Computation and Collation of Torque Expression in 0.018 Inch and 0.022 Inch Preadjusted Bracket Slots on Passive Insertion of Full-Size Archwire: A Finite Element Study

AIM: To quantify and compare the prescribed torque expressed in preadjusted edgewise 0.018-inch and 0.022-inch bracket slot on passive insertion of full-size archwire using finite element method. MATERIALS AND METHODS: Geometric model of the maxillary arch created with dimensions of the brackets and archwires scanned using microcomputed tomography were converted to finite element model using HYPERMESH V 12.0 software. Material properties were assigned and boundary conditioning was given. 0.017 × 0.025 inch, 0.018 × 0.025 inch, 0.019 × 0.025 inch, 0.021 × 0.025 inch stainless steel wires were inserted and ligated using 0.010 inch stainless steel wire. The amount of torque in each wire was quantified and compared. RESULTS: 0.018 × 0.025-inch stainless steel archwire in 0.018-inch slot expressed more torque than 0.017 × 0.025-inch wire; in 0.022-inch slot 0.021 × 0.025-inch wire showed more torque. Torque expression in 0.018-inch slot was more than 0.022-inch slot. Torque expressed was less than the prescribed value in both bracket slots.