Method: Ten examiners with previous experience in color matching and average/superior color discrimination competency (ISO TR 28642:2011) were asked to match 48 shade tabs of three VITA Classical shade guides in a viewing booth (JUST LED Color Viewing Light, JUST Normlicht, Weilheim/Teck, Germany) under two illuminants: D65 and D50. Gray, white, black, red, light blue color of background /surrounding area simulated various clinical situations. The average score of matches was calculated for each background, and the differences were statistically analyzed (Kruskal-Wallis test). The Influence of light, gender and examiners’ color competency for each background were assessed using Mann-Whitney U test (α=0.05)
Result: Overall, the highest scores were obtained with gray background (81.4% ± 13.0), and the lowest scores on the blue one (68.3% ± 16.9).There was a statistically significant difference between color matching scores on five backgrounds (χ2(4) = 12.572, p = 0.014). When neutral gray was used as reference, only blue proved to be statistically different (p=0.011, r =-0.56); no difference was found between gray and white (p=0.891), black (p=0.934) and red backgrounds (p=0.055). respectively. Significantly different results among the two groups (with superior and average competency) have been found only for gray (p=0.001), white (p=0.001) and red (p=0.004) background.
Conclusion: Color of background/surround influenced the results of color matching: the best color matching was achieved with a gray background, followed by white, black, red, and blue, respectively. Gender and lighting condition (D50 vs D65) did not influence color matching results, while color discrimination competency played a significant role.