Effect of Printing Orientation on the Dimensional Accuracy of 3D-Printed Denture Base

Additive manufacturing is now an integral part of digital prosthodontic workflows, and although stereolithography (SLA) is widely used for denture base fabrication, the dimensional accuracy of printed dentures remains highly dependent on manufacturing parameters, particularly build orientation. This study evaluated the influence of build orientation on the trueness and precision of SLA-printed maxillary and mandibular denture bases. Thirty complete denture bases were fabricated using SLA and divided into three groups according to build orientation: 0°, 45°, and 90° (n = 10). The intaglio surfaces of the printed dentures were scanned and compared with their corresponding digital reference models using three-dimensional inspection software. Trueness was quantified using root mean square error (RMSE) and directional deviations, while precision was assessed based on the variability of RMSE values within each group. Statistical analysis was performed using one-way ANOVA and Tukey's post hoc test (p ≤ 0.05). Build orientation significantly affected the trueness of maxillary denture bases, with dentures printed at 90° demonstrating the lowest RMSE values. No statistically significant differences in trueness were observed among build orientations for mandibular denture bases. Precision was not influenced by build orientation for maxillary dentures, whereas mandibular dentures printed at 90° exhibited significantly greater variability compared with 0° and 45°. Build orientation is a critical factor influencing the dimensional accuracy of SLA-printed denture bases in an arch-dependent manner. Optimizing build orientation may enhance both accuracy and reproducibility, thereby improving the predictability and clinical reliability of additively manufactured denture bases.