[Effect of ultrasonic in instrumentation on curved and obstructed root canal preparation].

Purpose: To investigate and evaluate the effect of ultrasonic instrumentation on curved and obstructed root canal preparation.

Methods: Ultrasonic preparation was used on 117 root canals of 92 teeth due to resinifying therapy, pulp mummification and aging which could not be reopened and treated with traditional methods.

Results: 108 canals were successfully reopened with a successful rate of 92.3%. Failure occurred in 9 cases. 2 of them were lateral perforation. 2 were obstructed on curving position. 2 of them were due to pulp calcification in older patients. 3 were failing after resinifying therapy.

Conclusion: The ultrasonic treatment of root canal was an effective and safe method. It was still limited in a cases with pulp calcification and some fine root canals treated by resinifying therapy.