Clinical Accuracy of Complete Arch Implant Scans Recorded by Using a Customized Metallic Ring‐Based Calibrated Framework: An In Vivo Study

AIM: To evaluate and compare the positional accuracy of complete arch intraoral digital implant scans obtained using a conventional scan body protocol and a customized metallic ring-based calibrated framework. MATERIALS AND METHODS: A completely edentulous arch restored with six implants was scanned using two complete arch intraoral digital impression protocols: a conventional scan body protocol (SB) and a metallic ring-based calibrated framework (CF). Twenty scans were obtained per group using the same intraoral scanner. A coordinate measuring machine (CMM) dataset served as the reference standard. All STL files were imported into dental CAD software to design a standardized virtual implant-supported bar, which was subsequently analyzed using reverse engineering software. Linear inter-implant distances and angular deviations were calculated. Trueness was defined as the absolute deviation from the CMM reference, and precision as the variability among repeated scans. Between-group comparisons were performed using independent t-tests with Welch correction and Holm adjustment (α = 0.05). RESULTS: The mean linear deviation was 0.034 (0.004) mm for CF and 0.124 (0.019) mm for SB (p < 0.01). The mean angular deviation was 0.31 (0.05) degrees for CF and 0.55 (0.10) degrees for SB (p < 0.01). CONCLUSIONS: The calibrated splinting protocol showed greater trueness and lower variability compared with the conventional scan body approach.