The severity of a black line in a dental sulcus needs to be judged by the cause of the black line. The more common clinical causes of black lines are deep anatomical structures on the tooth surface such as deep developmental grooves developmental sockets with long-term pigment accumulation, and this condition is generally not serious. If you feel that a black line in a tooth sulcus affects the aesthetics, it is recommended that you first go to a regular hospital or dental clinic for an examination to clarify the cause of the black line. If the black line is caused by melanin precipitation, it can be washed off by applying professional instruments for cleaning in the hospital or oral clinic; if it is caused by worm teeth, filling treatment should be carried out as soon as possible after removing the decay to avoid causing further damage to the dental pulp. If the defect is large, inlay restoration or full crown restoration can be carried out after removing the caries; for the deep caries destroying to the dental nerve, root canal treatment should be done. In daily life, we should pay attention to avoid frequent and large amount of irritating food, so as not to aggravate the stimulation to the dental nerve, which is detrimental to the normal development of the dental and jaw system. Normally, you should pay attention to oral hygiene, insist on brushing your teeth in the morning and evening, rinsing your mouth after meals, and going to dentistry to clean your teeth regularly, at least once a year.