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Abstract

Purpose: The aim of this study was to evaluate the influence of horizontal gingival displacement on the accuracy of an intraoral scanner (IOS) with 0.5 and 1mm subgingival finish lines. Materials and Methods: A 3D printed resin dental model was fabricated with a removable milled zirconia die of tooth #46 full crown preparation and 3D printed resin gingiva. A supragingival control group, and six test groups were designed and fabricated with varying horizontal gingival displacement (0.12mm, 0.25mm 0.45mm) each with subgingival finish line positions of 0.5mm (groups 1 to 3, respectively) and 1mm (groups 4 to 6, respectively). The Trios3 (3Shape) IOS was used to scan 18 samples per group and the scans were superimposed with a reference scan of the die without the gingiva. Absolute marginal discrepancies (AMD) between test and reference scans were measured at 8 fixed points around the prep, and at the largest marginal discrepancy (LMD) site. The one-way ANOVA test measured statistical differences between the groups, and the Games-Howell test compared each pair of groups. Results: The highest mean AMDs at fixed sites were on the distolingual surface for all study groups including the control group (p