Biomecânica do traumatismo em dentes decíduos e permanentes e os efeitos nas estruturas adjacentes: análise dinâmica não-linear por elementos finitos

Abstract

Dental trauma in primary and permanent maxillary incisors can cause various injuries on the dentoalveolar complex, however, its effect on structures adjacent to the impact as the permanent tooth germ in children and the possible complications to adjacent teeth is still unclear. This study was designed involving two objectives: Objective 1: To determine the stress distribution in adjacent teeth to an impacted maxillary central incisor in order to identify possible explanation for root resorption in non-traumatized teeth, similar to the clinical case treated at Dental Trauma Clinical Service at Federal University of Uberlândia. Objective 2: To evaluate the stress distribution on surrounding bone/soft tissue and on permanent tooth germ caused by dentoalveolar trauma in primary central incisor with three stages of physiological root resorption. The experimental method used was the nonlinear dynamic impact finite element, involving on the objective 1 the 3D models of impact with rigid metallic object and on the objective 2 involving 2D models of the children reaching the asphalt. For evaluation of the stress distribution were used von Mises and Modified von Mises criteria (MPa), and strain (µS) were evaluated as well. Based on the results it was concluded that the impact on permanent teeth results on considerable stress concentration on buccal and palatal areas of the adjacent root teeth to the traumatized incisor. Compressed areas were also visualized on proximal areas of adjacent root incisors. Considerable deformation was also observed on the lateral and central root incisors adjacent to the traumatic impacted tooth. Based on the results of the objective 2, the impact on the primary tooth resulted on stress concentration on surrounding bone/soft tissue and, in lower intensity, on permanent tooth germ, regardless of the direction of impact and the primary tooth resorption stage. Greater the physiological root resorption of primary tooth, lower is the stresses on the surrounding bone/soft tissue during the impact. The impact on the incisal edge resulted in higher stresses in the permanent tooth germ and on surrounding bone/soft tissue regardless of physiological root resorption stage. Stress concentrated at the primary incisor apex on model with complete root, which cause the compression of the blood vessels and nerves, can explain the generation of pulpal inflammation/infection of a primary tooth and consequences on periradicular tissues.