Three-Dimensional Analysis of Digital Models Generated from Intraoral, Extraoral, and CBCT Scanning Devices

Objective : To compare the intra- and inter-arch accuracy of three-dimensional (3D) digital models acquired from various orthodontic scanners, including: an intraoral scanner, an extraoral scanner, and a cone beam computed tomography (CBCT) scan compared with the original, trimmed stone models. Methods : Fifteen sets of maxillary and mandibular finished plaster models were scanned using: Carestream 3600 intraoral scanner, Ortho-Insight 3D Motion View extraoral scanner, and Carestream 9300 CBCT scanner. Dolphin Imaging software was used to calculate various anatomic measurements on the digital models. Digital calipers were used to calculate the same measurements on the original plaster models for comparative purposes. Intraclass Correlation Coefficients (ICC) and pair-wise analysis of variance (ANOVA) were utilized to compare the 4 methods (original plaster models and 3 scanning methods). Results : ICC values for all intra-arch measurements between the 4 data groups were all >0.90. ICC values for the two inter-arch measurements (overbite and overjet) were both 0.79. CBCT measurements were significantly smaller than the two scanned models as well as the stone models for many intra-arch parameters. On average, these differences were less than 0.5mm. Conclusion : Digital models produced from CBCT scans of plaster casts appear to have adequate accuracy for orthodontic treatment planning and recordkeeping. Further studies are needed to determine the clinical efficiency of appliance design, fabrication, and chairside delivery using CBCT scanning technologies.