van der Mei Henny, UMCG Groningen, The Netherlands

Mechanisms of Oral Biofilm Formation and Prevention

Henny C. van der Mei and Henk J. Busscher
Dept. of Biomedical Engineering, University Medical Center Groningen,
A. Deusinglaan 1, 9713 AV Groningen, The Netherlands, e-mail h.c.van.der.mei@med.umcg.nl

Mechanical plaque control without chemical support is insufficient to prevent oral diseases and an ongoing quest exists for new antimicrobials in oral health care. The first step in biofilm (dental plaque) formation in the oral cavity is bacterial adhesion to the salivary pellicle. The question is of course if reduction in initial adhesion also results in reduction of biofilm formation. Modifying the physicochemical surface properties of the salivary pellicle by treatment with antimicrobials as e.g. chitosans, aminefluoride, cetylpyridinium chloride is a possible and an interesting way to interfere in initial adhesion. Chitosan treated pellicles reduced bacterial adhesion and caused bacterial killing upon contact and therewith reduced biofilm formation. Despite the fact that aminefluoride treatment changed the surface properties of the salivary pellicle in vitro, only 3 out of 5 bacterial strains showed a reduction in adhesion. However, regardless of the strain involved, biofilm viability decreased significantly after AmF treatment. Since it is very difficult to mimic the oral cavity and therewith to translate in vitro results on oral biofilms to the in vivo situation, we have developed an improved method for quantitative assessment of antimicrobial efficacy and substantivity of oral antimicrobials in vivo. The proposed method holds promise for assessment of both immediate and retained antimicrobial actions of oral treatments against dental plaque in vivo.