Purpose: To evaluate the marginal and internal adaptation of all-ceramic crowns and inlays fabricated by different scanners of the same CAD/CAM system.

Materials and methods: All-ceramic crown preparations were performed on typodont maxillary first premolars, and mandibular first molars were prepared for ceramic Class II mesio-occlusal inlays. Two intraoral scanners (CEREC Bluecam and Omnicam, Dentsply Sirona) and one model scanner (CEREC inEos X5, Dentsply Sirona) were used to scan the preparations. All restorations were fabricated by milling single-feldspathic ceramic blocks (CEREC Blocks). The marginal and internal discrepancies of restorations were evaluated via micro-CT analyses.

Results: For linear crown measurements, the marginal gaps were 63.75 μm, 88.24 μm, and 90.89 μm for Bluecam, Omnicam, and inEos X5, respectively. For crowns at central groove areas, the maximum values for Bluecam, Omnicam, and inEos X5 were found to be 144.78 μm, 165.19 μm, and 129.49 μm, respectively. For inlays, the highest range at the midpoint of the axiopulpal line angle for Bluecam, Omnicam, and inEos X5 were determined as 138.57 μm, 184.33 μm, and 179.71 μm, respectively. In volumetric measurements, inEos X5 showed lower gap for both crowns (11.47 mm³) and inlays (5.65 mm³) compared to both intraoral scanners. These results are within a clinically acceptable range.

Conclusion: When all-ceramic crowns were evaluated, there were generally no significant differences found between scanners for the regional linear measurements, but more gaps occurred in restorations obtained with intraoral scanners for volumetric measurements. On the other hand, when the inlay restorations were evaluated, significant differences were found between groups except for the midpoint of the axio-pulpal line angle and the midpoint of the mesio-gingival margin. However, marginal and internal gaps of both crowns and inlays presented mean values less than 150 μm in many surfaces, which could be considered clinically acceptable.