Effect of cement color and tooth-shaded background on the final color of lithium disilicate and zirconia-reinforced lithium silicate ceramics: An in vitro study.

Objective: To evaluate the translucency and effects of different cement colors on the final shade of lithium disilicate ceramics (LDS) and zirconia-reinforced lithium silicate ceramics (ZLS) over an A1 and A3 tooth-shaded background.

Materials And Methods: Eighty-eight rectangular-shaped specimens were sliced from LDS and ZLS blocks. The final thickness of the specimens was set at 0.8 ± 0.01 mm. Spectrophotometric measurements for the translucency were taken against black and white backgrounds. Composite resin tooth-shaded background disks were fabricated in two shades (A1 and A3), as were resin cement disks (opaque and translucent) (n = 11). Next, the ceramic specimens and tooth-shaded backgrounds were connected with glycerin, and baseline measurements were taken. These measurements were used as a reference. Then, the ceramic specimens, cement specimens, and tooth-shaded backgrounds were connected together with glycerin, and a second set of measurements was taken. The CIEDE2000 (ΔE ) color formula was used to calculate the translucency and color differences. A Mann-Whitney U test was also performed for the translucency, and a three-way ANOVA (analysis of variance) test was performed for the ΔE values (α = .05).

Results: The LDS and ZLS groups had similar translucency (P = .055). The ΔE values of the specimens were significantly affected by the cement color and tooth-shaded backgrounds in the LDS and ZLS groups (P < .05). Using the opaque cement color resulted in statistically significant differences against the light and dark (A1 and A3) tooth-shaded backgrounds in both the LDS and ZLS groups (P = .022 and P = .006).

Conclusions: The material type did not affect the translucency or final color. However, the cement color did affect the final shade when thin ceramic restorations were used.

Clinical Significance: It should be noted that the cement color and tooth-shaded background used may change the final color of thin high translucency ceramic restorations that contain lithium disilicate and zirconia-reinforced lithium silicate.