Statement of the problem: There are various ceramic material systems available for implant-supported restorations. However, the influence of implant abutment materials and crown materials on the final color of these systems is still uncertain. Purpose of the study: The purpose of this in-vitro study was to evaluate the effect of different (i) abutment materials (titanium base abutment and titanium abutment with zirconia coping) and (ii) crown materials (lithium disilicate and zirconia) on the final color of all-ceramic screw-retained implant crowns, measured at the cervical location by spectrophotometric analysis. Materials & Methods: A sample size of n = 16 per group was obtained based on a pilot study and subsequent power calculation. A maxillary typodont was modified to resemble a partially edentulous arch with a missing central incisor that was replaced with an implant. The typodont was then scanned and identical monolithic screw retained implant crowns were designed in order to fit two different abutments: titanium base abutment and titanium with zirconia coping abutment. The crowns were milled in shade A1 using two different ceramic material: The Medium Translucent Lithium disilicate and the High Translucent Multilayered Zirconia. A spectrophotometer was used to measure the color difference (ΔE). The database of VITA shade A1 in the spectrophotometer software will serve as a control group. Welch's ANOVA was used to evaluate color differences between the tested groups. Results: The highest ΔE mean was recorded for group 1: Lithium disilicate crown on the titanium base abutment (3.44 ± 0.27), followed by group 2: Lithium disilicate crown on the titanium base abutment with zirconia coping (2.60 ± 0.24), whereas the lowest ΔE mean was recorded for group 3: HTML zirconia on the Titanium base abutment (2.07 ± 0.10). The means of all groups were significantly different (p < 0.001). Conclusion: Mean ΔE of Lithium disilicate on titanium base abutment (group 1) was higher compared to Lithium disilicate on titanium and zirconia abutment (group 2), and Zirconia on titanium base abutment (group 3) had the smallest mean ΔE.
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