Even after a body has been burned beyond recognition and fingerprints have decayed, the teeth remain intact and give forensic scientists the clues they need to identify a body.
The hardiness of teeth is important because someone's dental work is unique to that person, said Dr. Allan Warnick, a forensic odontologist speaking Friday at a coroners symposium at Medical College of Georgia Hospital.
Warnick works at the Wayne County Medical Examiner's Office in Detroit, but his expertise has taken him to several mass-casualty events, including the terrorist attacks of Sept. 11.
Forensic odontology dates back to at least 1435. Warnick said that centuries later, Paul Revere identified the exhumed body of Dr. Joseph Warren by the false teeth he had fashioned for Warren.
The field today is more advanced, with digital, handheld X-ray machines and computer programs to facilitate identification. The basic idea is still the same, though.
Odontologists take pictures, measurements and X-rays of the teeth in a body. If there's suspicion of who it is, investigators will contact the family to find the person's dentist and collect the deceased's dental records. Investigators also retrieve dental records from the military, prison and the Department of Veterans Affairs.
With the records, scientists examine the alignment of the teeth and the "pulp chambers" in X-rays. There is usually some imperfection in the dental work that scientists use as a clue.
An identity can be established based on just one tooth, so even if some of the 28 to 32 teeth most adults have in their mouth fall out, there are still several points of comparison.
Computers make work easier, but the final identification is always done by a human, Warnick said. The family relies on that identification for closure, and insurance companies wait on death certificates before distributing payouts.
"It is imperative that we are 110 percent certain," he said.