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.

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The aim of this study was to determine the effects of calcium hydroxide (Ca(OH)2) treatment on bond strength of resin cements to root dentin and retention force of fiber-reinforced composite (FRC) posts. Bovine root dentin was endodontically prepared and treated with Ca(OH)2 for 7 days. Root dentin for bond strength test was adhered to resin-composite with resin cements. For pull-out test, posts consisting of FRC posts and resin-composites were fabricated and cemented to root. Shear bond and pull-out tests were performed using a universal testing machine. No significant differences in bond strength and post retention force were found between Ca(OH)2 treated and untreated groups. Significant differences were found among the cements. A positive correlation was indicated between bond strength of cements and retention force of FRC posts. In conclusion, Ca(OH)2 treatment on root dentin did not affect bond strength of resin cements and retention force of FRC posts.

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