A simulated-use evaluation of a strategy for preventing biofilm formation in dental unit waterlines.

Background: Prevention of biofilm formation is important in the maintenance of dental unit waterline systems. Without effective control measures, the waterlines will become contaminated with routine use.

Methods: The authors used a simulated-use dental unit waterline system to evaluate the ability of a test product, A-dec ICX (A-dec, Newburg, Ore.), to prevent biofilm formation. They evaluated buffered distilled water and hard water models versus mixed-challenge suspensions of Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa.

Results: The authors documented development of significant biofilm in untreated test units, while treated test units showed no indication of biofilm formation throughout the 16-week study. Student t tests and 95 percent confidence intervals performed on the plate count data confirmed that untreated test units had significantly greater bacterial populations than did treated test units (P < .05). Qualitative images by scanning electron microscopy verified these findings.

Conclusion: In this simulated clinical-use study, the test product effectively reduced bacterial counts in incoming water and produced water quality exceeding stated recommendations of the American Dental Association.

Clinical Implications: The test product provides an approach to dental unit waterline maintenance that is simple to use and that, by continuously preventing biofilm formation, reduces concerns about bacterial contamination in dental unit water.