Bactericidal effect of electrolyzed neutral water on bacteria isolated from infected root canals

Objective. The purposes of this study were to examine the time-related chan ges in pH, oxidation-reduction potential, and concentration of chlorine of electrolyzed neutral water and to evaluate the bactericidal effect of elect rolyzed neutral water against bacteria from infected root canals. Study design. Various properties of electrolyzed neutral water-pH value, ox idation-reduction potential, and concentration of chlorine-were measured at different times after storage of the water in the open slate, the closed s tate, or the closed-and-dark state. The bactericidal effect of the various electrolyzed neutral water samples was then tested against 17 strains of ba cteria, including 15 strains isolated from infected canals, as well as agai nst 1 strain of fungus. Each bacterial or fungal suspension was mixed with electrolyzed neutral water, and the 2 substances were reacted together for 1 minute. After incubation for 1 to 7 days, the bactericidal effect of the electrolyzed neutral water was determined. Results. The pH value and oxidation-reduction potential of electrolyzed neu tral water remained almost unchanged when the water was stored in a dark, c losed container. However, the concentration of chlorine decreased from 18.4 ppm to 10.6 ppm. Electrolyzed neutral water showed a bactericidal or growt h-inhibitory effect against the bacteria. Conclusions. The results indicate that electrolyzed neutral water maintains a constant pH and oxidation-reduction potential when kept in a closed cont ainer without light and that it exhibits a bacteriostatic/bactericidal acti on against isolates obtained from infected root canals.