Teeth are the hardest substances in the body. Long after the flesh, organs and even bone have been degraded, teeth may still give clues as to the identity of an individual. Dental remains can still be used for identification after one and a half hours at almost 1,000 degrees celcius, or after 5 days inside a shark's stomach!
Dental records from the victim's dentist office may be compared for identification. Hospital records, molds for dentures or photographs may also be used for matching. Methods used for identification include photographs, radiographs (X-rays), dental charting, dental impressions, preservation of oral structures (i.e. dentures or braces), jaw articulation and occlusal analysis and DNA analysis. Dentures, for example, may contain mold numbers on the back of the denture teeth that can assist in identification.
Children may not have any dental records, but they may have misshapen teeth. Under the age of five years, it is often difficult to find dental records of children. However, DNA samples may be of great use. The number of adult/juvenile teeth that have penetrated the skin (erupted) can also serve as a rough guide to the age of a person. The amount of mineral build up on the teeth is another method used to determine age.
Bite marks may be compared to dental impressions, photographs, traces and models. Even if bite marks are not matched to an individual, the saliva left behind on a bite mark may be used for DNA analysis to find the identity of the perpetrator.
Remains from mass graves or aircraft wreckage sites may require identification from the forensic odontologist. It is often the case where bones and teeth are mixed together, complicating the identification of human remains. Here, several methods and a team of forensic odontologists may serve to identify the remains.
DNA typing is the most accurate method for identifying an individual. Before DNA testing is done, all other identification using the intact teeth should be completed. This is because the materials required for DNA typing are contained within the soft pulp located within the coronal pulp chamber, root canals and accessory canals. PCR (polymerase chain reaction) is used to make multiple copies of the sequence of the DNA for comparison against a known sample. Mitochondrial DNA typing is done for forensic odontology. For further explanation of DNA typing techniques see section on DNA.
