Comparing the accuracy of three digital impression techniques with conventional impression technique for...

To compare the accuracy of stereophotogrammetry (SPG), intraoral scanning (IOS), intraoral scanning with prefabricated splint scan body (IOSS) with the conventional impression technique (CI) for implant-supported fixed full-arch restorations.

Four digital files were obtained for each patient's full arch: a reference scan (laboratory scan of the plaster model obtained by CI) and three test scans (IOS, IOSS, and SPG). The digital files were converted into multi-unit abutment analogs using a digital library. Data were entered into a three-dimensional analysis software to evaluate the distance and angular deviations of the three digital impression techniques relative to the conventional impression technique.

A total of 18 edentulous arches were included. Using CI as a reference, SPG exhibited a significant advantage in distance deviation, with significantly lower deviation values compared to IOS and IOSS. Additionally, SPG demonstrated superiority in angular deviation compared to IOS. There were no significant differences between IOS and IOSS in terms of distance or angular deviation. Neither the implant position nor the number of implants significantly affected the distance and angular deviation of SPG and IOSS. However, IOS exhibited increased distance deviation with a higher number of implants, and mandibular implants showed greater location deviation compared to maxillary implants. In all three digital groups, there was no significant correlation between distance and angular deviation with implant system.

Stereophotogrammetry (SPG) demonstrated high accuracy, meeting clinical requirements for edentulous patients and enhancing the digital workflow. Intraoral scanning with prefabricated splint scan body (IOSS) provided better accuracy than intraoral scanning (IOS), meeting clinical demands effectively.