Purpose: The goal of this study was to determine the clinical acceptability of various cement space settings for the marginal and internal fit of a zirconia core manufactured using additive manufacturing.
Methods: The maxillary right incisor served as the master model. After scanning the maxillary right incisor with a dental 3D (three-dimensional) scanner, the stereo lithography file was created using different cement space settings of 40, 120, and 200 μm using computer-aided design software (Dental System 2018; 3Shape). The marginal and internal fit of the 3 groups were determined using the silicon replica technique. Measurement points were divided into the following three categories: margin, axial wall, and incisal. To ensure more accurate measurements, these three measurement points were divided into 8 points. The Shapiro-Wilk, one-way ANOVA, and Tukey’s honestly significant difference test (for all tests α=0.05) were the statistical analyses that were included in the study.
Results: The CS (cement space)-200 group had better marginal and internal fit than the CS-40 and CS-120 groups, and there were statistically significant differences at the marginal and incisal points, except for the axial wall points. CS-200 group, both marginal and internal fit were within 120 μm, which is the clinically acceptable value.
Conclusion: This study suggests that a 200 μm cement space setting is ideal for optimal marginal and internal fit of 3D-printed ceramic crowns.

Keywords: Additive manufacturing, Cement space, Marginal and internal fit, Silicone replica technique