Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy.
Laboratory of Personal Identification and Forensic Morphology, Department of Health Sciences, University of Florence, Florence, Italy.
J Forensic Odontostomatol. 2024 Aug 29;42(2):76-86. doi: 10.5281/zenodo.13474602.
Although dental patterns are unique, the use of bitemark analysis in personal identification remains controversial. To accurately reproduce and compare three-dimensional models of bitemarks and dental arches, intraoral three-dimensional scans, commonly utilized in clinical dental practice for precise and stable digital impressions, are recommended. This study aims to compare two different techniques for bitemark analysis: a digital method based on the superimposition of digital scans of dental patterns and lesions, and a visual method based on the physical superimposition of impressions and resin casts produced by 3D printing. A sample of 12 volunteers (6 males and 6 females) with a mean age of 26 years was collected as biters. Each subject was asked to bite on custom supports made from semi-rigid water bottles covered with imprintable dental wax. The dental arches and bitemarks were then recorded using an intraoral scanner and dental impressions. Scan superimposition analysis was conducted using CloudCompare software, while resin casts were printed using a 3D printer and physically superimposed on the bitemark impressions by a blind operator, who was not involved in sample collection, bite test execution, prior cast acquisition, or CloudCompare analysis. Both superimposition techniques relied on the selection of 10 corresponding landmarks (on canines and central and lateral incisors of the upper and lower arches) between the dental arches and impressions. The digital superimposition showed an average concordance of 92.5% for the upper arch landmarks and 85% for the lower arch landmarks, with an overall average concordance of 88.8% for both arches combined. In contrast, the visual analysis of resin casts showed an average concordance of 77.5% for the upper arch and 76.7% for the lower arch, with an overall average of 77.1% for both arches combined. In the analysis performed using CloudCompare, the maxillary arch demonstrated the best superimposition, with 4 landmarks (R0, R1, R2, R5) consistently overlapping. The digital analysis outperformed the visual analysis in all four quadrants, particularly in the upper right arch compared to the lower left arch, thereby supporting the integration of digital techniques in forensic applications. Further studies are necessary to validate the digital technique on a larger sample, including subjects with different dental characteristics, bite dynamics, and varying types of supports and substrates.
虽然牙齿模式是独特的，但在个人识别中使用咬痕分析仍然存在争议。为了准确复制和比较三维模型的咬痕和牙弓，建议使用口腔内三维扫描，这是临床牙科实践中用于精确和稳定的数字印象的常用方法。本研究旨在比较两种不同的咬痕分析技术：一种是基于数字扫描的数字方法，用于叠加牙齿模式和损伤的数字扫描，另一种是基于物理叠加的方法，用于叠加通过 3D 打印制作的印模和树脂铸型。采集了一组 12 名志愿者（6 名男性和 6 名女性）的样本，平均年龄为 26 岁，作为咬痕者。要求每位受试者在由半刚性水瓶制成的定制支架上咬一口，支架覆盖有可印模的牙科蜡。然后使用口腔内扫描仪和牙印模记录牙弓和咬痕。使用 CloudCompare 软件进行扫描叠加分析，而树脂铸型则使用 3D 打印机打印，并由一名盲操作员在物理上与咬痕印模叠加，该操作员不参与样本采集、咬测试执行、先前铸型获取或 CloudCompare 分析。两种叠加技术都依赖于在牙弓和印模之间选择 10 个对应的标记点（在上颌和下颌的犬齿以及中央和侧切牙上）。数字叠加显示，上颌标记点的平均一致性为 92.5%，下颌标记点的平均一致性为 85%，上下颌联合的总体平均一致性为 88.8%。相比之下，树脂铸型的视觉分析显示，上颌的平均一致性为 77.5%，下颌的平均一致性为 76.7%，上下颌联合的总体平均一致性为 77.1%。在使用 CloudCompare 进行的分析中，上颌弓显示出最佳的叠加效果，有 4 个标记点（R0、R1、R2、R5）始终重叠。数字分析在所有四个象限都优于视觉分析，特别是在上颌右弓与下颌左弓相比，因此支持将数字技术集成到法医应用中。需要进一步的研究来验证数字技术在更大样本量上的有效性，包括具有不同牙齿特征、咬合动力学和不同类型的支撑物和基底的受试者。
