Accuracy of Intraoral Scanners Versus Polyvinyl Siloxane Impression in Partially Edentulous Implant Rehabilitations: An In Vitro Comparison

Objectives: The aim of this in vitro study was to evaluate the accuracy of intraoral impressions obtained using the Trios 3Shape® (3Shape Trios, Copenaghen, Denmark) and Carestream CS 3600™ (Carestream Dental, Stuttgart, Germany) scanners, compared with traditional polyvinyl siloxane (PVS) impressions. A laboratory scanner served as the gold standard. Materials and Methods: The study was based on 3D-printed master models derived from partially edentulous clinical cases previously treated at our department (2017–2022). All cases required at least two implants. Data analysis was performed using one-way ANOVA and two-sample Z-tests (α = 0.05) to compare mean deviations and variability. Results: All techniques demonstrated high accuracy, with deviations from the reference point below 30 μm. The digital intraoral scanners (Trios 3Shape® and Carestream CS 3600®) showed superior accuracy compared with PVS analog impressions, with no statistically significant difference between the two IOS systems. Conclusions: Within the limitations of this in vitro study, both IOS systems and PVS analog impressions achieved clinically acceptable accuracy. Digital systems exhibited improved performance in terms of mean deviation and consistency. The higher accuracy and consistency of digital impressions may translate into improved clinical efficiency and prosthetic fit in implant rehabilitations. From a clinical perspective, these in vitro findings suggest that digital impressions may enhance prosthetic fit and workflow efficiency, though further in vivo validation is required. Clinical significance: This study supports the reliability of intraoral scanning compared with conventional impressions in implant-supported rehabilitations. By demonstrating high intrinsic accuracy, these findings contribute to optimizing digital workflows in implant dentistry and reinforce the potential of intraoral scanning in static computer-guided, flapless implant surgery. Trial registration: Ethical approval and trial registration were not applicable to the present in vitro investigation, as no patients were directly involved in the experimental phase. The digital data used to generate the laboratory master models originated from a separate clinical study conducted at ASST Santi Paolo e Carlo, Milan (Ethics Committee approval no. 1361, 12 July 2017; ClinicalTrials.gov registration, Unique Protocol ID 1361).