Open mouth breathing is usually caused by personal habits, dental developmental deformities, nasal inflammation, etc. It is recommended that patients be treated according to the cause. 1. Personal habits: if the patient is caused by personal habits, it is recommended to wear an oral positioner or a closed-mouth patch under the guidance of a doctor to improve the treatment. 2. Malformations of dental development: If open-mouth breathing is caused by malformations of dental development, patients can choose invisible brackets or wear braces under the guidance of the doctor to improve the treatment. 3. Nasal inflammation: If the patient is suffering from rhinitis, sinusitis and other nasal inflammation, it may lead to narrow nasal space, resulting in the habit of open-mouth breathing. It is recommended that patients can use saline to wash the nose under the guidance of the doctor, which can play an improved role. It is recommended that patients should develop the habit of breathing through the nose in their daily life so as not to cause abnormal facial development.