Influence of reciprocating NiTi instruments on the accuracy of apex locator integrated endomotors during simultaneous working length determination

Abstract

Objective: To compare simultaneous working length determination efficiency and electrical resistance of thermally treated NiTi files and their counterfeits.Methods: Access cavities were prepared for sixty human mandibular premolar teeth, which were then numbered with a marker. Actual working length was determined visually by introducing a #10 K-file into the root canal and the reference point was marked for further steps. By using flowable composite, the teeth were fixed at the cementoenamel junction to a hole in the center of a glass bottle cap and a second hole prepared on it for lip clip. Alginate impression material was filled into glass bottle then the tooth was embedded into it. Experimental models randomly divided into 6 groups as Group WOG (WaveOne Gold), Group WO (WaveOne), Group W+ (Superline W+), Group RB (Reciproc Blue), Group R (Reciproc), Group V (Superline V). Root canals were prepared until the endomotor stopped when reaching the apical foramen and the silicon stopper was moved to the previously marked reference point to determine the simultaneous working length. The electrical resistance of the files (from tip of file to notch of the shaft) was measured using a multimeter.Results: No readings could be obtained via apex locator for Group V. Group W+ was significantly less accurate compered the other groups (p<0.05). No significant difference was found among the groups WO, WOG, R, and RB (p>0.05).Conclusion: Thermal treatments of NiTi alloys had no effect on the accuracy of simultaneous working length determination. However, Counterfeit endodontic files failed to show of accurate simultaneous working length determination.