A new stainless steel archwire geometry for improved torque control: finite element evaluation of the Junaidi and Talabani geometry

Objective Solid stainless steel archwires exhibit excessively high torsional stiffness, while Ni-Ti and TMA wires of equivalent dimensions demonstrate less than half of that stiffness, often resulting in inadequate torque transmission to teeth. Conversely, using smaller stainless steel wires in a 0.022-inch slot increases play, thereby compromising torque expression. This finite element analysis (FEA) study aims to evaluate a novel archwire geometry designed to reduce the torsional stiffness of full-size stainless steel archwires without increasing play.Methods Two groups of stainless steel archwires were modelled and analysed. The first group comprised solid 0.019 × 0.025, 0.021 × 0.025, and 0.021 × 0.028-inch stainless steel wires, while the second included 0.021 × 0.025 and 0.021 × 0.028-inch stainless steel wires modified with the proposed geometry design. The FEA setup was calibrated to yield results consistent with existing experimental data. As the 0.019 × 0.025-inch wire demonstrated torque values within the clinically effective range, its performance guided the optimization of the new geometry cut dimensions. The wires with the optimized geometry were subsequently tested for comparison.Results The 0.021 × 0.025 and 0.021 × 0.028-inch stainless steel archwires incorporating the new geometry exhibited significantly reduced torsional stiffness compared to conventional solid stainless steel wires of the same sizes. Their torque values remained within the clinically effective range of 5–20 N·mm.Conclusions The new geometry offers an effective modification for stainless steel archwires, achieving optimal torque expression with reduced torsional stiffness and minimal torque loss; however, further experimental validation is required.