There are many causes of blackened teeth, common causes such as diet-related food pigmentation, dental caries, pulp necrosis, etc. In addition, there are some drug-related blackened teeth, such as tetracycline teeth. 1. Pigmentation: pigmentation on the tooth surface may lead to blackened teeth. Patients who smoke for a long time or often drink darker drinks, as well as oral cleaning is not done well, incorrect brushing method, will lead to pigmentation on the surface of teeth, gradually make teeth black, you can choose regular medical institutions to clean teeth to restore the original color; 2, dental caries: dental caries is the performance of bacterial metabolism acid production makes the hard tissue of teeth decay, thus appearing black, can be treated by decay Pulp necrosis: Pulp necrosis and loss of activity, or root canal treatment, 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 completing the treatment to improve the symptoms of black teeth; 4, tetracycline teeth: the period of tooth development, if excessive use of tetracycline drugs may affect the development of teeth, the formation of tetracycline teeth, which will also lead to teeth become black. Patients need to improve their habits in daily life, reduce the consumption of coffee, carbonated drinks, etc. If surgical treatment is to be performed, it is recommended that patients choose a regular hospital or dental clinic to avoid causing unnecessary complications.