Purpose: Most load-deflection curves of NiTi wires were obtained by three-point test methods, but only few comparative studies had been reported about load-deflection behaviors of superelastic NiTi wires using three-bracket bending test mothod. The purpose of this study was to compare load-deflection behavior of different superelastic NiTi wires using two different bending test including passive self-ligating brackets.

Materials and methods: The study comprised four groups of superelastic NiTi wires: 0.014-inch ThermoNiTi, 0.014-inch CuNiTi, 0.016 x 0.025-inch ThermoNiTi and 0.016 x 0.025-inch 27°C CuNiTi. Each group had 10 pieces of wires to be tested. Then, three-point bending test and three-bracket bending test that using passive self-ligating brackets H4 were performed to test load-deflection behaviors of those wires.

Results: The round 0.014-inch NiTi wires had lower load forces than the rectangular 0.016 x 0.025-inch NiTi wires for each brand. The CuNiTi wires had lower load forces than the ThermoNiTi wires for most wire sizes/ bending test combinations. The wires from 3-point bending test had lower load forces than wires from 3-bracket bending test. Meanwhile, stress hysteresis of wire from three-bracket bending was bigger than that from three-point bending test.

Conclusion: By using the self-ligating bracket in the three-bracket bending test method could explore the appropriate combination of wire size and materials in consideration of activation and deactivation force for clinical use.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.