Water cleaning systems improves the water quality in dental unit water lines (DUWL). A report from the Public Dental Health of Västra Götaland region, Sweden.

Abstract

Biofilms are formed in the dental unit waterlines, which leads to unacceptable high levels of bacteria in the water used for dental treatment. Public Dental Health in Västra Götaland, Sweden, decided in 2010 to install water cleaning systems in all dental units. This report shows the effect of this water-cleaning program comprising 841 dental units. The 841 dental units in 111 clinics in the Public Dental Health Service of Västra Götaland region participated in the study. 50 ml water was sampled from the air-water syringe after 2-3 hrs of use and were analyzed for the number of fast-growing (2 days incubation) and slow-growing (7 days incubation) bacteria calculated as colony forming units (CFU) per ml. Approved water quality was set to <100 CFU/ml accordingto the recommendations from the Board of Health and Wellfare (Socialstyrelsen). Altogether 77.3% of the dental units reached approved levels, which was considerable higher than the 25.2% that were approved in a similar study at FTV in the city of Göteborg 4 years earlier when no water cleaning systems were installed. Further, 474 dental units using the Alpron/ Bilpron weekend system 83.4% were approved, 136 units using Unit Clean system 87.5% were approved and 15 using the Sterilox system all reached below 100 CFU/ml. The 199 dental units with inbuilt cleanings systems by the manufacturers based on hydrogen peroxide only 56.3% were approved. A number of 45 (22.6%) showed very high levels (> 10 000 CFU/ml) indicating serious problems with the practical procedures or installation of the systems that needs further attention. The study showed generally improved conditions of the water in the dental units after the introduction of water cleaning systems in the clinics of Public Dental Health Service of Västra Götaland Region, Sweden although the problem still remains in many units.