Marijuana may increase gum disease


Frequent use of marijuana may triple the risk of severe gum disease, a study suggests. Tobacco already was known to raise the risk of periodontal disease. This is an infection of the gums and other tissues that support the teeth. It can lead to tooth loss. Researchers in New Zealand wanted to know if marijuana had a similar effect. The study included 903 people. Some had smoked marijuana an average of almost once a week for about 15 years. They were three times as likely to have severe gum disease as nonsmokers of marijuana. Reuters Health news service reported on the study on February 5, 2008. It was published in the Journal of the American Medical Association.1

What Is the Doctor's Reaction?

Controversy surrounding marijuana is nothing new. Some say that marijuana has medical uses. They argue that it's acceptably safe and effective for nausea, cancer, HIV-related weight loss and glaucoma (among other conditions). Some suggest it should be legalized. They point out that alcohol and cigarettes, though legal, have the potential to cause more serious health problems than marijuana.

On the other hand, there is convincing evidence that links smoking marijuana to the following:

  • Reduced coordination

  • Lower motivation

  • Withdrawal symptoms

  • A higher rate of car accidents

  • Lower sex drive

Other possible health effects include an increased risk of lung cancer and other lung disease, male infertility, schizophrenia and depression.

We still don't know all of the ways that marijuana can affect your health. A new study suggests that it may cause problems in an unexpected part of the body: your teeth and gums.

Researchers in New Zealand assessed the oral health and marijuana use of more than 900 people at age 18. They repeated these assessments every few years until age 32. The group that smoked marijuana most often used it an average of 41 times a year. This group also had the highest rate of serious gum (periodontal) disease.

About 1 in 5 people in the study were in this high-use group. Nearly one-quarter of them had significant gum disease. The rate among nonusers of marijuana was only 6%.

The researchers also looked at other factors that can increase the risk of gum disease. These include smoking cigarettes, having plaque on the teeth, and not having regular dental visits. Even after accounting for these other risks, the strong link between marijuana and gum disease remained.

This news may not do much to discourage marijuana use among young, healthy people. Then again, a young adult who has periodontal disease might think twice about continued use.

There's at least one more implication of this research. A dentist or periodontist seeing teenagers or young adults with unusually severe gum disease might want to ask about marijuana use. This can provide a chance to describe marijuana's possible links to gum inflammation, infection and tooth loss.

What Changes Can I Make Now?

Gum disease may affect more than your teeth and mouth. A growing body of evidence links gum disease with other health problems. These include:

  • Cardiovascular disease — Gum disease may increase the risk of heart attack and stroke. It may be that gum disease causes enough inflammation in the body to cause damage to blood vessels.

  • Premature births — Pregnant women with gum disease may have a higher risk of delivering babies that are premature or have a low birth weight.

  • Diabetes, rheumatoid arthritis and HIV infection — People with these conditions appear to have a higher rate of gum disease. In addition, diabetics tend to have more trouble controlling their blood sugar if they also have periodontal disease.

Just why gum disease is associated with these other problems is not well understood. Whatever the reasons, it makes sense to take care of your teeth and gums. Here are some of the most important changes you can make now:

See your dentist regularly for cleanings and advice about oral hygiene. Do your best to follow his or her advice. This is especially important if you have a family history of gum disease or if your gums swell and bleed when you brush or floss. These can be signs of gingivitis, an early stage of periodontal disease.

Don't smoke cigarettes (or anything else).

Consider orthodontics (such as braces) to straighten out crooked or crowded teeth. This can make it easier to brush and floss effectively. Better dental hygiene can lower your risk of gum disease.

If you grind your teeth, talk to your dentist about a mouth guard. Grinding your teeth may increase the risk of tooth loss from existing gum disease.

Ask your dentist or doctor about the medicines you take. Some may cause a reduction in saliva. That can lead to plaque formation, which increases the risk of gum disease. Common culprits include pills for depression and high blood pressure. Other medicines can cause gum swelling. This can make it harder to remove plaque. Phenytoin (Dilantin) and cyclosporine (Neoral) are examples.

What Can I Expect Looking to the Future?

Much is known about gum disease. But it's still not entirely clear why some people have it and others do not.

Genes are thought to play an important role. You can expect researchers to identify genes that increase the risk of gum disease. This could lead to a better understanding of how it develops. People who carry the high-risk genes also could be given more aggressive dental care, such as frequent cleanings.

You also can expect more research on the health effects of marijuana use, including its impact on the teeth and gums. Marijuana is the most commonly used illegal drug in the United States. Its popularity is increasing. So it's unlikely the controversy over marijuana use will end anytime soon.


Murray Thomson W. et al. “Cannabis smoking and periodontal disease among young adults.” Feb. 6, 2009. Journal of the American Medical Association.

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