Comparison of stress distribution in different mandibular implant-supported fixed dentures for immediate loading: non-linear analysis by 3D-FEA based on computed tomography

Abstract

The aim of this study is to compare 3 different mandibular implant-supported fixed dentures for immediate loading and conventional protocol with 2 surgical steps regarding the internal stress distribution and displacement of the structures in the -x, -y and -z axés through non-linear three-dimensional finite element analysis. Four mathematical models will be fabricated to represent an edentulous mandible supporting an implant-supported fixed denture with four external hexagon implants (3,75mm x 11,5mm) and distal cantilever of 10mm. Group A (control) - implants rigidly splinted by a metallic superstructure and submitted to the conventional protocol; group B - implants splinted by acrylic resin and submitted to immediate loading; Group C - implants rigidly splinted by an metallic superstructure and submitted to immediate loading; Group D - implants splinted by acrylic resin and submitted to immediate loading with prefabricated distal bar in the cantilever region. Tomographic images of an edentulous mandible will be obtained and imported to a software to convert 3D images in numerical models (Simpleware). The implants and components will be fabricated in a CAD software (SolidWorks) and inserted into the image of the mandible in the software Simpleware. For simulation of the immediate loading of the implants (Groups B, C and D), non-linear and frictional contacting elements will be used. The friction coeficient µ of 0.3 will be established between bone and implant. In the A, a contact in the bone-implant interface will be considered. The models will be transfered by the fininte elements software (Abaqus) to provide data related to the mechanical behavior of the implants and adjacent structures after unilateral posterior loading of 100N in the axial direction. The models will be fixed by force vectors in the region of insertion of the chewing muscles. Maximum and minimum principal stress, von Mises stress and displacements in the -x, -y and -z axes will be evaluated. A descritive statistical analysis will be conducted. (AU)