Mouth Breathing: I. Etiology and Effects (a Review)

Abstract

Mouth breathing may be defined as habitual respiration through the mouth instead of the nose. An important function of the nose is the preparation of the atmospheric air for use by the lungs. The nose cleans, moistens and warms the inspired air. Failure to do so, by breathing through the mouth instead of the nose, has been considered to be injurious to the tissues lining the respiratory tract and oral cavity because of the impact of cold, dry and dirty air. It has also been stated that mouth breathing has serious effects on the development of the facial skeleton and the occlusion of the teeth because of the displacement of normal labial, buccal and lingual muscular forces. The effects of mouth breathing on the tissues o f the nose and paranasal sinuses have been studied by the rhinologist. The effects o f the habit on the oral soft tissues have been observed by the periodontist, while the orthodontist and pedodontist have studied the effects of mouth breath­ ing on the occlusion of the teeth and the development of the facial skeleton. Thus, the problem of mouth breathing has been studied from different points of view. It is inevitable that some differences of opinion occur as a result of different viewpoints. The various statements and observa­ tions reported in the literature on the cause and effect of mouth breathing will be reviewed in an effort to separate fact from conjecture.