Influence of Dental Discoloration on the Covering Properties of Different Lithium Disilicate Masses

To evaluate the covering properties of lithium disilicate (LD) masses with varying translucencies and opacities when applied to discolored abutments, aiming to optimize esthetic outcomes in prosthetic restorations of dyschromic teeth.

Four resin abutments simulating various discolorations were fabricated, and 13 LD frameworks of high-opacity, medium-opacity, and low-translucency masses were heat-pressed to a uniform thickness of 1 mm. Color parameters (CIE L*, a*, b*) were measured using a spectrophotometer across abutment colors. Color differences (ΔE) were calculated relative to a nondyschromic reference abutment with different LD frameworks mentioned and statistically analyzed using nonparametric ANOVA and multiple comparisons tests (α = .05).

Significant ΔE differences were found among LD masses on dyschromic abutments (P < .0001). High-opacity 2 mass consistently showed the best masking performance, achieving ΔE values below the perceptibility threshold for light abutments but not for darker abutments. Low-translucency and medium-opacity masses exhibited intermediate results, with higher ΔE values on severely discolored abutments.

LD frameworks at 1-mm thickness are insufficient to fully mask dyschromic abutments while maintaining translucency. High-opacity 2 mass provided the best masking, but darker abutments required additional opaque veneering. The study highlights the limitations of minimally invasive LD restorations for severe discolorations. Furthermore, this study highlighted how, in dyschromic abutment covering, it would be easier to reach a perfect match with a light color (eg, VITA scale A1) using a high-opacity mass of LD rather than with more chromatic colors, which are more difficult to mimic.