Mandibular symphyseal distraction osteogenesis:: review of three techniques

Mandibular symphyseal distraction osteogenesis (MSDO) is an alternative strategy to correct mandibular transverse deficiencies and dental crowding. Only a limited number of practitioners have reported their clinical experience and potential complications of this procedure to widen the mandible in a large case series. This study involved retrospective analysis of 40 patients who underwent mandibular symphyseal distraction osteogenesis. Three different types of distractor were used to widen the mandible: tooth-borne in 21 patients, bone-borne in 5 patients and hybrid (both bone and tooth-borne) in 14 patients. The distraction amount ranged from 7 to 11 mm (mean 7.31 mm). While 39 patients underwent successful mandibular symphyseal distraction, there was one failure. Most of the complications were experienced in bone-borne distractors, such as breakage of the distractor rod, gingival recession, secondary infection and ptosis of the chin. In the light of these findings, it is suggested that a lingually placed tooth-borne hyrax appliance is more suitable and reliable than the other distraction devices. Further larger studies are needed in order to better evaluate the effectiveness of bone-borne or hybrid devices.