Coupled FE Modeling of Superelastic NiTi Arch Wire and Bone Remodeling to Simulate 3D Orthodontic Tooth Movement During Leveling Phase.

Orthodontic tooth movement results from alveolar bone remodeling induced by mechanical loads applied to the teeth over extended periods during the unloading phase of arch wires. In clinical practice, orthodontic arch wires are inserted into bracket slots without precise knowledge of the forces transmitted to individual teeth. Excessive loads may lead to undesirable side effects, whereas insufficient forces may fail to initiate bone remodeling and tooth movement. This study aims to develop a 3D numerical approach based on finite element method to simulate orthodontic tooth movement during the alignment phase while quantifying the loads applied by the superelastic nickel titanium arch wire. A common clinical case of buccal infraposition of the maxillary canine was selected. Patient-specific geometries of the teeth and alveolar bone were reconstructed from cone-beam computed tomography scans. A coupling strategy between the arch wire unloading response and an external bone remodeling model was implemented to predict teeth movement over a one-month treatment period as orthodontic appointments are typically scheduled every 4 weeks. During recovery to its initial shape, the arch wire delivered light and constant forces, leading to extrusion of the canine and intrusion of the adjacent first premolar and lateral incisor. This numerical framework captured the mechanical behavior of the superelastic nickel titanium arch wire and predicted teeth movement consistent with clinical ranges reported in the literature. This approach provides an efficient tool for orthodontists to predict patient-specific orthodontic outcomes and optimize treatment design during the leveling phase.