Effect of lithium disilicate ceramic thickness on the color outcome of titanium implant abutment

Abstract

Objective: This study aimed to compare the effects of lithium disilicate thickness on the final color outcome between ceramic restorations on titanium discs and natural die color discs.

Materials and Methods: To represent the color of crown on implant, 10-mm diameter IPS e.max (Emax) LT A2 discs with different thicknesses (1, 1.5, and 2 mm) were matched on the titanium disc. To represent the color of veneer on natural teeth (control groups), a 10-mm diameter Emax LT A2 discs with 0.5-mm thickness were placed on either ND2 (light color) or ND5 (medium-light color) natural die-colored composite discs. The specimens were measured at 4 points by the VITA Easyshade V. The data were captured by the CIELab color system. Mean values of L*, a*, and b* were calculated, and then the ΔE values were used to compare the color difference between the control and experimental groups. Data were analyzed by one-way ANOVA followed by Tukey’s post-hoc (P<0.05).

Result: The color difference (ΔE) values for Emax with a thickness of 0.5 mm on the ND2 composite disc
compared with Emax with a thickness of 1.5 mm (ΔE = 1.05 ± 0.45) and 2 mm (ΔE = 2.10 ± 0.67) on titanium discs, were found to be lower than perceptibility threshold (ΔE<2.6). When comparing Emax with a thickness
of 0.5 mm on ND5 composite discs, the Emax with a thickness of 1.5 mm (ΔE = 2.40 ± 0.35) and 2 mm
(ΔE = 1.19 ± 0.38) on titanium discs, were also found to be lower than perceptibility threshold (ΔE<2.6).
The thickness of ceramic had a significant effect on the color of restoration (P<0.05).

Conclusion: Titanium discs covered with Emax thicker than or equal to 1.5 mm could achieve color matching with 0.5-mm thickness of Emax on both ND2 and ND5 composite discs.