Accuracy assessment of intraoral scanning versus conventional impressions in edentulous patients with flabby ridges: a prospective clinical study

Abstract

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: 0.11 to 0.17, P = .0001), and average negative deviation (MD = -0.15, 95% CI: -0.17 to -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.