Control of bacteria in dental water supplies

A simple device which releases chlorhexidine acetate into dental unit water supplies is described. The device comprised methyl methacrylate resin containing 40% by weight of chlorhexidine powder, cast into a rod shape and placed in a reservoir. After initial cleaning by flushing with hypochlorite, five dental units were fitted with the device and five units acted as controls. The device successfully kept four units virtually free of bacteria over a 3-month period but effective cleaning of the tubing within the units was found to be essential for success. Sustained release of chlorhexidine offers one means of tackling the problem of contaminated water in dental units, without resorting to complex pumping or metering systems.