Biomedical Applications of Shape Memory Alloys

Shape memory alloys, particularly nickel-titanium (NiTi) alloys, exhibit unique thermally or mechanically activated behaviors known as the shape memory effect and pseudo-elastic effect. These behaviors result from the alloys' specific crystallographic structure, allowing them to recover their original shape even after significant deformations and to maintain a constant applied force during considerable displacements. Coupled with properties such as corrosion resistance, bending resilience, and compatibility with biological functions and magnetic resonance, these characteristics have led to the widespread use of shape memory alloys in the development of biomedical devices over the past two decades, particularly in minimally invasive techniques. This review provides an in-depth analysis of the primary applications of NiTi alloys within dental, orthopedic, vascular, neurological, and surgical domains. It highlights the essential features and benefits of using shape memory alloys in various devices and emphasizes the potential for innovative ideas that could expand the application range of these materials. Importantly, the review points out the necessity for collaboration among clinicians, engineers, physicists, and chemists to define precise problems and to identify optimal solutions in device design, ensuring the fine-tuning of NiTi alloy properties for effective clinical use.