Trueness and Precision of Three Intraoral Scanners for Full-Arch Digital Impressions Exported in PLY Format: An In Vitro Study

Abstract

Background: To evaluate the accuracy and precision of digital dental impressions using the Polygon File Format (PLY) across three intraoral scanners. Methods: A maxillary arch resin model with reference points was scanned 10 times using the intraoral scanners (3Shape TRIOS 5, Medit i900, Cameo Elegant 3) and a laboratory scanner. All scans were exported as PLY files. The linear measurement of distances between reference points and statistical comparison to assess trueness and precision. Results: There were statistically significant differences in scanner performance, with the 3Shape TRIOS 5 performing closest to the reference scanner, while the Medit i900 was the least. Still, all scanners produced results that fell within the range considered acceptable for clinical use (≤100– 150 µm). The ability to consistently measure precisely became more challenging as the span of the dental arch increased. Conclusion: Under controlled in vitro conditions, all intraoral scanners gave full-arch measurements within clinically acceptable limits for prosthodontic procedures when exported in PLY format. The 3Shape TRIOS 5 demonstrated the closest agreement with the reference scanner, although statistically significant differences were observed for two of the three measured distances. Prospective clinical investigations under intraoral conditions are warranted to validate these phantom-based observations.