Organic solvents and oils as vehicles for triclosan in mouthrinses: a clinical study

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)