Purge- and intensive-purge decontamination of dental units contaminated with biofilm

Introduction: During hygienic-microbiological monitoring of the water quality in dental units, the total bacterial colony count was found to exceed the limits for drinking water quality; in addition, mold contamination was detected. The presumed cause was irregular decontamination of the units through purging and intensive decontamination. Methods: To decontaminate the units, the manufacturer’s recommended program for cleaning and intensive decontamination was intensified by shortened intervals over a 2-week period. For Sirona units, instead of once a day, the automatic purge program was run every morning and evening for 20 min each time, and instead of once a month, intensive decontamination was performed every two weeks; this schedule has been maintained since then. For KaVo units, cleaning with the hydroclean function was carried out for 2.5 min every morning and evening. The automatic intensive decontamination was run daily instead of weekly. A maintenance log book was introduced, in which decontamination/cleaning was confirmed by the operator’s signature. Results: Within 5 weeks, all previously contaminated units were decontaminated. Discussion: By shortening the cleaning and intensive decontamination intervals in a 2-week period with subsequent control that the recommended maintenance intervals were kept, it was possible to guarantee drinking-water quality in the dental units of both manufacturers.