Background and Objectives: With the increased trend towards digitalization in dentistry, intraoral scanning has, to a certain extent, replaced conventional impressions in particular clinical settings. Trueness and precision are essential traits for optical impressions but have so far been incompletely explored. Materials and Methods: We performed a study to evaluate the differences in the three-dimensional spatial orientations of implant analogs on a stone cast when using an intraoral scanner compared to a dental laboratory scanner. We assessed the deviation of the intraoral scans compared to the laboratory scan for three standardized implant measurement plans and compared these results with control scans of the neighboring natural teeth. Results: We found no statistically significant correlation between the measurements at the scan body level and the landmarks chosen as controls on the neighboring natural teeth (p = 0.198). The values for the implant scans presented wider variation compared to the control scans. The difference between the implant and the control planes ranged from -0.018 mm to +0.267 mm, with a median of -0.011 mm (IQR: -0.001-0.031 mm). While most values fell within a clinically acceptable margin of error of 0.05 mm, 12.5% of the measurements fell outside of this acceptable range and could potentially affect the quality of the resulting prosthetic work. Conclusions: For single-unit implant-supported restorations, intraoral scanning might have enough accuracy. However, the differences that result when scanning with an intraoral scanner may affect the quality of prosthetic work on multiple implants, especially if they are screw-retained. Based on our results, we propose different adaptations of the prosthetic protocol to minimize the potential effect of errors that may occur during the digital workflow.
Keywords: digital dentistry; intraoral scan; scanning accuracy.