ABSTRACT
Statement of the Problem: By introducing the coloring liquids, it is claimed that it is possible to make the color of frameworks fabricated from zirconium oxide extremely close to the natural tooth color.
Purpose: The purpose of this research was to evaluate the effect of two staining techniques on value changing in zirconia crowns.
Materials and Method: Three groups A, B, and C, each containing ten zirconia crowns, were used. The zirconium cores samples were fabricated by a CAD/CAM device. Group A was left uncolored, Groups B was submerged for two minutes in A2 coloring liquid and Group C was stained with brush. Then all cores were sintered and the porcelain was applied by using the layering technique. Ultimately, the crowns color was determined using a spectrophotometer. Their color changing [Delta E] and value changing [Delta L] in relation to A2 color were also assessed. The data were analyzed with one-sample t-test, post-hoc Tukey, and one-way ANOVA tests with significant level set at 0.05
Results: The mean value in all groups was higher than the value obtained from A2 color samples [p= 0.001]. The highest mean value was 78.31 +/- 1.22 belonging to group C [staining with brush] and the lowest mean value was 76.99 +/- 0.65 belonging to group B [submerging]. The results of post-hoc Tukey regarding both Delta E and Delta L variables showed a significant difference between groups A [uncolored] and C [staining with brush] with P Delta E=0.006 and P Delta L=0.039, respectively. A significant difference between group B [submerging technique] and C [staining with brush] were shown when these two variables were compared [P Delta E=0.001, P Delta L=0.015]
Conclusion: Due to the higher value increase in surface staining [brush], it is recommended to use the submerging technique for staining zirconia cores