Accuracy is a behavior, not a number: a metrological reporting framework for complete-arch implant scanning

To propose a metrological reporting framework for complete-arch implant scanning studies, with the aim of improving cross-study comparability and prosthetically relevant interpretation.

Commonly reported accuracy endpoints in complete-arch implant scanning studies were critically examined and interpreted in relation to International Organization for Standardization (ISO) metrology terminology and the prosthetic requirement for rigid multi-implant seating.

Four complementary reporting domains are proposed. First, global surface deviation should be reported after a clearly declared rigid registration, specifying both the alignment surface and the comparison surface. Second, site-specific deviation should be reported for each implant, scan body, or multi-unit abutment (MUA) region without repeating a local best-fit alignment at each site. Third, implant pose error should be reported as translational and angular deviation, preferably at the implant platform or MUA level when this information is available. Fourth, fit-related or region-of-interest descriptors should be used to describe clinically relevant local discrepancy, with preference for robust upper-tail and dispersion metrics such as the 95th percentile absolute deviation and standard deviation. Transparent reporting of reference data, preprocessing, registration strategy, measurement region, color-map settings, and statistical unit is also recommended.

Complete-arch implant scanning accuracy cannot be fully described by a single numerical endpoint. A structured metrological framework may help distinguish global surface agreement, implant-level positional error, and clinically relevant fit-related discrepancy.

Clearer reporting of alignment strategy, measurement region, pose error, and fit-related descriptors may reduce confusion caused by non-equivalent outcomes and support more clinically meaningful interpretation of complete-arch implant scanning studies.