A pilot study comparing the disinfecting effects of commercialized stable ClO solution (free of activation) with conventional HO on dental unit waterlines in the dental practice setting.

Disinfection of dental unit waterlines (DUWLs) plays a key role in control and prevention of nosocomial infection in a dental clinic. The most conventional disinfectant is hydrogen peroxide (HO), while chlorine dioxide (ClO) has been considered however was limited by the "activation" procedures. With the availability of commercialized stable ClO solution (free of activation), direct application of ClO in the dental practice became possible. This study was designed to compare the disinfecting effects of stable 5 ppm of ClO solution with conventional 0.24% of HO on DUWLs in dental practice. Studies of colony-forming units (CFUs), confocal laser scanning microscopy (CLSM) and scanning electron microscope (SEM) were employed for evaluation. In CFUs studies, we found that the efficiency of ClO was no less than those of HO In the morphological studies, the stronger disinfecting effects of ClO was verified by both CLSM and SEM studies for removal and prevention of biofilm. Importantly, ClO solution achieved a better disinfecting efficiency not only at the surface of bacterial biofilm, but also, it has penetrating effects, presented disinfecting effects from the surface to the bottom of the biofilm. This pilot study provided evidence regarding the efficiency of stable ClO solution on disinfection of DUWLs in the dental practice setting. Application of stable ClO solution in dental practice is therefore become possible.