Color match of luting composites and try-in pastes: the impact on the final color of CAD/CAM lithium disilicate restorations.

Aim: Color matching of the restoration to the adjacent teeth can be difficult due to the translucency of the ceramic and the visual exposure of the polymerized resin cement through the ceramic material. The aim of this study was to identify color differences between try-in pastes and the corresponding luting resin composites.

Materials And Methods: The materials tested were Variolink Veneer, Variolink Try-In, Variolink Esthetic LC, and Variolink Esthetic Try-In. Blocks of IPS e.max CAD were bisected along the vertical axis, producing specimens of different thicknesses. The surfaces to be evaluated were finely polished with a metallographic machine using 6000 grit SiC paper. The IPS e.max CAD specimens cemented with resin cement or with the try-in pastes were superimposed on a resin composite specimen reproducing the tooth structure. Evaluation of the color differences between the try-in pastes and polymerized cements of the same shade was performed with a spectrophotometer and a visual evaluation by three observers.

Results: The measurements showed that for shades of Variolink Veneer and Variolink Esthetic LC resin cements and the corresponding try-in pastes there were significant color differences (ΔE > 2.23). Among the groups of different thicknesses, specimens of 0.5-mm thickness exhibited the highest ΔE values, while the specimens of 2-mm thickness exhibited the lowest.

Conclusions: The present study suggests that dentists should not rely on try-in pastes for the final color evaluation because they do not perfectly match the color shade of the cement used for the final luting of ceramic restorations. The originality of this study was the interpretation of color differences utilizing both a scientific spectrophotometer and visual observation.