EVOLUÇÃO DAS PROPRIEDADES MECÂNICAS DA LIGA DE NITI EM ENDODONTIA: REVISÃO DE LITERATURA.

The Nickel-Titanium (NiTi) alloy was developed by the metallurgist William Buehler, and it has since been introduced into various fields of knowledge due to its properties of super elasticity and shape memory effect. The introduction of NiTi revolutionized endodontics as it enhanced safety in the biomechanical preparation of curved root canals, even in larger diameters. Its utilization offered advantages over stainless steel files. This study aimed to conduct a literature review of the advancements in the mechanical properties of the NiTi alloy used in the manufacturing of endodontic instruments. The bibliographical research was conducted from the electronic search of articles indexed in English in electronic databases (PubMed, Scopus, and Web of Science) without time restrictions. Articles were identified by crossing the following descriptors: NiTi, Nitinol, and Endodontics. The initial endodontic instruments made of NiTi were austenitic, and, therefore, less flexible. The incorporation of new manufacturing methods, such as electropolishing and heat treatments allowed the creation of instruments with higher amounts of martensitic phase, resulting in greater flexibility and enhanced fracture resistance and ensuring safety in treating curved canals. The introduction of NiTi in the manufacturing of endodontic instruments is associated with an improved safety and efficiency in biomechanical preparation compared to stainless steel files. Heat treatments enabled the production of more flexible and fracture-resistant instruments for curved canal preparation. [ABSTRACT FROM AUTHOR]