If you brush your teeth every day and still have bad breath, you may have dental disease, periodontal disease or other systemic diseases, and you need fillings, periodontal treatment or other treatments according to the situation. 1. Dental disease: If the teeth are decayed or there is pulpitis or apical periodontitis, the food will be embedded in the cavities, and the bacteria will ferment and produce a bad smell. If there is no pulpitis, the decayed tooth tissue needs to be removed by grinding with instruments and then filled with resin; if there is pulpitis or apical periodontitis, it is necessary to fill the teeth after root canal treatment. 2. Periodontal disease: long-term chronic periodontal inflammation of the gums can appear liquid oozing or even overflow pus, and cause odor, the need for periodontal treatment, gingival cleaning subgingival scraping to remove tartar, to eliminate the inflammation of the gums. 3. Systemic diseases: when there are digestive diseases, such as gastric ulcer or respiratory diseases, such as bronchitis, the body will also emit odor, brushing can not be eliminated, need to be combined with the internal medicine physician to treat systemic diseases. Daily brushing or bad breath is recommended to go to the hospital in time to check the source of the odor and timely treatment.