Load Deflection Characteristics of Orthodontic Gummetal ® Wires in Comparison with Nickel-Titanium Wires: An In Vitro Study.

The aim of this study was to investigate the load deflection characteristics of Gummetal ® wires in comparison to nickel-titanium (NiTi) wires. Four different NiTi wires and one Gummetal ® archwire were analyzed in two dimensions (0.014″ (0.36 mm) and 0.016″ × 0.022″ (0.41 mm × 0.56 mm)) and in two different orientations (edgewise and ribbonwise) using three-point bending tests at T = 37 °C. Force-displacement curves were recorded and analyzed. The Gummetal ® 0.014″ wires exhibited higher forces compared to the NiTi wires at 2.0 mm deflection. At 1.0 mm deflection, the opposite pattern was observed. For the 0.016″ × 0.022″ Gummetal ® wires, the forces were within the force interval of the NiTi wires at 2.0 mm deflection. At a deflection of 1.0 mm, no residual force was measurable for the Gummetal ® wires. All the NiTi wires investigated showed hysteresis and a superelastic plateau. However, the Gummetal ® did not form a plateau, but hysteresis was present. An easier plastic deformability compared to the NiTi wires was observed for all the tested geometries.