The influence of different root canal instruments on root canal preparation: an in vitro study

Nine endodontic instruments from different manufacturers (Reamers, K-files, Hedstrom files, K-Flex files, Flexofiles, S-files, Burns Unifiles, Flexicut files and Flex-R files) were used to prepare 180 simulated root canals in resin blocks. The instrument's ability to reproduce a theoretical pre-established ideal canal shape was assessed by comparing the original canal path with the resulting enlarged canal shape by a double exposure photographic method. The individual ability of each instrument to transport debris was also observed during instrumentation under a stereomicroscope. Regardless of the instrument type, none was able to reproduce ideal results; however, clinically acceptable results could be obtained with all of them. The coronal and apical debris transportation characteristics proved to be similar with all instruments.