A Study on Microbial Quality of Water Used in the Dentistry Units of Yasuj City

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 of Yasuj city. In this research 120 samples of water from poir and turbine of units (before and after flushing) and two samples of urban water were collected. Sampling was performed on the first weekday (48 hours after the units were switched off) and mid week(16 hours after the units were switched off) before starting work. The samples were cultured on EMB Agar and Blood Agar and incubated at 37oC for purification for Gram positive or Gram negative bacteria and it was identifying with biochemical diagnostic test. Also the samples were counted by standard plate count. The average count of bacteria before flushing in Poir on the first weekday was 5360CFU/L and turbine was 2800 CFU/L and count of bacteria after flushing in Poir on the first weekday was 1040 CFU/L and turbine was 1020 CFU/L. While this result for midweek day: The average count of bacteria before flushing in Poir was 3220 CFU/L and turbine was 2720CFU/L and count of bacteria after flushing in Poir was 1772 CFU/L and turbine was 980 CFU/L. Several samples of before and after flushing were contaminated with E.coli, Pseudomonas, Proteus, Kelebsiella, gram positive bacilli, Streptococci, Staphylococci, Diplo cocci and Yeast. According to the result of this study the contamination rate of the unit’s water was high and it’s rate reduced after flushing. The patients saliva causes water unit contamination and it constitutes biofilm in pipe of unit. Existence of E.coli shows the contamination of water to sewage and staphylococcus explains contamination due to return of the patient’s saliva into suctions. dental units waterlines showed bacterial contamination which was eliminated after flushing.