Influence of Different Material Substrates on the Accuracy of Three Intraoral Scanners: A Single-Blinded In Vitro Study

George Michelinakis, DDS, MSc, MPhil/Dimitrios Apostolakis, DDS, MSc, MSc/Andreas Tsagarakis, DDS/Panagiotis Lampropoulos, DDS, Dr Med Dent: Purpose: To compare the accuracy of three commercially available intraoral scanners for the imaging of various dental material substrates. Materials and Methods: A maxillary dentate typodont model with 11 different dental material substrates was prepared and scanned using three intraoral scanners (Trios 3, 3Shape; CS 3600, Carestream; and Emerald S, Planmeca). The model was also scanned with a laboratory scanner (7series, Dental Wings) for reference. Files were exported in standard tessellation language (STL) format and inserted into a metrology 3D mesh software (CloudCompare). Results: In terms of the influence of different substrates on intraoral scanner trueness, a significant effect on the performance of Trios 3 and Emerald S was found. Pairwise comparisons revealed significant differences among scanners concerning accuracy when scanning more translucent and reflective materials. In terms of complete-arch trueness and precision, pairwise comparisons revealed that the Trios 3 had significantly higher trueness and precision compared to both the CS 3600 and Emerald S, but the complete-arch trueness and precision of the CS 3600 and Emerald S did not differ significantly. Conclusions: Dental material substrates influenced the accuracy of all three tested scanners. The full-metal crown exhibited significantly lower trueness compared to other substrates across all three scanners. For the high-translucency substrate group, the Trios 3 exhibited significantly higher trueness compared to the CS 3600. Polished and unpolished Class II amalgam restorations of similar dimensions did not exhibit significant differences in trueness regardless of intraoral scanner. In terms of complete-arch accuracy, the Trios 3 had significantly higher trueness and precision compared to both the CS 3600 and Emerald S. All three scanners exhibited a mean complete-arch accuracy below 100 μm.