Digital model ; CBCT scanning ; STL conversion ; Accuracy
Abstract
Objectives: The purpose of this study is to evaluate the accuracy of the digital models from Cone beam computed tomography (CBCT) scans of orthodontic diagnostic models by comparing the Digital Imaging & Communication in Medicine (DICOM) file to Stereolithography (STL) conversion data obtained by various voxel sized CBCT machines with the digital model obtained by a 3D optical extraoral scanner.
Materials and Methods: Three orthodontic diagnostic models were scanned with a 3D optical scanner and stored as STL file data. The three models were scanned with the 5 modes which were Object scan (100 μm), 300, 400 μm of RAYSCAN α+ and 300, 390 μm of Alphard 3030. The DICOM files were converted to STL file data. For each orthodontic model, two digital models obtained by CBCT and optical scanner were paired, and GOM inspect software was used to superimpose and obtain the deviation between two digital models. One way ANOVA test was performed to determine whether there is a statistical difference in the mean value of deviations between digital models by the 5 protocols.
Results: In three diagnostic models, the mean values of the deviations between the digital model of the Object scan (100 μm) and the digital model of 3D optical scanner were the smallest in comparison with other image protocols and there was a statistically significant difference (p<0.001). The mean values of the deviations were in the range of 0.0967 ~0.1022 mm. On the other hand, deviations of STL data from 400 μm of RAYSCAN α+ showed the largest mean value from 0.4007 to 0.4534 mm.
Conclusions: The STL file data of the Object scan (100 μm) of RAYSCAN α+ is more accurate than those of large voxel sized protocols of CBCT. It shows the availability as an orthodontic digital model.