In Vivo Comparison of the Trueness of Conventional and Digital Interocclusal Registration

The objective was to evaluate the trueness of interocclusal registration obtained with three intraoral scanning systems versus a conventional impression and bite registration in fully dentate patients. Twenty adults with complete dentitions and Angle Class I occlusion were enrolled. Complete-arch scans were obtained with Primescan, iTero Element, and TRIOS 4, followed by bilateral virtual interocclusal registration. Conventional impressions and polyvinyl siloxane records were used to fabricate stone casts, digitized with a laboratory scanner with the record and after manual articulation in maximum intercuspation. Industrial scanner datasets served as participant-specific references. Three-dimensional deviations were analyzed by repeated-measures ANOVA and Holm-adjusted paired t-tests (α = 0.05). The conventional workflow with an interocclusal record showed the greatest deviation (797 ± 308 μm; p < 0.001). Manual articulation (331 ± 167 μm) did not differ significantly from Primescan (262 ± 120 μm), iTero Element (256 ± 101 μm), or TRIOS 4 (325 ± 168 μm) (p ≥ 0.223); no differences were found among scanners under the conditions of this study (p ≥ 0.468). Virtual interocclusal registration showed greater trueness than the conventional workflow with a physical record, whereas manual articulation performed comparably to digital workflows. These conclusions apply only to fully dentate patients with stable occlusal support and maximum intercuspation.