By Nancy Volkers
InteliHealth News Service

Dentists say you should replace your toothbrush every three months. But they didn't have statistics to back them up. Now, research supports the idea that older toothbrushes don't work as well as new ones.

The research compared new toothbrushes and artificially used toothbrushes, which were worn down by machine to simulate three months of use. Both toothbrushes worked. That is, they both reduced the amount of plaque after brushing, compared with before. But the new toothbrushes remove more plaque (bacterial debris that builds up on teeth) and did a better job of maintaining healthy gums.

"I look upon at this as piece of research that confirms what the ADA [American Dental Association] and dentists have been recommending for many, many years," said Dr. Paul R. Warren, the lead author of the research. Warren is vice president of clinical research at Oral B Laboratories, a toothbrush manufacturer and the company that funded the study.

The research was published in the February issue of the Journal of Clinical Dentistry.

The research includes information from two studies. In one, 74 people who had been asked not to brush for 24 hours were asked to brush with either a new toothbrush or a worn toothbrush. In the second study, 108 people were given either a new or worn toothbrush and asked to use it for three months, brushing twice a day for a minute each time.

In both studies, the new toothbrushes removed significantly more plaque than the worn brushes.

In the three-month study, after one use, the new toothbrushes removed 11 percent to 17 percent more plaque than the worn brushes. The new brushes also were more effective at removing plaque after six weeks and 12 weeks of use.

Researchers also examined the people in the study for gingivitis before the study began, as well as after 6 weeks and 12 weeks. Gingivitis ? characterized by red, puffy gums that may bleed easily ? is the earliest stage of gum disease. At the 6-week and 12-week exams, people using the new toothbrushes had significantly less gingivitis than people using the worn brushes.

Warren said people in the United States typically replace their toothbrushes every five to six months. Europeans wait eight to nine months before switching to a new toothbrush and in other counties, toothbrushes get used for as long as 12 months.

The new research shows that getting a new toothbrush every three months is an easy and inexpensive way to improve oral health, Warren said.