Nasal airway function as it relates to the timing of mid and lower facial osteotomies.

It has been established in primate studies that mouth-breathing can affect lower facial development. We submit that mouth-breathing has a similar effect on human development--specifically, that chronic mouth-breathing during growth contributes to long-face syndrome. When reconstructive surgery is contemplated for this deformity, we believe that the sequence of surgical steps is important and that particular attention should be given to enhancing nasal respiration. The possibility that mouth-breathing is a factor in relapse following mandibular surgery is discussed.