الفهرس 
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Abstract
Objectives : This study was conducted to evaluate and compare the effect of teeth bleaching systems on color change and surface roughness of Nanofill resin composite. Material and Methods: Seventy standardized disc-shaped samples of Nanofill resin based composite (RBC) were prepared with 10 mm in diameter and 1 mm in thickness. The samples were packed, light-cured, and polished, then stored in distilled water. Forty samples were used for the color change test. The samples were immersed in a tea solution for 3h every day over 40 days. Then divided into 4 groups (n=10) bleached with conventional chemical-activated bleaching agent (Opalescence Boost), bleached with a light-activated bleaching agent (Philips Zoom), bleached with a modified chemical-activated bleaching agent (Philips Dash), and control/none bleached. The bleaching procedure was done according to manufacturer instructions. Color measurements were taken before and after bleaching with a spectrophotometer. The remaining thirty samples were used for the surface roughness test and randomly divided into three groups (n=10), the samples in each group bleached using one of the bleaching agents were mentioned according to manufacturer instructions. Surface roughness measurements were taken with a digital optical profilometer device. Result: Bleaching agents had shown a statistically significant effect on color change of RBC (pv≤0.001) with the highest change for the light-activated and lowest for the conventional chemical-activated, and had shown a significant increase in surface roughness (pv≤ 0.01). Conclusion: In-office bleaching systems had whitened the color of RBC but unfortunately increased the roughness of its surface. The light-activated system had a better effect in terms of color change than the chemical-activated.