Radiation in Teeth Can Help Date, ID Bodies, Experts Say

<< Back to Page 1   Page 2 of 2

Pinpoint Accuracy

Using mass spectrometry technology, scientists analyzed radiocarbon levels in 33 teeth from 22 dead individuals who lived in northern Sweden. These people, whose ages were known, all had similar diets.

The researchers then compared the radiocarbon levels in the teeth with the levels of atmospheric radiocarbon recorded in various years to determine when the teeth formed in each person.

"When you think of the strategy, it's not surprising that it works," Frisén said.

The researchers were able to pinpoint within 18 months the age of the teeth. Other methods, including the analysis of wear on teeth, are accurate only to within five to ten years.

"It turned out to be much better than we expected," Buchholz said. "It's a very powerful technique."

However, it does not work for individuals born before 1943. That's because atmospheric radiocarbon levels did not vary before nuclear testing began in 1955, and the final formation of enamel is for wisdom teeth at 12 years of age.

Tsunami Victims

The researchers emphasize that enamel dating cannot identify a specific person—that requires DNA analysis—but the method can be used to narrow down the number of people on a list of missing people in a disaster, for example.

"Knowing the age of an individual allows [us to] narrow in on fewer potential identities," Frisén said. "This is a strategy that has been used for ages, but with less precision than what can now be done."

Swedish forensic scientists found the technique to be particularly useful in narrowing their search for victims of the Southeast Asia tsunami. When bodies are left in water, as was the case with tsunami victims, they quickly deteriorate and become very difficult to identify.

"DNA analysis is favored, but [it] calls for … access to DNA," Frisén said. "The current technique can aid when DNA identification cannot be done."

Buchholz says his laboratory has made the technology available to authorities dealing with the aftermath of Hurricane Katrina.

"It's available if they want it," he said. "They will determine if they need it."

Free E-Mail News Updates
Sign up for our Inside National Geographic newsletter. Every two weeks we'll send you our top stories and pictures (see sample).

<< Back to Page 1   Page 2 of 2




NEWS FEEDS     After installing a news reader, click on this icon to download National Geographic News's XML/RSS feed.   After installing a news reader, click on this icon to download National Geographic News's XML/RSS feed.

Get our news delivered directly to your desktop—free.
How to Use XML or RSS

National Geographic Daily News To-Go

Listen to your favorite National Geographic news daily, anytime, anywhere from your mobile phone. No wires or syncing. Download Stitcher free today.
Click here to get 12 months of National Geographic Magazine for $15.