Antimicrobial Effects of Commercial Dentifrices in Distinct Oral Microenvironments

Objectives: Endogenous microorganisms of the human mouth are primary etiologic agents for common dental diseases. Chemotherapeutic agents inhibiting organisms in distinct oral niches such as supragingival plaque and mucosal surfaces offer patient relevant outcomes. Accordingly, this study determined antimicrobial effects on a range of bacteria in distinct oral niches after oral hygiene with three commercial dentifrices formulated with sodium fluoride, stannous fluoride (SnF2) or triclosan/copolymer. Methods: 35 adults completed a washout phase for this double-blind, triple-crossover design study. Baseline samples of plaque, saliva and scrapings from tongue and buccal mucosa were collected 12 hours after oral hygiene and evaluated in duplicate for anaerobic bacteria, Streptococci, Actinomyces, hydrogen-sulfide (H2S)-producing bacteria, Fusobacteria and Veillonella on appropriate microbiological agar. Subjects were randomly assigned a test dentifrice for twice daily oral hygiene for the next 13 days. On the 14th day, they performed oral hygiene in the morning and arrived 12 hours later to provide post-treatment samples for microbiological analyses similar to baseline. The experimental protocol was repeated twice more with the alternate dentifrices. Results: Evaluation of six organism types in four oral samples resulted in 24 post-treatment microbial outcomes for each dentifrice. Multiple comparisons demonstrate statistically significant reductions in all 24 microbial outcomes for triclosan/copolymer compared to both other treatments (p<0.01) with 62-80% greater effects than the SnF2 group. In comparison to the fluoride paste, the SnF2 group demonstrated significant reductions for only 14 of the 24 outcomes (p<0.01). No differences were observed between the NaF and SnF2 groups for 10 of the 24 microbial outcomes. This included all evaluations for Veillonella sp and Fusobacteria sp and for H2S bacteria in saliva and buccal scrapings (p>0.1). Conclusion: Brushing with a triclosan/copolymer dentifrice provided statistically significant reductions in a range of microorganisms in diverse oral niches in comparison to the fluoride or SnF2 dentifrice.