Accuracy of Intraoral Scanning vs Analog Impression for Prostheses Supported by Multiple Implants in Long Edentulous Spans: A Comparative Clinical Study
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Updated: May 29, 2025
Measuring the Complete-arch Distortion of an Optical Dental Impression
Published on: May 30, 2019
Purpose:
To evaluate the accuracy of intraoral scanning (IOS) impressions for multiple implants by comparing them to analog impressions.
Materials And Methods:
Patients with three adjacent implants in partially edentulous arches were recruited. For each arch, IOS impressions were obtained. Using the analog splinted-impression technique, casts were obtained and scanned with an extraoral scanner. Using metrology software, the distances and angles between the implants were measured in all IOS and analog impression STL files. The absolute values of the distance and angular deviation were calculated and analyzed by comparing the two impression methods.
Results:
A total of 34 patients with partially edentulous arches were enrolled. The distance deviation between the IOS and analog impressions was 85.09 ± 58.73 µm, which was significantly lower than the clinically acceptable threshold for error (150 µm; P < .001). The angular deviation was 0.515 ± 0.426 degrees. Distance deviations were significantly correlated with the interimplant distances (r = 0.384, P = .001) and angulations (r = 0.278, P = .022).
Conclusions:
For prostheses supported by multiple implants in partially edentulous arches, the distance deviation between the IOS and analog impression was within the clinically acceptable range of misfit and increased with increasing interimplant distance and angulation.
