Evaluating Bacterial Contamination of Water Supply in Dental Units at Alborz University of Medical Science Using Microbial Culture and Colony Count in 2019

Introduction: With respect to the outbreak probability of dangerous infections among the patients, the water sources of dentistry units were taken into consideration, in view of microbial contamination. The objective of this study was to assess of pathogenic organisms of the water used in the dentistry units at Alborz Dental School. Material and methods: In this study, 120 samples from high speed handpieces before and after flushing, syringes, drinking water of units and also 5 samples of tap water were taken as control. Then the samples were cultured on EMB and Blood agar plates and the number of the bacterial colonies were counted. The data were analysed using Descriptive statistics. Results: A total of 125 samples were examined for bacterial contamination. The mean bacterial count of primary turbine before flushing was 5463.33±6921.156 Cfu/ml, the mean bacterial count of turbine after 30 seconds of flushing was 3090.00 ±4354.336 Cfu/ml, the mean bacterial count of syringe was 2733.33±2666.307 Cfu/ml, the mean bacterial count of drinking water of unit was 1996.67±1060.411 Cfu/ml. Also the mean bacterial count of tap water was 83.666±280.00 Cfu/ml. Microorganisms isolated were as follow: Escherichia coli (41.64%), Klebsiella (30.83%), Non-pathogenic Staphylococci (26.6%), Micrococus (25.83%), etc. Conclusion: The result of this study demonstrated that bacterial contamination level of dental unit waterlines is high, and the microbiological quality of the water must be monitored regularly. Flushing decreases the contamination of DUWL, but in surgeries and in persons with immunedificiency, the use of other methods of DUWL decontamination is recommended.