Von Mises Equivalent Stresses Developed in Fixed Partial Denture Infrastructures on Implants According to Changes in Their Prosthetic Materials

Fixed partial prosthesis with a suspended intermediate element on implants (pontic) can reduce costs and/or make viable cases with limitations in the supporting bone structure. Greater biomechanical demands on the system and variation in the materials of the prosthetic infrastructures could interfere with the stresses developed. This study aimed to verify and compare these stresses in prosthetic infrastructures according to the variation in the material used to make them. The von Mises equivalent stresses (VMES) were qualitatively and quantitatively analyzed in the most significant stress areas in these infrastructures, which were divided into different experimental groups: cobalt-chrome (CoCr); nickel-chromium (NiCr); titanium (Ti); zirconia (Zr); lithium disilicate (LD); type IV gold (Au); and acrylic resin (AR). They were then analyzed using the finite element method (FEM) to verify the stresses developed, as well as their intensity and scope, using a color scale generated in a virtual computer analysis environment (Ansys Workbench Software). The results allowed us to observe that different stresses are generated in the material used in the prosthetic infrastructure, depending on its variation. A directly proportional relationship was found between the stiffness of the material and the stresses generated, meaning that greater rigidity results in greater stresses. It is important to highlight that there was no imminent risk of harm to the biomechanics in any varying situation in the infrastructure material, except acrylic resin, which reached stress thresholds in the prosthetic structure close to its maximum flexural resistance.