The development of a dental unit without a water supply pipe to prevent water contamination

Abstract

Water contamination from conventional dental units is serious problem. The ADA (American Dental Association) set recommended standard level of water quality from dental units as 200 CFU/mL (heterotrophic bacteria). However, there are no reports on dental units used worldwide meeting this standards. The purpose of this study was to develop a units without a water supply pipe, and meet water quality standards set by the ADA. So, we developed a dental unit installing a built-in removable water supply tank, without a water supply pipe to eliminate biofilm, the source of water contamination in the pipe. And, we grew heterotrophic bacteria on R2A agar medium at 20°C for 7 days, and measured bacterial numbers for water quality tests. The results showed that the number of heterotrophic bacteria from turbine, engine-handpiece and three-way syringe ranged between 2 and 80 CFU/mL, achieving the standard value of the ADA.