Mandibular adaptations following total maxillary osteotomy in adolescent monkeys.

The purpose of this study was to investigate the growth and remodeling changes of the mandible following superior anterior surgical repositioning (Le Fort I) of the maxilla in adolescent Macaca fascicularis monkeys. Eight adolescent monkeys served as controls, and seven monkeys underwent surgical procedures. All monkeys received tantalum implants on both sides of certain facial bones for stereometric and conventional cephalometry. The animals were followed up to 24 months postoperatively. Analysis of cephalometric head films taken at monthly intervals shows that both the maxillas and the mandibles of the experimental monkeys grew harmoniously, although the amount and direction of growth showed significant changes compared to the controls. The mandibles of experimental monkeys that underwent autorotation immediately following the surgical procedures showed 36 to 60 percent less growth as measured from condylion to menton, condylion to gonion, and gonion to menton. Similarly, the anterior dental-alveolar-symphyseal height showed 75 percent less increase as compared to the controls. The results show that, although the surgical procedure was performed on the maxilla, the mandibular growth showed significant modulation to adapt to the surgically changed maxillary environment. The role of occlusion and function is discussed in the context of the present findings.