Purpose: To evaluate the influence of different cements on the color outcomes of CAD/CAM lithium-disilicate implant crowns cemented to titanium-base abutments utilizing spectrophotometric analysis. Materials and Methods: A clinical situation with a missing lateral incisor was mimicked using a maxillary plastic model. Titaniumbase- supported monolithic lithium disilicate crowns with identical designs were fabricated using a laboratory CAD/ CAM system. The crowns were cemented with three provisional cements and with six definitive cements on both nonsandblasted and sandblasted titanium-base abutments for a total of 15 test groups. As a control group, identical crowns were attached with try-in paste on composite die abutments that duplicated the shape of the titanium-base abutments. The colors of the labial surfaces of the crowns and the peri-implant artificial soft tissue were measured with a spectrophotometer and recorded in CIE L*a*b* parameters. Color differences between the test and control groups were calculated as: ΔE = ([ΔL*]2 + [Δa*]2 + [Δb*]2)1/2. Kruskal-Wallis test was used to compare ΔE values across different groups. Results: The median ΔE values reported for crowns cemented with different definitive cements on titanium-base abutments ranged from 1.4 to 2.9 for the crown surface and from 1.7 to 1.9 on the peri-implant artificial soft tissue; when the titanium-base abutments were sandblasted, the respective median ΔE values ranged from 0.8 to 4.0 and from 1.4 to 2.2. Ceramic crowns cemented with Multilink HO 0 cement presented significantly (P < .01) lower ΔE values than the other cement types for the crown surface independent of sandblasting and for the artificial soft tissue surface when the titanium abutments were sandblasted (P = .011). Conclusion: Within the limitations of this study, Multilink HO 0 (Ivoclar Vivadent) cement showed the most favorable masking ability and the most favorable color outcome among the evaluated definitive cements. Cements of more opaque shades appeared in general to be more favorable in terms of masking the gray color of the titanium-base abutments.
