Abstract: Objective To evaluate the antibacterial effects of bioactive glass (BG) of different concentrations on three species of planktonic bacteria,single bacterial biofilms formed by the planktonic bacteria,and the subgingival early mixed bacterial plaque.Methods The minimal inhibitory concentration(MIC),minimal bactericidal concentration(MBC),minimal biofilm eradicationconcentration(MBEC) of Streptococcus sanguinis(Ss),Actinobacillus actinomycetemcomitans(Aa) and Fusobacterium nucleatum(Fn) were assessed.Inert silica glass (SiO2)and bioactive glass of 20,40,80 mg/mL were used to treat early mixed bacterial plaque for 24 h.Confocal laser scanning microscopy(CLSM) was used to observe and analyze the thickness and average fluorescence intensity of the plaque. Results The MBECs of BG to single bacterial plaque biofilm were significantly greater than the MICs and MBCs of planktonic bacteria.MBECs were 2~16 times greater than MICs.With the concentrations of bioglass increasing,there was a relative decrease in the thickness,mass and vitality of the mixed plaque.Statistically there was a significant difference between the blank control group and SiO2 groups (P<0.05).Conclusions BG can inhibit and kill planktonic forms of Streptococcus sanguinis,Actinobacillus actinomycetemcomitans and Fusobacterium nucleatum as well as the single form of bacterial plaque biofilm.However,the effect on single form of bacterial plaque biofilm was much better.BG of low concentration had certain antibacterial effects on the subgingival early mixed bacterial plaque.

Key words: bioactive glass, subgingival plaque, biofilm, antibacterial effect