Dark spots on teeth may be caused by pigmentation, caries, plaque and other factors, which can be treated by scaling, decay removal and filling. 1. Hyperpigmentation: If you smoke or drink tea for a long time, it may lead to plaque attached to the teeth, which will cause hyperpigmentation after a long time and black spots, you can go to the hospital to remove the black spots by way of scaling. 2. Dental caries: usually due to bacterial invasion, resulting in partial loss of teeth, and the formation of cavities. After a long period of time, decayed tissue may appear, which is black in color. It can be treated by removing the decayed tissue and filling the defective part of the tooth. 3. Plaque: Food debris or a large number of bacteria attached to the surface of the teeth, will show black spots on the teeth, you can use dental floss to clean the gap between the teeth to remove plaque. Teeth black spots can be treated according to the specific cause under the guidance of the doctor, and should not be treated blindly by yourself.