Water quality management in dental unit water lines

Dental unit water lines (DUWLs) are an integral part of dental treatment systems. They provide water for lubrication during mechanical processes, instrument cooling and irrigation during treatment.

Studies to evaluate the microbiological quality of water from DUWL systems have indicated that high levels of bacteria are frequently present in the water delivered from the unit to the patient's mouth (Barbeau et al, 1996; Walker et al, 2000). Bacterial contamination of DUWL output water results from feed water contamination and bacteria released from biofilm in the DUWL system.

Biofilm may support pathogenic species and therefore constitute a source of infection to patients and dental practitioners via aerosol inhalation, ingestion or surgical site infection. While documented infections by these routes are rare, some significant cases have been recorded (Ricci et al, 2012). Pathogenic species have been isolated from DUWLs and there is evidence that dental personnel experience higher levels of exposure to certain pathogens than other groups of workers (Atlas et al, 1995; Szymanska, 2004).