John Chang

Harvard Medical School, Boston, Massachusetts, United States

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Publications (1)2 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: To investigate the optical properties of resin-based composite cements and assess their effects on the color of all ceramic crowns. Optical properties of three cements (Variolink II, Esthetic, Nexus II) were analyzed using disk samples (100 microm and 1.0 mm diameter) based on CIELAB color coordinates L*a*b*C* and opacity index. Empress (Ivoclar) and Katana (Noritake) crowns were filled with four different shades of die material (IPS die material ST3, ST5, ST9 and Tetric Evo Ceram Bleach XL). The shade of the crowns was measured with each of three shades of composite cement (Chroma, Bleach and Opaque, Esthetic cement). ST3 and glycerin served as the control. Color differences were calculated in incisal, body and cervical regions. In the cervical and body regions, the color change caused by the bleach abutment could not be altered by using different colored cements for the Empress and Katana crowns. In the cervical region, the color changes effected by the dark brown abutment could be reversed with the bleach luting cement; in the body region this was true only for the Empress crown. Neither different abutment colors nor different luting cement shades resulted in perceptible color changes in the incisal regions. Mean DeltaE* values in the three areas (incisal, body, cervical) were significantly different (p-value<0.01); in the cervical and body regions Empress mean DeltaE* was significantly larger (p<0.01). The composite cements evaluated in this study created perceptible color differences with particular combinations of die material, cement and ceramic crown.
    Journal of dentistry 08/2009; 37(12):937-43. · 2.00 Impact Factor