A Comparative In-Vitro Study of the Effectiveness of Several Methods of Sterilizing Endodontic Files

Background Successful endodontic treatment depends on several elements. The most important of which is the elimination of microorganisms within the root canal system. To achieve this, sterility must be maintained during all steps of the treatment. Therefore, it is necessary to ensure the sterility of the tools used in endodontic treatment, whether new or reused. This study aimed to evaluate the effectiveness of several methods for sterilizing endodontic files by evaluating their ability to eliminate a specific type of bacteria. Methods Twenty stainless steel K files were divided into four groups. Files were contaminated with a strain of <i>Enterococcus faecalis</i>, and then groups were sterilized using different methods (group A: autoclave; group B: chemical solution; group C: no sterilization; group D: diode laser). After sterilization, files were placed in test tubes containing nutrient broth and then were incubated for 24 hours. After incubation, test tubes were monitored for turbidity, and a sample was taken from each tube to detect bacterial growth on plates containing Mueller-Hinton agar. After 24 hours of incubation, bacterial growth on plates and turbidity in test tubes were registered. Results Bacterial growth was registered on groups C and D plates, while no bacterial growth was registered on groups A and B plates. Turbidity was shown in groups C and D test tubes, while no turbidity was shown in groups A and B test tubes. Conclusions Within the limitation of this study, diode laser was not able to eliminate the bacteria, and thus cannot be used to sterilize endodontic files. The autoclave and the chemical solution were able to eliminate the specified bacteria.