# Accuracy, Time, and Comfort of Different Intraoral Scanners: An In Vivo Comparison Study
## 4 Discussion  
This study evaluated and compared the accuracy and patient satisfaction associated with digital impressions obtained using three different intraoral scanners (IOSs) in a sample of orthodontic patients. Specifically, this study was the first to include the newly introduced iTero Lumina alongside other popular IOSs, such as the widely used iTero models and the TRIOS, which have been extensively examined in previous clinical studies. The results provide valuable insights into the performance of these IOSs and found differences in their accuracy and patient satisfaction, which can guide clinicians in selecting the most appropriate scanner for their practice. The results of this investigation reported that all three examined IOSs successfully generated the reproducible surface topography of anatomical dental structures with no statistical differences. The intraoral scanners examined in this study showed good performance and comparable trueness. Our results were similar to other studies [19] that evaluated the accuracy of six IOSs for single crown preparations. The authors found that the accuracy of iTero and Trios was similar when four different scan strategies, guided by the various manufacturers' instructions, were used and concluded that both the examined digital devices provided sufficient flexibility for the acquisition of 3D images without affecting the accuracy of the impression. There were some statistical differences between TRIOS, iTero Element, and Lumina, as reported in the central incisors' region. The discrepancy found in the results may come from the intraoral conditions of the patients and the anatomical accessibility during the scanning phase [20]. Other characteristics such as the scanner's size and diameter are important for an improved scanning workflow. Also, the software updates strongly influenced the examined parameters of the IOSs (summary chart, scanning time, continuity, and accuracy) [21]. Furthermore, it has been reported in the literature that the clinically acceptable discrepancy with digital techniques impressions is at least 50 \(\upmu\)m as the minimum required for trueness and 10 \(\upmu\)m for precision [22]. The satisfaction survey conducted in this investigation revealed an overall preference for digital impressions performed with iTero Lumina, linked to increased comfort and painless practice of the IOS, which also offered a better technology visualization of the impression. There were no significant differences between the two IOSs in terms of dryness of mouth and gag reflex. This result shows also a great standard deviation, suggesting that these variables depend on the individual patient and their personal experience. However, an overall appreciation of the IOSs was found, suggesting that a general reduction in dry mouth and gag reflex during scanning contributed to the patients' general satisfaction may ultimately improve treatment adherence and outcomes, as reported in other studies [10; 11; 12; 13; 14; 18; 19; 20; 21]. The differences found between the two IOSs may come from the reduced size and diameter of iTero Lumina's handpiece. Furthermore, the preference for iTero Lumina over iTero Element among patients was also recorded in duration perception. Patients perceived the duration time to be shorter with iTero Lumina. Clinicians involved in this study also reported that the procedure with Lumina required a reduction in time when compared to iTero Element. This investigation underscores the importance of technological advancements and ergonomic design in digital impression systems. Overall, its findings emphasize the growing importance of digital technology in orthodontic practice. Further research is needed to explore digital innovation in scanning techniques to enhance patient care and improve treatment outcomes.