Accuracy of digital impressions captured by an intraoral scanner in a partially edentulous mandible

Background/purpose: The effectiveness of intraoral scanners in accurately recording partially edentulous mandibles is still under scrutiny. This study aimed to assess the accuracy of digital impressions obtained using an intraoral scanner in a partially edentulous mandibular arch. Materials and methods: A partially edentulous typodont model with missing five teeth was digitally scanned using a calibrated desktop scanner to create a reference model. The scan was saved as a standard tessellation language (STL) file and used as the control dataset. The same typodont model was then scanned 20 times using an intraoral scanner (IOS), with each digital impression exported in STL format. All datasets were analyzed using a best-fit registration algorithm in specialized software to compare the IOS scans against the reference model. Results: Three-dimensional positional deviations were analyzed, which quantified the average deviation between the scanned data and the control model, indicating accuracy. Tooth 37 (lower left second molar) had the lowest mean deviation (49.75 ± 10.05 μm), while tooth 45 (lower right second premolar) showed the highest (54.35 ± 7.23 μm). Moderate deviations were noted in teeth 34 (lower left first premolar) and 45 (lower right second premolar), with tooth 37 (lower left second molar) demonstrating the greatest variability. Statistical analysis of the datasets for teeth 34, 37, and 45 revealed no significant differences among them (p > 0.05). Conclusion: The findings of this study indicate that the intraoral scanner evaluated is capable of generating digital impressions with clinically acceptable accuracy in partially edentulous mandibular arches.