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How to avoid a root canal

Study shows smoking increases risk of dreaded oral procedure

Elizabeth Krall Kaye

If the likelihood of developing lung cancer isn’t enough to discourage people from smoking, perhaps new research showing that smokers are 70 percent more likely to need a root canal than nonsmokers will do the trick.

That’s the hope of Elizabeth Krall Kaye, a professor of health policy and health services research at the School of Dental Medicine. Kaye is the lead author of a study released yesterday that shows that the more you smoke, the greater the chance you’ll need the oral procedure whose pain and expense have become the stuff of legend.

Kaye analyzed 30 years’ worth of data and found that after smoking for 5 years, a person has double the risk of needing a root canal; after 12 years, the risk is 120 percent greater than it is for a nonsmoker. Even smokers who have been inhaling for four years or less, the research shows, have a 20 percent greater chance of needing a root canal.

Conducted through the Veterans Affairs Normative Aging and Dental Longitudinal Studies at the VA Boston Healthcare System, where Kaye is an investigator, the study followed the life of 18,893 teeth in more than 800 men. It began with data from 1968, and tracked the progress of the men’s dental and physical health over three decades.

While the study did not include women, Kaye says the results should be equally cautionary for female smokers. “Especially for young people,” she says. “I think they can relate to a root canal treatment more than lung cancer or heart disease, which is more likely to happen down the road.”

Root canals, which were once so uncomfortable that the words became synonymous with pain, are performed when a tooth’s dental pulp, the soft tissue containing nerves, blood vessels, and connective tissue, becomes inflamed. The infected tissue is removed, and the space is cleaned and filled to prevent the bacterial infection from recolonizing.

Kaye says she isn’t sure why the risk of root infection is increased among smokers, but she suspects that smoking reduces the body’s capacity to fight infection. 

The good news, she says, is that the study also shows the benefits of quitting smoking. “The total amount of time they smoked and total time they remained smoke-free was directly related to risk,” she says. The study shows that men who had not smoked for nine years had no more risk of needing a root canal than men who had never smoked.

“It’s one more reason to not start smoking in the first place, to quit, or to at least cut down,” says Kaye. “And it’s one more piece of the puzzle about how bad smoking is for your total health.”

Kaye presented the study’s findings in New York City on February 23 at the American Medical Association and American Dental Association media briefing on Oral and Systemic Health: Exploring the Connection.