Comparison of the mechanical properties of three commercial orthodontic NiTi round archwires

Abstract

© 2016 Trans Tech Publications, Switzerland. To compare mechanical properties of three commercial NiTi orthodontic round wires, three commercial brands of NiTi round wire (Nic-China, Ormco-USA, and Smart-Thailand) with sizes 0.014', 0.016, and 0.018'were studied. Five specimens each size of each brand were used to test mechanical properties; unloading force (N), spring back (mm), and yield strength (N/mm) with three-point bend test using an Instron Universal Testing Machine. Kolmogorov-Smirnov test and one-way ANOVA were employed to test the differences among groups with statistical difference at p<0.05.The average unloading force from lowest to highest were Ormco, Smart and Nic with 0.014", Smart, Ormco and Nic with 0.016"and Smart, Nic and Ormco with 0.018", respectively. The Nic brand had the highest value of unloading force, spring back, and yield strength in all wire sizes, except unloading force 0.018" Ormco and spring back 0.018" Smart. There were no statistically significant differences in unloading forces among all wire sizes. The three brands of commercial orthodontic NiTi wires presented similar unloading force, spring back, and yield strength properties. These mechanical properties are related to lower rates of deformation and are appropriate to be used in the initial phase of orthodontic treatment.