THE EFFECTS OF A 0.3-PERCENT TRICLOSAN-CONTAINING DENTIFRICE ON THE MICROBIAL COMPOSITION OF SUPRAGINGIVAL PLAQUE

144 subjects completed a 6-month, double-blind study which examined th e effects of a 0.3% triclosan/2% copolymer/0.243% sodium fluoride dent ifrice on the microflora of supragingival dental plaque. The subjects were randomly assigned to use, in an oral hygiene program, either the triclosan/copolymer/fluoride test dentifrice or a control dentifrice. The latter had the same formulation as the test dentifrice except it d id not contain triclosan. Supragingival plaque was collected from the buccal and lingual surfaces of 4 teeth at baseline, 3 months, and 6 mo nths, and microbiologically examined by darkfield microscopy, gram sta in morphology, immunofluorescence, and selective and non-selective med ia. Antimicrobial susceptibilities were determined by agar dilution an d whole plaque susceptibility methodologies on plaque samples from 136 subjects at each of the above sample periods and at 6-week intervals for an additional 6 months post-therapy. Both dentifrices resulted in highly statistically significant reductions in the total cultivable fl ora obtained at both the 3 and 6-month samples relative to baseline as well as at 6 months relative to the 3-month sample. The relative decr ease in total anaerobic counts and in strict anaerobes, while not stat istically significant, was more pronounced at both the 3- and 6-month sample periods in subjects receiving the triclosan dentifrice than for the controls. Neither dentifrice resulted in detrimental shifts in th e microbial composition of the normal flora nor led to the emergence o f periodontal or opportunistic pathogens. There was no difference in t he relative proportions of the microflora resistance to triclosan or i n the number of subjects harboring triclosan-resistant micro-organisms regardless of whether the subjects received the triclosan dentifrice or the control. The proportion of the cultivable flora resistant to tr iclosan was higher at baseline than at any other sample period. This s tudy demonstrates that the extended use of the 0.3% triclosan/2% copol ymer/fluoride dentifrice does not disrupt the normal microflora associ ated with supragingival plaque, favor the growth or colonization of pe riodontal or opportunistic pathogens, or promote the acquisition of mi crobial resistance.