The unique mechanical properties of Ni-Ti alloys make them ideal for use in instruments that are subjected to torsional stress and cyclic fatigue. Ni-Ti alloys exhibit superelasticity and high damping capacity, which allows them to undergo large deformations and resist fatigue failure. These properties make Ni-Ti alloys a popular choice for use in medical instruments such as orthodontic wires, endodontic files, and surgical instruments. Additionally, Ni-Ti alloys have good corrosion resistance and biocompatibility, making them suitable for use in the biomedical field.