& nbsp, Suzhou Dongwu Stomatology Department; & nbsp; & nbsp; & nbsp, Orthodontics; Normal human breathing is completed with the nose, and the lips are naturally closed and not separated during breathing. However, when there is a problem with the nose, children will breathe through their mouths, resulting in a narrow face, protruding front teeth, and the lower lip behind the front teeth. Diseases that cause mouth breathing include hypertrophy of the nasal concha, chronic nasal mucosal inflammation, deviated nasal septum, and enlarged tonsils. In such cases, first examine the nasal passage to see if there are any nasal diseases, and if any are found, they should be treated in time. The standard for cure is that when children are extremely emotionally agitated or engaged in intense exercise, they have no difficulty breathing through their noses. If a child has a short upper lip, orthodontics, and difficulty closing their lips, they should strengthen lip muscle training under the guidance of an oral doctor, and at night, adhesive tape can be used to close the upper and lower lips.