Answer:  The link between your mouth and your heart has been well established for thousands of years. One recent addition to the link is less romantic - it correlates the infection of heart valves to gum disease. The culprit is bacteria in your mouth that would travel in your blood stream to your heart.

Taking good care of your teeth and gums could prevent you from having a stroke or heart attack, according to a study published in 8 February 2005 edition of the journal Circulation.1

What did the study find?
The study found a strong link between gum disease and narrowing of the arteries (a process known as atherosclerosis), which can lead to heart attacks and stroke.

What is gum disease?
Teeth are covered by sticky plaque, made up of food, bacteria and bacterial waste products. If plaque is left on the teeth the gums become irritated and may bleed when you brush. This early stage of gum disease is called gingivitis.2

If gum disease is not treated, the gums may swell, forming a little pocket around the tooth. Plaque collects in this and cannot be removed by a toothbrush. When plaque is left on the teeth it may harden to form tartar (calculus).

As time goes on the pockets get deeper, trap even more plaque and tartar and may become infected. Over time gingivitis can develop into chronic (long term) periodontitis, in which the jaw bone can become infected and damaged, causing teeth to loosen or fall out.3

What is heart disease?
Atherosclerosis is when the arteries become narrow and damaged. It happens when the arteries are clogged up with fatty deposits or the walls of the arteries become inflamed.

This narrowing can happen in the arteries that supply blood to the heart, depriving it of the oxygen and nutrients it needs to work normally. When the blood flow through an artery is stopped, a heart attack can occur.4

Arteries supplying blood to the brain can also be affected by atherosclerosis. If a blood clot becomes lodged in a narrowed artery, blood flow to part of the brain may be stopped. This is called a stroke.

What did the researchers look for?
To measure whether or not gum disease is associated with an increased risk of developing atherosclerosis, the researchers tested people for 11 bacteria that cause gum disease.

They also tested each person for three factors that point to the development of atherosclerosis:1

• the thickness of the walls of the carotid artery, a major blood vessel in the neck that carries blood from the heart to the brain (the thickness of the wall is a measure of how clogged up the artery is)
• the number of white blood cells in the blood (raised levels are associated with increased risk of atherosclerosis)5
• the amount of a protein, called C-reactive protein, in the blood (this protein is found in higher levels when there is inflammation of the blood vessels and is a good indicator that atherosclerosis may develop in the future)6

What did the researchers find?
The study looked at 657 people who had no history of heart attack or stroke.

It found that those people who had higher levels of the 11 types of bacteria that cause gum disease also had:

• increased carotid artery wall thickness
• raised white blood cell levels

However, the researchers found that the level of bacteria that cause gum disease was not linked to levels of C-reactive protein in the blood.1

The researchers also discovered that these links existed only for gum disease causing bacteria and not for all the other bacteria that can live in the mouth.1

What does this mean?
The researchers suggest that the results mean that people who have gum disease may be at a greater risk of developing atherosclerosis and heart disease.1

Although the study suggests a link between gum disease and heart disease, it does not prove that gum disease actually causes heart disease.

Why might gum disease be linked to heart disease?
Studies in the past have suggested that the bacteria that cause gum disease may increase the rate at which arteries become blocked.1

The researchers believe that bacteria can leave people's infected gums and enter the bloodstream, activating the immune system (the body's defence mechanism) and making their artery walls inflamed and narrowed.7

Another theory is that the bacteria enter the blood and attach themselves directly to the fatty deposits that are already present in a person's arteries, causing further narrowing.4

Could the increase in the risk of heart disease be due to a different cause entirely?
Other lifestyle factors are known to increase the risk of heart disease, and they are often associated with poor dental health as well. For example:

• smoking
• poor diet
• low income

Some experts do not believe that the bacteria that cause gum disease are really responsible for increasing heart disease risk. Instead, they argue that the gum disease is due to smoking, poor diet or low income and that it is these factors that are also increasing the heart disease risk.

In an attempt to answer this argument, the researchers in this study adjusted their results to take the following factors into account:1

• smoking
• body mass index
• age
• gender
• education
• race/ethnicity
• diabetes
• blood pressure
• cholesterol levels

Even after they had adjusted their results to remove the effects of all these factors, the researchers found that the presence of gum disease causing bacteria was still associated with an increased risk of heart disease.1

How can you prevent gum disease?
The best way to prevent gum disease is to maintain good oral hygiene. This means brushing your teeth twice a day with a fluoride toothpaste and regularly visiting your dentist or hygienist (see below).2

Brushing is the most effective way of removing plaque and preventing the build up of bacteria. The following tips will help you to get the most out of your brushing routine:3

• brush your teeth at least twice a day
• use a fluoride toothpaste to provide protection against decay
• use a toothbrush that's small enough to reach all around your mouth, with soft or medium synthetic bristles
• use a gentle circular action and brush all the tooth surfaces thoroughly

For more on looking after your teeth, please see our fact sheet:

Factsheet: Caring for your teeth

How often should you go to your dentist?
Even thorough brushing and flossing cannot remove every trace of plaque, so your dentist needs to check your teeth regularly and remove any tartar build up. Your dentist will advise you how often to visit.3

What are the signs that you have gum disease?
Normally, gums are pink and healthy looking. When you have gum disease your gums may be red and swollen, although sometimes they may look normal.2

Sometimes the only sign of gum disease is bleeding gums when brushing. If you find that your gums are bleeding when you brush, it is vital that you clean them more thoroughly, not less. Make sure that you clean every surface of the tooth and use dental floss or interdental brushes to clean in between the teeth.2

How is gum disease treated?
Gum disease treatment aims to remove plaque and make it as difficult as possible for it to reform. With mild gum disease, more careful brushing and flossing may cure the problem without need for further treatment.

However, once a hard layer of tartar has formed, you cannot remove it yourself. Your dentist or hygienist needs to remove it with a specialist scaling tool. He or she will also polish your teeth's surfaces to make it harder for bacteria to attach themselves. Your dentist may recommend an antiseptic mouthwash to control plaque levels in the short term but these are not used for longer than one month.2

If the infection has developed into periodontitis and deep pockets have formed that are affecting the support of the tooth, your dentist or hygienist will need to clean these regularly. It may be necessary to visit your dentist as often as every two months. Your dentist may also carry out root planning (removal of infected base around the root).2

References

1. Desvarieux M, Demmer RT, Rundek T et al. Periodontal microbiota and carotid intima-media thickness: The oral infections and vascular disease epidemiology study (INVEST). Circulation 2005;111:576-582.
   http://circ.ahajournals.org
2. NHS Direct Online Health Encyclopaedia: Gum disease.
   www.nhsdirect.nhs.uk
3. British Dental Association: Smile.
   www.bda.org/smile
4. American Academy of Periodontology. Factsheet: Heart Disease and Stroke.
   www.perio.org
5. Chong DL, Folsom AR, Nieto FJ et al. White blood cell count and incidence of coronary heart disease and ischemic stroke and mortality from cardiovascular disease in African-American and white men and women: atherosclerosis risk in communities study. Am J Epidemiol 2001;154(8):758-764.
   http://aje.oupjournals.org
6. American Heart Association. Inflammation, heart disease and stroke: the role of C-reactive protein.
   www.americanheart.org
7. Columbia University press release: Columbia study suggests brushing your teeth may reduce risk of stroke and heart attack.
   www.cumc.columbia.edu