Composition and Transitional Temperature Range of Several Nickel-Titanium Alloy Wires in Orthodontic Treatment
Objective: The study aimed to clarify the compositions of 14 brands of superelastic NiTi orthodontic wires. Materials and Methods: The compositions were analysed through scanning electron microscopy and energy-dispersive X-ray microanalysis. The wires were tested in differential scanning calorimetry to find the transitional temperature range. Results: The compositions were nickel (50.085%-51.605%), titanium (46.675%-48.140%), copper (0.995%-1.155%), aluminum (0.220%-1.325%), chromium (0%-0.275%) and iron (0%-0.030%). None contained cobalt. G&H, Ormco, AMDG, IMD, Smart, TruFlex, Force 1, NIC, Sentalloy, Ortho Supply and Flexwire were almost or completely austenitic in the oral environment, whereas Highland, Grikin and Unitex were a mixture of austenitic and martensitic phase. The wires showed austenitic finish temperatures ranging from 17°C to 59°C. Conclusions: The results show that NiTi orthodontic arch wires have differences in composition and phase transformation. This information is valuable to evaluate differences in NiTi orthodontic wires for clinical use.
Ford Lumban Gaol, Mehdi Roopaei, Svetlana Perry and Jessica Xu
R. Isarapatanapong et al., "Composition and Transitional Temperature Range of Several Nickel-Titanium Alloy Wires in Orthodontic Treatment", Applied Mechanics and Materials, Vol. 87, pp. 20-25, 2011