Oral autopsy

DEFINITION: Examination of the mouth and teeth of a deceased person, usually for the purpose of establishing the person’s identity.

SIGNIFICANCE: In cases of multiple deaths in disasters such as hurricanes or airplane crashes, oral autopsies are important for establishing the identities of the deceased. This procedure is also used in individual cases when bodies are so decomposed or badly burned that little remains except bones and teeth.

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 (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.

Procedure

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 make 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 may also make a permanent cast of the teeth using a material called dental stone.

From the condition of the teeth, it is possible to estimate the age of the deceased. The types of materials used in crowns and fillings and the styles of such dental work provide clues to the country or region where the deceased lived when the dental work was done and may possibly also indicate socioeconomic status. This gives law-enforcement investigators some guidance regarding the best places to look for antemortem dental records for the individual. In the United States, investigators might seek dental records from a number of sources, including personal dentists, dental schools and clinics, dental insurance companies, the (a database maintained by the Federal Bureau of Investigation), and the Military Personnel Records Center.

After antemortem records are found for the person suspected to be the deceased, the forensic dentist compares the information gathered in the oral autopsy with the dental work detailed in the antemortem records. Based on this comparison, the records are declared a positive match, a possible match, or a definite nonmatch to the deceased, or the dentist states that too little information is available on which to base a conclusion.

It may be weeks or months following the oral autopsy before dental records are found for comparison. For this reason, the forensic dentist must make excellent notes and casts because the body may no longer be available for examination by the time antemortem dental records are in hand.

Possible Complications

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 notes can be stored easily and do not decompose. They remain readily available should a possible match in dental records turn up years later.

Bibliography

Arthanari, Abirami, et al. "Oral and Virtual Autopsy in Forensic Science." International Journal of Clinicopathological Correlation, vol. 5, no. 2, Jan. 2021, dx.doi.org/10.4103/ijcpc.ijcpc‗13‗21. Accessed 16 Aug. 2024.

Bowers, C. Michael. Forensic Dental Evidence: An Investigator’s Handbook. San Diego, Calif.: Elsevier Academic Press, 2004.

Fairgrieve, Scott I. Forensic Cremation: Recovery and Analysis. Boca Raton, Fla.: CRC Press, 2008.

Redsicker, David R., and John J. O’Connor. Practical Fire and Arson Investigation. 2d ed. Boca Raton, Fla.: CRC Press, 1997.

Roy, Jyotirmoy, et al. "A Literature Review on Dental Autopsy - An Invaluable Investigative Technique in Forensics." Autopsy Case Reports, vol. 11, 20 Aug. 2021, doi.org/10.4322/acr.2021.295. Accessed 16 Aug. 2024.

Saferstein, Richard. Forensic Science: An Introduction. Upper Saddle River, N.J.: Pearson Prentice Hall, 2007.