With the recent exceptionally cold weather, winter is a high season for nasal respiratory diseases, and the following spring is also a high season for nasal respiratory diseases such as allergic rhinitis. Common nasal respiratory diseases, such as chronic rhinitis, may cause turbinate hypertrophy and nasal ventilation dysfunction, resulting in open-mouth breathing. Another example is chronic tonsillitis, where the tonsils are enlarged, which can also cause respiratory dysfunction and lead to open-mouth breathing. When breathing with the mouth open, because the airflow does not pass through the nasal cavity and the airflow passes through the mouth, the front part of the mouth loses its closure and the upper and lower lips cannot be closed in their natural state, which over time reduces the function of the muscles that close the lips, resulting in lip ectropion and short and thick lips. The reduction of lip function destroys the normal lip-tooth relationship, causing the upper front teeth to grow forward excessively, resulting in anterior protrusion of the front teeth, commonly known as “party teeth” and “buck teeth”. When opening the mouth to breathe, the jaw drops, the tongue is pulled down at the same time, the inner side of the maxillary arch loses the normal pressure of the tongue, and the long-term pressure of the facial muscles on both sides causes the narrowing of the maxillary arch and the anterior protrusion of the upper front teeth, and even the front teeth do not bite on, and the face becomes longer. Therefore, the winter cold pay attention to the prevention and control of nasal respiratory diseases, timely removal of factors affecting nasal breathing and elimination of obstacles to the respiratory tract. Maintaining a normal nasal breathing pattern is also a good environment for maintaining the normal growth and development of children’s teeth. If a child is found to have open-mouth breathing, he or she should first look for the cause and ask an otorhinolaryngologist to examine it and eliminate any causes of respiratory ventilation disorders in order to correct the root cause of the mouth breathing habit. At present, nasal airway ventilation disorders can be detected both morphologically and functionally by X-ray and ultrasound, so as to clarify the site of ventilation obstruction and carry out the corresponding targeted treatment. After eliminating the airway obstruction, the normal function of the lip and mouth muscles and tongue need to be restored through functional training of the lip and tongue muscles. The use of orthodontic appliances to correct open-mouth breathing with the help of an orthodontist.