Here's something to chew on: ID in teeth
(China Daily)
Updated: 2006-03-01 05:40

It is the ID card you will never lose or forget to carry with you unless your teeth fall out. Scientists have implanted an ID chip into a tooth to show how detailed personal information can be stored.

The scientists say the tooth chip will be useful to forensic scientists trying to identify bodies after natural disasters and terrorist attacks with numerous victims. They say it will also have advantages over a simple identity card.

"You put your ID card in your pocket, we put it in a tooth," said Patrick Thevissen, a forensic odontologist at the Catholic University of Leuvenin in Belgium. The ID chip can carry information including a person's name, nationality, date of birth, gender and national ID code and can be read after death.

The idea came about because of the difficulty and expense of identifying victims of disasters from dental records. Trying to identify bodies after the Asian tsunami, for example, relied heavily on forensic dentists.

But it was difficult and time consuming, particularly when teeth had been badly damaged or when dental records were not available.

Dr Thevissen and his colleagues told the annual meeting of the American Academy of Forensic Sciences in Seattle that they had adapted an electronic identification tag which vets injected routinely into animals.

Similar radio frequency identification (RFID) tags are used by retailers to track stock. The tags, the size of a grain of rice, use the power from a radio pulse emitted by an electronic reader to send out a code which can be picked up.

This code can be linked to a database containing a person's details or, as Thevissen suggests, spell out simple information directly.

Guy Poelman, a member of the team, has tested RFID tags. In the lab, he drilled a hole into a tooth and inserted the chip as he would a filling. It withstood normal biting forces and worked after being heated to 450 C and cooled.

But repeated expansion and contraction of the tooth due to heating and cooling for example from hot drinks is a problem. Dr Poelman wants to modify the design to include an insulating layer. The advantage of the tag, he said, is that it will allow swift identification of a decomposed body.

"When you put all identification data in one place in the body there can be no mistakes. You have an immediate identification," said Thevissen.

Teeth are particularly hardy and can survive for hundreds of thousands of years. Many extinct primates, for example, are known only from tooth fossils.

"We want to store it in the tooth because it's the strongest and longest lived body part."

The Guardian

(China Daily 03/01/2006 page1)