The bacteria are able to wreak their havoc because of sticky, finger-like projections that allow them to gain a tight grip on teeth and gums, researchers report.

Rats infected with the bacteria experienced significant loss of dental bone, weakening support for their teeth, a new study found. In comparison, rats infected with the same strain of bacteria that had been modified to lack "tight adherence" genes did not suffer any bone loss during the three-month observation period.

The findings indicate these genes are necessary for the bacteria to grow and cause damage in the mouth, said study author Dr. Daniel H. Fine, director of the dental research center at the University of Medicine and Dentistry of New Jersey in Newark.

Having demonstrated the ability to modify the bacteria and prevent the disease in rats, the researchers are hoping to learn new ways to counter the disease in children.

"The goal of our research is to develop methods that will lead to early detection of disease and result in noninvasive, preventive and cost-effective interventions," Fine told Reuters Health.

The findings are published in the online early edition of the Proceedings of the National Academy of Sciences (news - web sites).

The bacterium is known as Actinobacillus actinomycetemcomitans. It causes a form of gum disease known as localized juvenile periodontitis or localized aggressive periodontitis. The disease, which may cause little pain, affects the front of the mouth, causing rapid tooth and bone loss. It occurs in 0.5 percent of U.S. adolescents and is 15 times more common in black children than whites, according to the report.

"It is often neglected because of the fact that periodontal disease is not highly expected to be seen in children," Fine said.

In addition, many of the affected children live in poor areas and may not see a dentist for checkups, he said.

Dentists can detect pockets in gum tissue that indicate the bacteria have taken hold and are causing destruction, Fine noted. The teeth become loose in more advanced stages of the disease.

Treatment may involve scaling and cleaning of the teeth and gums, antibiotics and surgery to remove damaged tissue, according to Fine.

SOURCE: Proceedings of the National Academy of Sciences 2003;10.1073/pnas.1237223100.