Comparison of the Accuracy in Identifying the First Occlusal Contact between Articulated Models and Digital Models Obtained with 3shape TRIOS and iTero Scanners

Model analysis plays a key role in orthodontic diagnosis. Traditionally performed on plaster casts, these models pose limitations such as volumetric distortions, storage requirements, and difficulty in sharing. In recent years, intraoral scanners have become popular, enabling the creation of digital models for computer-assisted analysis. However, the accuracy of these methods remains uncertain. The aim of this study is to compare the accuracy of first occlusal contact identification in centric relation at first attempt between digital models obtained using TRIOS 3 (3ST3) and iTero (iT) intraoral scanners, and plaster models mounted on a Panadent articulator (MA) evaluated with articulating paper. Thirty type IV plaster study models were scanned with both devices. A 63.3% agreement was observed between 3ST3 and MA, 50% between iT and MA, and 56.6% between both scanners. No statistically significant differences were found in the distance from the contact point to the vestibular plane between iT and MA, or between 3ST3 and iT, but there were significant differences between 3ST3 and MA. Under the methodology described, digital models from scanned analog articulator-mounted casts do not appear sufficiently accurate to locate the first occlusal contact in centric relation at first attempt.