Effect of airway obstruction upon facial growth.

This article explores both sides of the controversy concerning respiratory behaviors and dentofacial development. The literature is replete with statements that airway impairment alters facial and dental growth, but there also is substantial evidence to the contrary. Much of the confusion stems from the subjective criteria frequently used in defining the terms impairment and mouth breathing. Additionally, respiratory mechanics have often been viewed simplistically rather than in the realistic sense of a complex regulation/control system. Unfortunately, lack of objectivity may lead to an incorrect diagnosis and even worse, inappropriate treatment. Newer respirometric techniques offering more quantitative assessment of respiratory behaviors are now providing more relevant information and more objective definitions of airway impairment and mouth breathing. More recent findings suggest that nasal-oral breathing per se is not necessarily harmful to growth. However, in instances when the nasopharyngeal or oropharyngeal airspace is small, exaggerated postural responses in obligatory nasal-oral breathers may be detrimental to growth.