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," says Rodriguez, 26, of Long Beach. "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 may 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," says Dr. Salomon Amar, a periodontist at Boston University. "Gum disease was not considered something that could have any impact."
But as recently as last month, 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 this month'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.
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.