Orthognathic Surgery, Hard And Soft Tissue Change Research,

The orthognathic surgery has significant effect on the physiological function of the patients' old stomatognathic system and the respiratory tract. Because the bone is draged by the soft tissue such as muscle and skin, whether the new established nerve-muscle balance could be maintained stable for a long time? which kind of change could happen when the respiratory tract moves with the jaw? There all need further study.Though it is one of the classical analysis methods to analyze the cranial-facial morphology, cephalometrics still has some limitation. Finite element analysis (FEM) is one kind of data caculate measurement abroadly used in the engineering field which is effect and dependable. FEM could do credible analysis on the cranial-facial morphology precisely. It's one helpful complementarity to the cephalometrics and the foreground is nice.The objective of the study is to analyze the long-term stability post-operation of the mandibular protrusion and the changes of the upper respiratory tract pre- and post-orthoganthic operation, to understand the effect of the operation on the body and mind of the patients through the investigation on them post-orthoganthic operation on the aspect of aesthetics, psychology and function and study the morphological change of the soft tissue under the five different operation methods using finite element analysis.1.The long-term stability after the mandibular protrusion Operation11 patients with simple mandibular protrusion were applied cephalometry on 11 items pre- and one year after operation, and above 10 years later. The results of the measured items one year later and above ten years were compared using the paired t-test. The result shows that the lower jaws of the 8 patients above ten years after the operation has clockwise rotary-retreat movement. The lower jaws of the 3 patients have anterior-inferior anti-clockwise movement. But all the above mentioned movement are quite minute. The paired t-test showed that of the 11 measured items 9 has no significant change. Only the...