Defense Mechanism Of Gingiva PDF

DEFENSE MECHANISM OF GINGIVA GCF (Gingival Crevicular Fluid) is the fluid found in gingival crevice and it mainly consists of substances derived from serum, leukocytes, bacteria, activated epithelial cells, connective tissue cells, and bone cells as these possess a great potential for serving as in...

DEFENSE MECHANISM OF GINGIVA GCF (Gingival Crevicular Fluid) is the fluid found in gingival crevice and it mainly consists of substances derived from serum, leukocytes, bacteria, activated epithelial cells, connective tissue cells, and bone cells as these possess a great potential for serving as indicators of periodontal disease and healing after therapy. GCF plays a special part in maintaining the structure of junctional epithelium and the antimicrobial defense of periodontium.. Anatomy of gingival sulcus:  The gingival sulcus is the shallow crevice or space around the tooth, bounded by the surface of the tooth on one side and epithelium lining the free margin of the gingiva on the other. FUNCTIONS OF GCF  Cleanses the gingival sulcus  Contains plasma proteins that may help in the adhesion of the epithelium to the tooth surface  Possess Antimicrobials properties  Exert antibody properties in the defence of gingiva  The main pathway for the transport of substances through the junctional & sulcular epithelium are the intercellular spaces.  The passage through these spaces is passive & is hindered at times by intercellular junctions.  From the gingival connective tissue to the sulcus  From the sulcus into the gingival connective tissue 1. Absorbing paper strips 2. Micropipettes 3. Intra crevicular washing (Gingival washing) 4. Pre-weighed twisted threads Absorbing paper strips  The intra-crevicular method is the method used most frequently and can be further subdivided depending upon whether the strip is inserted just at the entrance of the crevice or periodontal pocket or whether the strip is inserted to the base of the pocket or ‘until minimum resistance is felt.  Evaluation of amount of fluid collected by paper strips can be done by following methods 1. By weighing the strip 2. Use of periotron: this is the latest and standard electronic method for measuring GCF on paper strips.  Following the isolation and drying of a site, capillary tubes of known internal diameter are inserted into the entrance of the gingival crevice.  GCF from the crevice migrates into the tube by capillary action and because the internal diameter is known, the volume of fluid collected can be accurately determined by measuring the distance which the GCF has migrated.  GCF is an inflammatory exudate its presence in clinically normal sulcus can be explained because gingiva that appears clinically normal invariably exhibits inflammation when examined microscopically.  The amount of GCF is greater when inflammation is present, and is sometimes proportional to the severity of inflammation  GCF production increased by  gingival inflammation  mastication of coarse foods,  tooth-brushing and gingival massage  ovulation and hormonal contraceptives  smoking  Circadian Periodicity: There is a gradual increase in GCF amount from 6 AM to 10 PM and a decrease afterward.  Smoking: Smoking produces an immediate transient but marked increase in GCF flow.  Periodontal Therapy: There is an increase in GCF production during the healing period after periodontal surgery.  GCF in diabetic patients: the exudates collected from the diabetic patients showed significantly more levels of glucose than that collected from healthy individuals  DRUGS IN SULCULAR FLUID  Drugs that are excreted through the GCF may be used advantageously in periodontal therapy.  Tetracycline and metronidazole are found to be excreted through GCF.  Metronidazole and tetracycline can eliminate tissue bacteria and in conjunction with scaling and root planing they suppress actinomycetemcomitans levels.  Tetracyclines in low doses inhibits activity of collagenase and other collagenolytic enzymes.  The biomarkers present in the GCF can be a reliable tool to detect the minute changes seen in the disease processes.  The GCF consists of various host and bacterial- derived products as well as biomarkers which in turn can be evaluated for the diagnosis, prognosis as well as management of the periodontal disease.  The leukocytes found in gingival sulcus are predominantly PMNs.  They appear in small numbers extra-vascularly in the connective tissue adjacent to the bottom of the sulcus; from there, they travel across the epithelium to the gingival sulcus, where they are expelled.  Salivary secretions are protective in nature because they maintain the oral tissues in a physiologic state.  Saliva exerts a major influence on plaque by mechanically cleansing the exposed oral surfaces, by buffering acids produced by bacteria, and by controlling bacterial activity.  Antibacterial Factors : Saliva contains numerous inorganic and organic factors that influence bacteria and their products in the oral environment.  Organic factors include lysozyme, lactoferrin, myeloperoxidase & lactoperoxidase which are shown to be bactericidal to some strains of Lactobacillus, actinobacillus and streptococcus.  Although immunoglobulins G (IgG) and M (IgM) are present, the preponderant immunoglobulin found in saliva is immunoglobulin A (IgA).  Major and minor salivary glands contribute all the secretory IgA (sIgA) and lesser amounts of IgG and IgM.  The enzymes normally found in the saliva are derived from the salivary glands, bacteria, leukocytes, oral tissues, and ingested substances.  Proteolytic enzymes in the saliva are generated by both the host and oral bacteria.These enzymes have been recognized as contributors to the initiation and progression of periodontal disease.  To combat these enzymes, saliva contains antiproteases.  In saliva the most important salivary buffer is the bicarbonate–carbonic acid system.  Saliva also contains coagulation factors (factors VIII, IX, and X; plasma thromboplastin antecedent [PTA]; Hageman factor) that hasten blood coagulation and protect wounds from bacterial invasion.  Leukocytes  In addition to desquamated epithelial cells, the saliva contains all forms of leukocytes, of which the principal cells are PMNs.  Clinicians need to be aware of defense mechanisms of the gingiva because dental treatment can impair gingival defenses.  The disruption of the epithelial lining of the gingival sulcus can occur with routine scaling and restorative procedures that involve the sub-gingival region, resulting in increased risk of inflammation as bacteria and their products have direct contact with the underlying connective tissue.  The junctional and oral sulcular epithelium have the capacity to heal and reform the epithelial barrier in 7 to10 days, and during this time, plaque control must be optimized to limit the risk of initiating periodontal breakdown.  Carranza's Clinical Periodontology, 11th edition, Michael G.Newman, Henry Takei, Perry R. Klokkevold, and Fermin A. Carranza (editors), Saunders Elsevier, 2011.