Control of microbial contamination in dental unit water systems using tetra-sodium EDTA |
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Authors: | R.S. Percival D.A. Devine B. Nattress P. Kite P.D. Marsh |
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Affiliation: | University of Leeds, Dental Institute, Leeds, UK; Aseptica, Inc., Washington, USA |
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Abstract: | Aim: To examine the efficacy of tetra-sodium EDTA in controlling microbial contamination of dental unit water systems (DUWS). Methods and Results: Ten dental units were treated once a week with either 4% or 8% tetra-sodium EDTA for four or two consecutive weeks, respectively. Before treatment, 43% and 60% of the water samples from the air/water triple syringe and high-speed hand-pieces, respectively, exceeded the American Dental Association (ADA) guidelines of 200 CFU ml−1 water during a 6-week baseline period. After each weekend treatment, the levels of microbial contamination in all DUWS fell significantly ( P < 0·001) to below the ADA guideline. By the end of the week, microbial counts in the outflowing water had returned to baseline levels indicating a transient effect of single doses of tetra-sodium EDTA, and the need for multiple applications. The biofilms were virtually eliminated after a single weekend treatment. Conclusions: Tetra-sodium EDTA is effective in controlling microbial contamination in DUWS. Significance and Impact of the Study: Inexpensive, effective and safe products for reducing the microbial load of water from DUWS are needed to meet ADA and other national guidelines. Tetra-sodium EDTA can significantly reduce microbial biofilms and bacterial counts in outflowing water, and is compatible for use in DUWS. |
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Keywords: | biofilms cross-infection dental unit water systems disinfection tetra-sodium EDTA |
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