[Feasibility of recycling mechanical properties of used NiTi orthodontic wires by electromechanical treatment]

ABSTRACT

The desirable mechanical properties of nickel-titanium alloy wires have prompted many clinicians to recycle these wires. The purpose of this study was to investigate the changes in mechanical properties of nickel-titanium alloy wires after recycling by electromechanical treatment. In this experimental study, round 0.018 inch nickel-titanium wires [American Orthodontics trademark] were used. For purpose of determining the behavior of samples in mouth, the transformation temperatures of alloy were carried by electrical resistance test. The types of nickel-titanium wires were separated into three groups 1- as received condition [control wires], 2- treated by low electrical current, 3- treated by high electrical current. Mechanical properties changes were observed by tensile testing. One-way analysis of variance and Tukey HSD [SPSS statistical package] was used for purpose of comparison. The results demonstrated significantly greater remained strains after recycling, but plateau stresses and elastic strain energies of the wires were decreased compared with the control wires. Super elastic property of electromechanical treated nickel-titanium wires is decreased following electromechanical treatments