The dental deterrent

IF the heightened risk of lung cancer, heart disease and emphysema -- to say nothing of stinky clothes -- hasn’t induced you to quit smoking yet, try this: Close your eyes and imagine the expense, inconvenience and sheer agony of having a root canal. Now, face a newly established fact: Smoking cigarettes roughly doubles your risk of needing one.

In the April issue of the Journal of Dental Research, Boston University Dental School’s Elizabeth Krall Kaye reports that cigarette smokers are, on average, 70% more likely to need root canal treatment than nonsmokers. The study, which tracked 811 men for 30 years, found that for those who smoked cigarettes five to 12 years, the incidence of root canals doubled, and after a man had smoked for more than 12 years it rose even higher.

There was some good news: After being smoke-free for nine years, a man’s risk of needing a root canal returned to the level of men who had never smoked. Also, smoking cigars or pipe tobacco was only weakly associated with a higher risk of tooth infection.

The root of the problem may lie with the known, immune-damping effects of cigarette smoking, say the authors. Root canals are necessary when a tooth’s internal soft tissue becomes infected and inflamed. Smokers are more likely to get cavities in the first place, and their habit may make them more susceptible to infection arising from those cavities.