Objective To investigate the color stability and translucency of four composite resin cements after ultraviolet（UV） aging. Methods 20 composite resin cement disks for four groups（Group A, dual cured, Biscem; Group B, light cured, Choice; Group C, self cured, PermaCem; Group D, self cured, RelyX Aplicap） were prepared according to their manufacture recommendation. Changes in color and translucency of test samples were determined before and after UV aging for 8, 16 and 24 hour using the CIE L* a* b* system by a colorimeter. The results were analyzed by LSD multi -compare tests. Results The color changes of composite resin cement disks suffering UV aging were significantly different when irradiated different time. For the same irradiated time, Group C had the highest delta E, and Group B and D had the smaller ones. Translucency was found no difference among different irradiated time for group A, B and D. Translucency of group C decreased after UV aging. Conclusion Translucency 0f composite resin cement kept stable after UV aging, and color coordinate changed after UV aging.
