Evaluation of the Bacteriological Quality of Dental Unit’s Waterlines, Tehran, Iran

Hossein Masoumbeigi, Ghader Ghanizadeh, Bahman Ramacandi, Hossein Kardan Yamchi


Oral and dentistry (O&D) services processes may lead to exposing of personnel and patients with several microorganisms and arising of health problems. This cross-sectional study was investigated the bacteriological quality of dental unit waterlines (DUWLs) in one of the O&D center in Tehran, Iran. One hundred ninety two samples were collected and examined based on standard microbiological procedures for determining and enumeration of heterotrophic plate count (HPC), Staphylococcus aureus and Pseudomonas aeruginosa. Data were analyzed by t-test, analysis of variance (ANOVA), Kruskal-Wallis and LSD tests with SPSS software (Ver.16). The results revealed that 70% of water samples (126 samples) had a high density of contaminations that higher than recommended values for DUWLs quality. The mean of bacterial density on Saturday was more than Wednesday and was 1838 CFU/ml, 739 CFU/ml and 11 CFU/ml for HPC, P. aeruginosa, and S.aureuse respectively. The LSD test implied that the mean of bacterial density of inlet and outlet waters had significant statistical difference in various wards of the O&D center (p < 0.05). In addition, the results demonstrated that bacteriological quality in discharging water of various wards was higher than the recommended values. This research revealed that microbial water quality assessment in O&D services centers should be considered for providing of an appropriate disinfection procedure from point of infection control in dental operation services.


Dental Center, Water Bacteriological Quality, Dental Unit Waterlines, Heterotrophic Plate Count, Staphylococcus aureus, Pseudomonas aeruginosa.

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Iranian Journal of Health, Safety and Environment e-ISSN: :2345-5535 Iran university of Medical sciences, Tehran, Iran