The effect of povidone iodine on plaque and salivary bacteria. A double-blind crossover trial

Chemical Plaque Control Strategies in the Prevention of Biofilm-associated Oral Diseases

Dental plaque is a biofilm that forms naturally on the surfaces of exposed teeth and other areas of the oral cavity. It is the primary etiological factor for the most frequently occurring oral diseases, such as dental caries and periodontal diseases. Specific, nonspecific, and ecologic plaque hypothesis explains the causation of dental and associated diseases. Adequate control of biofilm accumulation on teeth has been the cornerstone of prevention of periodontitis and dental caries. Mechanical plaque control is the mainstay for prevention of oral diseases, but it requires patient cooperation and motivation; therefore, chemical plaque control agents act as useful adjuvants for achieving the desired results. Hence, it is imperative for the clinicians to update their knowledge in chemical antiplaque agents and other developments for the effective management of plaque biofilm-associated diseases. This article explores the critical analysis of various chemical plaque control strategies and the current trends in the control and prevention of dental plaque biofilm.

Disinfectants to Fight Oral Candida Biofilms

Oral biofilms, especially those caused by oral mycobiota, which include Candida species, are very difficult to eradicate, due to their complex structure and recalcitrance. Moreover, the mouth is prone to be colonized since it presents different types of surfaces, especially biomaterials and dental implants, often associated with a high rate of infections. Therefore, although disinfection of the oral cavity is of major importance, the number of commercially available disinfectants is not high. However, new solutions, as silver nanoparticles are being developed to help oral biofilms' eradication.

Antibacterial agents in the control of supragingival plaque--a review

This review considers the main agents which have been used as antibacterial agents in mouthwashes and other vehicles to inhibit the growth of supragingival plaque. The agents discussed are bisguanide antiseptics, quaternary ammonium compounds, phenolic antiseptics, hexetidine, povidone iodine, triclosan, delmopinol, salifluor, metal ions, sanguinarine, propolis and oxygenating agents. The plaque inhibitory, anti-plaque and anti-gingivitis properties of these agents are considered along with their substantivity, safety and possible clinical usefulness. Clinical trials of these agents that have been published are also reported. The possible clinical uses of antiseptic mouthwashes are finally considered along with some advice about assessing manufacturers claims. Throughout this review the terms plaque inhibitory, anti-plaque and anti-gingivitis have been used according to the clarification of terminology suggested by the European Federation of Periodontology at its second workshop. This defines a plaque inhibitory effect as one reducing plaque to levels insufficient to prevent the development of gingivitis; an anti-plaque effect as one which produces a prolonged and profound reduction in plaque sufficient to prevent the development of gingivitis; and anti-gingivitis as an anti-inflammatory effect on the gingival health not necessarily mediated through an effect on plaque.

The effect of triclosan, stannous fluoride and chlorhexidine products on: (II) Salivary bacterial counts

A previous study demonstrated that triclosan and stannous fluoride containing oral hygiene products reduced plaque regrowth compared to saline but were not more effective than a conventional commercial fluoride/anionic detergent toothpaste. To further understand these results, this study measured the persistance of antimicrobial activity of the same products by recording the duration of salivary bacterial count reductions following a single exposure to each product. Comparison was also made with a chlorhexidine rinse as the positive control. From a panel of 16 volunteers, in an 8-cell randomised cross-over designed study, salivary bacterial counts were recorded at baseline and to 420 min. All test and control products were significantly more effective than saline and significantly less effective than chlorhexidine at suppressing bacterial counts. Unlike chlorhexidine, evidence of bacterial recovery was apparent after the 30-min sampling time. There were essentially no significant differences between the test and control products, although the stannous fluoride toothpaste performed marginally better than other products. The findings are consistent with the plaque regrowth results previously obtained and again demonstrate to date that it is difficult to surpass the antimicrobial and plaque inhibitory properties of conventional commercially available toothpastes by the addition of antimicrobial agents such as triclosan and metal salts.

Comparative effects of toothpaste brushing and toothpaste rinsing on salivary bacterial counts

The persistence of antimicrobial action of compounds and formulations in the mouth can be demonstrated by recording the magnitude and duration of the reduction of salivary bacterial counts following a single application. Such measures of substantivity appear to correlate with the plaque inhibitory properties of antimicrobial agents. For toothpastes, studies on the short-term inhibition of plaque formation use a number of delivery methods to measure the direct effect of the preparation divorced from toothbrushing. Such methods include paste slurries, paste in trays or cap splints. This study determined whether toothbrushing with a toothpaste produced the same effects on salivary bacterial counts compared to rinsing with a slurry. A group of 24 volunteers brushed or rinsed with a slurry of a commercial toothpaste. Each regimen was repeated twice on 4 separate days by all volunteers and salivary bacterial counts recorded at baseline and time periods to 7 hours. There were no significant differences between brushing or slurry rinsing on salivary bacterial counts and each method produced reproducible effects. This supports the use of the slurry method where the direct plaque inhibitory action of an antimicrobial toothpaste is to be assessed; and indicates that both methods equally make available and activate the relevant ingredients in formulations.

Chlorhexidine compared with other locally delivered antimicrobials. A short review

Based on the association of bacterial plaque with the initiation of chronic gingivitis and progression of chronic periodontitis, chemical antiplaque agents have been employed both in prevention of periodontal disease and its treatment. In supragingival plaque control regimens, chlorhexidine has not been superceded as a chemical anti-plaque agent, although other compounds have been shown to be useful. The local side-effects of chlorhexidine and other cationic antiseptics, however, limit their long-term use for prevention. Extrinsic tooth staining in particular remains the greatest problem. Short-term anti-plaque uses for chlorhexidine include as an adjunct to mechanical cleaning in the initial oral hygiene phase of treatment, in situations where mechanical oral hygiene is difficult, including postsurgery, intermaxillary fixation, fixed orthodontic therapy, physically and mentally handicapped individuals, systemic diseases with oral manifestations such as leukaemia. More recent interest in chlorhexidine has resulted from the delivery of compounds subgingivally in the treatment of chronic periodontitis. Such methods have extended the use of chlorhexidine into areas inaccessible to the action of antimicrobial drugs delivered locally by conventional means, such as tooth brushing or mouth rinsing. Available evidence suggests that chlorhexidine may not be as effective as some antimicrobial drugs whose activity is more specific for those organisms considered particularly pathogenic to the periodontal tissues.

