Introducing cobalt nickel aluminum ferromagnetic shape memory alloy for endodontic file manufacturing

Abstract

Since the introduction of nickel titanium (NiTi) to the field of endodontics, it paved the way for fast and reliable root canal instrumentation. Rotary instruments are solely manufactured from NiTi alloy, due to its favorable mechanical and physical properties such as flexibility and cutting efficiency. The main problem with rotary NiTi instruments is their high fatigue susceptibility, and the unexpected incident of instrument separation inside the root canal, complicating the case even further and might even doom the tooth for extraction it the fractured fragment was unretrievable with the presence of peri-apical pathology. Many attempts were made to enhance the physical and mechanical properties of NiTi alloy through modification to the manufacturing process or with different heat treatment or even adding alloying elements to it. However, there has never been an attempt to replace the whole alloy. Cobalt Nickel Aluminum (Co-Ni-Al) alloy is a ferromagnetic shape memory (FMSM) alloy, possessing favorable mechanical and physical properties making it a good candidate to replace NiTi in the manufacturing of rotary instruments. With its main advantage being the ability to be retrieved with magnetic pulses after being separated.