Forensic Dentistry as an Aid to the Pathologist
Dave Carlson - September 1, 2006
A specialized subset of forensic medicine is forensic dentistry. Physicians (generally pathologists) and dentists use their analytical medical skills to provide answers to legal questions about human remains. “Forensic dentistry attempts to identify people by matching dental records with human remains” (Charles, 2001, p. 49). In addition to matching teeth with dental records, forensic dentists compare a suspect's teeth to bite marks to offer an opinion about the likelihood of a match (Charles, 2001, p. 49).
Forensic dentistry is an elite discipline. There are only about 90 certified forensic dentists in the entire United States and Canada, including a meager two pediatric dentists (Charles, 2001, p. 49). On July 30, 2006, the American Board of Forensic Odontology, the certifying body for forensic dentistry, listed on their web site a sparse 91 members (ABFO, 2006, ¶ 1).
Because dental means are employed to identify remains the majority of time when the body is skeletonized, it is essential to recover as many teeth as possible (Haglund & Sorg, 1997, p. 383). “Antemortem facial trauma and taphonomic processes of the postmortem interval, such as decomposition, scavenging, and dispersion of remains by animals, can serve to confound recovery of teeth” (Haglund & Sorg, 1997, p. 383). Haglund and Sorg (1997) note that it is common for teeth to “become disassociated from their alveoli” (p. 383) as the surrounding soft tissue and the periodontal ligament degenerate (p. 383). It is imperative to recover as many of the teeth as possible, because “available antemortem dental records may document only a limited number of teeth” (Haglund & Sorg, 1997, p. 392). A partial collection of dentia material and limited dental records complicate this otherwise routine process.
Comparison of dental records to the teeth of human remains is a seemingly simple endeavor. However, “the nuances and complexities of the process are rarely understood” (Pretty & Sweet, 2001a, p. 360). To confirm identity through dental identification, the forensic examiner must compared postmortem dental remains with antemortem dental records, which may include study casts, written notes, radiographs, and other related items (Pretty & Sweet, 2001a, p. 360).
The primary reason dental identification is utilized so frequently is because it is very unlikely that two full collections of teeth would be exactly the same. Additionally, teeth “also survive most postmortem events that can disrupt or change other body tissues” (Pretty & Sweet, 2001a, p. 360), and most recovered teeth contain viable DNA (Griffiths, 2000, p. 29).
The process of comparing antemortem and postmortem records is methodical and systematic. Each tooth, along with its surrounding tissue, is examined in turn. The process is relatively uncomplicated if the postmortem sample includes a significant number of dental restorations (Pretty & Sweet, 2001a, p. 360), but features such as tooth type and position, root morphology, periapical pathology, alveolar process and lamina dura, maxillary sinus, anterior nasal spine, mandibular canal, coronoid and condylar process, temperomandibular joint, and other pathologies (Pretty & Sweet, 2001a, p. 361) all make significant contributions toward accurate identification.
Even when there are no antemortem dental records to compare, forensic dentistry can assist in the identification of the remains by eliminating certain possibilities and increasing the likelihood that the remains belong to a particular population pool. This process is known as postmortem dental profiling (Pretty & Sweet, 2001a, p. 362). An accurate postmortem dental profile can provide information about the deceased’s sex, age, socio-economic status, and ancestry background. In some cases, postmortem dental profiling also can provide reasonable hypotheses about dietary habits, typical behaviors, occupation, “and occasionally on dental or systemic diseases” (Pretty & Sweet, 2001a, p. 363).
The American Board of Forensic Odontology recommended that dental identification findings should be reported as one of the following four conclusions (Pretty & Sweet, 2001a, p. 362).
- Positive identification: The antemortem and postmortem data match in sufficient detail, with no unexplainable discrepancies, to establish that they are from the same individual.
- Possible identification: The antemortem and postmortem remains or the antemortem data have consistent features, but because of the quality of either the postmortem remains or the antemortem evidence, it is not possible to establish identity positively.
- Insufficient evidence: The available information is insufficient to form the basis for a conclusion.
- Exclusion: The antemortem and postmortem data are clearly inconsistent.
“Forensic dentistry plays a major role in the identification of those individuals who cannot be identified visually or by other means” (Pretty & Sweet, 2001a, p. 366). The forensic dentist also is able to provide critical evidence based on bite marks. “Bite marks are sources of both physical and biological evidence” (Pretty & Sweet, 2001b, p. 415).
A famous case involving forensic dentistry entailed a partially eaten apple. While a gunman was waiting for his intended victim, he got hungry and took a bite from an apple. After culminating his dastardly deed the gunman fled, leaving behind his victim and the apple. Bite marks and trace organic materials left on the apple provided “a full description of the gunman, including his physical appearance, and led to his arrest and conviction” (Griffiths, 2000, p. 29). Imagine the gunman’s surprise when he learned a star prosecution witness was an old apple.
There is no specific scientific evidence to establish that every human dentition or biting process is unique, but “much research is currently underway in an attempt to prove the suspicion that each human dentition is unique” (Pretty & Sweet, 2001b, p. 415). Even so, “conclusions from the analysis of bitemark evidence can assist the justice system to answer crucial questions about interactions between people at the scene of a crime” (Pretty & Sweet, 2001b, p. 418).
Forensic dentistry and odontology can aid the pathologist in identifying human remains through comparison of antemortem and postmortem dental records, as well as use bitemark patterns and trace biological materials to identify the person leaving the bitemark. Forensic dentistry’s unique perspective, along with other corroborating evidence, can provide positive identification of either the victim or perpetrator of a crime.
ABFO (American Board of Forensic Odontology). (2006, July 30). Diplomates of the American Board of Forensic Odontology. Retrieved September 1, 2006 from http://www.abfo.org/Member%20by%20State.htm
Charles, J. (2001, November 9). Teeth Expert. [Electronic version]. Silicon Valley/San Jose Business Journal, 19(28), 49. Retrieved August 17, 2006, from http://proquest.umi.com.proxy1.ncu.edu/pqdweb/?did=90998597&sid=5&Fmt=3&clientId=52110&RQT=309&VName=PQD
Griffiths, D. (2000, July). Forensic dentistry bites back. [Electronic version]. Australasian Science, 21(6), 29.
Haglund, W. D. and Sorg, M. H. (Eds.) (1997). Forensic taphonomy: The postmortem fate of human remains. Boca Raton, FL: CRC Press.
Pretty, I. A. and Sweet, D. (2001a, April 7). A look at forensic dentistry - Part 1: The role of teeth in the determination of human identity. [Electronic version]. British Dental Journal, 190(7), 359-366.
Pretty, I. A. and Sweet, D. (2001b, April 28). A look at forensic dentistry - Part 2: Teeth as weapons of violence -- identification of bitemark perpetrators. [Electronic version]. British Dental Journal, 190(8), 415-418.