We developed new ultrasonic tips for apicoectomy with retrograde gutta-percha root filling. To investigate the cutting efficency and safety of the ultrasonic tips, before clinical application we carried out an experiment on enlargment of the root canal of human extracted teeth. The results, showed that enlagement of the root canal with the ultrasonic system could be performed rapidly and accurately compared with manual enlargement using angle reamers. Our ultrasonic tips did not cause any problems for teeth during the experiment. We believe that our new ultrasonic tips are simple and convenient for clinical application.
