Accuracy Of Different Impressions For Multiple Implants: In Vitro Study

This study compared the accuracy of conventional impressions (CI) and 4 digital scanning groups: intraoral scanning with cylindrical scan bodies (IOSC), intraoral scanning with horizontal crossbars (IOSH), centripetal intraoral scanning (CIOS), and extraoral stereophotogrammetry (SPG) for full‐arch implant impressions. Master models for edentulous maxillary jaws were created with eight implants (a-h). CIs, IOSC, IOSH, CIOS and SPG were used for impressions. Three impression ranges (acfh, abcfgh, and abcdefgh) were chosen for analysis. Three-dimensional, angular, and linear deviations among the five impression techniques were calculated. The root mean square (RMS) deviations for trueness and precision were analyzed using two-way ANOVA and Kruskal-Wallis tests. The analysis of accuracy revealed statistically significant differences (p < 0.001) in both RMS and angular deviations, which was influenced by the impression method and impression range. When the implant spacing was small, there was no significant difference in trueness among CI, IOSH, CIOS, and SPG, all of which performed better than IOSC. However, when the implant spacing exceeded 15 mm, SPG and CIOS showed similar trueness, which was significantly higher than that of the other groups (p < 0.05). The precision of CIOS and SPG was consistent across the different distributions, showing no statistically significant differences. IOS of the full arch implant location is mostly affected by the implant spacing. When the implant spacing was greater than 15 mm, the accuracy decreased significantly with the increase of distance. CIOS was less affected by the implant spacing, and the data was more stable.