An audit improves the quality of water within the dental unit water lines of three separate facilities of a United Kingdom NHS Trust

Abstract

To improve the quality of water emanating from dental unit waterlines (DUWLs). A prospective clinical audit. Three geographically separate district dental facilities of a United Kingdom NHS Trust, involving two community clinics and one hospital orthodontic department, which were evaluated between 2002 and 2004. Samples of water discharged from the DUWLs were collected prior to the start and midway through a morning session. These were tested microbiologically at a United Kingdom Accreditation Service testing laboratory within six hours of sampling. One of the clinics followed the contemporaneous BDA advice of flushing water through its DUWLs while the other two clinics used separate intermittent disinfection purging regimes instead. One of them used a two stage protocol of Ethylene Diamine Tetra-Acetic acid followed by hydrogen peroxide, while the other used Bio 2000 as a single agent, which was subsequently superseded by the continuous use of super-oxidised water (Sterilox). To assess whether the samples either met the American Dental Association's guideline on the quality of DUWL water, or the more stringent European Union standards for potable (drinking) water. The two units which used a disinfection regime both complied with the ADA guideline and the EU potable water standard. However, the unit which only flushed through its DUWLs without using a disinfectant failed to comply with either of them. After all three dental facilities subsequently standardised their DUWL disinfection regimes by using Bio 2000, the colony counts from all of the water samples thereafter remained well below the EU recommended level. The unit which progressed to using Sterilox as a continuous disinfectant achieved and maintained zero readings from its water samples. Clinical audit can result in the improvement of the quality of water that is discharged through DUWLs, thereby minimising both the risk of cross infection to vulnerable patients, as well as to dental staff chronically exposed to contaminated aerosols.