Surprising Ways Mouth Bacteria Impacts Our Health

When I was a child, my mother had to have gum surgery because she had periodontitis, a serious condition of the gums surrounding the teeth.  The way she described it horrified me.   She had to healthy gum tissue removed from one part of her mouth and the tissue was then grafted onto the diseased area.  She showed me the stitches holding the grafted gums in place.  Awful!

Because of this, I always maintained a healthy fear of gingivitis.  But recent studies have given even more reason to fear the disease than merely a painful and unpleasant surgery.

Recent medical evidence has revealed that bacterial infection and inflammation in the mouth are actually associated with seemingly unrelated health problems in other parts of the body including:

• Heart disease
• Dementia
• Rheumatoid arthritis
• Premature birth
• Alzheimer’s Disease

What is Periodontal Disease?

We all have bacteria living in our mouths.  Certain harmful bacteria stick to teeth and form plaque, which can harden to tartar.  If plaque and tartar remain on teeth long-term, they can cause inflammation of the gums – also known as gingivitis.  Inflammation is part of the body’s immune response to something that is harming it and if gums are inflamed they will appear red and swollen.  Mild inflammation helps the body to heal, but chronic inflammation can create even more inflammation, which can further harm the body. If you have gingivitis, your gums become red and swollen and will bleed easily with vigorous brushing or flossing. Gingivitis is a milder form of gum disease that can be reversed with good oral hygiene, reducing the harmful bacteria in the mouth and regular dentist visits.  However, if the condition is not treated, it can cause tissue and bone damage and eventually even tooth loss.  This form of the disease is called periodontitis.  About half of all adults have some form of gum disease.

Periodontitis is the form of the disease that my mother had.  With periodontitis, the gums loosen away from the teeth and form pockets around them.  Bacteria and plaque can then get beneath the gums through the pockets.  When this happens, it triggers the bodies’ natural immune system to fight the infection. Both the bodies’ immune reaction to the gum disease and the toxins that the bacteria produce can weaken the structures in the mouth that hold your teeth in place.  When this happens, tooth loss occurs.  The number of bacteria in the mouth can increase up to 10,000 times (!) in a mouth with periodontitis compared to one without.

Interestingly, gum disease and periodontitis can be contagious – the bacteria that cause these conditions can be spread from one person to the next over an extended period of exposure, such as living together.  But don’t worry too much, a quick kiss or sharing a spoon over a romantic shared ice cream sundae should not spread the disease. But, please, no sharing of toothbrushes!

How do I know if I have Periodontal Disease?

If you visit your dentist regularly, your dentist will tell you if you have gum disease.  If you haven’t been to the dentist recently, any if any of the following sound familiar, you should quit making excuses and get in to see your friendly neighborhood DDS:

• Persistent bad breath unrelated to what you’ve eaten
• Red or swollen gums
• Sore gums
• Bleeding gums when brushing
• Bleeding when flossing (when you do!)
• Pain with chewing
• Loose teeth
• Sensitive teeth
• Receding gum line (your teeth appear longer than they used to)

Periodontal Disease and Other Conditions

There is some surprising evidence that shows that the dangers of gingivitis and periodontal disease extend beyond the mouth, as the bacteria and inflammation associated with it spread throughout the body.  This is a new area of research, and findings are still emerging. Gum disease has now been linked to heart attack, stroke, rheumatoid arthritis, Alzheimer’s and even risk of miscarriage.

Heart Disease

Periodontal disease and atherosclerotic cardiovascular disease (CVD) (a condition causing hardening and clogging of the arteries and that is leading cause of heart attacks and strokes) are two of the most common diseases in adults in the US. CVD disease is the biggest killer of adults in the US.  The two diseases, surprisingly, appear to be associated with one another.

The American Heart Association (AHA) has analyzed numerous current observational clinical studies on the link between periodontal disease and heart disease and has concluded that oral health and general health are related.  They have stated that, “studies have found an association between the two diseases that cannot be explained by the common risk factors.”  The AHA has suggested that since periodontal disease increases inflammation, both in the mouth and in the rest of the body, this increased inflammatory burden on the body may cause or worsen cardiovascular disease. The AHA has called for further research to determine if there is a cause and effect relationship between Periodontal Disease and CVD.  In other words, does one cause the other, or are they just correlated and commonly are found together?

