In Vitro Analysis of the Effect of Intraoral Scan Body Design on the Accuracy of Complete Arch Implant Scanning

Achieving a passive and accurate fit in full-arch implant-supported prostheses remains a significant challenge in digital dentistry. Intraoral scan bodies (ISBs) are essential components for transferring implant positions digitally. However, variations in ISB material, geometry, and height may influence the accuracy and precision of intraoral scans. This study aimed to evaluate how different ISB designs affect the trueness and precision of digital impressions in a completely edentulous maxillary arch with multiple implants.

An in vitro model with 8 implants was scanned using the Primescan intraoral scanner. Five ISB configurations were tested: four from different manufacturers (ELOS, GT Medical, ZIACOM, and 3Shape) and a fifth mixed group with alternating ISBs. A coordinate measuring machine (CMM) was used as the reference standard. Accuracy was assessed through linear (Euclidean distance) and angular (relative angulation) measurements. Statistical comparisons included ANOVA, pairwise analysis, and multivariate regression.

Significant differences were found among ISBs in both trueness and precision. ZIACOM showed the best precision overall, particularly in repeated linear (21 ± 16 μm) and angular measurements (0.102± 0.081 degrees), while ELOS displayed the lowest deviation in linear distance (40 ± 33 μm). The mixed ISB group yielded the highest variability and the most extreme errors. Although mean values were within clinically acceptable limits, maximum deviations reached 223 µm and 1.2°, potentially compromising passive fit.

ISB selection significantly affects the accuracy and reproducibility of intraoral scans in full-arch implant scenarios. Using a consistent ISB system is recommended, as mixing components from different manufacturers may increase variability and compromise the reliability of digital impressions in complex rehabilitations.