The root of the tooth is black may be root surface caries, or subgingival tartar due to staining black, can be treated by filling treatment and subgingival scraping, usually without extraction, as follows. 1. Root surface caries: caries can occur in both dentin and dentin, the treatment is to remove the decayed tooth tissue, and prepare cavities, using composite resin or glass ionomer filling treatment. 2. Subgingival tartar: Subgingival tartar can cause periodontitis, the treatment is subgingival scraping and root planing, if the tartar attachment is deeper, it can be surgically flipped, and the root planing can be carried out thoroughly under direct vision. There may be other reasons why the roots of the teeth are black, it is recommended to go to the hospital in time to receive professional treatment as soon as possible.