Dentures blackened can be improved by brushing or scaling and polishing. 1. Adding baking soda to toothpaste when brushing can whiten the blackened dentures. Drinking strong tea or coffee causes tooth staining, which is difficult to remove by simply brushing, and can be polished with the help of ultrasonic cleaning, which shakes and removes the pigmentation of teeth through the tiny vibrations of ultrasonic waves. 2. If the denture is blackened due to oxidation of non-precious metals, it is difficult to whiten by scaling or brushing, and needs to be restored with a new denture. Choose precious metal materials or all-ceramic crowns, which are more stable and difficult to oxidize in the air, and the possibility of blackening is smaller with prolonged use. So denture blackening can be improved by scaling or brushing, but also dental restoration can choose all-ceramic materials, specific can go to the dentist to consult.