Biomechanical Comparative Evaluation of the Atrophic Edentulous Mandible Using All-on-4, All-on-5 and All-on-6 Concepts: A Finite Element Analysis

Background: Full-arch implant-supported prostheses, including configurations such as All-on-4, All-on-5, and All-on-6, are widely used for the rehabilitation of the atrophic edentulous mandible; however, their biomechanical performance remains a critical factor for long-term success. Aim/Objectives: To evaluate and compare von Mises stress distribution and deformation patterns among mandibular All-on-4, All-on-5, and All-on-6 configurations using three-dimensional finite element analysis. Methods: The three-dimensional finite element models of an atrophic edentulous mandible were developed to simulate All-on-4 (Model 1), All-on-5 (Model 2), and All-on-6 (Model 3) implant-supported prostheses under standardized loading conditions (150 N anterior; 300 N posterior bilaterally). Von Mises stress (overall, implant, and bone) and total deformation were assessed. The results were analyzed using descriptive statistics, and a comparative evaluation of von Mises stress and deformation values was performed across the three implant configurations. Results: Model 2 exhibited the highest overall von Mises stress (76.821 MPa), followed by Model 3 (67.996 MPa) and Model 1 (38.016 MPa). Bone stress was lowest in Model 1 (5.787 MPa) and highest in Model 2 (16.443 MPa). Total deformation was greatest in Model 2 (3.156 × 10−3 mm), whereas Model 3 showed the least deformation (8.2489 × 10−4 mm). Conclusions: Within the limitations of this study, the All-on-5 configuration demonstrated the highest stress concentration and deformation under the present loading conditions. Increasing implant number does not linearly reduce stress. Among the three evaluated configurations, the modeled All-on-6 configuration demonstrated the lowest deformation under the present loading conditions. Implant positioning and load distribution play a more critical role than implant number alone. The findings are based on a specific finite element model and implant distribution and should not be generalized to all clinical All-on-5 configurations.