Sonni Mette Waaler

Biological activities of different triclosan—detergent combinations

Abstract Several previous studies have shown that the nature of detergents and solvents used in conjugation with triclosan is important for its clinical plaque-inhibiting effect. The aim of the present study was to compare the clinical effect of two detergents, sodium lauryl sulphate (SLS) and sodium lauryl sarcosinate (LS), when used as solubilizers of triclosan in mouthrinses, and furthermore to examine if the critical micelle concentration (CMC) of the detergents used in mouthrinses with triclosan had an influence on the clinical effect. The antibacterial activity of the mouthrinses in vitro was also tested. The results of the clinical trials showed that the SLS-containing mouthrinse had a better antiplaque effect than the one containing LS. SLS has a higher CMC than LS. When the CMC of SLS was reduced by the addition of salt, the clinical effect of this mouthrinse was also reduced. A higher CMC thus appeared to be associated with a good clinical effect. It seems that the concentration of monomers in the solution (which are probably associated with triclosan molecules) is significant, whereas the triclosan trapped within the micelles is probably less clinically active. The opposite seemed to apply concerning the antibacterial in vitro effect of detergent—triclosan combinations: a decreased CMC increased the antibacterial effect. It is suggested that the nature of receptor sites and the shear forces are different in the oral cavity and in the in vitro systems and that these factors contribute to the difference.