Comparison of Intraoral Scanning Modes in Three Distinct Full- Arch Digital Implant Impression Scenarios: An In Vitro Study

Purpose: To analyze the effect of scanning modes on the accuracy of the Trios intraoral scanner (IOS) for full-arch digital implant impressions. Materials and Methods: The trueness and precision of the intraoral scanning mode (IOSM) and the intraoral edentulous scanning mode (IOEM) of the Trios IOS were evaluated in three edentulous models, each featuring four, six, and eight implant analogs. Reference scanning data were obtained by scanning each model with a desktop scanner. Each model was scanned 10 times using the IOSM and IOEM modes of the Trios IOS to establish the test groups. The scan bodies in the test and reference scans were isolated and exported in the reverse engineering program. The scan bodies in each group were superimposed with the corresponding reference scan (trueness) or with each other (precision). The overall 3D deviation between the aligned scan bodies was computed by the root mean square (RMS) values. Results: No significant difference was found between scanning modes in any of the models. When comparing models, the eight- implant model showed significantly lower trueness than the four-implant model. However, it exhibited significantly higher precision than the four-implant and six-implant models. There were no significant differences in other pairwise comparisons between the models. Conclusions: Trueness and precision values were similar between the IOSM and IOEM groups across all the models. An increase in the number of implants in completely edentulous arches may have a negative impact on digital impression accuracy.