All wires were sectioned into 20-mm-long speci- mens, rested across the 2 supporting points, and left in the temperature-stabilized testing chamber for 3 min- utes, allowing the wire to reach the chamber tempera- ture. Then each specimen was deflected from 0 to 3.1 mm and back to 0 mm with a stainless steel pointed bar measuring 0.1 mm at its head, traveling at a speed of 10.0 mm per minute. A computer attached to the testing machine recorded 1000 data points for the force placed on and delivered by the wire through the entire loading and unloading process. Rectangular wires were measured under vertical loads that were applied on their long sides, mimicking the forces that teeth would expe- rience when being leveled occlusogingivally. To elimi- nate variability from cyclic loading, measurements were taken only on specimens that had never been tested or deflected before. To compare forces upon unloading, values recorded at 2 mm of deflection were used for all statistical analyses.