Defense Mechanisms of Gingiva

Defense Mechanisms of Gingiva

• Gingival Crevicular Fluid (GCF) is a fluid found in gingival crevices.
• GCF primarily contains substances from serum, leukocytes, bacteria, activated epithelial cells, connective tissue cells, and bone cells.
• These components are indicators of periodontal disease and healing.
• GCF plays a vital role in maintaining junctional epithelium structure and periodontium's antimicrobial defense.

Sulcular Fluid

• The gingival sulcus is a shallow space around the tooth, bordered by the tooth surface and the gingival free margin's epithelium.
• The sulcus is located between the tooth and the gingival tissue.

GCF Functions

• GCF cleanses the gingival sulcus.
• GCF contains plasma proteins aiding in the epithelium's adhesion to the tooth.
• GCF possesses antimicrobial properties.
• GCF exerts antibody properties to protect gingival tissue.

Permeability of Junctional and Sulcular Epithelium

• Substances travel through the junctional and sulcular epithelium primarily through intercellular spaces.
• This passage is passive and can be constrained by intercellular junctions.
• There is a passage from the gingival connective tissue to the sulcus and from the sulcus to the gingival connective tissue.

Methods of GCF Collection

• Methods for collecting GCF include:

  • Absorbing paper strips.
  • Micropipettes.
  • Intra-crevicular washing (Gingival washing).
  • Pre-weighed twisted threads.

• Intra-crevicular method is most used, with variations in insertion position (crevice entrance or bottom of pocket).

Evaluating GCF Amount

• GCF collected by paper strips can be evaluated by weighing the strip.
• A more advanced approach involves the Periotron, an electronic device to measure GCF on paper strips.
• The Periotron allows precise measurements facilitating laboratory investigations of GCF components.

Capillary Tubing or Micropipettes

• Capillary tubes are inserted into gingival crevices post-isolation and drying
• GCF migrates into the tube via capillary action, allowing for measured volume determination based on known tube internal diameter and migration distance.

Composition of GCF

• GCF contains inorganic ions like sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), and phosphates.
• Organic components of GCF include proteins, albumin, gamma globulin, immunoglobulins.
• GCF includes proteolytic and hydrolytic enzymes like acid phosphatases, alkaline phosphatases, cathepsin G, B&D, collagenase, elastase, beta-glucuronidase, and gelatinases.
• Biomarkers include interleukins (IL-1a, IL-1ß), tumor necrosis factor-alpha (TNF-a), lactic acid, hydroxyproline, cytotoxic substances, and antibacterial factors.
• GCF contains bacterial products like endotoxins, trypsin-like enzymes, acid phosphatase, alkaline phosphatase, and prostaglandins.

Clinical Significance of GCF

• GCF, even in clinically healthy gingiva, is an inflammatory exudate.
• GCF levels are higher in inflamed tissues and correlate to inflammation severity.

Factors Stimulating GCF Flow

• Factors increasing GCF production:
  • Gingival inflammation.
  • Chewing coarse foods.
  • Toothbrushing and gingival massage.
  • Hormonal (like contraceptive) and Ovulation cycles.
  • Smoking.
• Circadian periodicity: gradual GCF increase from 6 AM to 10 PM, with a decline afterwards.

Drugs in Sulcular Fluid

• Excreted drugs via GCF can be therapeutically used.
• Tetracycline and metronidazole are excreted via GCF.
• Antibacterial drugs can eliminate tissue bacteria in conjunction with periodontal therapies.
• Tetracycline, in low doses, inhibits collagenase activity.

GCF as a Biomarker

• GCF biomarkers can detect minute changes in periodontal disease processes.
• Various host and bacterial-derived products in GCF can aid in diagnosis, prognosis, and treatment strategy.

Leukocytes in the Dentogingival Area

• Gingival sulcus leukocytes are primarily neutrophils (PMNs).
• PMNs are found in small numbers outside blood vessels in the connective tissue adjacent to the sulcus bottom.
• They migrate across the epithelium into the gingival sulcus and are then expelled.

Saliva

• Saliva maintains oral tissues' physiological function.
• It influences plaque through mechanical cleansing, buffering acids produced by bacteria, and controlling bacterial activity.

Salivary Antimicrobial Factors

• Saliva has numerous antibacterial inorganic and organic factors that impact bacteria in the oral environment.
• Organic factors include lysozyme, lactoferrin, myeloperoxidase, and lactoperoxidase, showing bactericidal effects on various oral bacteria.

Immunoglobulins in Saliva

• Immunoglobulin A (IgA) is the predominant immunoglobulin in saliva.
• Major and minor salivary glands produce most of the secretory IgA and to a lesser extent IgG and IgM.

Salivary Enzymes

• Enzymes in saliva originate from salivary glands, bacteria, leukocytes, oral tissues, or ingested material.
• Proteolytic enzymes produced by both host and bacteria contribute to periodontal disease initiation and progression.
• Saliva contains antiproteases to combat proteolytic enzymes.

Salivary Buffers and Coagulation Factors

• Saliva's primary buffer system is bicarbonate-carbonic acid.
• Coagulation factors (e.g., factors VIII, IX, X, PTA, and Hageman factor) in saliva promote blood clotting, protecting wounds.

Additional Salivary Components

• Saliva contains desquamated epithelial cells and all types of leukocytes, with neutrophils as the predominant cell.

Clinical Implications

• Clinicians should be aware of gingival defense mechanisms to avoid potential treatment-related impairment.
• Routine periodontal therapies may disrupt the gingival sulcus epithelium, increasing inflammation risk due to bacterial contact.
• The junctional and oral sulcular epithelium has a 7-10 day recovery period during which optimized plaque control prevents periodontal breakdown.

References

• Carranza's Clinical Periodontology, 11th ed., 2011 by Newman, Takei, Klokkevold, and Carranza (editors).