A Study Examining the Antimicrobial Efficacy of Three Dentifrices

Oral biofilms can lead to caries and periodontal disease if not adequately controlled. Accordingly, dentifrices are often formulated with antimicrobial agents to supplement mechanical dispersion. Objectives: This study compared the antimicrobial effects of three dentifrices - stannous fluoride (SnF₂ , Crest Pro-Health), triclosan/copolymer (TCN/copolymer, Colgate Total), and fluoride (F, Crest Cavity Protection). In vitro antimicrobial activity was assessed using a panel of 24 bacterial strains including strains found in the normal oral cavity, in dental caries, in periodontal disease, and in halitosis as well as non-oral bacteria. Antimicrobial activity was also assessed using supragingival plaque from 10 adults. Materials and Methods: The minimum inhibitory concentrations (MIC) were determined for each of the three dentifrices in inhibiting the growth of 24 bacterial strains. For the ex-vivo study, supragingival dental plaque from 10 adults was pooled and serial dilutions of the plaque suspensions were distributed onto solid media containing two different concentrations of each dentifrice. Results: The lowest MIC's were observed with the TCN/copolymer dentifrice. TCN/copolymer inhibited the growth of gram negative bacteria such as veillonella and periodontal pathogens such as Aggregatibacter actinomycetemcomitans, Eikenella corrodens, and Fusobacterium nucleatum, gram-positive bacteria such as streptococci, oral yeast such as Candida albicans and non-oral bacteria including staphylococci and Bacillus sp. Analysis of the ex-vivo test data by ANOVA with subjects and dentifrice in the model demonstrated significant effects by the dentifrices (p<0.0005). Post-hoc Tukey multiple comparison tests indicate significantly higher bacterial growth inhibition by TCN/copolymer (>80%) than by either SnF₂ or F dentifrices (p<0.00005). No significant differences were observed between the SnF₂ and F dentifrices (p=0.99). Conclusions: The TCN/copolymer dentifrice demonstrated significantly higher antimicrobial effects (lower MIC's) against a panel of oral and non-oral bacteria and inhibition of human dental plaque microorganisms than the stannous fluoride and fluoride toothpastes.