Cleaning of endodontic instruments before use.

In this study, 120 new K-files and Hedström files from 3 different manufacturers were examined for surface debris with the scanning electron microscope. The instruments were examined immediately upon removal from their original packages. A second examination of the instruments was performed after they were cleansed in an ultrasonic bath. None of the studied instruments were free of metallic spurs or foreign particles as received from the manufacturers. The ultrasonic bath used together with a cleanser solution appeared to be an effective method to minimize the surface impurities from the manufacturing process prior to use in patients.