Confocal 3D Optical Intraoral Scanners and Comparison of Image Capturing Accuracy

Several capture techniques are used in intraoral optical scanners in the dental market, such as Triangulation (Cerec Omnicam, Dentsply Sirona), Activewave front sampling (3M ESPE) and confocal technology (iTero, Align). The accuracy of intraoral scanners is the most significant focal point for developers to research. This in-vitro study studied the accuracy of confocal scanners launched from 2015-2020 (Trios 3, Trios 4, iTero Element; 3Shape Trios A/S, Copenhagen, Denmark, and iTero Element2, and iTero Element5D; Align Technologies, San Jose, CA, USA). A 3D printing model modified from the American National Standard No. 132 was scanned five times each scanner. Both Trios3 and Trios4 were scanned using regular scan mode (N) and high-resolution mode (HR). All scanning methods followed the recommendations from the manufacturers. Then the digital models were exported and saved as STL files. Various measurements were determined in the digital model from each scan using Rhinoceros 3D Software (Rhino, Robert McNeel & Associates for Windows, Washington DC, USA). Measurements from the 3D printed model were used as control. All data were recorded in Microsoft Excel and then transferred to SPSS. Descriptive statistics were recorded. Multiple comparisons of various measurements were made among the different scanners and with the control using One-way ANOVA and post hoc using Sheffe (p < 0.01). The surface area in the X and Y axis ranged from 2-60 mm, while the depth (Z-axis) ranged from 2-8 mm. The Trios and iTero families showed similar accuracy. However, for the diagonal, the Trios series showed better results compared with the iTero series. Within the same brand, different versions showed no significant change regarding accuracy.