Clinical Performance, Esthetics, and Patient-Rated Outcomes of Porcelain-Fused-to-Metal Fixed Partial Dentures with Cobalt–chromium and Gold-alloy Frameworks: A 5-to-7 Year Retrospective Study

PURPOSE: To investigate and compare the clinical performance, esthetics, and patient-rated outcomes of porcelain-fused-to-metal (PFM) fixed partial dentures (FPDs) with CoCr-alloy-based and Au-alloy-based frameworks. MATERIAL AND METHOD: A total of 92 patients with 117 FPDs in either CoCr- or Au-alloy-based frameworks were followed for 5-9 years. Two calibrated examiners performed clinical and radiological examinations and recorded survival and biological and technical complications using a modified California Dental Association (CDA) index and a structured patient questionnaire on function, esthetics, and complications. Statistical analyses were conducted using chi-square, Fisher's exact, and multiple regression tests. RESULTS: The survival rate was 98.3% for CoCr-alloy-based FPDs and 93.0% for Au-alloy-based FPDs. While the incidence of chip-off fractures was similar between the two groups on FPD level, the difference was statistically significant on unit level with 4.7 % in the CoCr-alloy-group and 9.5% in the Au-alloy-group (p=0.009). CDA assessments showed overall acceptable outcomes in both groups, with differences observed in anatomical form, marginal characteristics, and patient-reported outcomes. CONCLUSIONS: In the present study, both Au-alloy-based and CoCr-alloy-based FPDs showed high survival rates. Chip-off fractures were more common in Au-alloy-based frameworks. Accordingly, CoCr-alloy-based frameworks are a cost-effective and clinically reliable alternative for PFM frameworks.