Microbial contamination of endodontic files received from the manufacturer.

This study was conducted to test the sterility of new unused endodontic files received from manufacturers. Fifteen types of hand and rotary files from five manufacturers were tested. Positive microbial cultures were obtained from 13% of the 150 files tested. Autoclaved files were intentionally contaminated with bacterial species recovered from the positive cultures to evaluate a chairside sterilization method. Immersion of contaminated files in 5.25% sodium hypochlorite for five minutes sterilized the files. The results of this study indicate that endodontic files should be sterilized before clinical use. It is also suggested that manufacturers list the sterility state of their endodontic files on their packaging.