Having studied the effect of maxillary advancement and maxillary impaction in parts 1 and 2 of this research, the purpose of this study was to investigate the biomechanical behavior of different fixation models in inferiorly and anteriorly repositioned maxilla following Le Fort I osteotomy. Two separate three-dimensional finite element models, simulating the inferiorly advanced maxilla at Le Fort 1 level, were used to compare 2- and 4-plate fixation. Model INF-2 resulted in 247 897 elements and 53 247 nodes and INF-4 consisted of 273 130 elements and 59 917 nodes. The stresses occurring in and around the bone and plate-screw complex were computed. The highest Von Mises stresses on the plates and maximum principal stresses on the bones were found in INF-2, especially under horizontal and oblique loads, when compared with INF-4. The present biomechanical study shows that the traditionally used 4-plate fixation technique, following Le Fort I inferior and anterior repositioning surgery, Without bone grafting, provides fewer stress fields on the maxillary bones and fixation materials.