Sleeping with the mouth open causes convexity of the mouth is generally difficult to self-cure, clinically can be improved through medication, orthodontics, osteotomy of the anterior part of the upper jaw and other ways. 1. Drugs: prolonged open-mouth breathing may be caused by abnormal effects on the nasal cavity and other respiratory functions, commonly caused by acute rhinitis, nasal septum deviation, nasal polyps, etc., and should be examined in the ENT department. Decongestant drugs (e.g., hydroxymethazoline, etc.) can be used to improve the condition, and surgical treatment can be performed if necessary. 2. Orthodontics: A protruding mouth with teeth protruding forward may require tooth extraction first to make some space, and then braces can be worn to make the front teeth recycle, thus improving the protrusion of the mouth. 3. Maxillary anterior osteotomy: Orthognathic surgery, i.e., extraction of a tooth behind the canine, and then amputation of the alveolar bone in the area, so that the teeth and the alveolar bone and other tissues in the area are moved as a whole, which will ultimately lead to an improved effect. To summarize, it is recommended that the patient consult a doctor in a timely manner to find out the cause of prolonged open-mouth breathing, and then follow the doctor’s instructions to treat the cause of the problem.