ABSTRACT
Objective:To evaluate the masking ability of the Rely XTM Veneer try-in pastes. Methods: 100 discolored teeth, including 50 nonvital ones and 50 vital ones, has been collected and restored respectively with all-ceramic crowns and veneers. Five try-in pastes including A1, A3, Translucent (Trt), White opaque(WOT) and B0.5 Opaque(B0.5),which were different in shade, were used to try in before adhesion. The color was measured by a digital colorimeter, and expressed in terms of 3 coordinate values(L*、a*、b*) of the CIE1976- L*a*b* system.Then the color differences of crowns and veneers ?E=[(?L*)2+(?a*)2+(?b*)2]1/2 as well as the value of Light (L= L*)、Chroma[C=〔(a*)2+(b*)2〕1/2] and Hue [H=arctan(b*/a*)] were calculated. The thickness of the measurement point was also measured and recorded. A one-way ANOVA was used to analyze ?E as well as L, C and H. Results:The chromatism of the veneers after try-in was higher than that of the crowns(P