Marijuana's Harmful Effects on the Mouth

About 8.1 million people in the United States use marijuana, also called cannabis, on a daily or almost daily basis, reports the 2013 National Survey on Drug Use and Health 1. Like tobacco, marijuana smoke contains high concentrations of many chemicals, and some of them are known cancer-causing substances. These chemicals put marijuana smokers at risk for many of the same mouth problems caused by tobacco smoking -- gum disease, dry mouth, tooth decay and oral cancer.

Dry Mouth and Tooth Decay

Using marijuana -- whether smoked or ingested -- reduces the amount of saliva produced in the mouth due to its effects on the nervous system. With frequent use, this effect can result in an uncomfortable condition called dry mouth, or xerostomia. Without sufficient saliva to wash away food and bacteria from the teeth and gums, xerostomia can cause bad breath and mouth sores. Additionally, a dry mouth promotes tooth decay and possible tooth loss if the decay is not treated promptly.

Gum Disease

Like tobacco smokers, marijuana smokers may be at risk for developing gum disease -- also known as periodontal disease. Gum disease occurs when oral bacteria are allowed to flourish in the mouth, causing inflammation of the gum tissue and bone that surrounds the teeth. Without treatment, gum disease can lead to tooth loss. Having a dry mouth due to smoking marijuana also contributes to the development of periodontal disease.

Oral Cancer

Both tobacco and marijuana smoke contain cancer-causing chemicals, including aromatic hydrocarbons, benzopyrene and nitrosamines. Marijuana users, who frequently smoke marijuana over long periods of time, have an increased risk of developing oral cancer, according to a study published in the January 2014 issue of "Cancer Epidemiology, Biomarkers and Prevention." The high temperatures of marijuana smoke when cannabis is smoked directly might irritate the oral tissues and trigger cellular changes -- potentially leading to the development of precancerous lesions in the mouth. Combined use of tobacco and marijuana may further increase the risk of oral cancer because tobacco use is a strong risk factor for this disease.

Avoiding and Treating Problems

Good oral hygiene, such as brushing with fluoride toothpaste and flossing daily, along with regular dental visits may help minimize oral complications associated with smoking marijuana. During routine checkups, dentists screen for oral cancer, check for tooth decay and gum disease, and can make suggestions on how to contend with dry mouth. Seeing a dentist promptly at the first sign of a problem can keep small problems from becoming serious complications.