Supragingival plaque

The rate of clearance of chlorhexidine from the mouth after one mouth rinse with 10 mL of a 0.2% aqueous solution follows approximately first-order kinetics, with a half-life of 60 minutes. This means that following application of a single rinse with a 0.2% chlorhexidine solution, the concentration of the compound exceeds the minimum inhibitory concentration (MIC) for oral streptococci (5 mg/mL) for almost 5 hours. The pronounced substantivity, along with the relative susceptibility of oral streptococci, may account for the great effectiveness of chlorhexidine in inhibiting supragingival plaque formation. 

B. None of the other compounds listed has been shown to decrease supragingival plaque in combination with the polymer in a commercial preparation. 

Disclosing agents are dyes similar to those in food colorings that, when introduced into the oral cavity, color the supragingival plaque and make it easily visible. Various dyes are available in both liquid and tablet form. They are used in the dental office and at home both to increase the patient s awareness of plaque and to demonstrate where self-care has been ineffective in removing plaque. 

A number of devices aid in the removal of plaque from surfaces between teeth, around bridgework, and in other areas that are difficult to reach. The limitation of many of these devices is that they are effective for control of supragingival plaque but, at best, can remove subgingival plaque only to a depth of few millimeters. Therefore, they are of minimal value against subgingival plaque located deeper within the gingival crevice, as is the case in periodontal disease. 

Eley BM. Antibacterial agents in the control of supragingival plaque — a review. Br Dent Rev 1999 186(6) 286—296. 

ThurnheerT, Gmur R, Shapiro S, Guggenheim B Mass transport of macromolecules within an in vitro model of supragingival plaque. Appl Environ Microbiol 2003 69 1702-1709. 

Such a dentifrice was used in a 6-month double-blind study to determine its effect on the microbial composition of dental plaque as compared to an identical dentifrice without essential oils. Supragingival plaque and saliva samples were collected at baseline and their microbial content characterized, after which the study was conducted for 6 months. The essential oil dentifrice did not signi cantly alter the microbial ora, and opportunistic pathogens did not emerge, nor was there any sign of developing resistance to the essential oils in tested bacterial species (Charles et al., 2000). 

A clinical pilot study compared the effect of 0.34% M. alternifolia essential oil solution with 0.1% chlorhexidine on supragingival plaque formation and vitality. Eight subjects participated, with a 10-days washout period between each treatment regime of 1 week. The plaque area was calculated... 

A similar protocol was used to compare the effects of Listerine against an amine fluoride/stannous fluoride-containing mouthrinse (Meridol ) and a 0.1% chlorhexidine mouthrinse (Chlorhexamed ) in inhibiting the development of supragingival plaque. On day 5 of each treatment, the results from 23 volunteers were evaluated. In comparison with their placebos, the median plaque reductions were 12.2%, 23%, and 38.2% for the fluoride, essential oil, and chlorhexidine rinses, respectively. The latter two results were statistically significant (Riep et al., 1999). 

Figure 35.10 The sequence of events initiated by supragingival plaque in the development of gingivitis, subgingival plaque, subgingival calculus and periodontal disease...

At present chlorhexidine is the agent of choice in the short-term control of supragingival plaque although it is not without its disadvantages. It adsorbs to a pellicle-covered enamel and to the surface of calculus and subsequently reacts with dietary components to produce a persistent brown stain. In addition, some patients report a burning sensation and loss of taste after prolonged use. 

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