Oral autopsy (Forensic Science)
Comparison of the dental characteristics of a deceased person with antemortem (before death) dental records of a known person is an accepted method of identification when it is not possible for investigators to rely on other methods, such as identification by a person familiar with the deceased, fingerprinting, or DNA (deoxyribonucleic acid) analysis. Oral autopsies serve as the primary means of identification in three general kinds of situations: when a body is burned beyond recognition, when a body is severely decomposed or skeletonized, and when multiple bodies must be identified following mass disasters in which people died violently.
Dentists trained in forensic pathology perform oral autopsies. This field is also called forensic odontology. In the United States, the American Board of forensic odontology has established guidelines to standardize the procedures of the oral autopsy and to ensure that oral autopsies yield the maximum possible amount of information and properly preserved evidence.
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Procedure (Forensic Science)
The oral autopsy is usually performed after any standard autopsy procedures have been completed, because the oral autopsy destroys facial tissue. The first steps in an oral autopsy are visual examination, photographing, and X-raying of the exterior jaw and mouth area. Next, the mouth is opened. In some cases, the forensic dentist can open the mouth manually, but in many cases, rigor mortis, carbonization (burning), or fragmentation of the body makes it necessary to gain access to the oral cavity by dissection. The jaw may be broken with a mallet and chisel or cut with pruning shears or a bone saw, or the dentist may expose the interior of the mouth by dissecting away the facial muscles. Interior photographs and X rays are then taken.
The forensic dentist next makes a dental chart, using a numbering system to record the presence or absence of each of the thirty-two teeth an adult usually has; the dentist notes whether each tooth is a primary (baby) tooth or a permanent tooth. For each tooth, any unusual features (such as chips) and dental work (such as fillings and crowns) are noted. The presence of dental prostheses (such as bridges) or orthodontic appliances (such as braces) is also recorded. If the body is not badly damaged, the dentist also records information about the soft tissue of the mouth. The dental chart is supplemented with a narrative record of what the dentist sees. Depending on the condition of the body, the dentist...
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Possible Complications (Forensic Science)
The teeth tend to withstand burning and trauma better than many other parts of the body. Nevertheless, some situations can complicate identification by oral autopsy. When a body is burned beyond recognition (carbonized), the teeth may remain intact but become very fragile. In addition, before the dentist can complete a dental chart and cast, the teeth must be cleaned with an enzyme solution, which is likely to make them even more fragile.
In mass disasters such as airplane crashes and bombings, the bodies of victims are apt to be fragmented. During the oral autopsy, the dentist may have to work with incomplete or misleading information. For example, if the jaw is splintered at the time of death, teeth may be missing that were present during life. The forensic team must collect all body fragments and determine to which set of remains each fragment belongs if complete dental records are to be made for individual victims.
Another kind of complication can arise because multiple systems are used worldwide to number teeth. When forensic dentists in the United States are working with dental records from other countries, they must be familiar with those countries’ numbering and nomenclature systems to make valid comparisons.
Sometimes antemortem dental records are simply unavailable, and sometimes those that do exist are incomplete or indecipherable. One advantage of an oral autopsy is that dental casts and...
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Further Reading (Forensic Science)
Bowers, C. Michael. Forensic Dental Evidence: An Investigator’s Handbook. San Diego, Calif.: Elsevier Academic Press, 2004. Outlines the basics of forensic dentistry for law-enforcement personnel and others who must handle and understand dental evidence but who are not dentists.
Fairgrieve, Scott I. Forensic Cremation: Recovery and Analysis. Boca Raton, Fla.: CRC Press, 2008. Examines the effects of fire on human tissue, paying special attention to the use of DNA and dental remains as means of reconstructing crimes and making identifications.
Redsicker, David R., and John J. O’Connor. Practical Fire and Arson Investigation. 2d ed. Boca Raton, Fla.: CRC Press, 1997. Thoroughly covers all aspects of fire investigations, with an emphasis on fires that cause deaths.
Saferstein, Richard. Forensic Science: An Introduction. Upper Saddle River, N.J.: Pearson Prentice Hall, 2007. Provides a general introduction to forensic laboratory work.
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