Evaluation of Bacterial Contamination in Dental Unit Water Lines in Zahedan in 2016-2017

Background & Aim: Due to a constant contact of dentists and patients with water and aerosols generated from the dental units, the quality of dental unit waters is very important. This study aimed to evaluate bacterial contamination of dental unit water lines in Zahedan in 2016-2017. Methods: In this descriptive analytical study, 2304 water samples from four parts of unit including cup filler, water spray, turbine duct, cavitroon and a sample from city water reservoir were collected. Water samples were taken on Saturday and Wednesday, before and after treatment on the same unit. Samples were transported in closed sterile containers to microbiology laboratory. All samples were incubated on Standard Method Handbook. Then, the grown colonies were counted in term of growth of heterotrophic bacteria. Wilcoxon and Mann-Whitney statistical tests were used for data analysis. Results: Total means bacterial count was 191.96±184.32 colonies per milliliter (CFU/mL). Mean bacterial contamination on Saturday 209.98±194.56 (CFU/mL) was more severe than that of Wednesday 173.94±171.67 (CFU/mL). Mean bacterial contamination before treatment 178.78±174.23 (CFU/mL) was less than the end of treatment 205.14±193.07 (CFU/mL). Also, mean bacterial contamination of turbines and cavitroon after flushing was decreased significantly (P < 0/05). Mean bacterial contamination on Saturday and Wednesday was also decreased significantly (P < 0.05). Conclusion: Due to high contamination of Dental Unit Water Lines, the dentists must be aware of the high level of microorganisms in the dental unit's water and take preventive strategies to minimize the risk of infection in both staff and patients.