A comparison of Greater Taper files, ProFiles, and stainless steel files to shape curved root canals

Objective. The purpose of this study was to evaluate the ability of engine-driven nickel-titanium files to maintain the original curvature of root canals during canal preparation. Study design. A total of 36 simulated curved canals on resin blocks were instrumented with Greater Taper (CT) files, Profiles, and stainless steel files. With the mounting device, which can reproduce the same position of the resin blocks and the camera, the unprepared and prepared canals were accurately compared by means of a double-exposure photographic technique. The analysis of variance test was used for the statistical analysis of data obtained. Results. The canals prepared by means of a Profile with a 6% taper up to the working length were excellent in taper and in maintaining the original curvature. The canals prepared with CT files were also found to be excellent in taper and in maintaining the original curvature; however, these canals showed a slight enlargement toward the inner side at the beginning of the curvature. The canals prepared with stainless steel files showed nontapered widening and severe transportation. Conclusion. The canals prepared with GT files and Profiles were excellently tapered and maintained the original curvature of the canals in comparison with the ones prepared with stainless steel files.