International Journal of Prosthodontics. 2011;24(5):417-27
PURPOSE: This paper aimed to practice evidence-based dentistry by critically appraising relevant evidence to address a common question in prosthodontics. It sought to answer whether the survival and complication rates of all-ceramic fixed dental prostheses (FDPs) were comparable or superior to those of metal-ceramic FDPs, and to use this knowledge to guide clinical decisions. MATERIALS AND METHODS: A 6S search was conducted. No decision support systems or summaries were available. The journal Evidence-Based Dentistry (zero synopses), Trip database (three synopses, discarded), Cochrane database (three systematic reviews, discarded), MEDLINE OVID (six systematic reviews, one accepted), and Embase (zero systematic reviews) were searched. The selected systematic review assessed the survival and complication rates of all-ceramic and metal-ceramic FDPs. One additional prospective cohort study was considered relevant. RESULTS: The systematic review addressed a well-focused clinical question, but its internal validity was compromised. The search was not systematic; inclusion methodology and impact of study characteristics on results were unclear. The external applicability was limited by compromised internal validity, broad outcome definitions, inaccurate results, and incomplete examination of stated aims. With care, however, the results could be applied to clinical practice. Estimated event rates and 5-year outcomes with a 95% confidence interval were calculated, with the survival rate of metal-ceramic FDPs significantly higher than that of all-ceramic FDPs. All-ceramic FDPs experienced a high incidence of technical failure. The prospective cohort addressed a well-focused clinical question with good internal validity. It compared outcomes of metal-ceramic FDPs provided before and after the introduction of implant therapy. Patient cohorts were clearly defined, similar at baseline, and treated equally. Ten-year Kaplan-Meier cumulative survival with standard errors was reported. Metal-ceramic FDP survival rates were high and significantly improved since the introduction of implants and the decreased use of structurally compromised abutments. CONCLUSION: The results of the systematic review and prospective cohort were complementary: Metal-ceramic FDPs had high survival, with a significantly greater 5-year survival rate than all-ceramic FDPs. Differences in complications were unknown, but evidence indicated that the complication incidence of metal-ceramic FDPs was lower than that of all-ceramic FDPs. This evidence was directly applicable to the clinical scenario and will help guide clinical decision making.