55 Nitinol wire: Force developed as a function of “elastic memory”

Abstract

Closing spaces is done either by translation of the edgewise brackets over an archwire or by the use of closing loops of some common design. This investigation suggests the concept of the further refinement of the "wire rubber band" as a means of closing spaces. Advantages of such a wire hypothetically would be to level the dentition, align the dentition, and condense spaces in the dentition with only one or two stretched nickel titanium wires having the proper temperature transition range (TTR). The temperature of the mouth would make such wires return to their original prestretched length. A correctly-sized wire would have sufficient stiffness at mouth temperature, and it would be kept at or above its TTR. The system eliminates friction from edgewise bracket translation and also the use of many auxiliary closing devices as well as reducing the number of archwire changes, thus saving chairside time.

Differences in the pseudoelasticity behaviour of nickel-titanium orthodontic wires

“…The shape memory effect and the pseudoelasticity of NiTi alloys were developed by Buehler et al [1] in the early 1960s and introduced into orthodontic applications by Andreasen et al [2][3][4][5]. These properties are related to a thermoelastic martensitic transformation (austenite ~ martensite) which can be produced by cooling or may be stress induced.…”

Differential scanning calorimetry (DSC) analyses of superelastic and nonsuperelastic nickel-titanium orthodontic wires

“…In additional publications, Andreasen and his colleagues described the force delivery and temperature dependence for nitinol wires. [4][5][6] Subsequently, Burstone et al 7 and Miura et al 8 introduced the Chinese and Japanese NiTi wires, respectively, to the specialty. These wires, now marketed as Ni-Ti (Ormco/Sybron, Glendora, Calif.) and Sentinol or Sentalloy (GAC International, Central Islip, N.Y.), displayed superelastic characteristics, where the deactivation plot contains an extended region of largely constant bending moment or tensile stress.…”

Friction of Stainless Steel, Nickel-Titanium Alloy, and Beta-Titanium Alloy Archwires in Two Commonly Used Orthodontic Brackets

“…16,33 Our SEM images of the three types of archwire showed that NiTi wire and TMA wire were rougher than the stainless steel wire. However, further experimental measurements, such as using atomic force microscope or specular reflectance, are needed to obtain quantitative surface roughness data.…”