<P> In other cases, the upper lip may be short, and the lips do not meet at rest ("lip incompetence"). </P> <P> Gingivitis, gingival enlargement, and increased levels of dental plaque are common in persons who chronically breathe through their mouth . The usual effect on the gums is sharply confined to the anterior maxillary region, especially the incisors (the upper teeth at the front). The appearance is erythematous (red), edematous (swollen) and shiny . This region receives the greatest exposure to airflow during mouth breathing, and it is thought that the inflammation and irritation is related to surface dehydration, but in animal experimentation, repeated air drying of the gums did not create such an appearance . </P> <P> It has been suggested that chronic mouth breathing in children can lead to the development of a long, narrow face, sometimes termed "long face syndrome", or specifically "adenoid facies" when the mouth breathing is related to adenoid hypertrophy . Malocclusion of the teeth (e.g., "crowded teeth") is also suggested to result from chronic mouth breathing in children . Conversely, it has been suggested that a long thin face type, with corresponding thin nasopharyngeal airway, predisposes to nasal obstruction and mouthbreathing, i.e., a long thin face may cause mouth breathing rather than the other way around . Facial form is also strongly influenced by genetic factors . </P> <P> The following other conditions are also associated with mouth breathing: cheilitis glandularis, Down syndrome, anterior open bite, tongue thrusting habit, cerebral palsy, sleep apnea, and snoring . </P>

Where did the term mouth breather come from