Impact of moisture condition, shade-taking device, zirconia color, and thickness on color difference values: an in vitro study

The purpose of this in vitro study was to investigate the effect of zirconia color, thickness, and moisture condition on color difference values (ΔE00) using two shade guides. Forty-two zirconia specimens were divided into three color groups: A1, A2, and A3 (n = 14 each). Each color group comprised two thickness groups (1.5 and 2.0 mm; n = 7 each) and underwent testing over 50 V anodization titanium background specimen (n = 7) in wet and dry conditions, yielding 12 experimental groups. All the specimens were examined using a spectrophotometer and compared with the two control groups (zirconia and vita shade guides, n = 1) to establish the color difference (ΔE00). The ΔE001 (zirconia shade guide) and ΔE002 (vita shade guide) values were calculated for the first and second hypotheses, respectively. ΔE00 values = 1.8 were considered 50% clinically acceptable threshold (AT). The data collected were statistically analyzed using analysis of variance and appropriate post-hoc tests (P = .05). The wet/dry condition, zirconia color, and thickness significantly affected the observed ΔE00 (P <.05) for both shade guides. The dry condition using 1.5- and 2.0-mm zirconia revealed values same as or greater than the estimated mean when compared with the wet condition (P < .05) for both shade guides. In contrast to the vita shade guide, all the mean and 95% confidence interval (CI) values of ΔE001were below 50% AT, except 1.5-mm zirconia with A1 and A3 shades in dry condition. The use of a 1.5-mm and A1–A3 shade zirconia over yellow-anodized titanium potentially results in acceptable color matching with 95% CIs using a combination of wet condition and zirconia shade guide.