Accuracy of the Calibrated Framework for Intra Oral Full Arch Scan (A Cross-over Study)

The passive fit of full-arch implant-supported prostheses is a critical factor influencing the long-term success of implant rehabilitation. Because dental implants lack a periodontal ligament, inaccuracies in transferring implant positions may result in framework misfit, leading to biological and mechanical complications such as screw loosening, component fracture, or implant failure. Conventional splinted open-tray impressions are considered the reference standard for full-arch implant impressions; however, they are technique-sensitive, time-consuming, and susceptible to material distortion and operator-related errors.

Advances in digital dentistry have enabled the use of intraoral scanners for implant impressions. Nevertheless, complete-arch digital scanning remains challenging because cumulative stitching errors may reduce scanning accuracy. The use of a calibrated framework has recently been proposed to improve the accuracy of complete-arch intraoral scanning by providing stable geometric reference points during image acquisition. Although promising, clinical evidence comparing this technique with the conventional splinted open-tray impression technique remains limited.

The purpose of this crossover clinical trial is to compare the accuracy of conventional splinted open-tray impressions and intraoral digital scanning using a calibrated framework in completely edentulous patients receiving full-arch implant rehabilitation.

Twenty healthy completely edentulous patients will be recruited. Following implant placement, each participant will undergo both impression techniques. The conventional workflow will consist of a verified splinted open-tray implant impression, while the digital workflow will involve intraoral scanning using a calibrated stock framework attached to implant scan bodies. STL datasets obtained from both techniques will be analyzed using Geomagic Control X software. The digital models will be superimposed to assess linear deviations along the x-, y-, and z-axes, angular deviations, and global three-dimensional deviations. The results will be statistically analyzed to determine whether the calibrated framework-assisted digital workflow provides transfer accuracy comparable to or greater than the conventional impression technique.