the effect of two shading techniques on value of zirconia-based crowns

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 (∆e) and value changing (∆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 ∆e and ∆l variables showed a significant difference between groups a (uncolored) and c (staining with brush) with p ∆e =0.006 and p ∆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 ∆e =0.001, p ∆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.