Elastic deflection study of nickel-titanium orthodontic wires: 3-point bending test X clinical simulation device

Introduction: The purpose of this study was to compare the most usual types of bending tests used to evaluate nickel-titanium orthodontic wires: the 3-point bending test and the clinical simulation device (CSD). Materials and Methods: Eleven groups of 0.014-inch nickel-titanium orthodontic wires of six different brands were tested. A 3342 Instron universal testing machine with a 10 N load cell was used, and the ISO 15.841 regulation was followed. T-tests were used to compare the evaluations. Results: At a deflection of 0.5 mm, the device released significantly lighter forces then the 3-point test. However, at deflections of 1; 2 and 3 mm, the device released significantly heavier forces. Conclusion: Because of the several differences between the tests and the inconsistency of the CSD, the 3-point bending test was elected the most reliable method to evaluate the elastic deflection of nickel-titanium orthodontic wires.