Three-dimensional mandible reduction: Correction of occlusal class I in skeletal class III cases

Background: The human face is a three-dimensional structure. However, many studies on mandible reduction procedures are based on a two-dimensional concept, with a particular focus on one dimension: the width of the lower face. Many Korean individuals have class I occlusion with a skeletal class III pattern. When a conventional mandible reduction procedure is used on such individuals to reduce the width of the lower face, an unsatisfactory facial outcome may result because the changes in the other two dimensions of the lower face, vertical height and anteroposterior distance, are disregarded. This is true because the skeleton of the lower face is well developed in all three dimensions. Methods: Bimaxillary surgery that reduces all three dimensions of the lower face was planned and conducted by the authors. This mandible reduction procedure reduced the protrusion of both the maxilla and the mandible and, at the same time, shortened the lower face height. The procedure consisted of a Le Fort I osteotomy for superior and/or posterior repositioning of the maxilla, followed by mandibular counterclockwise rotation and setback via a bilateral sagittal split osteotomy. Genioplasty was performed as necessary. Results: With this procedure, the entire lower face volume is reduced, and the overall profile is improved. Conclusions: Three-dimensional mandible reduction greatly enhances the aesthetic outcome by improving the skeletal characteristics of the face common in the Korean population so that the facial measurements more closely approach normal values.