Accuracy of Photogrammetry, Intraoral Scanning, and Conventional Impression for Multiple Implants: An In Vitro Study.

Objectives: This in vitro study compared the accuracy of conventional impressions (CNVs), photogrammetry (PG), and intraoral scanning (IOS) for recording implant impressions of edentulous segments, ranging from part to complete arches by different evaluation methods.

Methods: The master model for an edentulous maxillary arch was created with six implants (a-f). CNVs, PG, and IOS were used for impressions. Three impression ranges (bcde, bcdef, and abcdef) were chosen for analysis. The best-fit algorithm, absolute linear deviation, and angular deviation were used for evaluation. Trueness and precision were analyzed by two-way ANOVA and the Kruskal-Wallis test, respectively.

Results: The accuracy of multiple implant impressions was significantly influenced by the impression method and impression range (p < 0.05) regardless of the evaluation methods used. At smaller ranges (bcde and bcdef), there was no difference in the trueness of the three impression methods, whereas at a larger range (abcdef), both PG and CNV exhibited similar trueness, which was significantly higher than that of IOS(p < 0.05). The precision of PG was significantly better than that of CNV and IOS in most of cases (p < 0.05). As the range expanded, the trueness and precision of PG and IOS decreased (p < 0.05), whereas the accuracy of CNV remained stable.

Conclusions: In the case of large-range impressions, PG demonstrated a similar degree of trueness and better precision compared with CNVs, whereas the trueness and precision of the intraoral scanning were worse. This indicated that PG might be a promising method for multiple implant impressions.