ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the resulting color of veneers affected by adding a layer of veneering porcelain on Procera aluminium oxide core.</p><p><b>METHODS</b>Fifteen aluminium oxide disks were randomized into three groups. Each of five disks was veneered with porcelain of the Vita shade Al, A2 and B4 respectively. The color of the substrate covered with non-veneered disks and the veneered disks was measured separately and the color differences were calculated.</p><p><b>RESULTS</b>Statistically significant differences (P < 0.01) in color coordinates of dark substrate were recorded between the substrate covered by an aluminium oxide disks and the addition of veneering porcelain to aluminium oxide disks. Mean coordinates color difference (DeltaE, DeltaL *, Deltaa *, Deltab *) after adding the three shades of veneering porcelain showed increase from Al (2.311) to A2 (4.313) to B4 (8.778) in DeltaE, decrease from Al (-1.530) to A2 (-3.369) and B4 (-3.358) in DeltaL *, and increase from Al (-1.440) to A2 (2.198) to B4 (7.955) in Deltab *. The direction of the color modification correlated with values obtained from the liberation. The resulting color was also affected by the color of the underlying structure.</p><p><b>CONCLUSION</b>This study illustrates that color of aluminium oxide shell could be modified with feldspathic veneering porcelain, which may be used by practitioners to alter the esthetic outcome of porcelain veneers.</p>