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Previous experiments have shown that the nature of the detergents used in aqueous triclosan-containing mouthrinses affects the plaque-inhibiting effect of these mouthrinses, probably because of the properties of the micelles formed. It has also been shown that triclosan has a marked plaque-inhibiting effect when dissolved in pure propylene glycol. The aim of the present study was to compare the clinical effect of triclosan dissolved in oils and in the pure solvents glycerol (GLY) and polyethylene glycol (PEG). A test panel of 12 volunteers rinsed with the allocated mouthrinses for 4 days in a double-blind, crossover study. Three different oils were tested: olive oil, soy oil, and sunflower seed oil, as well as PEG and GLY. Triclosan was used in a 0.3% concentration to facilitate comparison with previous studies. However, only 0.15% triclosan was added to the GLY-containing rinse (maximum soluble concentration). In addition, soy oil without triclosan was tried. The mean plaque score for water was 1.42 +/- 0.19; for olive oil, 1.08 +/- 0.34; for soy oil with triclosan, 0.95 +/- 0.35; for pure soy oil, 0.94 +/- 0.09; for sunflower seed oil, 1.19 +/- 0.19; for PEG, 1.04 +/- 0.22; and for GLY, 1.12 +/- 0.28. The results indicate that triclosan dissolved in oils loses its clinical effect. However, oils in themselves exhibit significant plaque inhibition. In vitro tests showed no antibacterial activity of triclosan dissolved in oils. Toothpastes and mouthrinses contain flavoring oils and occasionally also GLY and PEG. Such substances may well interfere with the clinical effect of triclosan in these products.(ABSTRACT TRUNCATED AT 250 WORDS)

The aim of this study was to investigate the plaque-inhibiting effect of triclosan. It is known that triclosan and sodium lauryl sulfate (SLS) have a marked inhibitory effect. However, since SLS has a plaque-reducing effect in itself, the relative importance of triclosan and the surfactant is undecided. Twelve dental students participated in the trial, during which oral hygiene was suspended for 4-day periods when the different mouthrinses were used twice daily. The following mouthrinses were used: A, water (negative control); B, 0.2% chlorhexidine acetate (CHX) (positive control); C, 0.3% triclosan in water-free propylene glycol (PG); D, 0.3% triclosan with 1.5% SLS in PG; E, 0.15% triclosan in PG; F, 0.075% triclosan in PG; G, 0.3% triclosan in diluted PG (1:8 in water) with 1.5% SLS; and H, 0.3% triclosan in 0.5% sodium carbonate. The results showed that triclosan dissolved in the organic solvent PG had a significant plaque-inhibiting effect, whereas, dissolved in alkali, it had a negligible effect. The addition of SLS to PG somewhat reduced the antiplaque activity, and the aqueous solution of triclosan had markedly less effect. Lower concentrations of triclosan exhibited less clinical effect than higher concentrations. It can be concluded that triclosan alone, dissolved in a suitable solvent, has an antiplaque effect. The study confirmed the hypothesis that the nature of the detergent or organic solvent used to dissolve triclosan affects its clinical effect markedly.

The effect of triclosan on plaque inhibition was studied with various solvents. Eight subjects used the solutions as mouthwashes twice daily for 4 days while refraining from any other form of oral hygiene. Bacteriologic tests were also done with the same solutions. The study showed that the nature of the substance used to dissolve triclosan may be of clinical significance. Solutions of triclosan in polyethylene glycol, glycerol, or 3% sodium lauryl sulfate (SLS) alone showed marked antiplaque effect. (The first two solutions both contained 1.5% SLS). However, triclosan dissolved in Tween 80 had only a negligible clinical effect. In vitro experiment showed that antibacterial tests did not correlate well with clinical data. It is proposed that the nature of the micelles of the detergents which are used to dissolve triclosan is of significant importance. Strongly charged micelles such as SLS show clinical effect, whereas less charged micelles of SLS/Tween 80 or uncharged micelles of Tween 80 alone appear not to have this effect.

It has previously been shown that a toothpaste which contains triclosan and polydimethylsiloxane (silicone oil) improved gingival health in a test panel with established gingivitis more markedly than usually observed when testing commercial triclosan-containing toothpastes. In the present study the mode of action of combinations of silicone oil and triclosan was investigated. An in vitro experiment showed that triclosan was retained in a thin layer of silicone oil on the inner surfaces of test tubes that had been treated with the combination of triclosan and silicone oil. This triclosan was slowly released and inhibited the growth of bacteria in the test tubes. Silicone oil alone and in combination with triclosan was able to inhibit polysaccharide adhesion to the test tubes in the presence of a strain of Streptococcus sobrinus and a sucrose-containing medium. Corresponding in vivo experiments showed similar results; teeth topically treated with silicone oil and triclosan showed a marked plaque reduction, and those treated with silicone oil alone showed a moderate reduction, as compared with a placebo. The silicone oil plus 0.3% triclosan combination inhibited plaque formation also on proximal surfaces. It appears likely that this combination provides a reservoir of triclosan in the thin layer of silicone oil which binds strongly to teeth because of its low surface tension. Triclosan is then slowly released into saliva because of its low solubility in this fluid.

The aims of the present study were to assess the consumption of food preservatives during the last decades, and to study the effect of the preservatives, sorbic and benzoic acid, on growth and glycolysis of oral bacteria in vitro, and on acid formation by dental plaque in vivo. Five consumption reports from the Central Bureau of Statistics of Norway were used to estimate alterations in consumption of staple food containing the two preservatives. A modified broth dilution method was used to determine the MIC values of the preservatives against Streptococcus sobrinus and Streptococcus sanguis. Extracellular 14C-glycolytic metabolites were studied by HPLC analyses. Plaque-pH measurements were used to assess possible effects on acid production. The consumption reports indicated increased consumption of preservatives. The in vitro testing suggested that legal concentrations of preservatives may inhibit the growth of oral streptococci. However, the preservatives did not inhibit in vitro glycolysis at tested concentrations. In vivo testing with similar concentrations (0.4% w/v) showed a significant effect. A higher concentration (2% w/v potassium sorbate) had a tendency to inhibit acid-formation by dental plaque even more.

The aims of the present study were to investigate the antibacterial properties of glass-ionomer cements containing different concentrations of chlorhexidine and the possible release of chlorhexidine from the compound. Chlorhexidine gluconate or diacetate was mixed with glass-ionomer cements and tested in vitro against strains of Lactobacillus casei and mutans streptococci. A spectrophotometric test was used to monitor the release of chlorhexidine from the mixture. In a broth culture test, the higher the concentrations of chlorhexidine in the mixture, the longer the time of antibacterial effect on Streptococcus mutans and the greater the tendency of the material to deteriorate. Agar diffusion tests revealed bacterial inhibition in a dose-response manner. The tested bacterial strains were similarly inhibited and the antibacterial properties decreased with time. A minor portion of added chlorhexidine was released from the cement. The deterioration of the cements indicates that the material could be useful as a varnish-like chlorhexidine carrier.