Evaluation of digital dental models obtained from dental cone-beam computed tomography scan of alginate impressions

Abstract

ObjectiveTo investigate the dimensional accuracy of digital dental models obtained from the dental cone-beam computed tomography (CBCT) scan of alginate impressions according to the time elapse when the impressions are stored under ambient conditions.MethodsAlginate impressions were obtained from 20 adults using 3 different alginate materials, 2 traditional alginate materials (Alginoplast and Cavex Impressional) and 1 extended-pour alginate material (Cavex ColorChange). The impressions were stored under ambient conditions, and scanned by CBCT immediately after the impressions were taken, and then at 1 hour intervals for 6 hours. After reconstructing three-dimensional digital dental models, the models were measured and the data were analyzed to determine dimensional changes according to the elapsed time. The changes within the measurement error were regarded as clinically acceptable in this study.ResultsAll measurements showed a decreasing tendency with an increase in the elapsed time after the impressions. Although the extended-pour alginate exhibited a less decreasing tendency than the other 2 materials, there were no statistically significant differences between the materials. Changes above the measurement error occurred between the time points of 3 and 4 hours after the impressions.ConclusionsThe results of this study indicate that digital dental models can be obtained simply from a CBCT scan of alginate impressions without sending them to a remote laboratory. However, when the impressions are not stored under special conditions, they should be scanned immediately, or at least within 2 to 3 hours after the impressions are taken.

Linear Accuracy of Full-Arch Digital Models Using Four Different Scanning Methods: An In Vitro Study Using a Coordinate Measuring Machine

“…More and more imaging devices enabling digital data acquisition from impressions and plaster models have become available [7]. Accordingly, the accuracy of digital models has been assessed in many previous studies [2,10,14,15,20]. Studies have generally evaluated the accuracy of the digital models obtained by scanning plaster models with various devices or compared linear measurements of digital models with the corresponding values of plaster casts [1][2][3][4].…”

“…This method is advantageous in that an additional machine is not required for digital model generation, the scanning time is relatively short, the patient experiences no discomfort, and the characteristics of the X-ray penetrance prevent information loss regardless of the shape of objects such as undercut, in contrast to direct optical scans of the patient's mouth [11][12][13]. Digital Imaging and Communications in Medicine (DICOM) data that are obtained from CBCT devices can also be converted into STL data using various software [14][15][16]. Thus, the performance of the conversion software also affects the accuracy of the digital models.…”

Three-dimensional comparison of 2 digital models obtained from cone-beam computed tomographic scans of polyvinyl siloxane impressions and plaster models

“…However, extendedpour alginate with high volumetric stability can be scanned using CBCT to produce a digital model. 8,9 Although it is generally recommended to perform the CBCT scan immediately after impression tak ing, it can be delayed up to 2 or 3 hours when a highstabil ity impression material is used. 9 This study performed CBCT scans at a resolution of 0.1 mm, which improved the accuracy of the digital mod els relative to those obtained by scanning at resolutions of >0.15 mm to 0.3 mm, as performed in previous stud ies.…”

“…8 In previous studies, the dimensional accuracy of dig ital models obtained from CBCT scans of alginate im pressions was examined according to the elapsed time. 8,9 However, no published study has evaluated the dimen sional accuracy of digital models obtained using CBCT. Therefore, there is a lack of studies investigating the ac curacy of digital models produced using CBCT, and the width of individual teeth and the entire arch obtained us ing a digital model must be validated.…”

The Effect of disinfection of Extended-Pour alginate impressions on the surface roughness of stone casts

“…Recent studies reported that (Hydrogum 5) extended-pour alginate impressions show promising dimensional stable up to 120 hours at consistent temperature and humidity (20,25) . However, other study has shown that Hydrogum 5, was dimensionally constant for only 24 h (29) . Disinfection was performed with spraying ready-made commercial disinfectant material: AHD 2000 (Alcohol-based disinfectant).It was used because alcohols are widely used by dentists (30) .…”