Comparison of the in vivo and in vitro antibacterial properties of antiseptic mouthrinses containing chlorhexidine, alexidine, cetyl pyridinium chloride and hexetidine. Relevance to mode of action

A study was carried out to compare the antibacterial properties of four cationic antiseptics, three of which are available as commercial mouthrinse preparations. Minimum inhibitory concentrations for alexidine, cetyl pyridinium chloride, chlorhexidine gluconate and hexetidine against a range of standard test organisms, were determined by tube dilution. Similar values for Oxford staphylococcus were then obtained in Dubos medium to which protein as yeast, or food extract, or serum was added in doubling dilutions to 16%. Salivary bacterial counts after a single rinse with the antiseptics or water throughout the day were measured in 10 subjects together with the duration of any residual antiseptic activity in the saliva. All antiseptics were effective at low concentrations against the organisms tested but the minimum inhibitory concentration values for hexetidine were the highest. Food extract and serum markedly increased the minimum inhibitory concentration values of all antiseptics, although alexidine and hexetidine were the least affected in percentage terms. The activity of a 1% povidone iodine preparation, used for comparison, was almost completely vitiated. An immediate significant fall in salivary bacterial counts was produced by the cationic antiseptics. Return to pre-rinse levels was seen for hexetidine after 90 min, cetyl pyridinium chloride after 3 hours, alexidine after 5 hours and chlorhexidine gluconate after 7 hours. Residual salivary antibacterial activity remained to 90 min for cetyl pyridinium chloride, to 3 hours for hexetidine and alexidine and to 5 hours for chlorhexidine gluconate. The antibacterial properties measured, in particular the duration of effect in vivo, may be relevant to the anti-plaque activity of cationic antiseptics.

Comparison of the bisbiguanide antiseptics alexidine and chlorhexidine. I. Effect on plaque accumulation and salivary bacteria

A blind crossover trial was carried out to compare the effects of a 0.2% chlorhexidine gluconate mouthrinse and a 0.035% alexidine mouthrinse on plaque accumulation and salivary bacteria in a group of volunteers. The subjects refrained from all forms of oral hygiene during two 10-day periods and rinsed twice a day with the mouthwash randomly allocated to the respective period. Prerinse, day 4 and day 10 total salivary aerobic and anaerobic bacterial counts were determined during each period. Plaque scores were recorded at the end of each 10-day period. Significantly more plaque accumulated in subjects rinsing with alexidine when compared with chlorhexidine. Significant and comparable reductions in salivary bacterial counts were observed with both chlorhexidine and alexidine on day 4 and day 10 when compared with pre-rinse counts. Although at the concentrations used alexidine was less effective than chlorhexidine, it may be of value as a short-term adjunct to oral hygiene.

Connective tissue response to periodontal dressing

The effects of three periodontal dressings (Coe-Pak, PPC, Perio Putty) upon subcutaneous tissues in 26 Sprague-Dawley rats were investigated. The three dressings, and a control (Teflon), were placed into polyethylene tubes. Two tubes per animal were implanted on either side of the dorsal midline area. After 14 days the specimens were retrieved and prepared for histological examination. Three methods of scoring were utilized for evaluation. First, a system evaluating the overall number of inflammatory cells, connective tissue capsule thickness, and the vascular changes produced; second, an inflammatory cell count, the Inflammatory Index (I.I), computing the inflammatory cells in a particular field of view for each material; and third, a Reaction Spread Index (R.S.I.) comparing the distance of the spread of the inflammatory reaction into the connective tissues. Statistical analysis of the data was carried out utilizing the Chi-square test and analysis of variance. While the three scoring systems utilized did result in some comparative variation in reactions, the overall order of decreasing severity was always PPC, Coe-Pak, Perio Putty, and Teflon.

In vivo effect of four antibacterial agents upon the acidogenicity of dental plaque

The present study was carried out to compare the effect of chlorhexidine, iodine, alcohol and hydrogen peroxide on the acidogenicity of dental plaque in vivo. Plaque pH changes after application of sucrose were measured before and at various time intervals after the topical application of the agents. The MIC values of the different agents were assessed against plaque bacteria in vitro. The antimicrobial activity of chlorhexidine and iodine were similar whereas alcohol and hydrogen peroxide were less effective in the concentrations employed. The results showed that chlorhexidine 2%, iodine 2%, and alcohol 70% inhibited pH drops for a 24-h period after treatment whereas 3% hydrogen peroxide had no effect. Chlorhexidine 0.2% inhibited acid production to a greater extent than did alcohol 50% and iodine 0.2%. It is suggested that retention of chlorhexidine in plaque may explain the observed prolonged effect.

A review of chemotherapeutic plaque control

Of the plaque-control agents studied, it would appear that chlorhexidine is the most suitable agent to prevent plaque accumulation and the development of gingivitis. It also is attractive to speculate on the possibilities of a commercially available mouthwash. A trio of antibiotics--kanamycin, spiramycin, and vancomycin--may prove of value in the treatment of severe gingival and periodontal disease. The ultimate role of xylitol has yet to be determined. Regardless of the agent selected, access to the gingival sulcus region seems critical.