Influence of intraoral scanner type and partial edentulism scenario on scan-body position transfer accuracy in posterior implant-supported fixed partial dentures: an in vitro study

This study aimed to evaluate the effects of intraoral scanner (IOS) type, partial edentulism scenario, and implant configuration on the trueness and precision of scan-body position transfer in posterior implant-supported three-unit fixed partial dentures. In a maxillary typodont model, implant analogs were placed in the first premolar and first molar regions. Different partial edentulism scenarios were generated by sequential removal of adjacent teeth from a single master model, which was modified accordingly. Four IOSs—TRIOS 3, TRIOS 5, Medit i700, and Virtuo Vivo—were used to obtain 10 scans ( n = 10) per scenario. A separate reference STL dataset was generated for each scenario using an industrial optical scanner (Solutionix C500; Medit, Seoul, Korea). The IOS datasets were superimposed onto the corresponding reference datasets, and three-dimensional (3D), inter-implant distance, and angular deviations were calculated using reverse-engineering software. Data normality was assessed using the Shapiro–Wilk test. A univariate nested analysis of variance (ANOVA), followed by Tukey’s HSD post hoc test, was applied (α = 0.05). Because implant configuration was confounded with scanning side in the experimental design, the findings were interpreted as reflecting their combined influence. Significant differences were observed in three-dimensional deviations depending on the IOS type ( p < 0.05). T5 showed higher deviation values in most scenarios. Linear and angular deviations were significantly influenced by partial edentulism scenarios and IOS type ( p < 0.05). Comparisons between scenarios indicated that the partial edentulism condition had a notable effect on scan-body position transfer accuracy. Within the limitations of this in vitro study, IOS performance appeared to vary according to implant configuration and the partial edentulism scenario. Differences among IOSs were more evident under certain experimental conditions, with Mi700 showing lower deviation values in several comparisons, whereas T5 exhibited higher deviation values in some conditions. Clinically, all tested IOSs demonstrated clinically acceptable scan-body position transfer accuracy. Scanner selection may become more relevant in more complex implant configurations and partial edentulism scenarios, where differences among IOSs were more apparent.