Computation and Collation of Torque Expression in 0.018 Inch and 0.022 Inch Preadjusted Bracket Slots on Passive...

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.

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.

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.