Análise da distribuição das tensões em maxila submetida à expansão cirurgicamente assistida com aparelho ósseo-suportado

Abstract

região anterior e as tensões resultantes de forças transmitidas ao osso alveolar dos dentes adjacentes ao aparelho, parecem não ser suficientes para deslocar os dentes. Palavras-chave: Técnica de Expansão Palatina, Análise de Elemento Finito, Análise do Estresse Dentário ABSTRACTAnalysis of the distribution of maxillary stresses submitted to surgically assisted maxillary expansion with a bone-supported device Surgically assisted maxillary expansion (SARME) is the modality of treatment that aims to weaken the points of maxillary reinforcement allowing its gradual expansion. Such movement can be performed at the expense of dento-supported, dento-muco-supported, implanto-supported or bony-backed devices. The effects produced by the treatment range from skeletal changes (increase of nasal base, cavity and nasal air space) to dental inclinations (mainly in the supporting teeth of the expander apparatus), among others. The objective of the present research was to evaluate the distribution of stress produced by SARME in the maxillary structures using the bone-supported expander apparatus by the Finite Element Method (FEM). Material and methods:A three-dimensional hemi-maxilla model was simulated for SARME with a non-step descending LeFort I osteotomy with pterygomaxillary disjunction using a bone-supported device model for the 1mm aperture simulation test. The results showed a greater opening of the maxilla in the anterior region of the incisors to the premolar (1 mm) and smaller (0.6 mm) in the molar region. The principal maximal stress (TMXP) showed the concentration of the tension forces mainly in all the palatine face of the pre-molar maxilla to the maxillary tuft. Due to the lateral aspect, the TMXP was more evident in the posterior alveolar bone region, the molars and tuber, as well as in the epilating zygomatic region above the osteotomy.From the transversal plane, it was possible to observe the transmission of stress along the bony structures showing little dissipation for the roots of the molar.Meanwhile, the forces of compression (Principal Minimum Tension) evidenced by the principal minimal stress, were manifested in the areas of the zygomatic pillar adjacent to the osteotomies, as well as in the areas of contact of the support of the apparatus with the palatine bone. Tension and compression forces were also evidenced in the pterygoid process region. Von Mises' stress analysis showed that the most stressed part is the rod connecting the device module to the support platform. Conclusion:There was a greater opening of the maxilla in the anterior region and the resulting forces of tension transmitted to the alveolar bone of the teeth adjacent to the appliance did not seem to be sufficient to displace the teeth.