• Plaque Biofilm:
  • Quorum sensing: bacterial communication
  • Co-aggregation: Gram-negative adherence
• Microbial Shift (Health → Disease):
  • Facultative → Obligate anaerobes
  • Fermenting → Proteolytic
  • Cocci → Rods
  • Non-motile → Motile
• Immunoglobulins:
  • Saliva: IgA
  • GCF: IgG
• Interleukins & MMPs:
  • IL-1β: Most potent bone-destructive cytokine
  • MMP-8 & MMP-1: Collagenases
  • MMP-2 & MMP-9: Gelatinases
  • Activated by neutrophil proteases (e.g., cathepsin G)

Periodontal Fibers

Periodontal fibers play a crucial role in maintaining the integrity of the periodontal ligament and supporting the teeth within the alveolar bone. Understanding the different groups of periodontal fibers is essential for comprehending their functions in periodontal health and disease.

1. Gingivodental Group

• Location:
  • Present on the facial, lingual, and interproximal surfaces of the teeth.
• Attachment:
  • These fibers are embedded in the cementum just beneath the epithelium at the base of the gingival sulcus.
• Function:
  • They help support the gingiva and maintain the position of the gingival margin.

2. Circular Group

• Location:
  • These fibers course through the connective tissue of the marginal and interdental gingiva.
• Attachment:
  • They encircle the tooth in a ring-like fashion.
• Function:
  • The circular fibers help maintain the contour of the gingiva and provide support to the marginal gingiva.

3. Transseptal Group

• Location:
  • Located interproximally, these fibers extend between the cementum of adjacent teeth.
• Attachment:
  • They lie in the area between the epithelium at the base of the gingival sulcus and the crest of the interdental bone.
• Function:
  • The transseptal fibers are primarily responsible for the post-retention relapse of orthodontically positioned teeth.
  • They are sometimes classified as principal fibers of the periodontal ligament.
  • Collectively, they form the interdental ligament of the arch, providing stability to the interproximal areas.

4. Semicircular Fibers

• Location:
  • These fibers attach to the proximal surface of a tooth immediately below the cementoenamel junction (CEJ).
• Attachment:
  • They go around the facial or lingual marginal gingiva of the tooth and attach to the other proximal surface of the same tooth.
• Function:
  • Semicircular fibers help maintain the position of the tooth and support the gingival tissue around it.

5. Transgingival Fibers

• Location:
  • These fibers attach to the proximal surface of one tooth and traverse the interdental space diagonally to attach to the proximal surface of the adjacent tooth.
• Function:
  • Transgingival fibers provide support across the interdental space, helping to maintain the position of adjacent teeth and the integrity of the gingival tissue.

• Plaque & Bacteria:
  • Plaque: Mainly extracellular polysaccharides.
  • Pellicle: Thin film post-cleaning.
  • Bacteria in 1g plaque: 2 × 10¹¹.
  • Early plaque: Gram-positive.
  • Saliva: Streptococci dominate.
  • First oral colonizer: S. sanguis.
  • Secondary colonizer: S. mutans.
  • Red Complex: Most associated with periodontal disease.
  • Green Complex: A. actinomycetemcomitans, E. corrodens, Capnocytophaga.
• Tests & Toxins:
  • BANA test: Detects P. gingivalis, T. denticola, B. forsythia.
  • Leukotoxin (116-kDa): Secreted by A. actinomycetemcomitans.
  • Myeloperoxidase: Prevents A. viscosus attachment.
• Immunoglobulins:
  • Saliva: IgA.
  • GCF: IgG.
• GCF Lymphocyte Ratio: T:B = 1:3.
• TLRs: Absent on bacterial cells.

Necrotizing Ulcerative Gingivitis (NUG)

Necrotizing Ulcerative Gingivitis (NUG), also known as Vincent's disease or trench mouth, is a severe form of periodontal disease characterized by the sudden onset of symptoms and specific clinical features.

Etiology and Predisposing Factors

• Sudden Onset: NUG is characterized by a rapid onset of symptoms, often following debilitating diseases or acute respiratory infections.
• Lifestyle Factors: Changes in living habits, such as prolonged work without adequate rest, poor nutrition, tobacco use, and psychological stress, are frequently noted in patient histories .
• Smoking: Smoking has been identified as a significant predisposing factor for NUG/NDP .
• Immune Compromise: Conditions that compromise the immune system, such as poor oral hygiene, smoking, and emotional stress, are major contributors to the development of NUG .

Clinical Presentation

• Symptoms: NUG presents with:
  • Punched-out, crater-like depressions at the crest of interdental papillae.
  • Marginal gingival involvement, with rare extension to attached gingiva and oral mucosa.
  • Grey, pseudomembranous slough covering the lesions.
  • Spontaneous bleeding upon slight stimulation of the gingiva.
  • Fetid odor and increased salivation.

Microbiology

• Mixed Bacterial Infection: NUG is caused by a complex of anaerobic bacteria, often referred to as the fusospirochetal complex, which includes:
  • Treponema vincentii
  • Treponema denticola
  • Treponema macrodentium
  • Fusobacterium nucleatum
  • Prevotella intermedia
  • Porphyromonas gingivalis

Treatment

1. Control of Acute Phase:

   • Clean the wound with an antibacterial agent.
   • Irrigate the lesion with warm water and 5% vol/vol hydrogen peroxide.
   • Prescribe oxygen-releasing mouthwash (e.g., hydrogen peroxide DPF, sodium perborate DPF) to be used thrice daily.
   • Administer oral metronidazole for 3 to 5 days. If sensitive to metronidazole, prescribe penicillin; if sensitive to both, consider erythromycin or clindamycin.
   • Use 2% chlorhexidine in select cases for a short duration.

2. Management of Residual Condition:

   • Remove predisposing local factors (e.g., overhangs).
   • Perform supra- and subgingival scaling.
   • Consider gingivoplasty to correct any residual gingival deformities.

• Bence Jones Proteins: Mostly gamma chains
• Commonest lytic lesion site: Vertebral column
• Russell bodies: Found in plasma cells
• Bone scan not useful
• No ALP elevation
• High ESR: Often seen
• Prognostic marker: Beta-2 microglobulin

🔁 Pulse Patterns

🔊 Heart Sounds

• Loud S1: Short PR interval, tachycardia, mitral stenosis
• Fourth Heart Sound (S4): Heard during ventricular filling
• Opening snap: High-pitched, diastolic sound