Evaluation of the effect of reverse curved spee Ni-Ti wires with different depths in MBT and Roth brackets on...

The aim of our study is to analyze the forces generated by reverse curve archwires with three different depths and two different dimensions for Roth-type brackets and MBT-type brackets through finite element analysis (FEA) to assess their effects.

This study involves modeling wires of different dimensions and depths (20 mm, 25 mm and 30 mm) for Roth-type brackets with 0.018''slot size and MBT-type brackets with 0.022''slot size. 12 linear static analyses were conducted under specific loading and boundary conditions to evaluate tooth movements along the X, Y, and Z axes, total displacement, and von Mises stresses on the periodontal ligament (PDL).

0.022 slot MBT bracket with reverse curve of spee wire 0.019 × 0.025''and 0.021 × 0.025'' dimensions and 30 mm depth, 0.018 slot Roth bracket with 0.017 × 0.025'' and 0.016 × 0.022'' wire and 30 mm depth applied the most aggressive forces, leading to high displacement and PDL stress. In contrast, 0.022 slot MBT bracket with reverse curve of spee wire 0.019 × 0.025'' dimensions and 20 mm depth, 0.018 slot Roth bracket with reverse curve of spee wire 0.017 × 0.025'', 0.016 × 0.022''and 25 mm depth, 0.017 × 0.025'', 0.016 × 0.022''and 20 mm depth demonstrated more conservative force applications.

This comparative analysis of 12 different models demonstrates that varying orthodontic forces have a significant impact on both tooth movement and PDL stress. These findings highlight the significance of selecting the appropriate model based on the patient's periodontal health to ensure orthodontic treatments are performed effectively and safe.