Table of Contents
ISRN Dentistry
Volume 2011 (2011), Article ID 132408, 6 pages
http://dx.doi.org/10.5402/2011/132408
Review Article

Understanding the Shape-Memory Alloys Used in Orthodontics

1Department of Orthodontics, State University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
2Biomaterials Laboratory, Military Institute of Engineering, Rio de Janeiro, RJ, Brazil

Received 10 June 2011; Accepted 13 July 2011

Academic Editors: C. P. Lin and C. Misch

Copyright © 2011 Daniel J. Fernandes et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Nickel-titanium (NiTi) shape-memory alloys (SMAs) have been used in the manufacture of orthodontic wires due to their shape memory properties, super-elasticity, high ductility, and resistance to corrosion. SMAs have greater strength and lower modulus of elasticity when compared with stainless steel alloys. The pseudoelastic behavior of NiTi wires means that on unloading they return to their original shape by delivering light continuous forces over a wider range of deformation which is claimed to allow dental displacements. The aim of this paper is to discuss the physical, metallurgical, and mechanical properties of NiTi used in Orthodontics in order to analyze the shape memory properties, super-elasticity, and thermomechanical characteristics of SMA.