Dental unit waterline management: historical perspectives and current trends

Interest in and concern about the biofilms that occur in dental waterlines have been increasing in recent years. Dental unit waterlines harbor considerable amounts of bacteria that are derived from the biofilm on the inner surface of these lines. This continuous reservoir of bacteria carries the potential of causing infection to patients and dental workers. The majority of dental procedures require the use of water for cooling instruments, irrigation, and oral rinsing, so it is extremely important that the water used in oral procedures is of a high quality. The present study illustrates the conditions in waterline tubing that favor development of biofilms, and discusses the level of risk that such microbial growth poses for both dental professionals and their patients. The different methods to circumvent this problem are reviewed, and the recent recommendations that should be adopted in the dental clinic to provide the patients with water of acceptable microbiological standards are discussed.