Anti-biofilm Activity of Oral Health-care Products Containing Chlorhexidine Digluconate and Citrox.

To analyze in vitro new formulations with Citrox and chlorhexidine digluconate (CHX) regarding their antibacterial activity against planktonic bacteria and their potential to inhibit biofilm formation or to act on existing biofilms. Five oral health care products with 0.05%-0.5% CHX formulations (four rinses and one gel) were compared with Citrox preparations and additive-free CHX solutions. The minimal inhibitory concentrations (MIC) were determined against 13 oral bacteria associated with caries or periodontitis. Further, the activity on retarding biofilm formation and on existing biofilms was analyzed; both a 'cariogenic' (5 species) and a 'periodontal' (12 species) biofilm were included. The MIC values did not differ between the CHX mouthrinse/gel formulations and the respective additive-free CHX solutions. Citrox was active against selected periodontopathogens (e.g. Porphyromonas gingivalis). The CHX formulations more effectively retarded biofilm formation than did solutions with the same concentration of CHX but without additives. The anti-biofilm activities depended on the CHX concentration in the formulations. Both CHX solutions and formulations (rinse and gel) were only slightly active on an already formed biofilm. Citrox did not exert any anti-biofilm effect. The present in vitro data support the anti-biofilm activity of the novel CHX, Citrox, poly-L-lysine and xylitol oral health-care formulations. Further studies are warranted to confirm the present findings in various clinical settings.