Accuracy of a Novel Desktop Micro-CT Scanner for Direct Digitization of Dental Impressions: A Comparative In Vitro Study

Background/Objectives: This study aimed to evaluate the clinical feasibility of a novel desktop micro-computed tomography (micro-CT) scanner for digital impressions through comprehensively assessing its dimensional trueness and morphological accuracy in comparison with other optical-based scanners. Methods: A modified reference model was used to create ten silicone impressions and corresponding plaster models. Four digitization protocols were evaluated: (1) direct scanning of impressions via micro-CT scanner (MCTI), (2) extraoral scanning of impressions via F8 scanner (F8I), (3) extraoral scanning of plaster models via F8 scanner (F8PM), and (4) intraoral scanning of plaster models using Trios 5 scanner (IOSPM). Dimensional trueness was quantified via six linear measurements, and morphological accuracy (trueness and precision) was assessed by 3D surface deviation analysis. Results: Statistically significant differences in linear measurements between the digital impressions and the reference model were observed (p < 0.05). MCTI, F8PM and IOSPM demonstrated higher dimensional trueness than F8I. Although all methods showed high morphological precision, F8I (398.5 ± 43.0 µm) exhibited significantly greater root mean square (RMS) deviations for morphological trueness than MCTI (114.8 ± 42.2 µm), F8PM (142.1 ± 27.7 µm) and IOSPM (134.6 ± 12.0 µm) (p < 0.01). MCTI also demonstrated the highest reliability for morphological trueness according to relative standard deviation (RSD) analysis, with RSD values of 30.83% for MCTI, 41.80% for F8I, 37.26% for F8PM, and 42.55% for IOSPM. Conclusions: The novel micro-CT scanner enables accurate and reliable direct digitization of dental impressions. Its performance is comparable to scanning plaster models with high-end scanners and significantly superior to direct optical scanning of impressions, making it a promising alternative in digital dental workflow.