Comparison of Three Intraoral scanners for Digital impressions of Biologically Oriented Preparation: An In-vivo Study////Comparaison de Trois Scanners Intra-Oraux pour les Empreintes Numériques de Préparation à Orientation Biologique : Une Etude In-vivo

Introduction: The accuracy of intraoral scanners (IOSs) in capturing a Biologically Oriented Preparation Technique (BOPT) remains uncertain. The aim of this study was to evaluate the accuracy of digital impressions obtained with three intraoral scanners for recording BOPT preparations. Methods: A maxillary central incisor was prepared following BOPT. After temporization, a conventional polyvinyl siloxane impression was scanned with a desktop scanner to obtain a reference model. Forty-two scans (n D 14 per scanner) were recorded with three IOSs—Trios 3, Sirios, and Helios 680—by a single operator under standardized conditions. Accuracy was assessed using Geomagic Control X by calculating 3D surface deviation (RMS). Data normality was tested using Shapiro–Wilk and Kolmogorov–Smirnov tests. Trueness was compared with one-way ANOVA, and precision was evaluated using intraclass correlation coefficients (α ≤ 0.05). Results: Sirios showed the highest trueness in both analyses but statistically unsignificant (p < 0.05). Conclusions: All IOSs achieved clinically acceptable trueness for full preparations, with only Sirios meeting the threshold at the margin. Precision was similar across scanners.