Optimizing hydrogen peroxide shock treatment frequencies for dental unit waterlines contamination control: a pilot study.

OBJECTIVE

This study aims to determine the optimal disinfection frequency by comparing the effectiveness of different hydrogen peroxide (H2O2) shock treatment schedules in controlling contamination of dental unit waterlines (DUWLs).

METHODS

Three dental units were randomly assigned to groups A, B, and C. After initial treatment with the Biofilm-Removing Set (BRS®), continuous treatment with 0.0141% H2O2 was applied. Shock treatment with 1.41% H2O2 was conducted every three weeks for group A, every 2 weeks for group B, and weekly for group C over 6 weeks. Water samples were collected thrice weekly to monitor bacterial counts, with a compliance threshold of 100 CFU/mL. Electron microscopy was used to assess biofilm morphology.

RESULTS

A total of 132 samples were analyzed. Following BRS® treatment, bacterial counts decreased significantly to 15-45 CFU/mL. Groups B and C achieved 100% compliance, while group A had 68.42% compliance, with visible biofilm noted. There were significant statistical differences in compliance rates among three groups (p < 0.05).

CONCLUSIONS

Continuous treatment with 0.0141% H2O2, combined with biweekly or weekly 1.41% H2O2 shock treatment, may help control DUWLs contamination in the short term under the conditions tested. Future studies should expand the sample size and duration for long-term efficacy assessment.