Black spots on teeth may be related to pigmentation, dental caries, calculus and other factors. 1. Hyperpigmentation: in the long-term tea, smoking, eating a lot of pigmented food, if you do not pay attention to the oral cavity cleaning, will cause hyperpigmentation, thus appearing on the teeth of the phenomenon of black spots. 2. Dental caries: dental caries is commonly known as insect teeth or tooth decay, is a chronic disease that occurs in the dental hard tissue bacterial infection. When caries occurs, it may lead to black spots on the teeth. 3. Calculus: Calculus is a calcified and partially calcified substance attached to the surface of the teeth, which is actually a kind of dental stains, and in the case of not paying attention to oral hygiene in general, the phenomenon of black spots on the teeth may also occur. Patients with black spots on teeth are recommended to go to a regular dental hospital in time to identify the cause of the disease, and then actively cooperate with the treatment under the guidance of the doctor.