ABSTRACT

Objective: To investigate the accuracy of digital impressions obtained from two IOS (intraoral scanners) in capturing an upper edentulous arch using varying number of artificial markers, and explore the potential implications for edentulism rehabilitation in aging societies. Methods: An edentulous maxilla model, scanned by a desktop scanner (3Shape D900L), served as a reference. The model was fitted with varying numbers of markers (0, 3, 6, 9, 15, 21) and scanned thirteen times with each intraoral scanner. Scanned models were aligned with the reference using Geomagic software, and accuracy was assessed via root mean square (RMS) values for trueness and precision. Data analysis involved one-way ANOVA and a post hoc Tukey test (α=0.05). Results: Increasing the number of markers generally improved the scanners' trueness and precision. The 3Shape TRIOS3 and Medit i500 showed significant trueness enhancement with at least nine markers (42.7±8.7μm and 89.9±20.6μm, respectively) compared to no markers (66.7±27.8μm and 128.7±56.7μm). Precision also improved notably for Medit i500 with nine or more markers (76.3±23.0μm) versus none (124.0 ± 60.1μm). Conclusion: The 3D printed markers improved the accuracy of both 3Shape TRIOS3 and Medit i500 scanners. An optimal range of 9 to 15 markers is recommended for these scanners. This research contributes to the advancement of edentulous digital impression, which has a positive impact on the rehabilitation of edentulism in the aging society.