Evaluation of mandibular molar mesialization by various methods with finite element analysis

This study aimed to evaluate the biomechanical behavior of sliding mechanics of mandibular molar mesialization with different force application models using finite element analysis. Four models were created to simulate different force applications: force applied from the miniscrew to the second molar hook (Model 1), force applied from the miniscrew to an extended lever arm reaching the center of resistance of the second molar (Model 2), force applied to the second molar hook with indirect anchorage (Model 3), and force applied to the second molar hook with dental anchorage (Model 4). Maximum and minimum principal stresses in the tooth, alveolar bone, and around the miniscrew; Von Mises stress distribution; and tooth displacement patterns were analyzed separately for each model. In Model 1, mesial tipping of the molar was observed with concentrated stresses around the molar and miniscrew. Model 2 demonstrated a near-parallel displacement tendency of the second molar with more evenly distributed stresses. Models 3 and 4 showed similar tipping and mesialization of the molar but differed in stress and strain patterns. Applying force via an extended lever arm directed toward the tooth’s center of resistance produced a more parallel initial displacement of the second molar together with a more balanced stress distribution. Within the limits of an initial, linear-static analysis, miniscrew anchorage reduced the stress and strain transmitted to the adjacent teeth compared with dental anchorage.