A Case of skeletal Class III Treated by BSSRO following Intraoral Anterolateral Segmental Maxillary Distraction Osteogenesis

Abstract

The treatment of a 16-year-old female with skeletal Class III using segmental maxillary distraction osteogenesis via an intraoral device and a mandibular bilateral sagittal split ramus osteotomy (BSSRO) is presented. The patient had maxillaryhypoplasia, mandibular overgrowth, anterior crossbite and remarkable crowding. Maxillary distraction osteogenesis using a custom-made intraoral device was carried out to simultaneously improve the disharmony between the upper dental arch and maxillary alveolar base as well as the retroposition of the maxillary bone. The surgical technique followed a minimally invasive osteotomy along the lateral maxillary walls and anterior segmental osteotomy using the Wassmund- Wunderer method, separating the maxillary bone into 3 segments. Following a latency period of 4 days, the frontal segmented was distracted anteriorly (8mm) while lateral segments were gradually distracted laterally (6mm) at a rate of 0.8mm/day. Distraction osteogenesis successfully improved the anterolateral maxillary deficiencies aswell as dental arch to alveolar base discrepancy. Orthodontic treatment for dental discrepancy was commenced without extraction of teeth.After 2 years, with completion of orthodontic treatment BSSRO was carried out. Due to prior correction of maxillary anterior discrepancy via distraction, minimal mandibular setback wasneeded. Three years following initiation of treatment, desirable and stable occlusion was achieved upon completion of postoperative orthodontics. Concavity of the middle face and mandibular prognathism were remarkably improved by such treatment.In conclusion, the utilized treatment modality provided several advantages, including restoring the lost harmony between upper dental arch and alveolar base, correcting both anterior and transverse discrepancies of maxilla, as well as conducting orthodontic treatment without dental extractions.