Stability of the Le Fort I maxillary osteotomy after rigid internal fixation

Purpose: The purpose of this study was to evaluate the postsurgical stabili ty of the Le Fort I osteotomy with impaction in which rigid internal fixati on was used for stabilization. Materials and Methods: Lateral cephalograms of 19 patients were evaluated. Descriptive statistics were compiled that included absolute Linear and angu lar measurements as well as absolute changes in measurements for successive cephalometric radiographs. Comparisons were made from 1) presurgery to imm ediate postsurgery, 2) immediate postsurgery to splint removal, 3) splint r emoval to longest follow-up, and 4) immediate postsurgery to longest follow -up. Repeated measures analysis of variance were used to describe significa nt differences for absolute changes in measurements. Results: All surgical movements were significant except for horizontal posi tion of dental structures, horizontal position of the posterior mandible, a nd posterior vertical facial height. All significant movement from immediat e postsurgery to splint removal was secondary to removal of the occlusal sp lint. Changes were minimal from splint removal to longest follow-up,with on ly 3 of 24 measurements showing statistically significant differences. Thes e measurements related to tooth position and were affected by postsurgical orthodontics. The data derived from this study were also compared with thos e found in similar studies in which fixation was by wire osteosynthesis. Conclusions: The magnitude of postoperative movement was considerably less with rigid internal fixation than that reported with the use of wire fixati on. This is attributed to the increased stabilizing effect of rigid interna l fixation.