RESUMEN
OBJECTIVES: The accuracy of 3-dimensional images produced by the intraoral scanner (IOS) is affected by scanning-aid materials. This in vitro study aimed to elucidate the influence of scanning-aid materials on the accuracy (trueness and precision) of digital scanning on the bilateral upper posterior edentulous jaw (Kennedy class I). METHODS: The asymmetrical bilateral upper posterior edentulous model (reference model) was generated using a 3D printer with three groups (application of TiO2 powder - composite and no-treatment control). The experimental scans were executed (n = 10 per group) using TRIOS3 (3shape), while one reference scan was obtained by an industrial scanner (Solutionix - C500). Values of trueness and precision were evaluated using the 3D superimposition method on mean deviation values. The accuracy was assessed using mean deviation values following the 3D superimposition method. RESULTS: IOS had high trueness (20.6 µm), and significant differences were found between the no-treatment and TiO2 groups. Considering the cut-off value of deviations as 300 µm for clinical acceptability, the analysis clarified the most variations in the control group. There was a significant difference between the no-treatment group and others in the maxillary tuberosity area relating to long-span edentulous. The composite group had the best precision values (1.1 µm). Significant differences were found between composite and TiO2 groups (2.7 µm). CONCLUSIONS: The bilateral upper posterior edentulous jaw digital impressions obtained using IOS were accurate. However, the digital images in the palate and maxillary tuberosity area related to long-span edentulous differed significantly. TiO2-containing powder and composite landmarks affected the accuracy and stability of the IOS. CLINICAL SIGNIFICANCE: Scanning aid materials can increase the accuracy of the bilateral upper posterior edentulous jaw scanning with IOS.