Abstract
Statement of the Problem: Matching adjacent anterior all-ceramic restorations supported by natural teeth and implants to adjacent natural teeth or all-ceramic restoration is a demanding task for both clinicians and dental technician, especially when cemented to natural teeth and/or implant-supported abutments with different stump shades.
Aim: To compare the optical effect of dissimilar background and cement shades in terms of color differences (Delta E) after cementation to low-translucency lithium-disilicate glass-ceramic (LT-LDGC).
Material and NIetlimN: Sixty LT-LDGC specimens were sectioned from CAD/CAM block with a standard thickness of (1.5 +/- 0.2) nun. Four background materials (zirconia (white), nano-ceramic filled composite resin (shade A2), dual-cure composite core build-up (shades light opaque and A3) were used to fabricate rectangular square discs (n=15). Ceramic and background specimens were cemented with three shades of dual-cure self-adhesive resin cement (clear, white, and yellow). The 3 coordinates of the CIELAB system were measured using a spectrophotometer (Vita Easyshade Advance, Vita Zahnfabrik) twice (at baseline for the ceramic alone and after cementation). Then, color difference (Delta E-00) values were calculated for each sample with the baseline measurement as control. Two-way ANOVA was used to analyze the effect of the background and cement shade on the color difference at a significant level (0.05).
Results: Two-way ANOVA revealed a significant effect of the background shade, but not for the cement shade and their interaction on the color difference. The reported Delta E-00 values ranged between 2 to 8.5. Majority of the groups showed Delta E-00 values higher than clinically acceptable level (Delta E-00>2.25). Only one group of the combination of zirconia background and yellow cement showed means Moo values within the clinically acceptable level (1.3 < Delta E-00 <= 2.25).
Conclusion: This study demonstrated that the underlying background color influences the final color of the LT-LDGC restorations. Using variable cement shades failed in decreasing the color difference to a clinically acceptable level.