When gums speak volumes

The majority of Americans have gingivitis, an inflammation of the superficial structure of the gum that can be a precursor to gum disease. Although good brushing, flossing and favorable genetics can limit the extent of gingivitis and keep gum disease at bay, this condition of persistent inflammation affects 30% to 40% of American adults. Of those, about 10% have advanced cases that damage the structures (ligaments and bone) that support the tooth.

Other than bleeding, gum disease has few symptoms and rarely causes much discomfort. "The gums do not hurt until it is too late," Amar says.

Well before the gums or teeth start to hurt, the dual forces of infection and inflammation in the mouth appear to hitch a ride in the bloodstream and travel to other parts of the body, wreaking havoc once there. One of the most well-established links between gum disease and secondary infection, for example, is among people with mitral valve heart defects. Doctors have long warned valve patients to take antibiotics before teeth cleanings so that the bacterial disruption in the mouth will not travel through the bloodstream to infect the valve.

The other theory of how gum disease inflicts damage elsewhere in the body involves inflammation. Bacteria in plaque release toxins that cause the immune system to produce chemicals called cytokines. In excess, cytokines can increase inflammation and damage tissues throughout the body. Inflammation in general (no matter how it starts) is now considered a prime culprit in the development of many illnesses, including heart disease and some types of cancer.

"The key in gum disease is chronic inflammation," says Preston D. Miller Jr., president of the American Academy of Periodontology. "When it becomes chronic, it begins to release substances that destroy tissue."

There may be other ways that poor gum health causes trouble elsewhere in the body. Doctors at USC have connected a common virus, cytomegalovirus, to gum disease and complications in kidney transplantation. About 20% of all failed kidney transplants are related to cytomegalovirus infection, according to Hessam Nowzari, director of the periodontology program at USC School of Dentistry. Research shows that inflamed gums can be a reservoir for the virus.

"The virus originates and replicates in inflamed gums," says Nowzari, who has studied the connection. "That is going to lead to an attack on other parts of the body, including transplants."