Comparison of Subperiosteal Implant Designs Applied to Atrophic and Edentulous Mandible Under Traumatic Forces: 3D Finite Element Analysis.

This study evaluated the stress distributions of subperiosteal implants (SPI) made of titanium and polyetheretherketone (PEEK) in 1-piece and 2-piece designs in edentulous and severely atrophic mandibles subjected to trauma forces. This study applied 4 treatment methods to a severely atrophic edentulous mandibular model. Subperiosteal implant designs made of PEEK consisting of 1 piece in model 1 and two in model 2 were used. Subperiosteal implant designs made of titanium composed of 1 piece in model 3 and two in model 4 were used. Each of the subperiosteal implants was fixed on the mandibular model with 14 osteosynthesis screws placed in the tension lines of the mandible. A traumatic force of 2000 N was applied to the mandibular prosthesis in the anteroposterior direction. Maximum principal stress (Pmax), minimum principal stress (Pmin), and Von Mises stress (VMs) values were measured in MPa. In this study, model 3 showed the highest Pmax value in the symphysis region (45.888 MPa), whereas the values in the other models were similar. The mandibular condyle had the highest Pmax in model 2 (941.338 MPa) and the lowest in model 3 (905.756 MPa). All models compared the Pmin values measured in the symphysis, alveolar crest, and condyle region. The VM stress values on the abutments and abutment screws were lower and more stable in PEEK SPI models than titanium SPI models. However, VMs values on titanium SPI metal frameworks were lower than PEEK SPI models. In this finite element analysis, 1-piece PEEK SPI were the most advantageous design regarding mandibular fracture risk when evaluated under traumatic forces. PEEK SPI treatment may provide a less invasive treatment model for patients with severely atrophic mandibles. Additionally, 2-piece subperiosteal implants may provide greater design flexibility in clinical applications and offer advantages in stress distribution, expanding the range of treatment options available to clinicians.