Teeth and Scientific Advances

Counting growth rings in bear teeth is the best way to determine a bear’s age. In fact, specifically the two tiny teeth just behind the upper canines are the best gauge. These small teeth have no known function and can even be removed from live – but hopefully tranquilized! – bears.

Black bears are common in certain areas of the country, in particular, North Carolina. The N.C. Wildlife Resources Commission uses teeth sent in by hunters to assess the health of the state’s growing bear population and decide how to manage it.

The state’s Black Bear Cooperator Program has collected thousands of bear teeth during the 35 years since its inception, and the majority of the teeth have come from hunters.

Many bear hunters are happy to send in their teeth for examination and storage. Colleen Olfenbuttel, a scientist who works in the program, and her team receives teeth from 40 to 50 percent of the black bears killed each year, either by hunting or due to an accident.

Once Olfenbuttel collects a significant amount of teeth, she sends them to Gary Matson, a scientist in Montana.

Matson’s lab processes 400 teeth per day – about 90,000 per year – sent in from around the world. He processes the teeth by chemically softening them, then slicing them into very thin layers in order to count the age rings.

“Nobody understands why the annual rings are formed,” Matson said. But a dark layer corresponds to each winter of the bear’s life.

The distribution of ages of the bears represents the health of the overall population, Matson said.

Olfenbuttel then uses this age information to monitor and manage black bear populations in North Carolina, as do researchers in other states.

Did you know?

Cheese may help protect against cavities!

A new study published in the journal General Dentistry showed that eating cheese resulted in an increase in dental plaque PH, which corresponds to a decreased chance of developing dental carries.

“What I think is exciting about this is it shows that cheese — particularly as a snack — can reduce the acids that will cause cavities and gum disease,” said Dr. Jeffrey M. Cole, president of the Academy of General Dentistry.

Sixty-eight adolescent subjects between the ages of 12 and 15 were enrolled in the study. Dentists measured their dental plaque pH before they ate dairy and after.

After the initial dental plaque pH levels were taken, subjects were asked to eat either cheddar cheese, sugar-free yogurt, or milk.

The subjects who ate the milk and sugar-free yogurt had no pH changes. However, those who ate cheese had a quick, steady increase of pH as time progressed.

Researchers believe that eating cheese stimulates saliva production, which helps flush bacteria and food particles out of the mouth. It also contains pyrophosphates, a salt that is found in fluorides and toothpaste which can work to re-mineralize a tooth that has been damaged by acid exposure.

–Dr. Shannon Norman-Kotre, Ann Arbor Dentist