A recent study published in the Journal of the American Heart Association found that the health of your mouth may influence the health of your arteries and thus your heart.  One of the researchers in the study, Moïse Desvarieux, M.D., Ph.D. from Columbia University’s Mailman School of Public Health, stated, “These results are important because atherosclerosis progressed in parallel with both clinical periodontal disease and the bacterial profiles in the gums. This is the most direct evidence yet that modifying the periodontal bacterial profile could play a role in preventing or slowing both diseases.”  This is a fancy way of saying that reducing the number of bad bacteria in your mouth may improve, not only your periodontal disease, but also prevent or improve hardening arteries.

The study followed 450 adults over three years.  They evaluated the amount of eleven strains of bacteria associated with periodontal disease that were present in their mouths at the start of the study and then at the end of three years.  The researchers found that for those participants who had improved gum health and a decrease in the number of harmful bacteria at the end of the study, they also had healthier arteries than they did at the start of the study. For those whose gum health had deteriorated and had increased numbers of harmful mouth bacteria, their arteries had worsened.  The implication is that the bacteria causing periodontal disease are actually worsening or even causing hardening of the arteries and that treating periodontal disease will contribute to the health of your arteries.

Other studies have shown that treating periodontal disease can improve the markers associated with cardiovascular disease (CVD).  This is extremely exciting as it suggests that improving oral health is another potential way to improve heart health in addition to stopping smoking, exercise and eating well.

Stroke

Because CVD is also a cause of stroke, it is not surprising that a study that examined stroke found that patients who had had acute cerebrovascular ischemia (stroke) were more likely than the rest of the adult population to have a current mouth infection.  The American Heart Association has concluded that gingivitis is an independent risk factor for stroke for men and younger subjects.  Additionally, the AHA found that the worse the periodontal disease, the greater the risk of stroke (cerebral ischemia).  Those suffering from severe gum disease had four times more strokes than those with relatively healthy mouths!  Why this is the case, is not yet fully understood.

Miscarriage and Premature Birth

Pregnancy can cause gingivitis.  Gums swell when you are pregnant.  I was diagnosed with pregnancy-induced gingivitis, but it cleared up on its own after my son was born.

This may because the hormones associated with pregnancy spur bacteria growth, which causes gum disease.  Pregnancy hormones are like bacteria fertilizer – ugh!  It may also be that the body becomes more sensitive to the toxins that are produced by these bacteria, causing to gums to get inflamed more easily during pregnancy.

The Journal of the American Dental Association found that expectant mothers with chronic gum disease were 4 to 7 times more likely to give birth prematurely than others.  Moreover, expecting mothers with the most severe gum disease gave birth the earliest of those evaluated.1  Strange and a bit scary, right?

The British Dental Journal has reported a study that found that the risk of miscarriage between 12 and 24 weeks is increased in pregnant women with periodontal disease.

A common cause of pre-term births, generally, is infection.  Certain bacteria associated with periodontal disease, such as F. nucleatum, have been shown to be able to infect the uterus and actually cross the placenta and enter the amniotic fluid.  Pregnant mice had premature delivery and stillbirths when their uteruses were infected by researchers with the bacteria.  So much for no animals being harmed in that research study…

In addition to the infection caused by gum disease bacteria entering the uterus directly causing miscarriage, pre-term births and stillborn babies, scientists also suspect that the increased inflammation in the body associated with periodontal disease might be stressing the pregnant mother’s body and causing some of the miscarriages and preterm births.

Arthritis

There is a wide body of research linking various types of arthritis to the bacteria that cause gum disease.  Patients with rheumatoid arthritis in a study conducted in Germany were more than 4 times as likely than the healthy patients in the control group to have P. gingivalis in the joint fluid in the diseased joints.  So what? Well, guess what? P. gingivalis is the very same bacteria which is a main culprit in periodontitis.

Additionally, for young patients who were recently diagnosed with arthritis, they had higher levels of periodontal disease than the control patients in the study.  Researchers also found that the higher the level of the P. gingivalis, the more severe the rheumatoid arthritis.

As with other conditions associated with periodontitis, it is not yet know which comes first, the oral infection or the rheumatoid arthritis.  There is some exciting evidence, though, that for patients suffering from severe cases of rheumatoid arthritis, treating their mouth disease improve their arthritic symptoms.

Alzheimer’s

A recent study in the Journal of Alzheimer’s Disease, found bacteria which are typically associated with periodontal disease in the brains (!) of people who had been diagnosed with Alzheimer’s Disease.  Four out of ten brains with Alzheimer’s had P. gingivalis in them, versus zero found in non-diseased brains examined as part of a study.  However, there is not enough evidence to prove that these bacteria actually cause or worsen Alzheimer’s disease, it may just be that in brains that are diseased, it easier for the bacteria to travel to and enter the brain.

