Bactericidal activity of neutral electrolyzed water gel

Objectives: Electrolyzed waters have been widely used in clinical dentistry because of their excellent bactericidal activities. For the wider use, we reported the development of a preparation of gel with agar. Effects of conditions of use and storage on the bactericidal activities of neutral electrolyzed water gel were examined to find out the appropriate sterilization in this study. Methods: Neutral electrolyzed water gel was prepared by mixing high-density electrolyzed water and agar sol. Bactericidal activities of the gel when the quantity of it to mix with bacteria suspension changed were examined. After mixing, 0.1 or 1.0 ml was mixed with the fresh saline solution and the solution was added to the agar culturing media. Total number of the surviving bacteria was calculated from the number of the colonies in the media after incubation. And changes in the bactericidal activity under several storage conditions were examined. Results: The number of surviving bacteria decreased with the increase of the quantity of the gel. No surviving bacteria were detected after treatment with a quantity of gel more than 20 times that of bacteria suspension. When stored in the transparent syringe in the room, the deterioration of residual chlorine concentration of gel was larger than that of gel stored in the shaded syringe and the gel showed effective bactericidal activity only for 1 week. On the other hands, the gel when stored in the shaded syringe in the refrigerator for 9 weeks showed excellent durability of the bactericidal activity. Conclusions: It is necessary to use the gel exceeding 20 times the quantity of the bacteria suspension, taking into consideration the form of treated area and the presence of organic matter. And it is necessary for the gel to be stored in the shaded syringe in the refrigerator for long-term duration of bactericidal activity.