The effect of water storage and light exposure on the color and translucency of a hybrid and a microfilled composite☆☆☆★★★♢♢♢

Abstract 

Statement of Problem. Internal discoloration may occur with the intraoral use of resin-based restoration materials. Water storage and light exposure influence the color properties of microfilled and hybrid composites. Purpose. The purpose of this study was to determine color and translucency changes in a hybrid and a microfilled composite after light exposure with and without water storage. Material and Methods. A hybrid (Tetric) and a microfilled composite (Silux Plus) were subjected to artificial daylight with and without water storage. Tristimulus Yxy values were determined colorimetrically against a black or a white background. Differences from baseline were calculated as ΔE^*_ab for up to 1 month. After 1 month, ΔL^*, Δa^*, Δb^*, and the contrast ratio ΔC were calculated. Data were analyzed with 2-way analysis of variance (P<.05). Results. The ΔE_ab^* increased over time for wet and dry stored specimens of both materials. Wet storage for 1 month resulted in significantly higher ΔE_ab^* and ΔC but lower Δb^* than dry storage. The Δa^* was significantly higher for Tetric compared with Silux Plus. Both materials showed negative ΔL^* values under both storage conditions without significant differences between materials or storage conditions. Conclusion. The results of this in vitro study suggest that resin-based restoration materials undergo measurable changes due to daylight exposure. Increased changes occurred under the influence of water storage. (J Prosthet Dent 2002;87:264-70.)