Jackowski C, Wyss M, Persson A, Classens M, Thali M J, Lussi A
Center of Forensic Imaging and Virtopsy, Institute of Forensic Medicine, University of Bern, Bühlstreet 20, 3012 Bern, Switzerland.
Int J Legal Med. 2008 Jul;122(4):301-7. doi: 10.1007/s00414-008-0224-8. Epub 2008 Mar 12.
Dental identification is the most valuable method to identify human remains in single cases with major postmortem alterations as well as in mass casualties because of its practicability and demanding reliability. Computed tomography (CT) has been investigated as a supportive tool for forensic identification and has proven to be valuable. It can also scan the dentition of a deceased within minutes. In the present study, we investigated currently used restorative materials using ultra-high-resolution dual-source CT and the extended CT scale for the purpose of a color-encoded, in scale, and artifact-free visualization in 3D volume rendering. In 122 human molars, 220 cavities with 2-, 3-, 4- and 5-mm diameter were prepared. With presently used filling materials (different composites, temporary filling materials, ceramic, and liner), these cavities were restored in six teeth for each material and cavity size (exception amalgam n = 1). The teeth were CT scanned and images reconstructed using an extended CT scale. Filling materials were analyzed in terms of resulting Hounsfield units (HU) and filling size representation within the images. Varying restorative materials showed distinctively differing radiopacities allowing for CT-data-based discrimination. Particularly, ceramic and composite fillings could be differentiated. The HU values were used to generate an updated volume-rendering preset for postmortem extended CT scale data of the dentition to easily visualize the position of restorations, the shape (in scale), and the material used which is color encoded in 3D. The results provide the scientific background for the application of 3D volume rendering to visualize the human dentition for forensic identification purposes.
牙齿识别是在个体尸体有严重死后改变以及大规模伤亡事件中识别遗体最有价值的方法，因为它具有实用性且可靠性要求高。计算机断层扫描（CT）已被研究作为法医鉴定的辅助工具，并已证明具有重要价值。它还能在几分钟内扫描死者的牙列。在本研究中，我们使用超高分辨率双源CT和扩展CT尺度研究了目前使用的修复材料，目的是在三维容积再现中实现颜色编码、按比例且无伪影的可视化。在122颗人类磨牙上制备了直径为2毫米、3毫米、4毫米和5毫米的220个洞。用目前使用的填充材料（不同的复合材料、临时填充材料、陶瓷和衬层），针对每种材料和洞的尺寸在六颗牙齿上修复这些洞（汞合金除外，n = 1）。对牙齿进行CT扫描，并使用扩展CT尺度重建图像。根据所得的亨氏单位（HU）和图像内的填充尺寸表示对填充材料进行分析。不同的修复材料显示出明显不同的射线不透性，从而能够基于CT数据进行区分。特别是，陶瓷和复合填充物可以区分开来。HU值用于为牙列的死后扩展CT尺度数据生成更新的容积再现预设，以便轻松可视化修复体的位置、形状（按比例）以及所用材料，这些在三维中是颜色编码的。研究结果为应用三维容积再现来可视化人类牙列以用于法医鉴定目的提供了科学依据。
