2012 Volume 33 Issue 2 Pages 99-104
Abstract : For the removal of broken instruments, the application of ultrasonic vibration is the most common technique. This study attempted to analyze and consider the degree of difficulty associated with different broken portions and conditions. Eighteen patients treated with an ultrasonic device were selected from among patients who were referred to our university hospital from general practitioners to remove broken instruments during the 10 years from 2001 to 2011. The treatment records were analyzed to identify the teeth involved, the affected area, the types of files, and the treatment time for their removal using ultrasonic waves and microscopy. Finally, the reasons for any difficulty encountered during treatment were analyzed. The greatest number of broken files was found in molar cases. The accident site and types of files were related to the difficulty of removal, and the ability to directly observe the site decreased the difficulty. More time was needed for removal of a partially pushed out file compared to a completely broken file in the canal because contact pain occurred when the ultrasonic tip reached the fragment. The expansion or reversal of blades was observed in the separated files. These results show that use of the ultrasonic removal technique combined with microscopy is useful and effective for the removal of broken files, while the position and condition of the break contributes to the difficulty of removal.
