Evaluation of Bacterial Contamination of Water Supply in Dental Unit Water Lines at Shahroud Dental Offices 2015

Assessment of microbial contamination in dental unit waterlines has been focused on because of high risk of dangerous infections in immunocompromised patients. The purpose of this study was to evaluate the bacterial contamination of water supply in dental unit water lines at Shahroud dental offices. In this descriptive analytical study we investigated 560 water samples collected from four parts of each unit including air/water syringe, turbine hand piece (before &after flushing), cup filler and 2 water sample collected from city water reservoir in Shahroud dental office during 2015. Water samples were taken on Saturdays (the first working day in a week) and Thursday (the last working day in a week), before and after treatment on the same units.Samples were transported in closed sterile containers to microbiology laboratory. All samples were incubated on blood agar and McCaskey plates for 72 hours at 37°C. Bacterial contamination was then evaluated. All samples were analyzed for legionella. Data were analyzed by ANOVA and t-test. Total mean bacterial count was 4671 cfu/ml. Mean bacterial contamination on Saturdays (6320 cfu/ml) were higher than Thursdays (3860 cfu/ml). Mean bacterial contamination before treatment was (4050 cfu/ml) less than the end of treatment (6250 cfu/ml) on the same unit. Mean bacterial contaminations of self-Dental Office was higher than other clinics The result of this study demonstrated that microbiological level of dental unit waterlines is high. The dentists must be aware of the high level of microorganisms in the dental unit’s water and thus minimize the risk of infection in both staff and patients.