The long-term success of implant-supported prostheses (ISPs) is strongly influenced by material selection, which affects stress distribution within the implant system and surrounding cortical bone. This study aimed to assess the biomechanical behavior of a four-unit ISP supported by two implants in the posterior region, using different framework and superstructure material combinations through dynamic finite element analysis (FEA). Methods: A three-dimensional (3D) edentulous mandibular model was created using Mimics software, with two implants placed in the first premolar and second molar regions. Four framework materials—titanium (Ti), glass fiber–reinforced composite (GFRC), 3Y-TZP zirconia, and polyether ether ketone (PEEK)—were combined with two superstructure materials, 5Y-TZP zirconia and resin-matrix ceramic (RMC), forming eight groups. Dynamic loading simulated chewing forces, and stress distribution was analyzed using the von Mises criterion. Results: The results demonstrated that 3Y-TZP zirconia frameworks generated the highest stress values across implants, abutments, and cortical bone. RMC crowns consistently produced lower stress than 5Y-TZP zirconia across all the groups. PEEK showed the highest displacement, followed by GFRC, zirconia, and Ti. Conclusion: Materials with higher Young’s modulus tended to exhibit greater stress transfer to the implant, implant components, and cortical bone. In contrast, polymer-based materials may show a tendency toward greater deformation and displacement compared with metallic and ceramic materials.
Hajghani et al. (Wed,) studied this question.