Accuracy of four digital scanners according to scanning strategy in complete-arch impressions

STATEMENT OF PROBLEM: Although there are specific and general digital scanning guidelines depending on the system used, it is important to have the necessary flexibility in the acquisition of three-dimensional (3D) images to adapt to any clinical situation without affecting accuracy. PURPOSE: The purpose of this in vitro study was to identify and compare the scanning strategy with the greatest accuracy, in terms of trueness and precision, of four intraoral scanners in the impression of a complete dental arch. MATERIAL AND METHODS: Four digital scanners were evaluated with a 3D measuring software, using a highly accurate reference model obtained from an industrial scanner as a comparator. Four scanning strategies were applied 10 times on a complete maxillary arch cast inside a black methacrylate box. The data were statistically analyzed using one-way analysis of variance (ANOVA) and post hoc comparisons with Tamhane T2 test. RESULTS: The trueness of the Trios and iTero system showed better results with strategy “D,” Omnicam with strategy “B,” and True Definition with strategy “C”. In terms of precision, both iTero and True Definition showed better results with strategy “D”, while Trios showed best results with strategy “A” and Omnicam with strategy “B”. There were significant differences between the scanning strategies (p<0.05) with the iTero scanner, but not with the other scanners (p>0.05). CONCLUSIONS: The digital impression systems used in the experiment provided sufficient flexibility for the acquisition of 3D images without this affecting the accuracy of the scanner.