According to a study written up in the Journal of Alzheimer’s Disease, what those researchers currently believe is that the bad oral bacteria can leave the mouth and enter the blood stream, particularly after eating, chewing, tooth brushing and having invasive mouth surgeries, and then can enter the brain.  Once there they can trigger an immune system response and release chemicals which damage neurons.  Researches suggest that these brain changes can lead to Alzheimer’s Disease.

Additional research is underway to examine whether these periodontal disease causing bacteria have a causal relationship with Alzheimer’s and whether treating periodontitis can slow Alzheimer’s progression. Regardless, just the possibility of reducing the progression or severity of Alzheimer’s Disease is all of the motivation that I need to maintain a healthy mouth.

Preventing Gingivitis and Periodontitis

Having red inflamed gums, bad breath, risk of painful gum surgery and losing your teeth seem like reasons enough to keep your mouth healthy.  But with the potential for unhealthy mouth bacteria to also cause or worsen heart attack, stroke, rheumatoid arthritis, miscarriage and Alzheimer’s, it becomes very clear that preventing and treating gum disease is necessary to maintain overall health.

Certain people are more susceptible to gingivitis and periodontal disease than others.  Thirty percent of people are genetically susceptible to gum disease. Furthermore, as people age, their risk of periodontal disease increases.  Certain fillings or dental implants can cause create long-term safe harbors for bad bacteria to grow and colonize over time.

However, there are risk factors that can be controlled to reduce the chance of getting gum disease.

• Have your wisdom teeth removed or checked for signs of disease.
• Stop smoking!
• Floss.
• Keep your blood sugar within normal limits to reduce the chance of severe periodontal disease that is associated with diabetes.
• Lose weight, wich believe it or not can help prevent periodontal disease.

Maintaining the health of your mouth is of critical importance to preventing bad bacteria from taking hold.  Brushing, flossing, going to the dentist regularly and eating a well balanced diet are obvious steps to take.  If you see signs of gum disease, it makes sense to treat them promptly before they get worse.

Probiotics

People are starting to explore the possibility of whether promoting healthy bacteria in the mouth can decrease the number of bad oral bacteria. Some foods, such as yoghurt, soy and milk contain probiotics. There are oral probiotic lozenges on the market.

Our periodontist was skeptical about whether they work, but my husband, who has had bouts fighting tonsil stones and complained of pesky, annoying and smelly throat mucus has tried them anyway.  In his unscientific opinion, he felt that his mouth seemed a lot fresher, with less phlegm.

The theory behind why probiotics might help is that the beneficial bacteria will outcompete the harmful bacteria for places to adhere to in the mouth, reducing their ability to take hold and cause disease in the mouth.  Probiotics may also create a biofilm on the gums, which can protect them against harmful invaders.  Another way they may be helpful is that certain bacteria actually secrete antimicrobial substances that can harm or kill the bad bacteria. Finally, the helpful bacteria may reduce inflammation in the host and since inflammation can be the cause of other diseases, this is a good thing.

There have been studies that show that probiotics are beneficial in the fight against gum disease. High levels of Lactobacillus species (L. gasseri and L. fermentum) seem to inhibit P. gingivalis (one of primary bacteria that cause periodontitis) in the mouth.  Other studies have shown that patients with gingivitis saw their disease improve2 after taking lozenges or chewing gum3 containing probiotics.

This has very exciting implications for our efforts to stay healthy.  I look forward to seeing how the research in the area of oral health and disease prevention evolves.  It is exciting to think that we can become proactive in managing our mouth bacteria and have such profound impacts on our overall general health.

What do you think?  Please share your comments below.

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1. Journal of the American Dental Association 132 (7): 875–880. PMID 11480640 [↩]
2. Riccia DN, Bizzini F, Perilli MG, Polimeni A, Trinchieri V, Amicosante G et al. Anti- inflammatory effects of Lactobacillus brevis (CD2) on periodontal disease. Oral Dis. 2007;13(4):376-85. [↩]
3. Koll-Klais P, Mändar R, Leibur E, Marcotte H, Hammarström L, Mikelsaar M. Oral lactobacilli in chronic periodontitis and periodontal health: species composition and antimicrobial activity. Oral Microbiol Immunol. 2005;20(6):354-61. [↩]