Introduction: This study evaluated the effects of retrieval strategies of separated nickel-titanium files on the biomechanical behavior of endodontically treated teeth by finite element analysis.
Methods: Six FE models were created: intact tooth; simulated a scenario where the apical 3 mm of a nickel-titanium file is separated and retained; TD, simulated application of a trephine drill to expose 1 mm of the separated file; simulated troughing of 180° at the inner wall of root canal for an extra 1 mm of the separated file beyond the staging platform; simulated circumferential ultrasonic troughing done for an extra 1 mm after the TD; and PM, simulated iatrogenic perforation sealed using mineral trioxide aggregate. Occlusal loading followed the occlusal fingerprint of the tooth before maximum von Mises stresses, maximum principal stresses, safety factor, and number of cycles till failure were determined.