Linear and Angular Deviations of Complete-Arch Digital Implant Impressions Using Three Scan Body Systems: An In Vitro...

Background: Scan body systems may affect the transfer of implant positions in complete-arch digital impressions. This in vitro study compared linear and angular deviations among three systems in a mandibular All-on-4 model. Methods: Ten repeated scans per system (exploratory sample) were acquired with a TRIOS 5 intraoral scanner for Straumann Titanium, Straumann Exact and TruAbutment ioConnect scan bodies. A laboratory-scanned cast from a conventional impression served as the reference; deviations are relative to this workflow. After conversion to a common geometry and complete-arch registration, linear deviations were measured in a standardized 2D cross-section and angular deviations between corresponding component axes. Scan-level means of four sites were compared using Welch's ANOVA and Games-Howell tests (α = 0.05). Results: Mean linear deviations were 0.187 ± 0.025 mm (Exact), 0.234 ± 0.005 mm (Titanium) and 0.135 ± 0.060 mm (TruAbutment; p < 0.001). Titanium exceeded Exact (p < 0.001) and TruAbutment (p = 0.0014); Exact and TruAbutment did not differ significantly (p = 0.060). Mean angular deviations were 1.304 ± 0.067°, 2.691 ± 0.139° and 1.380 ± 0.065° (p < 0.001); Titanium exceeded both systems (p < 0.001), but Exact-TruAbutment did not (p = 0.050). Conclusions: Within this model and reference workflow, Titanium showed greater linear and angular deviations than Exact and TruAbutment. No difference was established between Exact and TruAbutment. The findings do not demonstrate equivalence or clinically acceptable fit.