WEDNESDAY, April 18 (HealthDay News) -- A new scientific statement issued by the American Heart Association says no convincing evidence exists linking untreated gum disease to heart disease or stroke. Nor is there strong evidence that treating gum disease can reduce your risk of heart disease or stroke, the report says.

For more than 100 years, it was said that gum, or periodontal, disease could lead to cardiovascular disease, a major cause of death in the United States, but an extensive analysis found no proof of that connection.

"It's a statement that current science does not support a direct association or a causative association," said Dr. Peter Lockhart, a professor, dentist and co-chair of oral medicine at the Carolinas Medical Center, in Charlotte, N.C.

The report has been in the works for more than three years, Lockhart said. "It was a matter of finding out, what is the state of the science?"

The statement, released April 18, is published in the journal Circulation.

The American Dental Association's Council on Scientific Affairs agrees with the statement. The World Heart Federation, a nongovernmental organization that fights heart disease globally, also endorses it.

Many U.S. adults suffer from some form of gum disease, which can range from mild swelling and redness to periodontitis, when the gums pull away from the teeth and develop pockets that get infected.

The writing group -- co-chaired by cardiologist Dr. Ann Bolger of the University of California, San Francisco -- combed the medical literature on cardiovascular and gum disease from 1950 until mid-July 2011. They found more than 500 studies, and looked in-depth at the most scientific ones.

Gum disease, heart disease and stroke all produce inflammation in the body. The conditions share some risk factors, such as cigarette smoking, age and diabetes, which is why they often develop in the same people.

However, the writing group did not feel the evidence is strong enough to say gum disease causes heart disease or stroke.

"So far, there is no conclusive evidence [of a cause-effect relationship]," Lockhart said. "If cause and effect is someday proven, it will probably be fairly minor," he said.

Other experts agree.

"If patients have heart disease and gum disease, they have two separate problems," said Dr. Robert Myerburg, a professor of medicine in the division of cardiology at the University of Miami Miller School of Medicine.

Those with gum disease and heart disease should be aware, Myerburg said, that treatment of gum disease is not going to improve their heart problems. "Nor will treatment of your heart problems improve your gum problems."

In agreement with the new statement, too, is the American Academy of Periodontology, said Dr. Pamela McClain, a periodontist in Aurora, Colo., and president of the academy. Its members treat patients with gum disease. "The academy agrees that science doesn't support a causal relationship between periodontal disease as a direct cause of cardiovascular disease," she said.

However, she disagrees with Lockhart's statement that if a cause-effect relationship is found, it will be minor. "It's hard to predict. We may find a stronger link," she said.

"The message should be, we can't say there is proof of a causal relationship," McClain said. "We know there is definitely a link between these."

Bottom line, all experts agree, is that if you have either disease, you need treatment.

And if you have gum disease, you can't expect treatment to prevent heart disease.

More information

To learn more about the heart, visit the World Heart Federation.