RESUMO
BACKGROUND: Benzalkonium chloride has been used in dental restorative materials to enhance the long-lasting antibacterial properties of materials. OBJECTIVE: To evaluate the antibacterial activity of benzalkonium chloride on oral common pathogenic bacteria in vitro. METHODS: The agar diffusion method was used to determine the inhibitory effects of antibacterial agents, 0.1% benzalkonium chloride, 3% H2O2and 5.25% sodium hypochlorite, on five kind of oral pathogens, Porphyromonas gingivalis (P.g), Prevotella intermedia (P.i), Actinobacillus actionmycemcomitans (A.a), Streptococcus mutans (S.m) and Enterococcus faecalis (E.f). The tube dilution method was used to detect the minimal inhibitory concentration of benzalkonium chloride against the five bacteria mentioned above. RESULTS AND CONCLUSION: The antibacterial effect of 0.1% benzalkonium chloride on P.g was not significantly different from that of 3% hydrogen peroxide (P＞0.05), while 0.1% benzalkonium chloride showed better effect on P.i than 3% hydrogen peroxide (P＜0.05). On P.g and P.i, the antibacterial effect of 0.1% benzalkonium chloride was worse than that of 5.25% sodium hypochloritethe ( P＜0.05). The antibacterial effect of 0.1% benzalkonium chloride on A.a and S.m was better than that of 3% hydrogen peroxide (P＜0.05), and similar to that of 5.25% sodium hypochlorite (P＞0.05). The antibacterial effect of 0.1% benzalkonium chloride on E.f was better than that of 3% hydrogen peroxide (P ＜ 0.05), but worse than that of 5.25% sodium hypochlorite (P ＜ 0.05). The minimal inhibitory concentration of benzalkonium chloride to P.g, P.i, A.a, S.m, E.f was 16, 2, 4, 2, 4 mg/L, respectively. To conclude, 0.1% benzalkonium chloride has strong antibacterial effects on P.g, P.i, A.a, S.m and E.f.