Significance of choice of solvents for the clinical effect of triclosan-containing mouthrinses.

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.