Objectives An impression accuracy study using a cadaver maxilla was performed using both prepared and intact teeth as well as palatal tissue. Materials and Methods Three crown preparations were performed on a cadaver maxilla. Seven different digital impression systems along with polyvinylsiloxane impressions were used to create digital models of the maxilla. Three‐dimensional (3D) files of the experimental models were compared to a master model. The 3D files were overlaid and analyzed using a comparison software to create color coded figures that were measured for deviations between the master and experimental models. Results For scanning tooth structure, only the Planscan was significantly less accurate than the rest of impression techniques. No significant differences in accuracy were found between models created using digital impressions and those created from traditional vinyl polysiloxane impressions with cross arch deviations ranging from 18 to 39 μm for each. Conclusions Impressions taken using all digital impression systems, save for the Planscan, were able to accurately replicate the tissues of a complete arch human maxilla. Clinical Significance Studies examining accuracy of digital impression systems have generally been performed on materials other than dental tissues. Optically, materials such as plastic and metal have properties different from enamel and dentin. This study evaluates accuracy of digital impression systems on human dentin, enamel, and soft tissues.

Structured Abstract Objective This study aimed to determine how the accuracy of digital impressions was affected by four common dental substrates using seven prevalent IOS systems to scan the complete arch of a human maxilla. Setting and Sample Population The Department of Oral Rehabilitation at the Medical University of South Carolina. A single cadaver maxilla. Materials and Methods Seven digital intraoral impression systems were used to scan a freshly harvested human maxilla. The maxilla contained several teeth restored with amalgam and composite, as well as unrestored teeth characterized by enamel. Also, three teeth were prepared for full coverage restorations to expose natural dentin. An industrial grade metrology software program that allowed 3D overlay and dimensional computation compared deviations of the complete arch and its substrates on the test model from the reference model. Results Substrates were significantly different from each other when considering scan data as a whole, as well as when comparing IOS devices individually. Only PlanScan failed to reveal trueness differences between the different substrates, while only Emerald revealed precision differences between the substrates. Conclusions Substrate type does impact the overall accuracy of intraoral scans with dentin being the most accurate and enamel being the least accurate. The four substrates scanned impacted the trueness of all IOS devices.