Mandibular anterior segmental osteotomy, is an alternative surgery for patients with pseudoprognathism who do not tolerate orthodontic treatment. When genioplasty is required as a concomitant procedure, this is easily accomplished without the deformation of occlusion by leaving a horizontal bony bar. However, for patients with a short chin, there is no space to leave a bony bar. Hence, a complete osteotomy is required to separate the mandible into several pieces, which include anterior dentoalveolar segment, mentum and two mandibular bodies, leaving no structural continuity of the mandible. In this case, it is essential to consider the occlusion, to use a wafer splint, and to proceed with a long duration of intermaxillary fixation.
The authors describe a modified procedure from the one described above for mild pseudoprognathism and a short chin. An 18-year-old female was concerned about her asymmetric lower facial appearance and anterior cross-bite with protruding short chin. After mandibular anterior segmental osteotomy and setback reposition, we made an angulated bony bar. Another horizontal osteotomy was performed 2mm apart from the previous osteotomy line and angulated 30 degree leaving about 8mm on the posterior cortex. The movable chin segment was repositioned posteriorly and fixed to the bony bar using two 11-mm screws. The long-term result was satisfactory both functionally and aesthetically.
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