A novel 3D image analysis leading to different treatment planning and outcome in orthognathic surgery

• Main Authors: Ting-ShuanLin, 林廷宣
• Other Authors: Tung-Yiu Wong
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/79367032700346204770

碩士 === 國立成功大學 === 口腔醫學研究所 === 102 === Two basic problems have been associated with traditional 2D cephalometry. First, 2D cephalometry is a 2D representation of 3D structures and is subjected to systematic errors such as magnification and projection error. Second, conventional cephalometry is difficult to evaluate patients with facial asymmetry. 2D image could not give us sufficient information to diagnose and determine a suitable treatment plan, especially to identify the mandibular angle of facial asymmetry patients even though it has combined with 3D dental casts. This is due to the above-mentioned limits of 2D image and poor connection between 2D image and dental casts. The development of 3D CT not only made us more understand the 3D nature of facial structures but also improved the insufficiency of 2D image. In addition, 3D CT navigation system software enables 3D reconstruction and provides a more accurate facial symmetry image analysis and prediction. Our department also developed a software system of 3D image analysis and prediction. The aim of the study is to know how 2D and 3D image analysis affect the treatment plans and outcome of orthognathic surgery patients. The samples in the study are patients who had orthognathic surgery in NCKUH. The study is divided into two parts. The first part is to compare the treatment plans derived from 2D and 3D image analysis simultaneously in the same patient. The second part is to compare the post treatment photographs, PA cephalometry and lateral cephalometric radiographs to identify the different treatment outcome of facial asymmetry patients with treatment plans derived from 2D or 3D image analysis individually. In first part, 18 patients were collected. Significant differences were observed in vertical movement of maxilla and sagittal movement of mandible between conventional and novel 3D treatment plans. In second part, 10 patients in each group were collected. Evaluation of post-surgical symmetry made in PA cephalograms, the Ag plane angle could be corrected better by using novel 3D method. The evaluation of postoperative facial symmetry in photographs, the faces were symmetrical in both groups. There was almost no statistical significant difference of postoperative skeletal stability between conventional and novel 3D groups. In conclusion, significant differences were observed in vertical movement of maxilla and sagittal movement of mandible between conventional and novel 3D treatment plans, and there was a significant difference in postoperative symmetry of Ag plane angle between conventional and novel 3D treatment outcome.