Estudo da distribuição de tensões e do deslocamento na maxila e nos dentes resultantes do uso do expansor maxilar diferencial através do método de elementos finitos

Abstract

The aim of this study was to determine the stress distribution patterns in the maxillary structure and periodontal ligament and tooth displacement by simulating screw activations of the maxillary expander with differential opening (EDO) using the finite element method (FEM). Methods: Part of the maxilla with the teeth of an upper hemiarch, the midpalatal suture (MPS) and the EDO appliance were modeled. Three models were simulated with different activations on the anterior and posterior screws. In model M1, a 0.25mm activation was simulated on the anterior screw and the posterior screw. In M2, an opening of 0.5mm in the anterior region and 0.25mm in the posterior region was simulated. And in the M3 model, a 0.25mm activation was simulated only in the anterior screw. The stress distributions in the maxilla were registered in each model. Results: All the simulations showed tooth displacement with buccal inclination of the crown, concomitant with intrusion of the buccal surface and extrusion of the palatal surface. The MPS opening had an anterior and posterior vertex in all models, and the area of stress concentration in the maxilla was located in the mid-palate region with subsequent dissipation in an anterior direction and towards the pterygoid process. The M2 model had greater tooth displacements and stress distributions in the maxillary structure and periodontal ligament. Conclusion: The activation of the anterior and/or posterior screws of the EDO interfered with the displacement, stress distribution pattern and stress intensity in both the maxilla and the periodontal ligaments. When activating both screws with anterior overload, there was a greater mechanical effect of the device on the anatomical structures.