Background <p>The adaptation of crown restorations is critically influenced by marginal and internal fit, which may be affected by the digital workflow. With the increasing use of intraoral scanners and 3D-printed materials in restorative dentistry, evaluating how different scanner technologies and resin types influence restoration accuracy is essential. This in vitro study aimed to compare the marginal and internal fit of 3D-printed crown restorations fabricated using various intraoral scanners and resins, assessed via micro-computed tomography (micro-CT). The null hypothesis was that neither scanner nor resin type would significantly affect the fit.</p> Methods <p>A standard preparation was performed on an upper first premolar model, which was scanned using three different intraoral scanners (Trios 5, Medit i600, and Primescan). The datasets were used to fabricate restorations with either Saremco CrownTec or VarseoSmile Crown Plus resin using DLP 3D printing. A total of six experimental groups were evaluated, with <i>n</i> = 5 specimens per group (total <i>N</i> = 30). The restorations were seated on corresponding resin models and scanned in axial, coronal, and sagittal planes using micro-CT. Measurements were taken from standardized reference points. Data were analyzed using two-way ANOVA and Bonferroni post hoc tests.</p> Results <p>Both scanner and resin type, as well as their interaction, resulted in statistically significant differences in marginal and internal fit in specific regions (<i>p</i> &lt; 0.05). The Primescan + VarseoSmile group exhibited the lowest mean gap (0.06 ± 0.02&#xa0;mm), while the Trios + Saremco group showed the highest (0.12 ± 0.04&#xa0;mm).</p> Conclusions <p>The type of intraoral scanner and the resin’s material properties significantly influence the fit of 3D-printed restorations. Particularly in marginal and axial areas, scanner–resin compatibility appears to be a critical factor for clinical success.</p>