Decontamination of dental unit water systems: a review of current recommendations

Abstract

It is now recognised that water delivered to dental handpieces and air/water syringes via dental unit water systems may become significantly contaminated with micro-organisms which originate from the incoming water supply and, to a lesser extent, with oral micro-organisms. The purpose of this article is to review the literature relating to the risks associated with contamination of dental unit water systems and methods which may be used to minimise these risks.

Electro-chemically activated water in dental unit water lines

“…However some very real concern has been expressed by many about the threat that these opportunistic pathogens may pose to the ever increasing population of immunocompromised patients. 5,[25][26][27] Two cases of postoperative infections in cancer patients, caused by Pseudomonas aeruginosa apparently originating from dental unit water, have been reported. 5 The implications of potential pathogens being iatrogenically transmitted to patients undergoing dental treatment are serious.…”

“…To overcome these problems the use of independent water systems and microfilters has been suggested. 10,26,27,32 It was also advised that a strict maintenance regime, consisting of daily flushing and purging with sodium hypochlorite be followed. The use of special in-office DUWL monitoring technology has also been prescribed.…”

Microbial Biofilm Formation and Contamination of Dental-Unit Water Systems in General Dental Practice

“…and opportunistic and true human pathogens (e.g., Pseudomonas aeruginosa, Legionella pneumophila, Mycobacterium spp., and Staphylococcus spp.) (10,14,16,21,30). Such organisms may originate from incoming local water supplies, although organisms commonly found in the oral cavity have also been recovered (37,38), suggesting that some bacteria may be derived from the patient following back siphonage.…”

Evaluation of the efficacy of Alpron disinfectant for dental unit water lines

“…That is, the triple syringe and high speed water outlets (both P = 0.001), with significant decreases in log 10 TVC at week 1 and week 6 compared with the baseline for the high speed line and the triple syringe. An analysis of the microbial counts from each of the six units included in the study (Tables 1-4) (2) 24 (2) 2 (2) 2 (0) Baseline 1525 (0) 4875 (0) 100,000 500 (1) 1695 (0) 2625 (615) (100,000) (4) 184 ( (2) 262 (4) 214 ( (18) 158 (2) 4 (2) 0 (0) There have been several attempts to reduce the microbial contamination of dental unit water lines including autoclaving of handpieces, handpiece replacement between patients, flushing of the unit prior to use, 'anti-contamination' devices to prevent retrograde aspiration of oral secretions into the water supply line, 19 connection to a separate water supply (for example, connection to bottles of distilled water), ultra-violet radiation disinfection and the use of in-line water filters. 3,[20][21][22] Many workers have suggested treatment with various disinfectant solutions, including hydrogen peroxide, 23 chlorhexidine gluconate, 24 sodium hypochlorite, 25,26 chlorine dioxide, 27 povidone-iodine, 28 Listerine mouthwash 29 and electro-chemically activated water.…”