Distribuição de tensões em incisivos centrais superiores restaurados com pinos de fibra de vidro medindo 1/2 e 2/3 do comprimento radicular, durante a aplicação de forças ortodônticas: um estudo comparativo pelo método de elementos finitos

Abstract

Endodontically treated teeth and restoratives with intraradicular posts are subject to different levels of stress. This study evaluated, using the finite element method (FEM), the distribution of force on the root of maxillary central incisors restored with fiberglass posts (GFP), with two different lengths, indicated by orthodontic forces. There were two models of the maxillary central incisor with periodontal ligament, cortical bone and trabecular bone. In one of the models, the incisor was restored with a GFP measuring the equivalent of 1/2 of the root length and the other with a post measuring 2/3 of the root length. After the creation of the three-dimensional mesh of finite elements, the applications of two orthodontic forces were simulated, a buccolingual one of 65gf and a mesiodistal one of 70gf. Forces were applied parallel to the palatal plane. The maximum stresses generated in the root, from buccolingual and mesiodistal forces were, respectively, 3,680 x 10-1 MPa and 4,796 x 10-1 MPa (1/2) and 3,642 x 10-1 MPa and 4,755 x 10-1 MPa (2/3). The area of greatest root tension in both models was located in the cervical third, being on the buccal surface, for buccolingual force, and on the mesial surface, for mesiodistal force. The incisor restored with the GFP of greater length (2/3) had lower tension values in the root and higher values in the surface of the post, for both movements studied. The maximum stress values are within the safe margins for the dental structure integrity when forces considered ideal for orthodontic movement are applied.