Mandibular widening by intraoral distraction osteogenesis

Transverse mandibular deficiency with crowding of the mandibular anterior teeth is frequently present in patients with Class I and II malocclusions. The hallmarks of treatment by compensating orthodontics, functional appliances or orthopaedic devices are instability, compromised periodontium and compromised facial aesthetics. A new surgical technique has been developed to widen the mandible. The method is based upon gradual osteodistraction following vertical interdental symphyseal osteotomy. Ten patients with transverse mandibular deficiency and significant dental crowding were treated by symphyseal distraction and subsequent non-extraction decompensating orthodontic treatment. Either an intraoral tooth-borne Hyrax appliance or a new custom-made bone-borne osteodistractor was used to gradually widen the mandible. The surgical procedures were accomplished under local anaesthesia and intravenous sedation in an ambulatory surgical setting using an individualized distraction protocol. The appliances were activated 7 days after symphyseal osteotomies, once each day at a rate of 1 mm per day and stabilized for 30-60 days after distraction. After the segments mere distracted, non-extraction orthodontic alignment of the mandibular anterior teeth was accomplished. The symphyseal distraction gaps were bridged by new bony regenerate. Distraction osteogenesis provided an efficient surgical alternative to orthognathic surgery for widening the mandible and treatment of transverse mandibular deficiency without extraction of teeth.