The color stability of seven commercial composite restorative materials under conditions of accelerated aging was evaluated by reflection spectrophotometry at baseline and 300, 600, and 900 h. During early aging the composites generally became darker, more chromatic, and more opaque. Changes in color of the conventional composites during aging were influenced by erosion of the resin matrices and exposure of filler particles. Color stability of the microfilled composites under the in vitro conditions tested was better than that of the conventional composites and did not appear to be influenced as much by erosion.

Two conventional composites and one microfilled composite were exposed to cigarette smoke in vitro in a smoking chamber. Colour parameters were measured using refiectance spectrophotometry. The conventional composites showed more extensive staining than the microfilled composite. The stains were effectively removed by extensive cleaning.

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In this study, a maxillofacial silicone elastomer was stained with cigarette smoke. The stain was then removed by solvent extraction using 1,1,1-trichloroethane. The cigarette smoke produced large color changes in the elastomer as measured from spectrophotometric reflectance curves. The solvent was totally effective in removing the cigarette stain without changing the color of the silicone base.