Abstract
In recent years, digital technology for implant prostheses has greatly advanced and the method of using an intraoral scanner to take optical impressions has attracted attention. However, there are still many unclear points about the reproducibility of implant position in cases with full arch implants. Therefore, the aim of this study was to evaluate the optical impression captured by the intraoral scanner and the silicone impression by 3-dimensional analysis software, using a maxillary edentulous jaw model with six implants implanted in 16, 14, 12, 22, 24, 26(the master model).
The master model was fitted with six scan bodies, which provided the basic data. Then, the scanning data of the optical impression recommended by the manufacturer (IOS1) and optical impression omitting the scanning process (IOS2) were both provided. Next, the impression of the master model was obtained by the open-tray method, and the cast model was fabricated by both the one-time injection method (IMP1) and the two-times injection method using a drinking straw (IMP2) to obtain respective data. The basic data as well as IOS1, IOS2, IMP1, and IMP2 were superimposed by software respectively, and the data were evaluated based on the adaptation ratio and the color mapping image. IOS2 showed a statistically significant difference from IOS1, IMP1 and IMP2. Since the alveolar ridge was the landmark before scanning the scan bodies, the positional relationship of the scan bodies was clarified. IOS1 showed a higher adaptation ratio than IOS2. On the other hand, since there was no statistically significant difference between IOS1, IMP1, and IMP2, it became clear that the accuracy of optical impressions taken by the intraoral scanner by the manufacturer was comparable to that of silicone impressions. In addition, since the IMP2 data showed smaller dispersion than that of IMP1, it was proven that the dental stone injection method using drinking straws was more accurate than the standard method. IOS1 showed smaller vertical error than IMP1 and IMP2 from the color mapping image. Therefore, it will be simple to adjust the occlusion of the implant superstructure fabricated by the intraoral scanner. However, since IMP1 and IMP2 showed displacement in the vertical error, occlusion adjustment of the implant superstructure and accuracy of the framework must be done carefully.
This study found that the method of taking optical impressions by an intraoral scanner could be applied to cases of full arch implants.
