An objective evaluation comparing the physical properties of two brands of stainless steel endodontic hand files

The purpose of this study was to evaluate the physical properties of a flexible stainless steel K-type hand file recently introduced by Brasseler USA (F-Style files; Brasseler USA, Savannah, GA), in comparison to those of a well-studied instrument (Flex-o-files; Maillefer-Dentsply, Ballaigues, Switzerland), that has been on the market for more than 20 yr. The physical properties measured included torque at failure, angular deflection at failure, flexibility, and consistency of diameter at 3 mm from the cutting tip; and the evaluations were carried out on size #10 through #50 files of each of the two brands being tested. The results indicated that the Brasseler instruments were inherently more flexible, but had smaller diameters, lower torque, and angular deflection values at failure, than those of the Maillefer files.