The effect of operator scanning speed on the trueness and precision of full-arch digital impressions captured in vitro using an intraoral scanner

Aim This in vitro study aimed to assess whether different scanning speeds affected the trueness and precision of a full-arch digital impression captured using an intraoral scanner. 

Materials and methods A fully dentate unprepared mandibular model (Dental Model ANA-4, Frasaco GmbH, Tettnang, Germany) was scanned using the intraoral scanner CEREC Omnicam (Dentsply-Sirona, PA, United States, Software CEREC SW 5.0). The same operator scanned the full-arch model ten times each at a slow, normal, and fast speed. Thus, the number of total scans was 30 scans. The same model was scanned with two high-resolution reference scanners to compare the trueness of each group. Linear distances between three identical key points on each scan were used as the metric throughout. Bartlett’s test for Homogeneity of Multi-variances was used to assess the precision, and one-way ANOVA was used to compare the trueness across the three groups.

Results The precision did not vary significantly across any of the scanning speeds, for any of the linear distances measured  (p>0.05 in all cases). A significant difference was found in the trueness between Standard and Slow scanning speeds for one of the three measured distances (p=0.041). The trueness of the other two measured distances did not differ significantly with scanning speed. The trueness of the inter-molar distance showed errors of 0.5mm or more in all cases.

Conclusions The precision of full-arch digital impressions taken using an intraoral scanner did not differ significantly when captured using different scanning speeds.  The trueness of full-arch digital impressions differed significantly between Standard and Slow scanning speeds in one out of three linear measurement groups.