Color stability of composite, ceromer, and ormocer after accelerated aging

ABSTRACT

The aim of this study was to determine the color stability of 3 modern esthetic restorative materials after accelerated aging. The materials studied were TPH spectrum [Hybrid composite], Tetric cream [ceromer], and Definite [ormocer]. Four common shades of [B2, A2, A3, and A4] of each material were selected. Five specimens of 10 mm diameter and 1.5 mm thickness of each shade were mode by condensing the material into a Teflan mold. Pre-cure color values, L[x],a[x],b[x], were measured with a spectrophotometer. The material was light polymerized and post-cure color parameters were obtained. Specimens were then immersed in distilled water at 60°C. After 4 and 8 weeks, the color values were remeasured and the color differences [deltaE[x] ab] were calculated. Although all materials underwent color changes during light polymerization, the magnitude of the differences were slight. After accelerated aging, the materials were significantly darker and lighter shades showed smaller discoloration compared to darker ones. However, non of the tested materials exhibited a visually perceptible color change [deltaE[x] ab > 3.3] after 8 weeks of accelerated testing. The low discoloration observed with modern materials is probably related to the high inorganic filler contents and to the direct grafting of the resin to the filler particles. The nature of the resin may also account for the color stability of the restorative materials