Hemifacial microsomia treated with the Herbst appliance. Report of a case analyzed by means of roentgen stereometry and metallic implants.

The effect of Herbst appliance treatment on facial growth of one patient was recorded in terms of displacement of the mandible and the maxillary bones in relation to the frontal bone. The recordings were made with an accuracy of 0.1 degree and 0.05 mm. (S.D.). Before treatment the jaws were displaced posteriorly and to the affected side with growth, increasing the degree of retrognathia and facial asymmetry. During treatment facial growth was redirected and the jaws were displaced anteriorly and to the unaffected side, decreasing th degree of retrognathia and asymmetry. At the same time, however, the tilt of the mandible to the affected side was increased, possibly because of the morphologic and functional conditions of the jaws in hemifacial microsomia. The dental malocclusion was corrected partly through displacement of the jaws and partly through dentoalveolar adaptation.