Marques Jeidson, Musse Jamilly, Caetano Catarina, Corte-Real Francisco, Corte-Real Ana Teresa
State University of Feira de Santana, Brazil.
Faculty of Medicine University of Coimbra, Portugal.
J Forensic Odontostomatol. 2013 Dec 1;31(1):1-7.
The use of three-dimensional (3D) analysis of forensic evidence is highlighted in comparison with traditional methods. This three-dimensional analysis is based on the registration of the surface from a bitten object. The authors propose to use Cone Beam Computed Tomography (CBCT), which is used in dental practice, in order to study the surface and interior of bitten objects and dental casts of suspects. In this study, CBCT is applied to the analysis of bite marks in foodstuffs, which may be found in a forensic case scenario. 6 different types of foodstuffs were used: chocolate, cheese, apple, chewing gum, pizza and tart (flaky pastry and custard). The food was bitten into and dental casts of the possible suspects were made. The dental casts and bitten objects were registered using an x-ray source and the CBCT equipment iCAT® (Pennsylvania, EUA). The software InVivo5® (Anatomage Inc, EUA) was used to visualize and analyze the tomographic slices and 3D reconstructions of the objects. For each material an estimate of its density was assessed by two methods: HU values and specific gravity. All the used materials were successfully reconstructed as good quality 3D images. The relative densities of the materials in study were compared. Amongst the foodstuffs, the chocolate had the highest density (median value 100.5 HU and 1,36 g/cm(3)), while the pizza showed to have the lowest (median value -775 HU and 0,39 g/cm(3)), on both scales. Through tomographic slices and three-dimensional reconstructions it was possible to perform the metric analysis of the bite marks in all the foodstuffs, except for the pizza. These measurements could also be obtained from the dental casts. The depth of the bite mark was also successfully determined in all the foodstuffs except for the pizza. Cone Beam Computed Tomography has the potential to become an important tool for forensic sciences, namely for the registration and analysis of bite marks in foodstuffs that may be found in a crime scene.
与传统方法相比，法医证据的三维（3D）分析的应用得到了突出强调。这种三维分析基于被咬物体表面的配准。作者建议使用牙科实践中使用的锥形束计算机断层扫描（CBCT），以研究被咬物体的表面和内部以及嫌疑人的牙模。在本研究中，CBCT应用于食品咬痕分析，这可能会在法医案件场景中出现。使用了6种不同类型的食品：巧克力、奶酪、苹果、口香糖、披萨和蛋挞（酥皮糕点和蛋奶冻）。将食物咬出痕迹，并制作可能嫌疑人的牙模。使用X射线源和CBCT设备iCAT®（美国宾夕法尼亚州）对牙模和被咬物体进行配准。使用软件InVivo5®（美国Anatomage公司）对物体的断层切片和三维重建进行可视化和分析。对于每种材料，通过两种方法评估其密度估计值：HU值和比重。所有使用的材料都成功重建为高质量的三维图像。比较了研究中材料相对密度。在所有食品中，巧克力密度最高（中位数为100.5 HU和1.36 g/cm³），而披萨密度最低（中位数为-775 HU和0.39 g/cm³），在两个尺度上均如此。通过断层切片和三维重建，可以对除披萨外的所有食品咬痕进行测量分析。这些测量也可以从牙模中获得。除披萨外，所有食品的咬痕深度也成功确定。锥形束计算机断层扫描有潜力成为法医学的重要工具，特别是用于对犯罪现场可能发现的食品咬痕进行配准和分析。
