiva in health?

  Pink and ‘knife edged’ with stippling
• What occurs during the initial lesion of periodontal disease?

  • Plaque accumulation leads to inflammatory response
  • Dilation of blood vessels and increased vascular permeability
  • Fluid exudation resulting in oedema
  • Migration of neutrophils towards the sulcus
  • Increased flow of gingival crevicular fluid
  • Clinically, gingivae look healthy but slightly inflamed

  
• What are the clinical signs of an early lesion in periodontal disease?

  The gingivae are erythematous and slightly swollen
• What happens to fibroblasts during the early lesion stage?

  • Degeneration of fibroblasts through apoptosis
  • Collagen destruction leading to collagen-depleted areas
  • Proliferation of junctional and sulcular epithelium into collagen-depleted areas
• What leads to subgingival plaque formation during the early lesion stage?

  The swollen gingiva causes the sulcus to become deeper
• What characterizes the established lesion in periodontal disease?

  • Significant inflammatory infiltrate
  • Plasma cell dominated infiltrate in older patients
  • Lymphocytes dominate in younger patients
  • Destruction of gingival collagen and epithelial pocket formation
  • May be ulcerated leading to bleeding on probing

  
• What is gingival hyperplasia and how is it expressed clinically?

  Gingival hyperplasia is swelling above the cervical region, expressed as redness and easy bleeding
• What occurs during the advanced lesion stage of periodontal disease?

  • Transition from gingivitis to periodontitis
  • Host susceptibility and bacterial load/quality
  • Extension of inflammation into supra-alveolar connective tissue
  • Destruction of collagen fibres and loss of attachment
  • True pocket formation and apical migration of junctional epithelium

  
• What happens to bone during the advanced lesion stage?

  Osteoclasts start resorbing bone
• What are the types of bone loss observed in advanced lesions?

  • Vertical bone loss leads to infra-bony pockets
  • Horizontal bone loss leads to supra-bony pockets
• What is the histology of the periodontal pocket?

  • Bound by the root surface and pocket epithelium
  • Base has a zone of junctional epithelium attached to the root
  • Contains subgingival plaque and calculus
  • Inflammatory exudate with neutrophils
  • Plasma cells infiltrate connective tissue