Cytotoxicity of Electrochemically-Activated Water Solutions for Human-Pulp-Fibroblasts and Human-Gingival-Fibroblasts

The commercial market for electrochemically activated (ECA) water solutions is a fast developing environment. With all the proven and unproven claims of antibacterial, antifungal and antiviral activity it is inevitable that these products will find their way into the dental clinic as disinfecting solution for waterlines, irrigation solution and or general rinsing solution. The safety of these solutions for human consumption and for use in the dental clinic has however not been proven. Objectives: This study determined the in vitro cytotoxicity of three different ECA solutions (Sterilox – Millners Dental Suppliers; Steds1 - Medical Waters; Steds3 – Medical Waters) on human pulp fibroblasts (HPF) and human gingival fibroblasts (HGF). Methods: HPF and HGF were cultivated in DMEMS in a humidified incubator (37°C, 95% air + 5% CO2). After standardization and calibration of the cell concentrations, monolayers of the respective cells were exposed to different concentrations of ECA solutions for different time intervals. After exposure the survival of cells were determined and cells were also re-incubated in DMEMS to allow recovery of cells. Survival and growth in these samples were determined after 24 hours and 1 week after exposure to the ECA solutions. Results: All ECA solutions had a significant cytotoxic effect on both HPF and HGF. For some ECA solutions the cytotoxicity varied for different concentrations and the exposure time of the cells to ECA solutions. Both 100% Sterilox and Steds3 killed all HPF and HGF immediately after exposure. Sterilox 10% and Steds1 had variable cytotoxicity on HPF and HGF. Sterilox 5% had the lowest cytotoxicity as cells were surviving one week after exposure. Conclusion: ECA solutions are cytotoxic for survival and growth of HPF and HGF. Lower concentrations and short exposure times however limited relative cytotoxicity.