The Effect of Intraoral Scanner Generation on Full-Arch Digital Impression Accuracy: An In Vitro Study

The accuracy of full-arch digital impressions remains a topic of debate despite advancements in intraoral scanning technologies. This in vitro study aimed to evaluate the effect of different intraoral scanner generations (TRIOS 3, TRIOS 5, and TRIOS 6) on full-arch digital impression accuracy by comparing dentate and fully prepared models. A dentate and a fully prepared maxillary model were digitized using a high-accuracy desktop scanner to create reference datasets. The models were fabricated with a 3D printer, and a total of 60 digital impressions were obtained, with 10 repeated scans for each scanner–model combination. Accuracy was assessed by comparing STL datasets with the reference models using root mean square (RMS) deviation values. The results showed that TRIOS 3 and TRIOS 5 demonstrated similar accuracy performance across both model types, whereas TRIOS 6 exhibited higher deviation values, particularly in the fully prepared model. Furthermore, model type had a significant effect on accuracy, and a statistically significant interaction was observed between scanner type and model type. These findings indicate that digital impression accuracy is influenced not only by scanner generation but also by surface morphology and reference characteristics.