Predictability of intraoral scanner error for full-arch implant-supported rehabilitation

Abstract

Objectives The present study aimed to analyze the behaviors of three intraoral scanners (IOSs): evaluating the interdistance and axial inclination discrepancies in full-arch scans, predictable errors were searched. Materials and Methods Six edentulous sample models with variable numbers of dental implants were used; reference data were obtained with a coordinate-measuring machine (CMM). Each IOS performed 10 scans per model (180 total scans). The origin of each scan body was used as a reference point to measure interdistance lengths and axial inclinations. Precision and trueness of interdistance measurements and axial inclinations were evaluated to address error predictability. Bland–Altman analysis, followed by linear regression analysis and Friedman’s test (plus Dunn’s post hoc correction), was performed to evaluate the precision and trueness. Results Regarding interdistance, Primescan showed the best precision (mean±SD: 0.047±0.020mm), while Trios3 underestimated the reference value more than the others (p < 0.001) and had the worst performance (mean±SD: −0.079±0.048mm). Concerning the inclination angle, Primescan and Trios3 tended to overestimate angle values, while CS3600 underestimated them. Primescan had fewer inclination angle outliers, but it sporadically added 0.2–0.4° to the measurements. Conclusions IOSs showed predictable errors: they tended to overestimate or underestimate linear measurements and axial inclinations of scan bodies, one added occasionally 0.2-0.4° to the angle inclination values. In particular, they showed heteroscedasticity, a behavior probably related to the software or the device itself. Clinical Significance The presence of constant errors and unique heteroscedastic behavior were demonstrated for the first time.