[Labial incompetence. Therapeutic considerations of esthetic and functional deficits]

The lips constitute an anatomic, physiologic and aesthetic specific entity which is integrated between nasal and chin areas. Inocclusion of the lips at rest forms an anomaly which affects mandibular growth, lip function and facial morphology. This vertical labial dysharmony implies on one hand an architectural skeletal unbalance at inferior third of the face, mostly associated with dento-alveolo-maxillary disturbance, on the other hand a disorder of oro-facial muscular behaviour. The treatment's aim is the restoration of a spontaneous lip seal at rest. It will be institute as early as growth-hood using functional orthopaedic devices. In adolescent and adult, the correction of existing dento-alveolar dysharmonies by orthodontic means will be completed, if necessary, by surgical procedures either orthognathic correcting retrognathism or maxillary anterior alveolar hyperplasia with dental extrusion, or morphologic to achieve elongation of congenital upper short lip or elevating of lower lip attracted towards the chin. Orthopaedic and morphologic analyses are necessary to locate the site of the responsible anomalies and indicate particular surgical technics relative to the magnitude of functional and aesthetic repercussion.