Influence of manufacturing technique on the accuracy of maxillary complete denture bases: An in vitro comparison between 3D printing and conventional methods

Objective: Complete edentulism affects oral function and requires prosthetic rehabilitation. Denture accuracy depends on fabrication technique. While digital additive manufacturing offers advantages, evidence on 3D-printed versus conventional dentures is conflicting, and no study compares the manufacturing accuracy of pack-and-press, pour, and 3D printing together. Methods: Sixty denture bases were fabricated (n = 15 per group) using a standardized reference cast. The experimental groups included: 3D printed dentures printed at 0° (DP-0), 3D printed dentures printed at 45° (DP-45), dentures made using the pack and press technique (PP), and dentures fabricated via the pouring technique (PO). All intaglio surfaces were scanned and compared to the reference model using 3D metrology software, measuring Root Mean Square (RMS) values across five anatomical regions. Statistical analysis included ANOVA and Kruskal-Wallis tests, with significance set at p < 0.05. Results: The 3D printed group at 45° showed the highest overall accuracy, with significantly lower RMS trueness and RMS precision values compared to PP and PO techniques (p < 0.05.) The PP and PO methods exhibited greater deviation at the borders compared to DP techniques (p < 0.0001), while the PO technique showed improved trueness over PP (p < 0.01). The ridge area consistently showed the lowest RMS values across all techniques. Conclusion: Manufacturing technique and printing orientation significantly influence denture base accuracy. Among the tested methods, 3D printing at a 45° angle yielded the most accurate results. Future studies should explore intraoral factors and optimized post processing strategies to further validate these findings.