Root canal preparation using a manual option of instruments manufactured with controlled memory NiTi technology: preliminary observations

Resumen

Controlled memory (CM) NiTi instruments have been manufactured using a special thermomechanical process that controls the memory of the material, making the instruments extremely flexible but without the shape memory of conventional superelastic NiTi instruments. An instrument with greater flexibility may cause fewer undesirable changes in the shape of curved root canals, present particularly to the posterior teeth. The aim of this report was to describe a novel manual option of CM NiTi instruments recommended for endodontic treatment of posterior teeth. In this novel handoperated technique, a size #10 hand ISO stainless steel K-file is used to negotiated the coronal 2/3 of the root canal. After enlarging the coronal portion of the canal with #25/.06 (CM NiTi) manual instrument, the working length (WL) is determined with a size #10 K-file. Then, the root canal preparation is completed with #25/.01 (conventional NiTi), #15/.05 (CM NiTi), and #25/.06 (CM NiTi) instruments, in that order to WL, using hand-operated rotary movement. In larger canals, the use of additional stainless steel hand files may be required to complete the apical enlargement. This sequence of instruments, recently launched on the market by Easy, received the name of “ProDesign M” system and it was proposed to meet a demand for endodontic treatment of posterior teeth in undergraduate dental school clinics, mainly in institutions where there are no available motors for the use of engine-driven CM NiTi rotary instruments. The advantages of this manual technique include a reduced number of stainless steel instruments for preparation, which, combined with the greater flexibility of the CM NiTi instruments, may lead to less risk of ledging, transportation, or perforation during educational practice in undergraduate dental programmes.