Purpose: To compare the stress distribution between the all-on-4 and all-on-6 treatment concepts with various prosthetic-framework materials through finite element analysis. Materials and Methods: A 3D finite-element model of an edentulous maxilla was simulated using computerized topographic data of a patient. Four implants were placed according to the all-on-4 concept. In addition to the all-on-4 concept, two more axial implants were placed in the anterior region to create the all-on-6 concept. Four framework materials were investigated: cobalt-chromium (CoCr), zirconia (Zr), titanium (Ti), and polyetheretherketone (PEEK). Simultaneously, a 100-N load was applied to the anterior region, a 150-N oblique load was applied to the premolars, and a 200-N oblique load was applied to the molars. Principal stresses in bone and von Mises stresses in the implants and frameworks were calculated and compared. Results: The all-on-6 concept showed lower von Mises stress values on the implants and frameworks and lower principal stress values on the bone than the all-on-4 concept. PEEK exhibited the highest stress values on bone and implants, while CoCr showed the lowest stress values. Conclusions: Stress distribution was influenced by the framework materials. The use of a framework material with the appropriate physical properties for the correct indication might be particularly important in determining the success of the implant-supported prostheses.
