Purpose: to evaluate fracture resistance of implant supported superstructures fabricating of high translucent zirconia and PEEK restoration under static and dynamic load Materials and methods: 32 epoxy resin blocks were fabricated. Two implant analogues were inserted centrally in epoxy resin block to replace the first premolar and first molar. The samples were divided according to material of superstructures into two groups, high translucent zirconia and high performance Polyether-ether-ketone PEEK (BioHPP). All copies were processed by CAD\CAM technology. PEEK samples were veneered by veneering composite. Half samples were exposed to fatigue procedures then all samples were loaded by universal testing machine until failure. All fracture samples were inspected. Data were statistically analyzed by SPSS Program.Results: For static test, the mean fracture load value was 2319±139 N for PEEK(BioHPP) group and 1350±89 N for HTZ group. The results of dynamic loads showed that the mean fracture load value was 1850±136N for the PEEK (BioHPP) group and 716±79 N for the HTZ group.In HTZ group, framework fracture was detected. In PEEK, the samples showed veneer and framework fracture. Conclusions:Restorative material of implant supported superstructure are affected the fracture resistance of dental restoration. PEEK (BioHPP) has higher fracture strength than HTZ in both static and dynamic tests.

Regardless of the favorable criteria of zirconia based ceramic, it has poor translucency, (3) so it was utilized as core material veneered with translucent