Department of Forensic Medicine, College of Medicine, National Taiwan University, No.1 Jen-Ai Road Section 1, Taipei 10051, Taiwan.
Institute of Forensic Medicine, Ministry of Justice, New Taipei City 23016, Taiwan.
Forensic Sci Int Genet. 2023 Nov;67:102945. doi: 10.1016/j.fsigen.2023.102945. Epub 2023 Oct 14.
Teeth are one of the body tissues remaining after severe decomposition from which a DNA profile can be obtained to aid in human identification. Currently, the standard approach to isolate DNA from teeth requires pulverizing the entire tooth. This destructive approach compromises any further morphological or anthropological study. We report on two methods of DNA isolation that minimizes destruction of the tooth when accessing the DNA within pulp and cementum. Forty-nine teeth, removed as part of normal dental procedures, were buried for up to 92 days, with a further nine teeth acting as unburied controls. Additionally, four teeth samples collected during a forensic examination were included in this study. The two processes were: using a fine drill to access the pulp from the crown and then using endodontic files to collect the biological material; and using a sterile blade to scrape the cementum. It was found that the samples collected from the cementum had greater DNA quality compared to those samples obtained from the pulp. Microbial activity was found to play a role in the degradation of the nuclear material, reducing DNA yields from pulp. DNA profiling data from 24 loci, including 22 STR markers, indicated that multi-rooted teeth provided better DNA quantity and quality than those with a single root. The DNA quantity obtained from pulp samples of teeth which exhibited cavities was adversely affected, although this DNA loss was not from samples collected from the cementum of teeth in similar condition. Obtaining samples from DNA profiling from the cementum was found to be ideal if the morphological preservation of the tooth is required. Obtaining pathogen DNA is of interest when an occlusal approach to retrieve pulp may serve as a good alternative to prepare DNA without destruction of the tooth structure.
牙齿是人体组织之一，即使在严重腐烂分解后，仍可从中获取 DNA 图谱以协助进行人类识别。目前，从牙齿中提取 DNA 的标准方法需要将整个牙齿粉碎。这种具有破坏性的方法会影响对牙齿进一步进行形态学或人类学研究。我们报告了两种从牙髓和牙骨质中获取 DNA 的方法，这两种方法可在获取 DNA 的同时最大限度地减少对牙齿的破坏。将 49 颗作为常规牙科程序一部分而被移除的牙齿进行了掩埋，最长时间达 92 天，另有 9 颗未被掩埋的牙齿作为对照。此外，还包括在法医检查中收集的四颗牙齿样本。这两种方法是：使用细钻头从牙冠进入牙髓，然后使用牙髓锉收集生物材料；以及使用无菌刀片刮取牙骨质。结果发现，与从牙髓中采集的样本相比，从牙骨质中采集的样本具有更高的 DNA 质量。研究发现微生物活动会导致核物质降解，从而降低从牙髓中提取的 DNA 产量。从 24 个基因座（包括 22 个 STR 标记物）获得的 DNA 图谱数据表明，多根牙齿提供的 DNA 数量和质量比单根牙齿要好。尽管从类似条件的牙齿的牙骨质中采集的样本并未受到影响，但那些表现出龋齿的牙齿的牙髓样本中提取的 DNA 数量受到了不利影响。如果需要保存牙齿的形态，则从牙骨质中获取 DNA 样本是理想的选择。如果从咬合面获取牙髓的方法可以作为不破坏牙齿结构制备 DNA 的替代方法，则获取病原体 DNA 是有意义的。
