Mouth convexity caused by open mouth breathing can usually be corrected. Orthodontics, anterior maxillary osteotomy, and bimaxillary surgery are usually available to treat mouth bulge caused by open mouth breathing.1. Orthodontics: A bulbous mouth with only teeth protruding forward can be improved by orthodontics. The force generated by wearing orthodontic appliances causes changes in the teeth, muscles and jawbone to improve the symptoms of a convex mouth. 2. Anterior maxillary osteotomy: This is a more commonly used procedure to treat a convex mouth by removing a tooth behind the canine and then amputating the bed bone in that area, and the overall correction method of moving the bed bone and teeth in that area is more effective. 3. Double jaw surgery: Generally, the bones of the upper and lower jaws are surgically osteotomized to return the mouth to the correct position. If the chin has anti-jaw, asymmetry, short chin, these problems, also need to correct the treatment at the same time, in order to achieve a better correction effect. In addition, the root cause of the problem should be addressed. Frequent open mouth breathing or open mouth breathing during sleep may be caused by poor ventilation due to tonsillar hypertrophy, which can be treated by adenoids scraping and low temperature plasma ablation. The condition may also be caused by acute rhinitis, deviated nasal septum, nasal polyps, etc. The patient should go to the ENT department for examination to determine whether there is inflammation, allergy, foreign body, tumor, etc. in the nose and treat the cause.