A comparative analysis of the distribution of trauma-induced stress on atrophic and edentulous mandible models with subperiosteal implants, the all-on-four technique, and standard endosseous implant designs using finite element analysis

The aim of this study was to compare the stress distribution due to facial trauma in the frontal direction between subperiosteal implants, all-on-4 technique, and standard in-bone implant designs applied to atrophic and edentulous mandibular models using finite element analysis. An edentulous and atrophic mandible model was created with the data obtained using tomography images of an adult individual and a single, two and three-piece subperiosteal implant made of polyether ether ketone (PEEK) or titanium, four intraosseous implants applied with the all-on-four technique and six intraosseous implants placed by lateralizing the inferior alveolar nerve in the mandible were designed computer-aided including prosthetic elements. Three-dimensional finite element analysis was used to simulate a traumatic force in the anteroposterior frontal direction of the prosthesis. The maximum and minimum principal stress values at the identified points on the bone, such as the symphysis and condyle, and the von Mises stress values on the implants, screws, abutments, and metal substructure were recorded and compared. The maximum principal stress values in the mandible bone after frontal trauma were concentrated in the condyle region in all models. The highest Pmax stress calculated in the condyle region was observed in the two-piece PEEK subperiosteal implant design and the lowest in the all-on-4 scenario. The highest von Mises stress values at the abutments occurred at the most posterior abutments in all models. All PEEK subperiosteal implant models had lower von Mises stress values at the abutments than the titanium subperiosteal implant models and Model 2.The All-on-4 technique transmitted lower stress values to the condyle and the entire mandible compared to all subperiosteal implant designs, reducing the possibility of fracture development in these areas. The scenario with the most unfavorable stress distribution in this regard was the three-piece titanium subperiosteal implant design. Rehabilitation of atrophic and edentulous jaws, which are already fracture-prone due to both bone resorption patterns and fracture susceptibility, with the all-on-4 technique can be recommended as a strong alternative to subperiosteal implant treatments.