Accuracy of single-tooth restorations based on intraoral digital and conventional impressions in patients.

OBJECTIVES: The purpose of this clinical study was to compare the marginal fit of dental crowns based on three different intraoral digital and one conventional impression methods. METHODS: Forty-nine teeth of altogether 24 patients were prepared to be treated with full-coverage restorations. Digital impressions were made using three intraoral scanners: Sirona CEREC AC Omnicam (OCam), Heraeus Cara TRIOS and 3M Lava True Definition (TDef). Furthermore, a gypsum model based on a conventional impression (EXA'lence, GC, Tokyo, Japan) was scanned with a standard laboratory scanner (3Shape D700). Based on the dataset obtained, four zirconia copings per tooth were produced. The marginal fit of the copings in the patient's mouth was assessed employing a replica technique. RESULTS: Overall, seven measurement copings did not fit and, therefore, could not be assessed. The marginal gap was 88 mum (68-136 mum) [median/interquartile range] for the TDef, 112 mum (94-149 mum) for the Cara TRIOS, 113 mum (81-157 mum) for the laboratory scanner and 149 mum (114-218 mum) for the OCam. There was a statistically significant difference between the OCam and the other groups (p < 0.05). CONCLUSION: Within the limitations of this study, it can be concluded that zirconia copings based on intraoral scans and a laboratory scans of a conventional model are comparable to one another with regard to their marginal fit. CLINICAL RELEVANCE: Regarding the results of this study, the digital intraoral impression can be considered as an alternative to a conventional impression with a consecutive digital workflow when the finish line is clearly visible and it is possible to keep it dry.