Evaluation of techniques for Dental and DNA identification for mass disaster victim Introduction: A mass disaster is an unanticipated event that results in serious injury and death to a large number of people. Mass disaster can be categorised into three categories, natural disasters, accidental disasters or even intentional terrorism acts. Natural disasters could include events such as earthquake, flooding or tsunamis. Accidental disasters could be associated with events aircraft, ship or train collision. While terrorism acts may include airplane hijacking or suicide bombings (Alonso, A. Martin, P. , Albarran, C et al. , 2005). Traumatic experiences such as those mentioned above results in a large number of unidentified victims, this is when disaster victim identification comes into play. Disaster victim identification (DVI) is a necessary task that must be undertaken after any mass fatality incident (Graham, E. A. M. , 2006). This responsibility involves many specialists from search, rescue, and recovery teams to forensic pathologists, odontologists and anthropologists, which assist in identifying the deceased (Hemphill, L. T. , 2005).
There is a variety of different techniques available for disaster victim identification which include visual identification, fingerprinting, DNA typing, radiology, inspection of unique medical features and dental comparisons (Hemphill, L. T. , 2005). The purpose of this paper is to analysis and evaluate techniques associated with identification of victims based on DNA analysis and dental characteristics. As many studies have shown that DNA analysis and dental identification are the most reliable and effective ways of identifying remains of disaster victims.
To evaluate the two methods mentioned above this study will identify factors which influence the accuracy of victim identification as well as its benefits and limits. Discussion: Dental Characteristics: Forensic examiners have a variety of techniques to identify human remains. History shows that a large number of these techniques are based on dental characteristics of each individual. Dental identification is the most common technique used in disaster victim identification investigations. This is due to the fact that most mass disasters have extreme impact on their victim’s physical appearance.
Therefore only most resistant post-mortem tissues of their victims are preserved (Nedel, F et al. , 2009). This method is particularly useful for disaster victim identifications as dental structures are considered the most indestructible part of the body (Whitaker, D. K. , 1995). This is because dental tissue is known to resist harsh conditions, conditions such as exposure to high temperatures, humidity and extreme pressure as it has a high mineral content (Nedel, F et al. , 2009). Dental identification process begins with the forensic dentistry team collecting the relevant remains of disaster victims.
Then dental structures are then analysed to see if the victim had any work done on their teeth in the past such as, fillings, bridge work, or even dental implants (Balwant Rai B. D. S. , 2007). Once dental structure is analysed it is than compared with ante mortem information collected from family and past records. Another reason why dental structures are used in disaster victim identifications is because each person has a unique set of teeth so it is easier for specialists to tell each victim apart. This could be due to different foods, customs and environments which could impact their teeth.
Usually dental characteristic and dental structures are different to each person which is the primary reason why dental data is considered one of the most reliable methods of human identification (Whitaker, D. K. , 1995) and therefore can positively assist in differentiating between unknown individuals and correctly identify victims (Nedel, F et al. , 2009). Dental identification has a relatively high success rate for identifying mass fatality victims. However this rate is strongly dependent on factors which influence the final results for identifying victims of mass disasters.
Such factors include nature of the incident, the country of residence, living standards and the availability of sufficient dental records. For example two fatal bus accidents occurred in Spain, the first accident involved many tourists while the second bus had mainly local passengers. This case resulted in all victims being identified while the second case only resulted in sixty percent of unknown individuals being identified i. e. seventeen out of twenty eight. This was due to the lack of available dental records which in turn caused many problems for specialists in identifying victims (Valenzuela, A. t al. , 2002). There are also some limitations associated with dental identification process as this method is strongly dependent on ante mortem dental records. Specialists need to take into account the variation in quality of dental records between different countries. Specialists need anticipate incomplete and inaccurate dental records due to unqualified personnel, lack of standardisation of records, as well as the quality of documents especially those in developing countries which are necessary components for human identification (Nedel, F et al. 2009). Therefore without sufficient data victims of such tragic events cannot be successfully identified as insufficient evidence is provided to identify victims using dental records, which would result in specialists turning to alternate techniques. DNA analysis: Another method of disaster victim identification is DNA analysis which stands for deoxyribonucleic acid (Genetics home reference, 2009). Forensic analysis has experience a major change since the discovery of hyper variable DNA regions, which allow scientists to uniquely identify individuals.
There is a variety of different techniques used to analyse DNA, yet the most used in forensic case work is DNA profiling by analysis of STR loci. (Thomsona et al. , 1999). Short tandem repeats (STRs) are polymorphic loci found throughout all eukaryotic genomes. Which consist of DNA repeats of short sequences, usually around 2-6 bases long and is usually repeated in tandems of 10 or more (Peakall, 2009). STRs are popular DNA markers as they are easily amplified by polymerase chain reaction and are often variable within and among individuals.
This in term makes it unproblematic for forensic scientist to easily identify individuals. One of the advantages of using DNA analysis for identifying victims is that it allows forensic scientist is to express numerically the power of DNA evidence present in court. Meaning that by using DNA for identification, scientists have began analysing the DNA evidence instead of just simply excluding a non-match person (Lee, Lee, Park, Hwang, 2000). Therefore analysis of DNA evidence is essential for identification as there is a chance that at the examined loci, two unknown persons have the same DNA profile sequence.
