To evaluate the efficacy of screw osteosynthesis for the patient suffering from mandibular prognathism with severe open bite, postoperative stability was studied cephalometrically in 11 cases (positioning screw in 5 and transosseous wiring in 6) who underwent bilateral sagittal split ramus osteotomy. The degree of “severe” open bite was defined as the difference between pre- and postoperative Mop angle with 1.86 degrees or more considered to be severe.
The patients ranged from 17 to 29 years old (mean: 20.5 years). The average period of intermaxillary fixation postoperatively was 16.0 days and 43.2 days for the screw group and the wire group, respectively. Cephalometric measurements at the point of Me and the angle of SN-Mp were performed preoperatively and postoperatively and at release of intermaxillary fixation, 6 months later, 1 year later, and long-term follow-up thereafter in each case.
In conclusion, the results revealed some distinct advantages of screw osteosynthesis over transosseous wiring to reduce not only the period of intermaxillary fixation but also postoperative relapse of the distal segment.