Color stability of individually stained monolithic zirconia following occlusal adjustment.

Staining that is resistant to occlusal adjustments and abrasion is only possible if the staining solution infiltrates sufficiently deep into the ceramic structure. This study provides for the first time in the literature numerical values that describe the thresholds of acceptability of color differences in zirconia ceramics. These values are essential because they determine the extent of possible occlusal adjustments, and thus the color stability. Further research is necessary to improve the infiltration depth of staining solutions.