Review of properties and clinical applications of orthodontic wires.

During the last decades, a variety of alloys has been used in orthodontics to manufacture wires. The orthodontic clinician is called to select from a large number of materials that meet the biomechanical requirements of the clinical case to be treated. Mechanical properties of orthodontic wires are assessed by different laboratory tests, such as tensile, torsional, and bending tests. Although wire characteristics determined by such tests cannot be directly linked with their clinical application, they provide a basis for useful comparisons. The "ideal" wire characteristics have been specified by a number of authors. However, each wire may be considered ideal or not, depending on the targeted clinical outcome on each case. The clinician should know the properties and biomechanical behavior of available wires in order to choose the appropriate wire depending on the targeted outcome in different orthodontic treatment phases. The aim of this literature review is to summarize orthodontic wire properties and demonstrate their clinical applications as shown by their general properties. Stainless steel, cobalt-chromium, nickel-titanium, beta-titanium and multistranded wires are studied. Moreover, the so-called "aesthetic" wires are reviewed, as well as their potential development expected in the near future.