Influence of the shade designation on the color difference between the same shade-designated resin composites by the brand

摘要

Objectives. The objectives were to measure the difference in color and color coordinates between the same shade-designated resin composites from different brands, and to determine the influence of shade designation on the difference in color and color coordinates between them.rnMethods. Eight light-curing resin composites, a total of 32 shades, were investigated. Color of specimens (1 mm in thickness) was measured on a reflection spectrophotometer over a white background. Differences in color (△E_(ab)~*) and color coordinates such as CIE L~* (lightness), a~* (red-green coordinate) and b~* (yellow-blue coordinate) between each pair of the same shade-designated resin composites were calculated. The influence of the shade designation on these differences was analyzed with one-way analysis of variance (p<0.05). Results. The range of △L~* between the same shade-designated resin composites by the brand was 0.1-10.2 (mean: 2.9), that of △a~* was 0.0-2.4 (mean: 0.9), that of △b~* was 0.1-7.0 (mean: 2.0) and that of △E_(ab)~* was 0.7-11.0 (mean: 4.2). △L~* and △a~* were not influenced by the shade designation; however, △b~* and △E_(ab)~* were influenced by the shade designation based on oneway ANOVA (a = 0.05). Half of the color difference values between the same shade-designated resin composites were perceptible (42 pairs among 83 pairs, AE_(ab)~* > 3.7). Significance. Since the color difference between the same shade-designated resin composite from different brands varied by the shade designation and was perceptible in more than half of the compared pairs (△E_(ab)~* > 3.7), optical properties of resin composites should be considered differently by the shade designation and brand when selecting these materials.