Efficacy of Dentifrices on Distinct Dental Plaque Biofilms

OBJECTIVES: Plaque biofilms representative of nascent supragingival plaque (hydroxyapatite disc biofilm reactors; HDMs), developed supragingival plaque (modified drip-flow biofilm reactors; MDFRs) and subgingival plaque (multiple sorbarod devices; MSDs) were used to compare the antimicrobial effects of dentifrices containing triclosan/copolymer (CT) and a stannous fluoride/sodium hexametaphosphate/zinc lactate (CPH) combination. METHODS: Triplicate biofilms were inoculated with saliva and maintained for 2 d (HDMs), 5 d (MSDs) or 6 d (MDFRs). Effects of either single or multiple exposure to dentifrices were evaluated by differential culture for streptococci, facultative anaerobes, Gram-negative bacteria and facultative anaerobes. RESULTS: Only CT significantly reduced all functional groups in nascent supragingival plaques in HDMs after one treatment (p<0.05). CT exhibited significant broad-spectrum antimicrobial effects after one exposure (p<0.05) in comparison to CPH which caused significant reductions only in the facultative anaerobes and the Gram-negative anaerobes (p<0.05). In multiple dosing studies, CT caused greater reductions than CPH on streptococci and Gram-negative anaerobes in the MSD representative of simulated supragingival plaques (p<0.05). In simulated subgingival plaques (MDFRs), CT was more effective than CPH at reducing Gram-negative anaerobes and streptococci (p<0.05). CONCLUSIONS: These results indicate that CT is more efficacious than CPH at reducing the amounts of bacteria in plaques for outcomes relevant to oral hygiene