Comparative Evaluation of Mechanical Failure of Different Rotary Endodontic Files: An SEM Study

ABSTRACT

Conventional endodontic instruments make the intracanalprocedures versatile with more efficiency and minimumcomplication. The development of microfractures in the I-RaCeNickel-Titanium rotary (NTR) file and ProFile NTR file wasevaluated by using Scanning electron microscopy (SEM).Thirty six maxillary buccal roots and thirty six mandibularmesial roots with an average canal curvature of 37° wereassigned to each group and prepared with 21mm, 0.04 taperNTR files as follows (1) I-RaCe (2) ProFile. File sizes 0.06 to0.04 were used in a crown-down technique to a master apicalfile (MAF) size of 0.04/25. The MAF instruments wereevaluated by SEM before use, after completion of 7 canals,and after completion of 14 canals. All I-RaCe instrumentsdeveloped microfrcatures by the seven canal evaluation. TheProFile instruments showed no microfrctures at the 7-or-14canal evaluations. I-RaCe files separated at a higher rate thanProFile instruments. Under the conditions of this study, uniquefile design and electropolishing did not inhibit the developmentof microfractures in I-RaCe NTR.