The causes of blackened teeth include pigmentation, dental caries, pulp necrosis or tetracycline teeth. Patients are suggested to visit the stomatology department of regular hospitals to clarify the specific causes and then deal with them accordingly.1. Pigmentation: pigmentation on the tooth surface may lead to black teeth. Patients who smoke for a long time, or often drink dark-colored drinks, such as coffee, strong tea, etc., oral cleaning is not done properly, incorrect brushing methods, etc., will lead to pigmentation on the tooth surface, gradually making the teeth darker. You can choose regular dentistry scaling to restore the original color of the teeth; 2, dental caries: dental caries is a manifestation of acid production by bacterial metabolism, which makes the hard tissue of the teeth decay, thus appearing black, and can be treated by decay filling; 3, pulp necrosis: pulp necrosis loses activity, or root canal treatment is carried out, which will lead to tooth discoloration and gradual deepening of color. If the pulp is necrotic and has not been treated, systematic root canal treatment is needed to achieve sterilization and disinfection, and porcelain crown or veneer restoration is done after the completion of root canal treatment to improve the symptoms of black teeth; 4, tetracycline teeth: If excessive tetracycline drugs are used during the development of teeth, it may affect the development of teeth and form tetracycline teeth, which will also lead to teeth turning black. Patients need to improve their habits in daily life and reduce the consumption of coffee, carbonated drinks, etc. If surgical treatment is to be performed, patients are advised to choose a regular hospital dentistry department or dental clinic to reduce the occurrence of complications.