- 期刊
經由減少錐狀射束電腦斷層掃描之旋轉弧度來檢測上顎第一臼齒的第二近心頰側根管
Reducing Cone-Beam Computed Tomography Rotation Arc for Detecting MB2 Canal of Upper First Molar
摘要
牙齒形態和根管系統知識不足可能是牙髓治療失敗的最常見原因之一。為了確保牙髓治療成功，在根管治療前，必須評估根管的解剖結構及其多種變化。多個角度的傳統術前X 光片可幫助牙醫師識別根管系統，但常因解剖構造重疊，可能造成根管治療期間遺漏根管的發生，而產生侷限性。近來，錐狀射束電腦斷層掃描（Cone-beam computed tomography, CBCT）的快速發展已逐漸應用於研究根管形態的系統，除了避免影像失真外，亦可提供牙齒和鄰近結構之軸向、矢狀、橫截面的三維影像。與傳統的電腦斷層掃描（CT）相比，CBCT提供的輻射劑量更少、掃描時間更短，並且有更高的準確度和解析度。這項體外研究的目的是比較以CBCT之全旋轉和半旋轉弧度拍攝的影像，以判斷檢測乾燥顱頭右上第一臼齒的第二近心頰側根管（second mesiobuccal canal, MB2）的能力。使用Morita 3D Accuitomo 170在5 mA，90 kV，360°和5 mA，90 kV，180°，以限制的照野（6×6 cm）和高解析度模式掃描人類頭骨的牙齒。十名觀察員（五名牙髓專科根管訓練醫師和五名實習牙醫師）確定右上第一臼齒上的參考點：MB2根管開口（orifice）和MB與MB2根管之間的峽部（isthmus），並記錄從牙齒咬合面（cusp tip）到參考點的距離。比較測量結果，並經由曝光設置和不同的觀察者組進行匹配。所有觀察者都能夠在兩種曝光設定下檢測到MB2根管開口和峽部。儘管在這項研究中發現，在全旋轉弧度下可以早期檢測到MB2根管開口和峽部，但是在全旋轉和半旋轉弧度之間沒有顯著差異，牙髓實習生和實習牙醫的測量之間也沒有顯著差異。這項研究證明，在5 mA，90 kV，180°旋轉弧度下，高解析度6×6 cm CBCT能夠檢測MB2根管開口和峽部的能力與全旋轉弧度相似。因此，我們得出的結論是，經由使用半旋轉弧度可以大幅降低輻射劑量，並仍保持足夠的影像品質以進行術前解剖學評估。
並列摘要
Failed to detect the anatomy of root canal system is one of the most common reason in the failure of endodontic treatment. In order to ensure the success of endodontic treatment, it is essential to understand the variability of the root canal system. Periapical films taken with different angles prior to the treatment can help clinicians understanding the complexity of root canal system. However, there is still some shortage of periapical films due to the superimposed images, which may lead to missing canal and treatment failure. Cone-beam computed tomography (CBCT) has been used to evaluate root canal system. It can provide sagittal, coronal and axial view of the tooth structure. Compared to conventional CT, CBCT provides less radiation dose, shorter scanning time and better resolution. The aim of this in vitro study was to compare two CBCT images taken with full rotation and half rotation the detection ability of the second mesiobuccal (MB2) canal in the upper right first molar of a dry skull. A dentate human skull was scanned in Morita 3D Accuitomo 170 with a limited field of view (6×6 cm) and high-resolution mode under 5mA, 90kV, 360°, and 5mA, 90kV, 180°. Ten observers (5 endodontic trainees and 5 intern dentists) identified landmarks (MB2 orifice and isthmus between MB and MB2 canals) on upper right first molar, and the distance from cusp tip to the landmarks was recorded. The measurements were compared and matched by exposure settings and different observer groups. All the observers were able to detect MB2 orifice and isthmus in both exposure settings. Although an early detection upon the MB2 orifice and the isthmus in full rotation mode was noted in this study, there was no significant difference between full rotation and half rotation protocols. There was also no significant difference between the measurements of endodontic trainees and intern dentists. This study showed the ability to detect MB2 orifice and isthmus with high-resolution 6x6 cm volume CBCT under the 5mA, 90kV, 180° protocol was similar to that of a full rotation mode. Therefore, we concluded that endodontists can lower the CBCT exposure settings by using half rotation mode to greatly reduce radiation dose and still maintain sufficient image quality for preoperative anatomy assessment.