The upper airway, which is regarded as the “lacuna of life”, is surrounded by hard and soft tissues and plays a very important role in breathing and phonating. The hard and soft tissues around the upper airway affect its size, patency, and morphology, which in turn affect normal breathing and sleeping. The upper and lower jaws and the soft tissues can be changed by orthodontic treatment, which changes the morphology and physiological function of the upper airway. In recent years, with a deeper understanding of sleep-related breathing disorders, research on the effects of the orthodontic treatment on the upper airway has become very popular. This paper illustrates recent studies on the progress of orthodontic treatment effects on the upper airway.
