Precise implant impressions are essential for accurately reproducing the three-dimensional (3D) orientation of implants. Digital protocols using intraoral scanners (IOSs) and scan bodies provide significant benefits over traditional elastomeric approaches. Nevertheless, the geometry of scan bodies can influence the accuracy and fidelity of IOS-derived data, and the ideal design parameters are not yet established. This systematic review aims to analyze how variations in scan body geometry affect the trueness of digital implant impressions captured via IOSs. Comprehensive searches were performed in PubMed, Scopus, EMBASE, Web of Science, Cochrane Library, and Google Scholar databases up to 25 February 2025. Studies examining the relationship between scan body geometry and the accuracy of implant-level digital impressions using IOSs were included. Methodological quality was evaluated using the Quality Assessment Tool for In Vitro Studies of Dental Materials (QUIN). Twenty-eight studies met inclusion criteria, including twenty-six in vitro investigations. The publications, dated from 2020 to 2025, revealed that both macro- and micro-geometry variations influenced linear and angular accuracy. Cylindrical configurations with appropriate proportions typically demonstrated superior outcomes compared to cuboidal or spherical shapes. Design alterations, such as reinforced bar extensions or faceted surfaces, frequently enhanced scan precision. Some hybrid or modified geometries performed similarly to standard scan bodies. Based on QUIN assessment, twenty-seven studies were of moderate quality, and one was rated as high quality. The geometry of scan bodies significantly affects the accuracy of intraoral digital implant impressions. Simplified or reinforced structural forms tend to improve both trueness and reproducibility. Additional standardized clinical trials are required to identify ideal geometric features and to corroborate existing in vitro evidence.
