Evaluation of A Chlorine Dioxide Disinfectant for Dental Unit Waterlines / 中华医院感染学杂志

ABSTRACT

OBJECTIVE To investigate the use of a chlorine dioxide-based dental unit waterline(DUWL) treatment to reduce the colonization and growth of heterotrophic bacteria.METHODS Twenty-two dental units with self-contained water systems were randomly selected.Three of the units and tap water served as controls.Twenty-three water samples were taken at baseline and once a week for five weeks.They were serially diluted,spread-plated in duplicate onto R2A agar plates and incubated at 37 ℃ for 7 days.RESULTS At baseline,the 3 control DUWLs had a median count of 8440 colony-forming units/milliliter(CFU/ml) and the 19 treated DUWLs had a median count of 9160 CFU/ml.By week 1,18 of the 19 treated DUWLs had counts of less than 200 CFU/ml,and by week 4,the median count for all of the treated DUWLs was 0 CFU/ml.The measurement at week 5 showed that the reduction to below 200 CFU/ml had been maintained.Scanning electron examination revealed a similar results,with biofilm accumulation more evident in the untreated control specimens.CONCLUSIONS Using a chlorine dioxide-based disinfectant in DUWLs can achieve the American Dental Association(ADA) goal of less than 200 CFU/ml of heterotrophic bacteria per milliliter of unfiltered output water.