Precision of two iOS on single posterior abutments in vitro

Objectives: To compare the accuracy of digital impression of single abutments prepared for esthetic overlay obtained by two contemporary intraoral scanners in vitro.
Methods: Twenty extracted intact molars were used for this in vitro study. The samples were prepared to receive an overlay. The abutments were scanned with two intraoral scanners (Trios 3, prototype of Intro Oral Scanner from GC) by one single operator. Twenty scanning shots for each iOS were made. The .stl files generated by the two scanners were elaborated with the Exocad software and were one by one over-imposed in order to detect possible differences. Differences were visibly evaluated by a color scale ranging from 0 to 100 microns of difference. Statistical analysis across the scanner groups was performed using ANOVA with Bonferroni correction.
Results: All over-imposition of full arch showed a minor discrepancy between the iOS impressions (media around 20 microns). A wider discrepancy was noted mainly at bottom of the inter proximal margins and/or in small areas of axial wall of the interproximal box (till 100 microns). There was no difference between the two iOS systems.
Conclusions: The two intraoral scanners produced similar precision on teeth. The higher discrepancy was recorded in the margins of interproximal boxes. All discrepancies were within a clinical acceptable range. Both scanners showed to be reliable on taking impressions of single posterior abutments.