PURPOSE: . This prospective clinical study aimed to evaluate the accuracy of intraoral scanning (IOS) as an alternative to the conventional window technique impression (WTI) for recording maxillary flabby ridges in edentulous patients. MATERIALS AND METHODS: . Twelve edentulous participants with maxillary flabby ridges underwent both IOS (TRIOS 5, 3Shape, Denmark) and WTI. WTI impressions were made using zinc oxide-eugenol paste and plaster of Paris as the reference. All scans were exported in STL format. Accuracy was assessed via trueness and precision, using RMS, average negative, and average positive deviations, calculated with Medit Compare software. RESULTS: . IOS showed significantly higher trueness than WTI in RMS (mean difference (MD) = -0.11, 95% CI: -0.15 to -0.06, P = .0001) and average negative deviation (MD = 0.13, 95% CI: 0.07 to 0.19, P = .0001). The average positive deviation had no significant difference (MD = 0.02, 95% CI: -0.01 to 0.05, P = .11). In terms of precision, IOS had significantly higher precision across all parameters: RMS (MD = 0.23, 95% CI: 0.21 to 0.26, P = .0001), average positive deviation (MD = 0.14, 95% CI: 0.11to 0.17, P = .0001), and average negative deviation (MD = -0.15, 95% CI: -0.17to -0.13, P = .0001). CONCLUSION . This study suggests that IOS may provide improved accuracy compared to the conventional window impression technique for capturing maxillary flabby ridges in edentulous patients. Further research with larger sample size and clinical outcome assessments is needed to confirm its efficacy.

PURPOSE: The aim of this prospective clinical study was to compare the influence of palatal vault forms on accuracy and speed of intraoral (IO) scans in completely edentulous cases. MATERIALS AND METHODS: Based on the palatal vault form, participants were divided into three equal groups (n = 10 each); Class I: moderate;Class II: deep; Class III: flat palatal vault. A reference model was created for each patient using polyvinylsiloxane impression material. The poured models were digitized using an extraoral scanner. The resultant data were imported as a solid CAD file into 3D analysis software (GOM Inspect 2018; Gom GmbH, Braunschweig, Germany) and aligned using the software’s coordinate system to determine its X, Y, and Z axes. Five digital impressions (DIs) of maxilla were captured for each patient using an intraoral scanner (TRIOS; 3Shape A/S, Copenhagen, Denmark) and the resultant Standard Tessellation Language (STL) scan files served as test models. Trueness was evaluated by calculating arithmetic mean deviation (AMD) of the vault area between reference and test files while precision was evaluated by calculating AMD between captured scans to measure repeatability of scan acquisition. The scan time taken for each participant was also recorded. RESULTS: There was no significant difference in trueness and precision among the groups (P = .806 and .950, respectively). Average scan time for Class I and III palatal vaults was 1 min 13 seconds and 1 min 37 seconds, respectively, while class II deep palatal vaults showed the highest scan time of 5 mins. CONCLUSION Palatal vault form in edentulous cases has an influence on scan time. However, it does not have a substantial impact on the accuracy of the acquired scans.