Does Brushing Invite Tooth Decay?

March 2, 2006

OMAHA, Neb. Brushing your teeth prevents tooth decay and gum disease, right? Maybe not.

Omaha television station KETV revealed that brushing your teeth may actually contribute to tooth decay and gum disease if your toothbrush isn't sanitized. Sanitizing a brush involves more than just a quick rinse under the sink when you're finished brushing.

Rachelle Kuchar agreed to allow a camera to follow her into her brushing routine. She said she brushes twice a day and stores her brush in a drawer to protect it from whatever bacteria is flying around her bathroom.

"I line the drawer, so I'm hoping that if I throw it in there, it's semi-clean," Kuchar said

Experts say that even if you have your toothbrush in a closed drawer, it's still damp and dark in there. The station took Kuchar's toothbrush to the Creighton University School of Dentistry, where Dr. Gary Westerman turned it into a research project for his first-year students.

First, Westerman and his students tested how much bacteria stays on a brush after it's rinsed off.

"That bacteria's got to go someplace," Westerman said. "Most of it will be in the saliva, which we will ultimately rinse out or swallow. But some of it will be on the toothbrush."

The proof was in the petrie dish. After just 24 hours of incubation, one student's brush yielded 2,300 bacterial colonies.

"This is pretty typical," said student Shannon Sena. "We had 14 samples that I counted yesterday, and they were all in the ballpark of this, about 2,000 colonies per person."

Westerman said that much bacteria can cause tooth decay and gum disease, but it shouldn't make you sick. It's bacteria that will be waiting for you the next time you brush your teeth.

There are ways you can sanitize your toothbrush. Our students put three options to the test.

One group of students soaked their brushes after using them for 10 minutes in an antibacterial mouth rinse. Part of the group used Listerine. Another used a prescription rinse called Peridex.

In a third test, the students placed their brushes in a $30 Violight toothbrush sanitizer. Its makers say the ultraviolet light kills "up to 99.9 percent of bacteria" in seven minutes.

"The light shines on the bristles, but how far down on the toothbrush does it go? And, did it really get all the bacteria on the head of the toothbrush?" Westerman asked, before he subjected the Violight to more petrie dish testing.

The Listerine and Peridex treatments killed 98 to 99 percent of the bacteria, testing showed. The Violight also killed between 98 and 99 percent of bacteria.

Westerman suggested that brushers sanitize after each use with mouthwash or the Violight and then allow the brush to air dry. Don't store a brush in a drawer. Don't store it in a cover, which may trap bacteria inside. Don't soak your brush for hours in an antibacterial rinse -- 10 minutes is enough, then air dry.

Whether you have a manual or electric brush, dentists said, change the brush every three months.

Distributed by Internet Broadcasting Systems, Inc.