Effect of Resin Cements for Porcelain Veneers on the Color Stability after Accelerated Ageing

To assess the color stability of different resin cements after accelerated ageing. Four different resin cements were included in the study (1mm thickness). The resin cements were bonded to ceramic disks (0.5mm thickness) built with the VITABLOCS MARK-II ceramic (n=7). All of the samples were stored in 37 degrees C distilled water at dark. Then color measurement were determined using spectrophotometric before and after accelerated ageing in a weathering machine with a total energy of 150kJ/m(2). Changes in color (Delta E) were obtained using the CM Lab system coordinates where a Delta E data above 3 was accepted as visible discoloration. The Delta E of Superbond C&B, RelyX ARC, Variolink Veneer and Tetric Flow were 2.24 +/- 0.52, 2.47 +/- 0.28, 0.62 +/- 0.31 and 0.72 +/- 0.31 respectively. The Superbond C&B and RelyX ARC achieved significant higher Delta E than the other groups (P<0.05). There was no significant difference between Superbond C&B and RelyX ARC as well as Variolink Veneer and Tetric Flow (P>0.05). All of the resin cements assessed in this study show varying degrees of discoloration after accelerated ageing. However, the color change is not beyond the clinical aesthetic demand. And the Tetric Flow and Variolink Veneer demonstrate higher color stability.