- 學位論文
在生理狀態下建立一個新的方法來量測 活動假牙之三維運動
A New Method to Assess the Denture Movements during Function under Physiological Circumstances
摘要
實驗目的： 對於下顎運動學和活動假牙運動學的研究發展伴隨著量測技術的進步而不斷演進，由傳統單平面、多平面的運動軌跡測量，一直進步到三度空間六個自由度的立體測量，但是為了紀錄活動假牙之運動，架設一個穿出口腔之目標框架一直無法避免，所以對自然的生理運動會造成較大之干擾，使測量所得結果之客觀性受到質疑。另外對評估假牙運動本身無法做定量和定性，也是一直以來研究假牙穩定性是否好壞的一大難題。 實驗方法 本實驗之研究目的為應用單平面動態X光立體量測技術和牙科錐狀斷層攝影，結合醫學工程影像契合技術，將之應用於臨床評估活動假牙運動的分析研究，試圖建立一個不需架設穿出口腔之目標框架且可定量分析之立體量測技術。實驗上選取臨床一名全口活動假牙患者且下顎為兩支植體支持之活動假牙，假牙與植體皆使用良好。我們於受試者之下顎活動假牙固定直徑三點五公釐之定位球作為照射時的標記點。受試者先裝戴兩支附著體進行咀嚼動作之動態X光攝影，接著移去兩支附著體模擬未植牙的全口活動假牙，一樣進行咀嚼動作之動態X光攝影；最後進行高解析度之電腦斷層攝影來建立標記點和下顎的立體模型。在臨床實驗開始前機器都會先校正以取得校正參數來模擬動態X光之射源和感光板間的幾何關係，再於模擬系統中模擬出標記點和下顎骨之立體模型，最後將立體模型投射影像和動態X光影向上實際的標記點位置做最佳化運算，當模擬投影點和影像平面上的標記點契合時，便可得標記點空間位置的估計值。取得這些估計值後便可在Matlab程式上做運算，定量出活動假牙和下顎間的相對運動量，並可做3D立體之模擬運動重現。 結論 實驗結果顯示利用使用牙科錐狀斷層攝影和單平面動態X光攝影在臨床上成功建立一不須架設穿出口腔之目標框架之量測平台，對生理運動的干擾微小且可對活動假牙之運動作定量分析，可明確的讓我們瞭解在臨床有兩支植體做支持之下顎全口活動假牙比起沒有植體時的狀況，假牙的確要穩定的多。對於未來之牙醫學研究，本實驗所建立之量測平台對於活動假牙設計、植牙補綴物探討或顳顎關節運動的研究提供了一個具有三維模擬紀錄性、客觀性且可以定量之量測方式。
並列摘要
Introduction: To record the denture movements during function, i.e. the denture kinematics, is an essential, but a missing tool to answer certain key issues attributed to success or failure of denture fabrications. By using single-plane fluoroscopy a new 2D/3D registration technique has been successfully applied to study the in situ kinematics of knee joint prosthethsis and spines, which were not able to be achieved due to problems of marker placements. Such technique might be possible to be used to study the denture kinematics under physiological circumstances. The aim of this study was thus to adapt the 2D/3D registration technique to record the denture movements during physiological functions. Materials and Methods: A mid-aged female with upper conventional full single denture and lower implant retained denture was invited to participate to this study. Four 3.5 mm radiopaque markers were attached to the embrasure of canine and molar regions of lower denture to represent the denture rigid body. The patient wore the denture to receive a volumetric scan to yield the virtual model of the mandible and lower denture with a conebeam CT. Then single-plane fluoroscopy was used to record the chewing movements of the mandible and denture with different combinations of implant attachment placements. Based on projection geometry from a pointed x-ray source, the rigid body motion of the mandible and denture can be derived from the projected 2D single-plane fluoroscopy, i.e. the 2D/3D registration technique. Results: The denture movements during function can be successfully derived from the 2D/3D registration technique. The denture movements under different conditions can be presented not only by virtual model, but also in a quantitative way. The low denture movements are almost eliminated by using only two implants with locator attachments. Conclusion: The complete rigid body motions of dentures during physiological functions can now be recorded. It opens a door for future studies of retention, support, and stability of dentures.