Purpose <p>This study aimed to evaluate the influence of scan body geometry on the trueness of intraoral scanner (IOS) acquisitions.</p> Methods <p>An in vitro study was conducted using three groups of scan bodies with varying designs. Trueness was assessed by measuring deviations from a reference model obtained using a high-precision industrial scanner. Three model types were analyzed: a fully edentulous with six implants, a partially dentate with four implants, and a partially dentate with two implants.</p> Results <p>In all models, the reduced-length scan body (Group 2) showed the highest trueness, with the lowest mean deviations: 87 μm (6-implant model), 104 μm (4-implant model), and 10 μm (2-implant model). The standard design (Group 1) showed moderate deviations, while the more complex design with three flat surfaces (Group 3) consistently showed the highest deviations. Shorter, simpler designs performed best across all configurations.</p> Conclusions <p>Scan body geometry, particularly length and head design, plays a critical role in scanning accuracy. Simplified, shorter scan bodies enhance trueness, while greater height or geometric complexity may compromise it. These findings suggest that optimizing scan body geometry—particularly reducing height—can enhance the accuracy of digital implant impressions, with potential implications for improving reliability in implant-supported prosthetic workflows.</p>