Smoking Makes Root Canals Likelier

People Who Smoke at Least 12 Years Most Vulnerable

Medically Reviewed by Ann Edmundson, MD, PhD on February 23, 2006
From the WebMD Archives

Feb. 23, 2006 -- New research shows that smokers are more likely than nonsmokers to get root canals.

Root canals are done when a tooth's dental pulp -- which includes nerves, blood vessels, and connective tissue -- becomes infected and inflamed. The infected tissue is removed, and then the hollow area is cleansed and filled to prevent the infection's return.

Elizabeth Krall Kaye, PhD, MPH, and colleagues reported their findings in New York, at a media teleconference organized by the American Medical Association and American Dental Association.

"Our study has shown that men have almost twice the risk of having root canal treatments if they smoke cigarettes, compared to men who never smoke," Kaye said, in the teleconference.

Kaye is a professor in the department of health policy and health services research at Boston University's Goldman School of Dental Medicine.

About the Study

Kaye's team got data from a study of 811 men who were followed for up to 28 years. The study started in the late 1960s and early 1970s. Back then, the men were about 48 years old, on average. The men were mostly middle-class whites.

Every three years, the men got their teeth examined and had dental X-rays taken at the study site. The men also reported their smoking habits.

A total of 230 men had never smoked. Another 440 men were former smokers. Most of the smokers smoked cigarettes. Few smoked pipes or cigars.

The researchers checked the X-rays to see if root canals had been done. They spotted 998 teeth that had root canals done on them. Those teeth belonged to 385 men, so many men got more than one root canal.

Reduce the Odds of Root Canal

Among current smokers, those who had smoked for more than 12 years were most likely to have a root canal. Current smokers who had smoked for fewer years had a lower risk, but they were still more likely than nonsmokers to have root canals.

Pipes and cigars weren't linked to high odds of getting root canals. But there wasn't much data on those smokers, Kaye's team notes.

Quitting cigarettes -- and staying smoke-free -- helped, the study shows.

"There is good news from this study for people who do smoke, and that is that if you quit, your risk of root canal treatment will go down," Kaye says. She notes that men who quit cigarettes for nine or more years were about as likely as lifelong nonsmokers to get root canals.

Dentists' Role

All dentists should ask their patients if they smoke and want to quit, Kaye notes.

"Dentists can provide the nicotine patch and other types of cessation products, and they can refer them to smoking cessation clinics and programs," she says. "I think it should be a part of every dentist's program."

The X-rays don't show why cigarette smokers were more likely than nonsmokers to get root canals. "We couldn't in this study determine what the biological mechanisms might be," Kaye says.

She and her colleagues describe several possibilities in their report:

  • Smoking makes it harder to fend off infections.
  • Smoking increases inflammation.
  • Smoking damages the circulation system and lowers oxygen levels.

Kaye also points out that the "dose-response" findings of this study strengthen the case that smoking is a cause of dental disease. The men who smoked the most had the highest number of root canals, and the nonsmokers and those that had quit the longest had the least.

The findings probably apply to women, Kaye says. "Perhaps it might be harder to detect, because at least historically, women haven't smoked as long or as much per day as men have, but I think the risk would still be there."

Show Sources

SOURCES: Kaye, E. Journal of Dental Research, March 24, 2006; online edition. Elizabeth Krall Kaye, PhD, MPH, professor, department of health policy and health services research, Boston University's Goldman School of Dental Medicine. News release, American Medical Association.
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