A causational analysis and management of 23 cases of rotary instrument breakages during dental root canal preparation with crown-down technique

AIM:The growing use of engine-driven instruments especially NiTi rotary apparatus in endodontic practice could increase the cases of failures after dental root treatment. To clarify the cause of instrument breakages could minimize the incidence of the failure.METHODS:Total of 23 cases of rotary instrument breakages in root canal preparation with crown-down or step-down technique in last two years were reported. The cause of the failure of the instrument breakage during root canal preparation and the offset management were also discussed. RESULTS: The instrument breakage complication could be leaded under following incorrect managements:①do not handled the root canal in terms of the operating instruction;②improper operational approach;③neglect the importance of hand canal instrument;④insufficient irrigation of the root canal during the operation;⑤unsuitable rotary instruments we used in a crown-down approach. After offset management, most of the cases could be successfully retreated by either extracted the breakage instruments or established bypass in the root canal.CONCLUSION:Unsuitable process could lead to form ledge, perforation and stripping of the canal. Also,metal fatigue and variable of torsional loading were two important factors in instrument fracture. With awareness of the appropriate manipulation and special attention to the equipment used and applied, integrated with hand or ultrasonic endodontic instruments, NiTi systems are safe with minimal incidence of instrumental failure.