There are three main possibilities for black teeth: calculus, caries and pigmentation, which can be recovered. 1. Calculus: Calculus is the plaque adhering to the surface of the teeth and soft tartar calcification deposits, generally gray or black, can be deposited in any part. The calculus in the gap between the teeth can be removed by supragingival cleaning (scaling). 2. Caries: the neighboring surface of the contact between the teeth is a good site for oral caries, early caries between the teeth of the surface rough, late caries generally have obvious cavities. Filling treatment is sufficient, and root canal treatment is required for caries that affects the pulp. 3. Pigmentation: Long-term diet containing pigmented food, smoking and other patients will deposit pigment on the surface of the teeth, and the gap between the teeth will appear black. Generally, sandblasting can eliminate. It is recommended to go to the regular hospital, the physician examination after a clear diagnosis, symptomatic treatment.