The purpose of this study was to examine early skeletal and dental changes following mandibular advancement with bilateral split sagittal osteotomy, comparing lag screw stabilization with conventional wire osteosynthesis. The wire group exhibited greated anterior dental compensation, posterior-inferior relapse at the symphysis, loss of posterior facial height, and increased mandibular plant steepness. Skeletal changes were statistically greater than those seen in the rigid group, and the denal changes approached the level of statistical significance. In this sample, rigid fixation by lag screw compression osteosynthesis provided improved stability over that possible with wire osteosynthesis.