A big tooth all black is mainly related to exogenous pigmentation, dental caries, dental inflammation and other factors, you can pay attention to oral care, fillings, root canal treatment and treatment for inflammation. 1. Exogenous pigment: a big tooth all black may be poor mineralization in the process of tooth development, enamel underdevelopment, resulting in the surface of the tooth has a depression, easy to adsorb exogenous pigment, resulting in the surface of the tooth black. Daily attention to oral cleaning, eat less dark-colored food, regular annual scaling. 2. Dental caries: a big tooth all black may be caused by dental caries, dental caries will also bring dental pain and other discomforts. Caries should be filled and repaired in time to avoid becoming more serious. 3. Tooth inflammation: a big tooth all black may be related to pulpitis or apical periodontitis, the need for timely root canal treatment to eliminate inflammation, so that the tooth to restore health. Afterwards, the blackened tooth will be restored with a crown. When you find a big black tooth, it is recommended to go to the dental hospital first.