Effect of scan substrates on accuracy of 7 intraoral digital impression systems using human maxilla model.

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.