Micro-CT Analysis of Y-TZP Copings Made by Different CAD/CAM Systems: Marginal and Internal Fit

PURPOSE: The aim of the study was to measure the marginal and internal adaptation (MIA) of zirconia copings, made of 4 ceramic systems for CAD/CAM, using microcomputed tomography (micro-CT) technology. MATERIAL AND METHODS: Two identical stainless steel models were used, representing a preparation for full ceramic crown on a lower molar. The master models were then scanned for the production of copings from specific yttrium oxide partially stabilized tetragonal zirconia polycrystal ceramic blocks of each system (n=10): Cerec/inCoris Zi, Sirona; Cercon/Cercon base, Dentsply; Ceramill/Ceramill Zi, Amann Girrbach; and Lava/Lava Frame Zirconia, 3M ESPE. MIA was evaluated measuring 4 points as follows: marginal gap (MG), axial wall gap (AW), axio-occlusal angle gap (AO), and central occlusal area gap (CO). The data were statistically analyzed by ANOVA and Tukey's test (α = 0.05). RESULTS: The ceramic system Lava showed greater internal desadaptation (80.75 ± 22.69 µm) while CEREC presented the lowest values (49.92 ± 11.77 µm). There were significant differences between the measurement points evaluated. CO demonstrated the greater values (77.03 ± 22.61 µm). All marginal and internal adaptation values were considered clinically acceptable. CONCLUSION: It was concluded that there was an influence of the type of ceramic system in marginal and internal adaptation of copings in zirconia.