Abstract
Aim: To use finite element analysis to evaluate the peri-implant stresses caused by the cobalt-chromium and titanium frameworks for maxillary all on four prostheses.
Material and methods: Three-dimensional finite elements modeling of an edentulous maxilla restored with a hybrid fixed prosthesis supported by four implants was done for this study. Anterior implants were placed vertically and bilaterally in the lateral-canine area. At the second premolar region, posterior implants were placed with a 17-degree distal angulation. Every implant featured a multi-unit abutment. The titanium framework for the first model was designed, and the cobalt-chromium framework for the second model was proposed.

Results: Von Mises stress, maximum stress, and directional deformation were assessed in the peri-implant bone area. Von Mises stresses on the screw-retained prosthesis were very similar in cobalt chromium and titanium frameworks compared to the underlying bone and implants.
Conclusion: For edentulous maxilla, the use of titanium or cobalt-chromium frameworks in conjunction with an all-on-four prosthesis is regarded as a dependable therapeutic alternative.