Abstract
Introduction. Infection control is a major concern in dentistry, due to the possibility of the transmission of diseases. The aim was to investigate the efficiency and duration of sterilization of endodontic hand and rotary files in dental practice. Materials and methods. A total of 158 endodontic files (K and H hand and rotary files) were collected from the Department of Endodontics and divided into five groups, based on the method of sterilization, as follows: Group 1: Unused, straight from the package (n=14; control group); Group 2: Used, unsterilized (n=12); Group 3: Autoclaved; Group 4: Scrubbed and autoclaved; Group 5: Ultrasonic cleaning followed by scrubbing and autoclave. The files in Groups 1 and 2 were individually immersed in a sterile plastic container containing 5 ml of sterilized thioglycolate for 24 h at 37 degrees C. Subsequently, the samples were transferred to three types of culture media: blood agar, chocolate agar (for Gram-positive bacteria) and Mac Conley agar (for Gram-negative bacteria), to assess their contamination levels. The presence of contamination in groups 3, 4, and 5 was evaluated with Mueller-Hinton agar, immediately, as well as 3 days, 5 days, 7 days, and 14 days after sterilization. Results and discussion. All files were contaminated before sterilization. No contamination was observed after two weeks of sterilization in any of the files from groups 3, 4, and 5. In addition, no significant difference in the level of contamination was observed between the three types of sterilization methods. Conclusions. These findings indicate that it is important to sterilize all files before use. Furthermore, the effect of sterilization remained even after two weeks.