The “All-on-four" concept for treatment of edentulous arch consists of four implants placed in between mental foramina; two mesial implants placed perpendicular to the bone crest, and two distal implants installed inclined. The prosthetic framework material is an important parameter in stress concentration at the implants, framework, and the underlying bone. Aim: The aim of the study is to evaluate the effect of Zirconia, PEEK, and CFR-PEEK as framework materials compared to titanium framework in All-on-four implant-retained mandibular restorations.
Materials and Methods: The finite element model components were created on “Autodesk Inventor" Version 8 and were exported as STEP files, to be assembled and meshed in ANSYS environment. The model simulates a clinical situation where an edentulous mandible was restored with All-on-four restoration. Four different framework materials were tested; Titanium, Zirconia, PEEK and CFR-PEEK. A unilateral load of 200N was applied vertically and at 30º on distal implant as two loading cases.
Results: Von Mises stress for the Cortical bone was higher with PEEK framework 72 MPa followed by CFR-PEEK 68.5 MPa, Titanium 62 MPa and the least was the Zirconia framework 58 MPa in case of oblique loading. Zirconia framework showed the maximum Von Mises stress on the implant assembly 625 MPa followed by PEEK framework, CFR-PEEK framework and the least was the titanium framework 467 MPa.
Conclusion: Framework material has an effect on success of All-on-four prosthetic option. PEEK and CFR-PEEK frameworks should be applied with caution and need further research.