A Case of Micrognathia with Mandibular Asymmetry Treated by Surgical Orthodontic Approach.

Micrognathia with mandibular asymmetry is caused by either acquired or congenital underdevelopment of the mandible before adolescent growth spurt. The facial deformity develops progressively until the end of growth resulting in a bird face appearance associated with facial asymmetry, and surgical-orthodontic treatment is indicated for reconstruction of the unfavorable facial morphology and occlusion in such cases. This report describes a surgical-orthodontic treatment of a patient of micrognathia with mandibular asymmetry.The patient was a 23-year 5-month-old female who had the chief complaint of facial asymmetry and masticatory dysfunction. The underdevelopment of the mandible on the shifted side might have been caused by inflammation of the mastoid process in infancy. Radiographic examinations depicted a severe deformity of the right mandibular ramus, condyle and mandibular body, and cystic appearances in the apical region of the lower anterior teeth. After preoperative orthodontic treatment, surgical treatment was performed employing mandibular sagittal split ramus osteotomy combined with an osteotomy for midline correction. The shifted side of the mandible was advanced, and the lower edge of the mandibular body on the contralateral side was rotated and twisted outward in this treatment. Eight months later, midline osteotomy was performed again to detail the facial symmetry. The resultant Class I occlusion was apparently stable for a long time. Improvement in masticatory function and facial esthetics was successfully obtained in this case.