Displacement of mandibular dentition during total arch distalization according to locations and types of TSADs: 3D Finite element analysis

The aim of this study was to evaluate the biomechanical effects of temporary skeletal anchorage devices (TSADs) on the mandibular dentition and mandible during total arch distalization according to locations and types of the TSADs using finite element (FE) analysis.A model of the mandible and teeth was used to build an FE analysis model.Four FE models were constructed: Ramal plate (Type A), Sugawara plate (Type B), buccal shelf miniscrew (Type C) and interradicular miniscrew (Type D). A retraction force of 300 g per side was applied to the mandibular archwire.In the sagittal plane, the plates Type A and B showed more distal displacement than the miniscrew Types C and D, especially in the posterior teeth. Type A presented the greatest amount of distal displacement, followed by Types B, C and D. Type A was closest to the line of occlusion, which showed the lowest degree of buccolingual angulations of the molar crowns. Vertically, Type A showed a greater amount of extrusive displacement of the posterior teeth than the other types of TSADs, while Type B showed intrusive displacement of the molars.The ramal plate showed a greater amount of distal and extrusive displacement of the posterior teeth than the miniscrews. Therefore, clinicians should consider the displacement of mandibular dentition during total arch distalization according to types of the TSADs.