Comparative Finite Element Analysis of Slot Deformation in Conventional and Self-Ligating Orthodontic Brackets Using Pre-Torqued Stainless Steel Arch wires.

Introduction: Torque expression depends on accurate bracket slot dimensions and stable archwire–slot engagement; slot deformation can reduce the transmission of prescribed torque. Conventional and self-ligating brackets may differ in their structural response to torsional forces and therefore in their torque expression. Hence, the present study evaluated slot deformation in three conventional and three self-ligating brackets using pre-torqued stainless-steel archwires through FEA. Objectives:. To evaluate slot deformation in three conventional pre-adjusted edgewise brackets and three self-ligating brackets using pre-torqued 0.019×0.025-inch and 0.021×0.025-inch stainless steel archwires through finite element analysis Methods: A three-dimensional finite element model of maxillary anterior teeth with orthodontic brackets and archwires was constructed using scanning and CAD modelling software. Conventional brackets included 3M Unitek Gemini, Mini Master (American Orthodontics), and Mini Diamond Twin (Ormco). Self-ligating brackets included SmartClip (3M Unitek), Empower 2 (American Orthodontics), and Damon Q (Ormco). Pre-torqued stainless steel wires (0.019×0.025-inch and 0.021×0.025-inch) were inserted into the bracket slots. Torque values of 5°, 15°, and 30° were applied, and slot deformation was evaluated at the top, middle, and bottom regions of the bracket slot. Results: Conventional brackets demonstrated greater slot deformation compared to self-ligating brackets across all torque values. Mini Diamond Twin brackets showed the highest deformation, whereas SmartClip and Empower 2 brackets exhibited minimal slot distortion. Larger archwires (0.021×0.025-inch) produced less deformation compared to 0.019×0.025-inch wires. Conclusions: Self-ligating brackets demonstrated better resistance to slot deformation compared with conventional brackets. Among all groups, Empower 2 and SmartClip brackets showed the least deformation, suggesting improved torque efficiency during orthodontic treatment.