Comparative evaluation of in vivo and in vitro accuracy of intraoral scanners in splint therapy of functional disorders

Abstract

The aim of this study was to conduct a comparative in vivo and in vitro assessment of the accuracy of intraoral scanners in generating a virtual dental arch model during splint therapy. The study design comprised a clinical (in vivo) phase and a laboratory (in vitro) phase. In the first phase, the trueness of scanning of the dental arches in 27 patients was evaluated using the Medit i600, Primescan AC, and iTero Element 2 scanners. The reference standard comprised virtual models obtained by laboratory scanning of silicone impressions using the Medit T710 scanner. In the second phase, the trueness and operator-induced variability during scanning of polymer jaw models with the same devices were assessed. Virtual model superimposition and linear measurements in the incisor, molar, and interdental distance regions were performed using Exocad software. Results. In vivo, the iTero Element 2 scanner yielded the smallest deviations in interdental distances from the reference standard (the median deviation in the 3.6–4.6 tooth segment was 87 µm); however, it exhibited the greatest discrepancies on the surfaces of individual molars (up to 141 µm). In 82.7% of cases, the discrepancy in the posterior teeth exceeded the clinically significant threshold of 100 µm. During in vitro evaluation, the accuracy of all devices predictably improved. The least operator influence was observed when scanning with the Primescan AC, with surface deviations ranging from 12 to 28 µm depending on the dental arch segment. The trueness of dental arch geometry reconstruction in vitro was higher for the iTero Element 2.