Forensic odontology is the branch of forensic science that applies dental knowledge to assist in both civil and criminal cases. A forensic odontologist is a highly specialized dentist that can assist in a variety of investigations, yet the primary function of a forensic dentist is in providing human identification. This specialized area of forensic medicine is invaluable when someone has died a violent death. This is especially true in events of mass casualty or a natural disaster, if the person has been burned or horribly disfigured during death, and when the body is in the late stages of decomposition or where there are only skeletal remains.
Teeth Survive in Extreme Conditions
Teeth can survive high temperatures and extreme conditions which mean even in death it is likely that some or all of our teeth will usually survive. When skeletal remains are found teeth are almost always present. This makes the use of dental records a reliable source of decedent identification. The more complex dental work someone has received throughout his or her lifetime the more likely the forensic odontologist will be able to establish a positive identification.
According to the website Forensic Dentistry Online and the American Board of Forensic Odontology, a post mortem examination that includes dental records can have 1 of 4 outcomes:
- positive identification
- possible identification
- insufficient evidence
- exclusion
Tooth Development Begins in Pregnancy
Human teeth start developing during fetal development at around six weeks gestation. It is around 12 to 16 weeks gestation that the tooth enamel forms. During infancy, the first tooth erupts (usually on the bottom center gum line) at around the age of 4 months and although every infant is unique the primary teeth erupt with a fairly predictable rate of progression so that by the age of 2 years most children have all 20 primary teeth in place. During childhood dental exams the dentist documents the number and condition of each tooth.
Around 6 years of age the primary teeth begin to fall out one at a time and are replaced by a permanent tooth, and by the time the teen years arrive so have all 32 permanent or adult teeth. Dental x-rays are obtained periodically during child and adulthood to look for evidence of caries (cavities), and determine if there is any loss of tooth enamel or bone density. There are three main reasons why teeth are useful in human identification. Teeth are resistant to decomposition and destruction. Teeth are unique to each person. Teeth are recorded early in life during dental exams or work.
Postmortem Documentation of Teeth
Although there are several ways to properly count and document teeth, the most common way is through the universal system. When using the universal system one begins counting from the upper right side of the mouth over to the upper left side, and then continues counting on the lower left side of the mouth and continues counting until reaching the last tooth on the lower right side. Each tooth is documented as present or missing during the initial comparative examination.
Next every surface of each tooth is examined for decay, erosion, discoloration, staining and restoration work (there are two kinds of restorations, amalgam or gold and resin or porcelain). Each tooth has 5 surfaces used to describe any damage or dental work. The mesial (M) is the front side of the tooth. The distal (D) is the back side of the tooth. The facial (F) is the side closest to the cheek, and the lingual (L) is the side closest to the tongue and the occlusal (O) is the surface on the top of the tooth.
Teeth Speak for the Dead
In reality a great deal of information can be determined about certain cultural, dietary, and life style choices the person made from a comprehensive postmortem examination of their teeth. Even some medical conditions (including if the person was bulimic), had a dry mouth, or had a specific sexually transmitted disease can be determined due to specific changes to the tooth enamel or structure. Teeth provide a lifelong history that is often only evident after death.
In addition to helping to establish or exclude identification, forensic odontology often can often closely establish the age of skeletal remains. Other ways that forensic dentistry is applied to criminal investigations is through bite mark analysis. A forensic odontologist can help determine if a bite wound is of human or animal origins, and help determine the biter’s identity in cases of negligence and abuse, assault, rape, or death.
Sources:
- Forensic Dentistry Online “Identification” (accessed April 2, 2011).
- Lucile Packard Children's Hospital at Stanford “Anatomy and Development of the Mouth and Teeth” (accessed April 3, 2011).
- The American Board of Forensic Odontology (ABFO) “The American Board of Forensic Odontology” (accessed April 4, 2011).
Erika Lyn Smith - Erika Lyn Smith - is a Psych RN, who has completed the UMSL Medicolegal Death Investigator Training Course, and is finishing a BS in ...
