Methods: Seventeen dental unit waterlines were evaluated, including two in a control (untreated) unit and fifteen in units equipped with antimicrobial bottles and utilizing either the PureTube BR360, PureTube PLUS, or the PureLine 50 disinfection products (N=5 each) (Sterisil, Castle Rock, CO). Water samples were collected aseptically from the waterlines at baseline, day 1, week 2 and week 5 for microbial (CFU) evaluation. The heterotrophic plate count CFU/ml was determined using the membrane filter method.
Results: Baseline samples collected from the seventeen untreated waterlines ranged from 6,030 to 1,704,000 CFU/ml. After five weeks of treatment, the following results were recorded: Plate counts for the untreated control waterline samples ranged from 27,300 to 51,000 CFU/ml. PureLine 50 water treatment samples demonstrated the best results, with all five plate count samples below the applicable standard of 500 CFU/ml (all five, in fact, were 0 CFU/ml). The PureTube BR360 samples had all five plate counts below 500 CFU/ml (range 1-173 CFU/ml). Plate counts for the Pure Tube Plus waterlines ranged from 0 to 165,600 CFU/ml (only two out of five samples had plate counts below 500 CFU/ml). On average, HPCs were reduced by 100% after five weeks where PureLine 50 water treatment was used, 99.95% where the PureTube BR360 was used, but, on average, the HPC was not reduced with the Pure Tube Plus.
Conclusion: Five weeks of treatment with either PureLine 50 or PureTube BR360 was quite effective in reducing bacterial contamination in dental unit waterlines. Treatment with Pure Tube Plus over the same period did not produce a consistent reduction in bacterial contamination in the waterlines.
This study was supported by Sterisil Inc.