The influence of colored zirconia on the optical properties of all-ceramic restorations.

This study investigated the effects of different colored tetragonal zirconia polycrystal (TZP) core on the optical properties of TZP framework restorations. Three various colors of TZP discs (Katana Zirconia) 14 mm in diameter and 0.5 mm thickness were layered with 2 shades of veneering ceramics (shade A1 and A4: Cerabian ZR). These specimens were polished to approximately 1.5 mm. CIE L*a*b* coordinates, translucency (TP), and opalescence (OP) on the TZP restorations were evaluated. Consequently, TZP core color affected CIE L*a*b* values of TZP restorations however TP and OP did not significantly differ among the 3 core colors. Translucency and opalescence for colored TZP framework restorations were not influenced by the underlying TZP core color when veneering ceramics were layered to thicknesses of 1.0 +/- 0.1 mm.