Effects of core build-up resin composite translucency on IOS accuracy: an in-vitro study.

Abstract

The accuracy of 3-dimensional images produced by intraoral-scanner (IOS) is affected by the optical characteristic of restorative materials such as metal, ceramic, and resin. This in-vitro study aimed to investigate the impact of core build-up resin composite translucency on IOS's accuracy. A core build-up procedure was performed on a proprietary 3D-printed model using injectable composites with 4 levels of translucency (highest to lowest: GC AE, A3, AO3, and EX). Ten experimental scans/group were operated using IOS Medit i700 on the phantom head-mounted model. Reference scans were obtained by an industrial scanner (Solutionix C500). Values of accuracy (trueness and precision) for the respective groups were evaluated using mean deviation values following 3D superimposition. Composite translucency caused scale reduction of optical impression. Values of trueness showed the highest scale reduction in the AE group significantly, followed by A3, AO3, and EX. Considering the cut-off value of deviations as 50μm for clinical acceptability, the analysis elucidated the most deviations in AE and A3. Similar results were found in precision where AE showed the highest deviation value statistically, then A3, AO3, and EX. Composite translucency affects the accuracy of optical impression, causing the fitting error of CAD/CAM prosthesis. The more translucent the composite, the less accurate the optical impression. This suggests the proper compensation during prosthesis designing for an optimal clinical result. Besides, practitioners should indicate the proper restorative materials regarding not only the aesthetics and mechanical properties but also the optical characteristics in the digital workflow.