A centripetally rotating implant scan body concept for complete-arch scanning: An in vitro study

Objectives: To assess the in vitro metrological performance of a centripetally rotating implant scan body (ISB) system (GeoXact®), designed to standardize scan-body orientation and create a compact concentric reference geometry to mitigate cumulative stitching drift during complete-arch implant scanning on multi-unit abutments (MUAs), and to investigate site-related effects. Methods: A maxillary resin cast with four implant sites restored with MUAs was digitized with an industrial optical scanner to generate the reference STL. GeoXact® ISBs were rotated into a centripetal contact configuration to standardize orientation and reduce inter-ISB spacing. Twenty complete-arch scans were acquired with an intraoral scanner (Primescan 2; Dentsply Sirona) by capturing only a partial portion of each ISB head (≥3 planar faces) along the contact chain. Experimental datasets were generated by CAD library replacement. Each dataset was rigidly aligned to the reference using ICP in CloudCompare (global registration). Global mean deviation was computed after global alignment; site-level mean deviations were computed under the same global transformation (no additional per-MUA best-fit), whereas per-MUA rigid alignment was used only to extract translational and angular parameters. Outcomes were global mean deviation, mean deviation per MUA, translational magnitude, angular deviation, Δ interimplant distance, and scanning time. Results: Global mean deviation was 0.009 ±0.005 mm (n = 20). Mean deviation per MUA was 0.010 ±0.011 mm (n = 80). Translational magnitude and angular deviation averaged 0.064 ±0.092 mm and 0.203 ±0.165°, respectively. Mean Δ interimplant distance was 0.003 ±0.007 mm overall; the distal site showed the largest mean (0.008 ±0.011 mm). Mean scanning time was approximately 9 seconds. Conclusions: Under controlled in vitro conditions, the tested ISB workflow enabled rapid complete-arch acquisition with small 3D pose deviations on MUAs and limited site-related effects mainly at the distal implant position. Clinical Significance: In this in vitro model, the GeoXact® centripetal configuration enabled a compact reference geometry and rapid complete-arch acquisition with small metrological deviations.