[Orthognathic surgery and facial asymmetry: successes and disappointments].

Used alone, Lefort I procedures and surgical mandibular reduction and de-rotation do not always restore facial symmetry; but by first correcting mesiodistal disharmonies, the orthodontist makes it possible for the surgeon to achieve the best results. Sometimes, long term stability of these improvements is jeopardized when the occlusal plane gradually begins to tilt again and asymmetry reappears in the mandible. By using electromyographic analysis in a series of patients with severe transverse facial disharmony she has treated, the author shows the important role played by the muscles of mastication in such relapses.