Oral Bacteria Linked to Health Problems

By Shari Roan
Tribune Newspapers: Los Angeles Times

May 1, 2007

Gustavo Rodriguez had expected numerous physical exams and blood tests before checking into the hospital last July for a long-awaited kidney transplant. But he was bewildered when told to see a dentist.

"My gums were really bad, but I didn't know that mattered," said Rodriguez, 26, of Long Beach, Calif. "They said I had to be bacteria-free before my surgery. I learned a lot ... like every little thing in your body counts."

And as doctors and dentists now suspect, gum disease is no little thing.

Research compiled over the last five years suggests that gum disease, especially if the condition has persisted for a long time without treatment, can contribute to diabetes, cardiovascular disease and stroke, pregnancy complications, and perhaps even Alzheimer's disease, osteoporosis and some types of cancers. Infections in the mouth also might increase the risk to people undergoing several types of surgery, including transplantation and cardiac-valve replacement.

"For years the mouth was never considered a part of the body," said Dr. Salomon Amar, a periodontist at Boston University. "Gum disease was not considered something that could have any impact."


But as recently as March, a study published in the New England Journal of Medicine found that treating severe gum disease can improve the function of blood-vessel walls, improving heart health. And in April's Journal of Periodontology, two studies found periodontal bacteria (bugs normally found in inflamed gums) in the arteries of people with heart disease and in the placentas of pregnant women with high blood pressure.

It's still too soon in the evolution of this research to say with certainty that gum disease directly causes other illnesses. But the evidence is compelling enough that it's beginning to unite dental and medical professionals, two groups that have had only a nodding acquaintance.

And it's leading to one of the most sweeping changes in the dental-insurance industry in more than a decade. Several health-insurance companies, particularly those that offer both dental and medical insurance, are beginning to offer free or low-cost "enhanced" dental benefits to certain high-risk patients who might experience broader health benefits by having a cleaner mouth.

Gum problems begin when the bacteria in plaque, the sticky film that forms on teeth, persists long enough to inflame the gums.

Usually, inflammation is considered a positive response to bacteria, a sign that the body is fighting back. But if inflammation rages unchecked, it does more harm than good.


At some point most Americans will 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 percent to 40 percent of American adults. Of those, about 10 percent have advanced cases that damage the structures (ligaments and bone) that support the teeth.

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

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," said Preston D. Miller Jr., president of the American Academy of Periodontology. "When it becomes chronic, it begins to release substances that destroy tissue."

Periodontal Benefits

Although gum disease could worsen many conditions, experts and dental insurance companies are most interested in heart disease, diabetes and pregnancy -- conditions in which successful periodontal treatment could yield ample benefits.

Studies are needed to conclusively prove whether treating gum disease affects various conditions, said Bryan Michalowicz, an associate professor at the University of Minnesota School of Dentistry and lead author of a study showing that treatment of gum disease did not prevent premature birth.

"There are a number of criteria that have to be met before we can conclude that something is a cause," he says.