Rapid chairside sterilization of endodontic files using 6% sodium hypochlorite

J Endod. 2009 Sep;35(9):1253-4. doi: 10.1016/j.joen.2009.05.032.


Introduction: The purpose of this study was to assess the percentage of new endodontic files (taken directly from the manufacturers' packages) that were contaminated with viable microorganisms and to determine the amount of time new files needed to be immersed in 6% sodium hypochlorite to achieve sterility.

Methods: Endodontic files from four manufacturers were placed either immediately in thioglycolate broth or immersed in 6% sodium hypochlorite for 1, 2, or 5 minutes before placement in the broth. The files were aerobically incubated for 72 hours and sterility determined by the absence of broth turbidity, as determined by a blinded examiner. The data were analyzed using the Cochran-Q test followed by the McNemar test for pair-wise comparisons. The level of statistical significance was set at alpha = 0.05.

Results: When pooling all manufacturers' files, no significant differences were found between groups.

Conclusion: New files demonstrated a 6% contamination rate and none of the immersion times in NaOCl achieved file sterility.

MeSH terms

  • Dental Disinfectants*
  • Dental Instruments* / microbiology
  • Equipment Contamination
  • Immersion
  • Infection Control, Dental / methods*
  • Nephelometry and Turbidimetry
  • Root Canal Preparation / instrumentation*
  • Sodium Hypochlorite*
  • Sterilization / methods*
  • Time Factors


  • Dental Disinfectants
  • Sodium Hypochlorite