Dental unit water contamination.

Bacteria-laden biofilms located on the lumen surface of dental unit water lines have resulted in the persistent and widespread microbial contamination of dental unit water supplies. These biofilms are resistant to chemical disinfection. As such, they act as reservoirs that facilitate the continuous re-contamination of dental unit water. The microbial populations of the biofilms found in dental unit water lines include opportunistic pathogens of unknown significance. Strategies to control the contamination are discussed.