Comparative Study on Mechanical Properties of Novel Ultra-Fine Ni-Ti Rectangular Archwires and Conventional Ni-Ti Round Wires in Orthodontics

doi:10.13701/j.cnki.kqyxyj.2026.01.011

Abstract

Abstract: Objective: To conduct a comparative study on the mechanical properties of novel ultrafine nickel-titanium rectangular wires and conventional nickel-titanium (NiTi) round wires under simulated oral temperature conditions. Methods: Three types of novel ultrafine NiTi rectangular wires (OO, Size 1: 0.006×0.025 inches; Size 2: 0.008 × 0.023 inches; Size 3: 0.010×0.022 inches) and five ultrafine NiTi round wires Diameter of (0.012-0.016 inches) from four brands (3M, PT, XY, LS) were selected. A three-point bending test was performed using an universal testing machine at 37 ℃ water bath conditions to evaluate differences in mechanical properties, including average unloading force, platform length, and stress hysteresis values. Results: The OO size 1 rectangular archwire exhibited the lowest mean unloading force (0.40±0.02 N), which was significantly lower than that of all other brands of NiTi round wires (3M, PT, XY, LS; P<0.0001). The stress hysteresis values increased with increasing archwire dimensions in OO rectangular wires, but remained lower than those of superelastic/heat-activated round wires from other brands. Conclusion: Novel ultrafine NiTi rectangular wires provide clinically equivalent light and stable orthodontic forces, comparable to those of conventional NiTi round wires, while enabling early torque control. Their application in initial alignment phases may reduce the frequency of wire changes and lower treatment costs compared to conventional round wire protocols.

Key words: orthodontics, NiTi square wire, NiTi round wire, superelastic (SE) archwire, heat activated (HA) archwire

JI Li, ZHONG Tingjin, SONG Wenlu, CHEN Ziyang, HAN Yu. Comparative Study on Mechanical Properties of Novel Ultra-Fine Ni-Ti Rectangular Archwires and Conventional Ni-Ti Round Wires in Orthodontics[J]. Journal of Oral Science Research, 2026, 42(1): 59-63.

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