Effect of arch wire size on orthodontic reverse closing loop and retraction force in canine tooth distalization :...

The purpose of this study is to compare the effects of different wire size reverse closing loop and retraction forces in canine tooth distalization using the finite element analysis method.

Maxillary alveolar bone, maxillary first molar, second premolar and canine teeth were constructed in three dimensions along with their periodontal ligaments and standard edgewise brackets of 0.022 inch and stainless-steel reverse closing loop of 0.016 × 0.022 inch and 0.019 × 0.025 inch were designed. Force of 0.98 N and 1.96 N were applied to the arch wire from the posterior region of the molar tooth in the distal direction for activating the reverse closing loop. The stress distribution and displacement of the maxillary canine tooth were performed using the three-dimensional finite element analysis method.

The maximum deformation on the canine tooth was higher in the x‑, y‑, and z‑axes in both arch wires with 1.96 N force activation. Moreover, 1.96 N caused more stress on the canine tooth in both arch wires compared to the application of 0.98 N. In terms of von Mises stress distribution on alveolar bones, the amount of stress was higher during the application of 1.96 N than the application of 0.98 N.

The finite element method is a reliable instrument which allows the effects of biomechanics applied in orthodontics to be evaluated. The finite element analysis method precisely predicted the mechanical effects of reverse closing loop of different wire sizes and different retraction forces.