正顎手術的模型手術計畫系統，傳統是透過面弓(Facebow)轉移患者的上下顎咬合關係到咬合器，轉移過程除了手動操作外，更需要臨床醫師的經驗、技術以及患者的配合。特別是在顏顎面歪斜畸形例子，面弓難以全面呈現咬合狀態。面弓裝置在紀錄了患者咬合關係後，鎖固面弓各節機構固定紀錄咬合關係，當鎖固拆除後，記錄的咬合關係便無法重現。當前除了傳統面弓，尚未有新方法能實際轉移患者咬合關係至咬合器的新工具。本研究旨在研發一套針對正顎手術計畫的免面弓轉移系統，提供轉移咬合關係至咬合器的新技術，能永久保存當時咬合關係並在咬合器上重現。
系統包括軟體虛擬轉移及咬合器實物置位兩部分，軟體藉由電腦斷層影像轉移患者咬合關係至虛擬咬合器，並提出實體置位定位件及機械臂技術，將虛擬咬合器中的咬合關係轉移至真實咬合器。軟體的可量化誤差包含數位牙模疊合到電腦斷層影像牙模的誤差，實驗找出疊合最大誤差為0.277±0.134mm。從軟體計畫到實物置位的整體誤差，分別在定位件及機械臂置位牙模咬合最大誤差為0.569mm、0.652mm，而置位後平移誤差最大分別為2.149mm、6.21mm，最大角度誤差分別為1.17°及3.92°。

Traditionally, before an orthognathic model surgical planning, patient’s occlusal relationship is transferred to an articulator with dental casts mounted on by facebow transfer. This manual facebow transfer procedure requires clinician’s experience with the patients present. Syndromes of some of the cases are craniofacial deformities, the auricle or external auditory canal may be displaced or absent. In such situation, the occlusal relationship may be difficult to record when using facebow. Joints of the facebow are fixed in order to record occlusal relationship. The record cannot be reproduced after joints fixation is removed. Except facebow, there is no state of art tools to transfer individual occlusal relationship to articulator. The study aims to develop a novel facebowfree transfer which is particular designed for orthognathic surgery. The way of transfer can permanently store the individual occlusal relationship and plaster casts mounted on articulator.
The facebowfree transfer system includes a virtual transfer software and physical mounting implementation. First of all, we utilized reconstructed mandible and maxilla model from computed tomography imaging, transfer the occlusal relationship of patient from digital casts to virtual articulator on computer. We proposed two approaches of physical implement to transfer individual occlusal relationship to the articulator. Design positioning tool mounted well on the articulator was the first approach. The second invoked a desktop robotic arm. The maximum superimpose errors between digital casts and denture models is 0.277±0.134mm. The maximum occlusal errors, displacement errors, and rotation errors of transferring occusal relationship from virtual to physical articulator using the positioning tools and the robotic arm are 0.569mm and 0.652mm, 2.149mm and 6.21mm, and 1.17°and 3.92°, respectively.

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