The microbial profiles of dental unit waterlines in a dental school clinic

What is it about?

Background: The microbiological quality of water delivered in dental units is of considerable importance since patients and the dental staff are regularly exposed to aerosol and splatter generated from dental equipments. Dental-Unit Waterlines (DUWLs) structure favors biofilm formation and subsequent bacterial colonization. Concerns have recently been raised with regard to potential risk of infection from contaminated DUWLs especially in immunocompromised patients.Objectives: The study aimed to evaluate the microbial contamination of DUWLs at RAK College of Dental Sciences (RAKCODS) and whether it meets the Centre of Disease Control’s (CDC) recommendations for water used in non-surgical procedures (≤500 CFU/ml of heterotrophic bacteria).Materials and Methods: Ninety water samples were collected from the Main Water Source (MWS), Distilled Water Source (DWS) and 12 random functioning dental units at RAKCODS receiving water either directly through water pipes or from distilled water bottles attached to the units. Bacterial enumeration and molecular identification were performed. Results: The MWS had the lowest bacterial count (499 CFU/ml).The bottled units contained significantly higher numbers of CFU (2632±1231.783) compared to non-bottled units (1484.75±1395.093), p<0.02.Ralstonia spp. was the most common bacteria present in the MWS and DWS (in 96% of the samples). Other bacteria were Sphingomonas paucimobilis 88.8% and Leifsonia spp. 73.5%.Conclusion: There is a need for regular water monitoring at dental clinics, in addition to regular maintenance and disinfection programs to ensure quality water delivery that meets the CDC guidelines for non-surgical water.Keywords: Maintaining dental unit waterlines, microbial contamination, biofilm formation, non-surgical water.

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