Biocidal Activity of Antiseptic Mouthrinses in Saliva-Derived Biofilm Model

Objective: This study was designed to compare the plaque biofilm biocidal activity of antiseptic mouthrinses CoolMint Listerine® (L-essential oils) mouthrinse, Peridex® (P-0.12% chlorhexidine), Perio Aid (PA-0.05% cetylpyridinium chloride and 0.05% chlorhexidine), Meridol (M-amine fluoride and stannous fluoride, containing 250 ppm fluoride) and Crest® Pro-Health™ (CPH - 0.07% cetylpyridinium chloride) in an ex vivo saliva-derived biofilm model. Methods: Antimicrobial activity was determined by confocal laser scanning microscopy analysis of vital - stained treated biofilms. Saliva from six subjects was used as inoculum for both 16-18 and 65 hr mature biofilms. Three test protocols were: 30 or 60 sec single treatment of 16-18 hr saliva derived biofilms or two separate 30 sec exposures of mature 65 hr biofilm, with a 6 hr interval between the first and second 30 sec exposures. The two 30sec treatment method was designed to simulate “twice daily” label directions and to assess relative substantivity of the different rinses. Although Meridol label direction is for once daily use, it was also tested via the two 30 sec exposures, to compare mode of action with other actives. Results: Single 30 or 60 sec exposures showed L was significantly more effective in reducing vital stained biofilm cells: L > P = PA > M > CPH. The 60 sec treatment demonstrated CML again was more effective: L > PA > P > CPH > M. In the “twice daily exposure” experiment, L and P were significantly more effective than other rinses. Conclusion: In this saliva-derived biofilm model, two treatments of mature biofilm with 6 hours between them produced results that more closely approximated published clinical results than did a single 30 or 60 sec treatment.