Enhanced antibacterial effect against Enterococcus faecalis by silver ions plus Triton X-100 with low concentrations and cytotoxicity

Enterococcus faecalis ( E. faecalis ) is commonly considered to be one of chief culprits of secondary and persistent root canal infections. As antibiotic resistance has become a global issue, in order to reduce the use of antibiotics, metal ions have recently been widely used as an alternative. Silver ions (Ag + ) have been proved to be a strong bactericide but with high cytotoxicity and discoloration property. Triton X-100 (TX-100) and Ag + were co-used for the first time as a clinical intracanal medication to obtain both enhanced antibacterial effect and low cytotoxicity. The synergistic antibacterial effect of TX-100 + Ag + was tested on both planktonic and biofilm-resident E. faecalis on dentine. And the cytotoxicity was tested on MC3T3-E1 cells. Results confirmed the antibacterial activity against both planktonic and biofilm-resident E. faecalis was dramatically improved after TX-100 incorporation. TX-100 and Ag + mixture demonstrated a similar inhibitory effect as the 2% chlorhexidine (CHX), while the cytotoxicity was much lower than 2% CHX ( p  < 0.05). In conclusion, TX-100 + Ag + mixture might be developed into a new effective intracanal medication as the 2% CHX.