Journal of Prosthodontics News
Accuracy of Merging Scans of Definitive Fixed Prosthodontic Impressions
Now online in the Journal of Prosthodontics, a study evaluating the accuracy of merging scans to create an error-free digital file, co-authored by ACP members Carl Drago, DDS, MS, FACP, Mohamed Elshewy, DDS, MS, FACP, and Geoffrey A. Thompson, DDS, MS, FACP.
Many elastomeric impressions sent to commercial laboratory dental technicians may include marginal defects. To fabricate accurate restorations, digital technology may be used to merge digital files of defective impressions into a single standard tessellation language (STL) file free of errors.
This study compared the accuracy of digital master casts reconstructed from merged STL files of defective impressions with the file of the original defect-free preparations. Merging multiple impressions with imperfections to produce a single master cast may save clinicians chair time and make the impression-making process easier.
Ivorine teeth on a dentoform were prepared to receive a posterior fixed dental prosthesis (FDP) with complete coverage preparations and wax was used to create defects. All impressions were digitized using an extraoral scanner. Then the corresponding STL files were paired and merged, and a master cast was created by eliminating the defects using the scanned data.
The accuracy of the final data set was dependent on the cumulative errors that may have occurred during data acquisition and merging. Careful attention to every step in the process was critical.
Obtaining a reference cast through indirect digitization of a master impression demonstrated a high level of precision. Digital elimination of defects in the test impressions resulted in accurate master casts within clinically acceptable parameters.
Raffa O, An H, Drago C, Elshewy M, Thompson GA. Accuracy of merging scans of definitive fixed prosthodontic impressions to obtain single, accurate digitized master casts. J Prosthodont. 2024; 1–8. https://doi.org/10.1111/jopr.13811
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