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Accuracy of scanning partially edentulous mandibular arches using an intraoral scanner : an in-vitro pilot study Tayan, Noura

Abstract

Purpose: The study examined the accuracy of intraoral scanning of partially edentulous dental models. Materials and Methods: A mandibular dentoform with 16 individual acrylic teeth was used to remove specific dental units to create the four models of partially edentulous Kennedy classes. In all four situations, premolars (#34 & #44) were left to be used as reference points for accuracy assessments. The removed teeth sockets were filled with red wax, and each Kennedy class model was scanned ten times using a Trios 4 intraoral scanner (3Shape, Copenhagen, Denmark). These scans were compared to a reference digital scan of the fully dentate typodont model using an E4 laboratory benchtop scanner (3Shape, Copenhagen, Denmark). Comparisons were made using the CloudCompare alignment software. The best-fit alignment method was used to compare premolars #34 and #44 in all four Kennedy groups. Also, comparisons were made with the benchtop scan of the corresponding benchtop Kennedy scan at both premolars #34 and #44 and the edentulous ridges. The deviations from the benchtop scan were calculated as the root mean square (RMS) in mms, and the acceptable fit was ≤ 0.2 mm. Results: Intraoral scans of occlusal tables of #34 and #44 of all four partially edentulous Kennedy groups showed no statistically significant differences to the fully dentate benchtop scan and all had an acceptable fit. When compared to the corresponding benchtop scan, premolars #34 and #44 showed statistically significant differences between Kennedy Class II (0.061 ± 0.011 mm) and Class I (0.049 ± 0.008 mm) and between Class IV (0.05 ± 0.009 mm) and Class II. For the edentulous ridges, there was a statistically significant differences between Class I (0.072 ± 0.028 mm) and all other Kennedy Classes. Class I demonstrated the lowest accuracy and the accuracy values all measured within the acceptable threshold of 0.2 mm in both premolars and edentulous scans. Conclusions: Trios 4 intraoral scanner provided acceptable record of the remaining teeth and edentulous areas for all partially edentulous Kennedy groups.

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Attribution-NonCommercial-NoDerivatives 4.0 International