Smelly teeth may be caused by caries, periodontitis and other diseases, the treatment method for filling treatment and periodontal treatment, as follows. 1. Caries: Decomposed tooth tissue and decayed food residues in the cavity may cause tooth odor, the treatment method is to remove the decayed material and prepare the cavity, using composite resin filling or inlay repair. 2. Periodontitis: Porphyromonas gingivalis and Porphyromonas intermedia in periodontal pockets can produce odor, the main source of odor is methyl mercaptan, the treatment is through the gingival cleaning, subgingival scraping and root planing and other periodontal treatments, to remove plaque plaque attached to tartar, to alleviate the inflammation of periodontal tissues. Smelly teeth may have other reasons, it is recommended to go to the hospital in a timely manner, to clarify the cause of the disease for targeted treatment.