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Revolutionary development of endodontic instruments and its implications

After introducing the NiTi instruments in 1988, the files were developed in various shapes of cross sections while having similarly tapered shaft as 4% and 6% (fixed taper). In this first generation, the files were made of conventional NiTi alloy without any special treatment. They were introduced mainly with the advantages of better cutting efficiency and better flexibility to follow the curved root canal with reduced transportation.