The outcome of retained instrument removal in a specialist practice

Abstract

To determine the success rate of a microendodontic technique for the removal of fractured instruments from root canals. Removal was attempted on a total of 170 consecutive referral cases with fractured instruments. All removal attempts were performed using an operating microscope and ultrasonic tips using a technique described by Ruddle (2003). Of the 170 fractured instruments, 162 could be removed without perforation of the root canal, corresponding to a success rate of 95%. At a failure rate of 5%, eight instruments could not be removed, with root wall perforation occurring in one case. The lowest success rate of 93% was found in maxillary molars, the highest success rate of 100% in maxillary premolars and anterior and canine teeth of the maxillary and mandibular jaw. All removal failures occurred in cases where the fractured instruments were located apically or in the middle and apical part of the root. Regarding the angle of root canal curvature, the lowest success rates were found between 21 degrees and 50 degrees. The position of the instrument within the root canal, the angle of the curvature of the root canal and the location of the fractured instrument in relation to the root canal curvature were the decisive factors that had a negative influence on the treatment outcome.The removal method tested represents a highly effective technique for the retrieval of fractured instruments.