Background: A precise so-called passive fit of implant-supported prostheses (ISPs) to implant abutments is regarded as essential to protect screw joint and implant load-bearing capacity from high stresses. Objectives: To determine the relative efficacy of cemented-interface and section-index-and-solder methods to correct ISP inaccuracies following casting, and to measure the load-bearing capacity of the modified frameworks. Methods: Standardized ISP frameworks were fabricated to fit a mandibular model with five abutment analogues (EsthetiCone, Nobel BioCare) using either, Preci-Disc Conical (PDC, Alphadent) system (n=8) (palladium-gold, cobalt-chromium, or silver-palladium-gold alloys), or cast-over method (n=3) (palladium-gold). Before and after framework modification, the three-dimensional (3D) distortion of the frameworks related to the prosthetic analogues was assessed with a coordinate measuring machine (Starrett). The PDC frameworks were modified by resin cementation of titanium interfaces, and the cast frameworks were modified by section-index-and-solder (SIS). The tensile load-bearing capacity of the modified frameworks was measured with an Instron universal testing apparatus. Results: None of the unmodified frameworks provided a completely passive fit with mean 3D distortions of 151 ± 30 µm (PDC) and 134 ± 34 µm (cast-over) (p>0.05). Both modification methods reduced the 3D distortions of the frameworks relative to the prosthetic analogues (p<0.005). The SIS modification reduced the 3D distortion to 65 ± 13 µm, and the PDC system showed a greater reduction to 25 ± 4 µm (p<0.01). During the mechanical test, two solder joints failed in the SIS group, while none of the PDC interfaces failed. Conclusion: The PDC system was more efficacious when compared with the SIS method, in improving framework fit to the master model regardless of the alloy used, and without apparent reduction in the frameworks' mechanical properties. Acknowledgements: Nobel BioCare (Canada) grant.

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