When using DNA analysis for disaster victim identification specialists such as medical examiners, archaeologists and anthropologists must follow a protocol to ensure the preservation of samples used for DNA analysis. This is usually due to the large number of victims that results in such disasters. Therefore specialists must be detailed and document every bit of evidence. DNA identification involves compiling and matching DNA profiles of post-mortem tissue samples with ante mortem DNA samples.
There are normally two types of reference samples used when collecting samples used for comparing remains of unknown disaster victims. One being family reference, as direct family have similar DNA, the second being personal effects such as biopsies and bloodstain cards (Alonso, A. , Martin, P. , Albarran, C et al). These samples are then examined to identify the unknown victim. The most effective method of DNA identification is a comparison between each victim multi-locus STR profile and direct samples of the victim.
Direct samples include such things as hairbrushes and other used items. However a disadvantage to this method is direct samples as well as DNA samples can be contaminated. For example someone else could have used the hairbrush. Another example is due to mass disaster cross-body contamination, meaning contamination of blood or tissue between victims, therefore specialist try and extract tissue from the least affected areas. Apart from some contamination problems involving DNA identification it is one of the most accurate and reliable and effective methods of identification used today.
As many studies have shown a strong correlation between DNA analysis and identification while other techniques have shown poor correlation (Graham, E. A. M. , 2006). Both dental and DNA identification are similar in the way that they are both reliable methods of disaster victim identification because they can used to identify decomposed or damaged bodies. However without ante mortem information and records these methods are relatively useless as both methods are strongly dependent on comparative data. This could be problematic when dental records or direct family members are unavailable.
Therefore specialists would have to seek other methods of identification. A disadvantage of DNA identification in comparison to dental identification is that is relatively more expensive, technically demanding difficult to apply on a large scale, while dental identification on the other hand is simple and affordable. For example countries like Thailand have not been exposed to as much DNA technology in comparison to countries like Australian. Therefore Thailand would consider using dental identification as it is cost efficient.
Thus, DNA identification should only be applied with other methods such as dental identification has been unsuccessful in identifying mass disaster victims (Balwant Rai B. D. S. , 2007). Conclusions This studies has shown that when identifying disaster victims, dental identification and DNA identification are reliable and accurate indicators of an unknown individual’s identity, when there is relevant and appropriate ante-mortem dental and direct DNA samples available to compare with. Evidence has shown that these methods are dependent on complete and accurate past dental and DNA samples.
In terms of dental identification other factors that forensic examiners need to consider are variation in the quality of dental documents across different countries, as sufficient documents could be appropriate for one country but not for another, which could potentially influence the final result. On the other hand in terms of DNA identification forensic specialists need to account for contamination of reference sample as well as direct samples from the victim, because when these samples are contaminated it could result in false-positive result which could falsely dentify a victim. This in turn could lead to false hope for family and friends. When comparing DNA identification and dental identification, dental identification would be the first method specialist should consider. This is because it is simple and cost effective, only when methods such as dental identification have not been successful will specialists turn to DNA identification in disaster victim identification as forensic examiners will need to account for a large number of individuals in events such as mass disasters.
Overall DNA and dental identification are simple and accurate indicators for disaster victim identification only when there is relevant comparative data such as dental records and DNA samples. Therefore if there is not relevant comparative data available for forensic examiners to use they should turn to other means. Bibliography: 1. Alonso, A. , Martin, P. , Albarran, C et al. (2005) Challenges of DNA profiling in mass disaster Investigations. Croat Med Journal, (4) pp 540-548 2. Graham, E. A. M. (2006) Disaster victim identification.
Forensic science, Medicine and Pathology, (2-3) pp 203-207 3. Hemphill, L. T. , (2005) Forensic dentistry key in identifying victims of tsunamis, other disasters. International & American Association for Dental research, viewed 12 September 2009. http://www. medicalnewstoday. com/articles/21122. php 4. Nedel, F. , Nedel, A. P, Da Silva, R. H. V. , Lund, R. G. (2009) Evaluation of identification cases involving forensic dentistry in the city of Pelotas, RS, Brazil, 2004-2006. Braz J Oral Sci. , (8) pp 55-59 5. Whittaker, D. K. (1995) Forensic dentistry in the identification of victims and assailants.
Journal of Clinical Forensic Medicine, (2) pp 145-151 6. Balwant Rai B. D. S. (2007) Role of Forensic Odontology in Tsunami Disasters. The Internet Journal of Forensic Science, (2) viewed 12 September 2009 http://www. ispub. com/ostia/index. php? xmlFilePath=journals/ijfs/vol2n1/tsunami .xml 7. Valenzuela, A. et al. (2002) Comparative study of efficiency of dental methods for identification of burn victims. The American Journal of forensic medicine and Pathology, (4) pp 390-393 8. Genetics home reference. , What is DNA, viewed 12 September 2009, http://ghr. nlm. nih. ov/handbook/basics/dna 9. Thomson, J. A. , Pilotti, V. , Stevens. P. , Ayres, K. L. , Debenham, P. G. (1996) Validation of short tandem repeat analysis for the investigation of cases of disputed paternity. Forensic Science International, (100) pp 1-16. 10. Peakall, R. 2009, Biology 2151 Forensics week 1, Lecture notes distributed in Biology 2151 Introductory Genetics, Australian National University. 11. Lee, J. W. , Lee, H. S. , Park, M. , Hwang, J. J. (2000) Evaluation of DNA match probability in criminal case. Forensic Science International, (116) pp 139- 148.