“Chameleon” Effect – How to Measure Color Adjustment of Resin Composites

Some esthetic materials tend to adjust their color to the color of the surround. The term blending effect ("chameleon" effect) refers to the perceived color difference between esthetic dental materials and hard dental tissues, and manifests as a smaller color difference when observed together than would be expected if they were viewed in isolation. This is primarily perceptual phenomenon, not measurable with conventional colorimetric devices. However, the translucency of dental materials (when they overlay hard dental tissue) would also be expected to contribute to the degree to which a restoration is visually acceptable. This latter is a physical phenomenon that can be measured. Color difference, ƒxE*, between some dental materials and the hard dental tissue is frequently smaller when the dental material is in situ than when the two are in isolation, because of their translucency. Disc-shaped specimens (n=5) and dual specimens (n=5) of A1 and A3 shades of Venus Diamond (Heraeus Kulzer), Tetric EvoCeram ( Ivoclar Vivadent), and Filtek Supreme Plus (3M ESPE); M1 and M5 shades of Ceram X mono (Dentsply Caulk) were evaluated. Color evaluations were performed by means of spectroradiometer. All specimens were be positioned in focus on a clear acrylic stand and measured with no backing. A 1-mm circular area, with its center in the middle of the specimen was measured. The data were analyzed by analysis of variance. Fisher's PLSD intervals for comparison of means were calculated at the 0.05 level of significance. Results clearly demonstrate that: (a) a majority of resin composites exhibited color adjustment potential; (b) color adjustment potential was highly varied and was composite- and shade-dependent; and (c) because of huge differences in color adjustment potential among materials and its possible influence on esthetic outcome, it can be beneficial to quantify the color adjustment potential of resin composites both scientifically and clinically. It was difficult to tie differences in color adjustment potential values to information reported by manufacturers on composite type, particle size, filler content, or monomer. Within the limitations of this study, the most pronounced color adjustment by product/shade was recorded for Venus Diamond (A1), followed by Ceram X Mono (M5), Tetric EvoCeram (A1), and Filtek Supreme Plus (A3).