The effects of steam sterilization and usage on cutting efficiency of endodontic instruments

The effects of steam sterilization and usage on sharpness were evaluated on #25 endodontic files. Files were used to instrument 1, 5, and 10 molars. Control groups determined the effect of steam sterilization alone on cutting efficiency of unused files. A cutting efficiency test was performed on an apparatus that compares sharpness of files when used in linear motion. Scanning electron microscopic analysis was performed in each group. Significant differences were found between experimental files used to instrument 1 molar and those used for 5 or 10 molars. The difference in cutting efficiency between the second and third experimental groups was not significant, indicating that most of the decrease in sharpness occurred with use between one and five molars. No significant difference was found between the control groups, indicating no decrease in cutting efficiency by sterilization alone. The scanning electron microscopic analysis supported the statistical data.