Análise biomecânica de implantes cone morse estreitos x convencionais para reabilitações unitárias anteriores - estudo pelo método dos elementos finitos

Abstract

Anterior rehabilitation of the maxilla represents a challenge for implant dentistry due to poor bone thickness. To solve this problem, the industry launches narrow diameter implants. However, there are still doubts about the biomechanical behavior of this type of implant. Thus, the aim of this study was to analyze the biomechanical behavior of implants in this region by comparing conventional diameter (3.75 mm) and narrow implants (3.5 and 2.9 mm) using the Finite Element Method (FEM). Three 3-dimensional models were simulated representing bone blocks of the right anterior maxillary region, with an implant in the lateral incisor region, always 13 mm lenght, in the diameters mentioned above. On implants, it was simulated crown fully cemented ceramics. Finite element analysis was performed using ANSYS software using loads of 178N applied with 0, 30 and 60 degree inclination in relation to the long axis of the implants. Analysis of the von Mises stress maps showed that there were higher stress concentrations located in the intermediate region, regardless of force direction, increasing as the force application angle increased, and dissipating along the implant threads. There was a slight increase in stresses for the 2.9 mm implants when compared to the others. The larger diameter implants presented higher areas of stress concentrations in the intermediate region and along the threads to the apical region when compared to the 2.9 mm models. The same was true for the analysis of maximum principal stress in 30 and 60 degree loads, especially under tensile stresses. For loading of 0 degrees it was not possible to observe influence of the diameter of the implants in the concentrations of stresses in the region of the bone tissue. Within the limitations of the study, it was possible to conclude that in all models, the higher stresses were concentrated in the intermediate region and first threads of the implant, being larger as the force inclination increased or the implant diameter decreased. Despite this, the 2.9mm diameter implant presented the best biomechanical behavior in front of narrow bone tissue. Replace lateral incisors with narrow diameter implants where low oclusal stress are present represents a good option for treatment.