Abstract: Objective To compare the antibacterial properties of a toothpaste containing both fluoride and chlorhexidine with a toothpaste only containing fluoride. Methods The antibacterial ring sizes of different toothpastes against Porphyromonas gingivalis (P.gingivalis), Streptococcus sanguis (S.sanguis), Streptococcus mutans (S.mutans), Escherichia coli (E.coli), and Staphylococcus aureus (S. aureus) were measured. A threespecies biofilm model that consists of S.mutans, S.sanguis and P.gingivalis was established on the hydroxyapatites discs (HAs, d=6 mm) in vitro. The biofilms on the surface of HAs were detected by crystal violet staining and LIVE/DEAD bacteria staining to evaluate the antibiofilm properties of different toothpastes. Results Toothpastes with both fluoride and chlorhexidine and toothpaste with fluoride both had a certain antibacterial effect on five kinds of bacteria. The viability of the threespecies biofilms was significantly inhibited by two kinds of toothpastes. The biomass and thickness of the biofilms were significantly reduced by the toothpaste containing both fluoride and chlorhexidine. Conclusion Toothpastes containing both fluoride and chlorhexidine have greater effects on antibacterial properties than a conventional fluoridecontaining toothpaste.

Key words: Toothpaste, Chlorhexamine, Fluoride, Biofilm