OBJECTIVE: To compare the in vitro scan accuracy (trueness and precision) of recently introduced wireless intraoral scanners (IOSs) to commonly used wired IOSs in different fixed partial denture (FPD) situations. METHODS: Three partially edentulous maxillary models with implants located at different sites (lateral incisors [Model 1]
right canine and first molar [Model 2]
right first premolar and first molar [Model 3]) were digitized with wireless (Primescan 2 [P2] and TRIOS 5 [T5]) and wired (Primescan [P1] and TRIOS 3 [T3]) IOSs (n = 14 per IOS-model pair). The models were also digitized with an industrial-grade optical scanner for their reference scans. The IOS scans were superimposed over the reference scans to evaluate the 3D distance, angular, and 2D interimplant distance deviations (trueness). The variance of measured deviations was defined as the precision and all data were analyzed with bootstrap analysis of variance and Holm-corrected Welch tests (α = 0.05). RESULTS: The IOS, FPD situation, and their interaction affected the scan accuracy (P <
0.001). P2 scans mostly had the highest and the scans of Model 2 mostly had the lowest 3D distance accuracy (P ≤ 0.030). P1 scans had the highest angular accuracy within each model, followed by the P2 scans in Models 1 and 2 (P ≤ 0.002). P1 scans mostly had higher 2D interimplant distance accuracy (P ≤ 0.047). CONCLUSIONS: Digital impressions of tested FPD situations had high accuracy mostly with P1 and P2. The scans for a posterior 4-unit FPD might have higher inaccuracies, regardless of the tested IOSs.