Dental records can be used to identify remains when no other options exist. Photo credit: Getty.

When medical examiners identify a body after a crash or disaster, dental records are sometimes all they have to go on.

Teeth are incredibly durable. They can withstand heat up to 1,200 degrees, said Dr. Roy Sonkin, the forensic dentist who is the deputy borough chief forensic odontologist at the Office of the Chief Medical Examiner in New York City. Consequently, they are often the only identifiable feature left if a victim perishes in a car crash, such as the one that killed actor Paul Walker over the weekend, or if remains are exposed to the elements for a long period of time.

To make an ID, a forensic dentist compares the dental records from when a person was alive to photographs, X -rays and visual observation of a person's teeth after death, Sonkin explained.

"The dentist methodically and meticulously goes over everything, tooth by tooth, comparing each crown, cavity, implant and "virgin" tooth that has been untouched by a dentist," he said. "We often ask the family for photographs of the person smiling for further confirmation."

This comparison is then checked by computer, although some areas of the country still rely exclusively on a pen and paper approach, Sonkin said.

In cases where there is a "presumptive identification" and the person is known, confirming someone's identity is typically straightforward. If someone has been through a traumatic event, the jaw and teeth may be fragmented, making identification more difficult though usually not impossible, Sonkin said.

Sonkin noted identifying dental remains can be a gut-wrenching process for family and friends. And, he said, as a dentist he often feels a connection to the person he is tasked with identifying.

"You always remember that this is someone's loved one," he said. "That can weigh on you emotionally."