- The primary characteristic of nickel-titanium (NiTi) alloys that makes them particularly advantageous for use in endodontic rotary instruments is their superelasticity.

- NiTi alloys exhibit superelasticity, which allows the instrument to undergo significant deformation and return to its original shape without permanent deformation.
- This property is crucial during root canal procedures, where instruments need to navigate the complex and curved anatomy of root canals.
- The superelastic behavior reduces the risk of instrument fracture and enhances flexibility, improving both safety and efficiency in endodontic treatment.

- While the shape memory effect is another important property of NiTi alloys, it is mainly relevant for applications where the material returns to a predetermined shape upon heating.
- This effect is less critical during the mechanical stress encountered in rotary endodontic instruments.
- Moreover, corrosion resistance and high thermal conductivity, although beneficial in other contexts, do not play a primary role in the performance of NiTi rotary files in endodontics.

In summary, the superelasticity of NiTi alloys allows endodontic instruments to flex and return to their original shape within the curved root canals, minimizing the risk of fracture and improving clinical outcomes.

Reference: Cohen's Pathways of the Pulp, 12th Edition, Chapter 16: Biomechanics of Endodontic Instruments, Page 345