Purpose: The purpose of this study is the development of a new method to remove gutta-percha and cement using an Nd:YAG laser. The use of an Nd:YAG laser may be helpful in removing canal sealers, posts, or broken instruments during endodontic re-treatment, without damaging the root canal walls. Materials and Methods: Forty extracted human teeth were selected, endodontically treated using Ni-Ti instrumentation, and filled with gutta-percha and sealer. Then the teeth were re-treated using different methods: thirty of them underwent Nd:YAG laser treatment at three different power levels (1.5, 2, and 5.6 W). The root canals of 10 control specimens were re-treated using conventional Ni-Ti instrumentation. In all teeth, gutta-percha removal was completed also using traditional manual instruments. Finally, all teeth were split longitudinally in half and observed by SEM at different magnifications. Results: The results of SEM observations show a better removal of debris and gutta-percha from dentin surfaces in groups where higher laser power levels were used. Conclusion: Nd:YAG laser application seems to be an effective method for achieving good removal of the filling material. However, the laser should be used at slightly higher energies than those suggested by the manufacturer and in tandem with the conventional instrumentation for best results.
Keywords: endodontic re-treatment, dentin, Nd:YAG laser, gutta-percha, root canal, scanning electron microscopy