Lee Ki-Wook, Kim Yeun, Perinpanayagam Hiran, Lee Jong-Ki, Yoo Yeon-Jee, Lim Sang-Min, Chang Seok Woo, Ha Byung-Hyun, Zhu Qiang, Kum Kee-Yeon
Department of Conservative Dentistry, Dental Research Institute, Seoul National University Dental Hospital, Seoul National University School of Dentistry, Seoul National University, Seoul, Republic of Korea.
Division of Restorative Dentistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada.
J Endod. 2014 Mar;40(3):417-22. doi: 10.1016/j.joen.2013.09.014. Epub 2013 Oct 25.
Micro-computed tomography (MCT) shows detailed root canal morphology that is not seen with traditional tooth clearing. However, alternative image reformatting techniques in MCT involving 2-dimensional (2D) minimum intensity projection (MinIP) and 3-dimensional (3D) volume-rendering reconstruction have not been directly compared with clearing. The aim was to compare alternative image reformatting techniques in MCT with tooth clearing on the mesiobuccal (MB) root of maxillary first molars.
Eighteen maxillary first molar MB roots were scanned, and 2D MinIP and 3D volume-rendered images were reconstructed. Subsequently, the same MB roots were processed by traditional tooth clearing. Images from 2D, 3D, 2D + 3D, and clearing techniques were assessed by 4 endodontists to classify canal configuration and to identify fine anatomic structures such as accessory canals, intercanal communications, and loops.
All image reformatting techniques in MCT showed detailed configurations and numerous fine structures, such that none were classified as simple type I or II canals; several were classified as types III and IV according to Weine classification or types IV, V, and VI according to Vertucci; and most were nonclassifiable because of their complexity. The clearing images showed less detail, few fine structures, and numerous type I canals. Classification of canal configuration was in 100% intraobserver agreement for all 18 roots visualized by any of the image reformatting techniques in MCT but for only 4 roots (22.2%) classified according to Weine and 6 (33.3%) classified according to Vertucci, when using the clearing technique.
The combination of 2D MinIP and 3D volume-rendered images showed the most detailed canal morphology and fine anatomic structures.
显微计算机断层扫描（MCT）能显示传统牙齿清理方法所无法呈现的详细根管形态。然而，MCT中涉及二维（2D）最小强度投影（MinIP）和三维（3D）容积再现重建的替代图像重格式化技术尚未与清理方法进行直接比较。本研究旨在比较MCT中的替代图像重格式化技术与上颌第一磨牙近中颊根（MB）的牙齿清理方法。
扫描18个上颌第一磨牙的MB根，重建二维MinIP和三维容积再现图像。随后，对相同的MB根进行传统牙齿清理。4名牙髓病医生对二维、三维、二维+三维和清理技术的图像进行评估，以对根管形态进行分类，并识别诸如副根管、根管间交通和根管袢等精细解剖结构。
MCT中的所有图像重格式化技术均显示出详细的形态和众多精细结构，因此没有一个被归类为简单的I型或II型根管；根据Weine分类，有几个被归类为III型和IV型，或根据Vertucci分类为IV型、V型和VI型；由于其复杂性，大多数无法分类。清理后的图像显示细节较少、精细结构较少且有许多I型根管。对于通过MCT中的任何图像重格式化技术可视化的所有18个牙根，根管形态分类在观察者内的一致性为100%，但在使用清理技术时，根据Weine分类仅4个牙根（22.2%）、根据Vertucci分类仅6个牙根（33.3%）的分类具有观察者内一致性。
二维MinIP和三维容积再现图像的组合显示出最详细的根管形态和精细解剖结构。
