Assessing the accuracy of intraoral scanners in controlled laboratory and clinical conditions

The accuracy of intraoral scanners (IOSs) remains uncertain, particularly for full-arch applications and under variable clinical conditions. This study evaluated the accuracy of IOSs under controlled laboratory and clinical conditions, focusing on trueness and precision in both arches over time. This study included two phases: (1) laboratory validation, and (2) clinical accuracy assessment. (1) Typodonts arches were scanned using a reference scanner (InEos X5) and two IOSs (CS3600 and Primescan). Trueness was assessed by superimposing IOSs onto the reference model; precision was assessed through repeated IOSs scans at three time points. (2) The arches of fourteen patients were randomly assigned to two groups (n = 7 per scanner) and scanned twice by a single operator. 3D inspection software was used for model superimposition. Root mean square (RMS) values assessed accuracy, with standard deviation (SD) and interquartile range (IQR) used for descriptive statistics. Statistical analyses included Shapiro–Wilk and Mann–Whitney U tests (α = 0.05). Color-coded deviation maps revealed discrepancies, especially in interproximal regions. In the laboratory phase, CS3600 demonstrated significantly lower RMS values than Primescan in both arches (maxilla: 0.111 ± 0.031 mm vs. 0.273 ± 0.005 mm, p = 0.011; mandible: 0.132 ± 0.007 mm vs. 0.224 ± 0.029 mm, p = 0.027). Intra-IOSs analysis showed consistent performance for CS3600, while Primescan displayed higher variability, particularly in the maxilla. In the clinical phase, RMS values did not differ significantly between scanners or arches (p > 0.05). A significant difference between clinical and laboratory phases was observed only for the Primescan in the maxilla (p = 0.017). Scanner performance exhibited variability under different setting conditions. However, clinical outcomes demonstrated comparable accuracy. These findings highlight the viability of digital workflows in dentistry, highlighting the importance of selecting scanner models based on specific clinical needs and anatomical considerations. This study offers evidence-based guidance for selecting and using intraoral scanners in full-arch digital impressions.