Role of deoxyribonucleic acid technology in forensic dentistry

Identifying missing people: the contribution of forensic dentistry and DNA

Abstract Introduction Human identification is considered one of the major steps concerning missing people. The Forensic Anthropology Sector of Legal Medical Institutes identifies corpses. Forensic dentistry and DNA tests stand out among the existing standard tests. Objective This article aimed to evaluate human identification effectiveness through forensic dental examination performed in the forensic anthropology sector in a Forensic Medical Institute, comparing them with DNA analyses. Methodology This is a cross-sectional study using secondary data available in the department´s database, from 2008 to 2014, concerning identification procedures using forensic dentistry and DNA techniques. Result The analysis of the examinations eligible to this study (241) showed that DNA analysis was the method used for identification in 79.3% of the cases and forensic dental examinations were used in 20.7% of the cases. As for the type of biological material used during these examinations, unidentified corpses corresponded to 131 cases (53.9%), skeleton structures corresponded to 109 cases (44.9%) and there were 3 cases of body segments (1.2%). When analyzing the time spent to complete the tests, dental examinations were faster than DNA tests. The time spent for forensic dental examination does not depend on the type of dental documentation evaluated. Conclusion The analysis of the results in this study showed that human identification through forensic dentistry is effective, rapid and less costly, contributing to greater agility in solving issues related to locating missing people.

Extrication of DNA from Burnt Teeth Exposed to Environment

INTRODUCTION

Teeth are good sources of DNA in mass disasters especially in fires and explosions because they are largely protected from environmental and physical conditions. It is possible to obtain mitochondrial DNA (mtDNA) even in cases of degraded human remains.

AIM

To obtain DNA from burnt teeth exposed to environment for a period of six months and 12 months and to highlight the importance of DNA obtained from tooth in identifying a deceased in fire accidents after being subjected to environment.

MATERIALS AND METHODS

Randomly 20 extracted teeth samples were collected. The teeth were divided into two groups (Group 1 and 2) and were subjected to 700°C using a Delta burnout furnace. Burnt teeth were exposed to environment for a period of six months and 12 months respectively. Data was analysed by Statistical Package for Social Sciences (SPSS) version 16.0. Data was summarized by percentages for count data. The comparison within group was done by single proportion test and the comparison between two groups was done by two proportion test. All p-value less than 0.05 were considered as statistically significant.

RESULTS

The present study revealed that mtDNA was obtained from eight extracted teeth samples among Group 1 and six extracted teeth samples among Group 2.

CONCLUSION

Teeth are good source of DNA, even in cases where the bodies are burnt and exposed to environment.

The use of a DNA stabilizer in human dental tissues stored under different temperature conditions and time intervals

Objective

The present study evaluated the use of a reagent to stabilize the DNA extracted from human dental tissues stored under different temperature conditions and time intervals.

Material and Methods

A total of 161 teeth were divided into two distinct groups: intact teeth and isolated dental pulp tissue. The samples were stored with or without the product at different time intervals and temperature. After storage, DNA extraction and genomic DNA quantification were performed using real-time PCR; the fragments of the 32 samples that represented each possible condition were analyzed to find the four pre-selected markers in STR analysis.

Results

The results of the quantification showed values ranging from 0.01 to 10,246.88 ng/μL of DNA. The statistical difference in the quantity of DNA was observed when the factors related to the time and temperature of storage were analyzed. In relation to the use of the specific reagent, its use was relevant in the group of intact teeth when they were at room temperature for 30 and 180 days. The analysis of the fragments in the 32 selected samples was possible irrespective of the amount of DNA, confirming that the STR analysis using an automated method yields good results.

Conclusions

The use of a specific reagent showed a significant difference in stabilizing DNA in samples of intact human teeth stored at room temperature for 30 and 180 days, while the results showed no justification for using the product under the other conditions tested.

Forensic dentistry in human identification: A review of the literature

An update is provided of the literature on the role of odontology in human identification, based on a PubMed-Medline search of the last 5 years and using the terms: “forensic dentistry” (n = 464 articles), “forensic odontology” (n = 141 articles) and “forensic dentistry identification” (n = 169 articles). Apart from these initial 774 articles, others considered to be important and which were generated by a manual search and cited as references in review articles were also included. Forensic dentistry requires interdisciplinary knowledge, since the data obtained from the oral cavity can contribute to identify an individual or provide information needed in a legal process. Furthermore, the data obtained from the oral cavity can narrow the search range of an individual and play a key role in the victim identification process following mass disasters or catastrophes. This literature search covering the last 5 years describes the novelties referred to buccodental studies in comparative identification, buccodental evaluation in reconstructive identification, human bites as a method for identifying the aggressor, and the role of DNA in dental identification. The oral cavity is a rich and noninvasive source of DNA, and can be used to solve problems of a social, economic or legal nature.

Key words:Forensic identification, DNA, forensic dentistry, rugoscopy, cheiloscopy, saliva.

Maximizing postmortem oral-facial data to assist identification following severe incineration

PURPOSE

This paper reviews the literature for methods of maximizing the postmortem oral-facial information available for a comparison to be made for identification following an incident resulting in incineration.

METHOD

A search was initially instigated utilizing PubMed, Scopus, and Google Scholar, with further library searches and correspondences among peers around the world leading to a comprehensive review of the literature.

CONCLUSION

Maximizing postmortem dental evidence in a severe incineration event requires correct recognition and recording of dental data. Odontologists should attend the scene to facilitate this recognition. The information should be documented, photographed, and stabilized before retrieval. Wrapping, padding, and further support of the remains during transportation to the examination mortuary will aid this process. Examination at the mortuary requires further photography, complete charting, and radiographic examination of any dental material available, as well as awareness of other possible medical evidence, to enable identification of the human remains.