The optical effect of composite luting cement on all ceramic crowns

Purpose: To investigate the optical properties of resin-based composite cements and assess their effects on the color of all ceramic crowns. Material and methods: Optical properties of three cements (Variolink II (R), Esthetic (R) Nexus II (R)) were analyzed using disk samples (100 mu m and 1.0 mm diameter) based on CIELAB color coordinates L*a*b*C* and opacity index. Empress (R) (Ivoclar) and Katana (R) (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 (R)) cement). ST3 and glycerin served as the control. Color differences were calculated in incisal, body and cervical regions. Results: 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 (R)) and Katana(B) 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 (R) crown. Neither different abutment colors nor different luting cement shades resulted in perceptible color changes in the incisal regions. Mean Delta E* values in the three areas (incisal, body, cervical) were significantly different (p-value < 0.01); in the cervical and body regions Empress (R) mean Delta E* was significantly larger (p < 0.01). Conclusion: The composite cements evaluated in this study created perceptible color differences with particular combinations of die material, cement and ceramic crown. (C) 2009 Elsevier Ltd. All rights reserved.