A comparative evaluation of the efficacy of two instrumentation techniques in simulated root canals when using contemporary rotary files

Background: Over the past many years, rotary nickel–titanium (NiTi) instruments have become widely used in endodontics. These superelastic instruments offer benefits over hand instrumentation for preparing curved root canals, including less transportation of the canal and reduced operating time. The purpose of this in vitro study was to compare single length with crown-down methods' shaping ability using Mtwo NiTi files. Subjects and Methods: One hundred extracted human first and second mandibular molars were divided into two experimental groups. In Group A, single length technique was used, and in Group B, root canals were prepared by the crown-down technique. Pre- and postpreparation canals were photographed in a standardized manner and were superimposed. Results: Statistical analysis revealed that in Group A, the inner wall was predominantly removed (P < 0.01), whereas in Group B, dentine was equally removed within the canal coronal to the curvature. Conclusion: There was no significant difference between the single length method and crown-down technique using Mtwo for the preparation f the apical and middle portion of canal curvature.