Abstract
We report a case of skeletal mandibular retrusion with a narrow maxillo-mandibular dental arch in which satisfactory occlusion was achieved by lateral expansion of maxillary and mandibular bones with horizontal distraction osteogenesis followed by maxillo-mandibular advancement. The patient was a female aged 24 years and 5 months at the first visit with a chief complaint of maxillary protrusion. She had a convex facial profile with prominent tension around the lips when her mouth was closed. When she smiled, she showed a gummy smile with large buccal corridor. The molar relationship was Angle Class Ⅱ. Cephalometric findings revealed retrusion of the mandibular bone and labial inclination of the anterior maxillo-mandibular teeth.
Lateral expansion was performed for the maxilla by 6.0 mm and for the mandible by 7.0 mm at the median of the maxillo-mandibular bones using horizontal distraction osteogenesis. Three months after completing expansion, preoperational orthodontic treatment was started, and maxillo-mandibular advancement was performed 1 year and 6 months after the expansion. The screws were removed and genioplasty was performed 8 months after the operation. Then, screws were further removed from the corresponding site at 5 months, and as appropriate occlusion was achieved, we completed the active treatment 12 months after the orthognathic surgery and started maintenance. The treatment required 3 years. Her large buccal corridor was resolved after lateral expansion of the dental arch using horizontal distraction osteogenesis. With this extra space, maxillo-mandibular growth was achieved and labial inclination of the anterior teeth was improved. Furthermore, her gummy smile was improved with maxillo-mandibular advancement, and her convex facial profile was also improved by concomitant use of genioplasty.
