Accuracy of 3D Printed and Digital Casts Produced from Intraoral and Extraoral Scanners with Different Scanning Technologies: In Vitro Study.

Abstract

To compare the accuracy of 3D printed and digital casts produced from various intraoral and extraoral scanners with different scanning technologies. A conventional stone cast was fabricated from the reference typodont cast and scanned with two intraoral scanners (TRIOS 3 version 1.4.7.5, and Dental Wings version 2.1.0.421), and two extraoral scanners (S600 Arti, Zirkonzahn, and Ceramill map 600, Amann Girrbach GmbH). All digital scans were saved in the form of STL files and measurements were calculated using Geomagic analysis software. Two types of measurements were assessed on the casts: tooth- and arch-level measurements. Absolute errors were calculated by subtracting the measurements on 3D printed, digital, and conventional stone casts from the measurements on the reference typodont cast. One-way ANOVA was used for comparing different measurement errors between groups. Linear regression was performed to determine the association between different explanatory variables, and the average measurement errors (dependent variable) adjusted to reference cast measurements. Regression coefficients (B) and 95% confidence intervals (CI) were calculated. For both 3D printed and digital casts, Dental Wings showed significantly greater error compared to other scanners and to the conventional stone cast at all measurements except arch lengths (in the 3D printed modality only), while conventional casts showed the lowest error. Error was significantly higher in intraoral than extraoral scanners (B = 0.009, 95% CI = 0.005, 0.02), and in arch level measurements than tooth level measurements (B = 0.03, 95% CI = 0.01, 0.04), and significantly lower in 3D printed than digital casts (B = -0.04, 95% CI = -0.05, -0.04). There were no statistically significant differences between measurement errors of both arches (maxillary and mandibular arches). Extraoral scanners showed higher accuracy than intraoral scanners, and 3D printed casts showed higher accuracy than their digital counterparts. Dental Wings scanner had the greatest measurement error.