Comparison of Slot Deformation in Different Types of Bracket During Torque Application—A Finite Element Study

Torque in orthodontics plays a significant role in final positioning of the teeth. This twisting force in wire helps in transferring the applied forces to bracket, which sometimes causes deformation of slot. This slot deformation can vary torque prescription and affect tooth position. To compare the deformation of slots of different bracket materials after torque application using finite element analysis. A finite element model of maxillary central incisor with bracket slot 0.022 × 0.028 inch dimensions was constructed. The different bracket materials such as stainless steel (SS), ceramic, and titanium were used with rectangular SS archwire (0.019 × 0.025 inch). The slot deformation was obtained after various degrees of torque application at 5°, 10°, 15°, and 20°. This slot deformation was also seen at the top, middle, and bottom locations in the slot. All these models were then analyzed using the Ansys software. The results showed that there was a gradual increase in deformation of all the bracket slot walls from bottom to top locations. The bracket slot deformation for 20° twist was 0.78, 1.85, and 4.53mm (SS); 0.24, 0.70, and 2.50 mm (ceramic bracket), and 1.82, 2.85, and 4.83 mm (titanium brackets) in bottom, middle, and top slot wall locations, respectively. Slot deformation was seen highest in titanium brackets and least in ceramic brackets. Further in the slot wall, the deformation was highest in top location as compared to middle and bottom locations.