In vitro and in vivo accuracy of full-arch digital implant impressions.

Abstract

The main objective of the study was to compare the accuracy of full-arch digital implant impressions for fixed dental prosthesis under in vitro and in vivo conditions. Eight patients (five women and three men) with at least one edentulous arch and with 4-6 osseointegrated implants participated in this study. For each edentulous arch (n=10), experimental screw-retained titanium bar with attached four scan bodies was fabricated. The bar containing four scan bodies was screw-retained intraorally on implants and scanned with Trios 3 intraoral scanner eight times (IOS group, in vivo). Then, the bar was attached to the master cast and scanned eight times again with the same intraoral scanner (MIOS group, in vitro). Finally, the bar with scan bodies was scanned 8 times with a laboratory scanner (reference). Precision and trueness were calculated for 3 distances and 3 angles between the scan bodies (1-2, 1-3, and 1-4) in IOS and MIOS groups. Precision and trueness for the largest distance (1-4) were found to be 44±18µm and 32±19µm for the IOS group and 31±16µm and 30±14µm for MIOS group, respectively. Precision and trueness for the angle between the most distant scan bodies (1-4) were 0.22±0.14° and 0.18±0.10° for the IOS group and 0.16±0.11° and 0.07±0.05° for MIOS group, respectively. Intraoral conditions moderately affected the precision and trueness of Trios 3 (3Shape) intraoral scanner. Results of in vitro accuracy studies cannot be directly transferred to the clinical field.