Marginal and Internal Discrepancies of Posterior Zirconia-Based Crowns Fabricated with Three Different CAD/CAM Systems Versus Metal-Ceramic

Purpose: The aim of this study was to analyze the marginal and internal fit of metalceramic and zirconia-based crowns. Materials and Methods: Forty standardized steel specimens were prepared to receive posterior crowns and randomly divided into four groups (n = 10): (1) metal-ceramic, (2) NobelProcera Zirconia, (3) Lava Zirconia, and (4) VITA In-Ceram YZ. All crowns were cemented with glass-ionomer agent and sectioned buccolingually. A scanning electron microscope was used for measurements. Kruskal-Wallis and Wilcoxon signed rank test (α = .05) statistical analyses were conducted. Results: Significant differences (P .0001) in marginal discrepancies were observed between metal-ceramic and zirconia groups. No differences were found for the axial wall fit (P = .057). Significant differences were shown among the groups in discrepancies at the occlusal cusp (P = .0012) and at the fossa (P = .0062). No differences were observed between surfaces. Conclusions: All zirconia groups showed better values of marginal discrepancies than the metal-ceramic group. Procera Zirconia showed the lowest gaps.