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The mouth is a gateway to systemic infection: The role of oral health in transplant patients

Jan. 18, 2024
Bacteria in the mouth can enter the bloodstream and cause infections throughout the body. Learn more about the critical role oral health plays in the lives of transplant patients, who are at particular risk of oral-systemic complications.

Good oral hygiene is an essential part of the basic management of kidney and liver disease. Oral health care is particularly important for transplant patients as they are often at increased risk of oral infections and their associated complications.

Health of the kidneys and liver is closely linked to the well-being of the whole body, and oral health also affects the functioning of these organs. Poor oral health can increase the body’s risk of inflammation and reduce overall immunity, which in turn can negatively affect the management of kidney and liver diseases.1

Dr. Jukka Meurman, professor emeritus of oral and maxillofacial diseases at the Helsinki University Hospital, says, “Kidney and liver diseases and their treatments are often associated with a weakening of the body's defense mechanisms, which can make any infection dangerous. This is especially true if patients are prescribed immunosuppressive medication, as is always the case after transplantation.”

Inflamed gums provide a direct route for bacteria in the mouth to enter the rest of the body. “From the mouth and teeth, bacteria can easily enter the bloodstream through gingivitis, periodontitis, caries cavities, and mucosal ulcers. Infections of the mouth are harmful because they result in a low-grade inflammatory condition, at worst involving the whole body,” Meurman continues.

Oral infections are particularly harmful for chronically ill people—including those with diabetes, rheumatic and kidney diseases, defense system disorders, and patients on immunosuppressive medication. Recent research suggests that dental infections may even increase the risk of cancer.2,3 Chronic inflammation is a factor.

You may also be interested in … Poor oral health and oral dysbiosis: A link to systemic diseases and cancer

Preventing the risk of bacteremia 

Bacteremia is a bacterial infection that occurs when bacteria entering the bloodstream trigger the body’s defense response. In worst cases, it can trigger damage to one or more organs, which is called sepsis.4 The risk of bacteremia is higher in people with long-term conditions.

Bacteria can enter the bloodstream from inflamed areas of the oral cavity during toothbrushing, flossing, or dental procedures. In most cases, bacteremia is short-lived, and the body can fight it off. However, a weakened immune system or recurrent bacteremia can cause more serious problems.

Dr. Meurman says, “In chronically ill patients, every effort should be made to prevent bacteremia. Oral health is crucial, as the mouth is the most common source of normal bacterial growth in the body. Mucous membranes, teeth, and gums must be kept in healthy condition through daily effective oral hygiene maintenance.”

Studies have shown that in patients at risk of heart disease, bacteremia resulting from dental procedures is one of the causes of bacterial endocarditis, an infection that affects the endocardium, the inner membrane of the heart, and can be particularly serious in people with compromised immunity. This infection can damage the heart valves and requires immediate treatment.5

Aiming for an infection-free mouth

At the time of transplantation, the teeth and mouth must be healthy and free of infection. Oral health also impacts recovery from surgery. Transplant patients are at risk of infection for the rest of their lives, so it is essential that they strive to maintain good oral hygiene every day, and all available methods should be put in place well in advance of any surgery.

Oral infections and their resulting distant infections can be fatal for surgical and chronically ill patients. All oral and dental infections should be diagnosed and treated before transplant surgery. This often involves extraction of infected teeth with poor prognosis. Deep cavities or deep periodontal pockets must be removed.

On the other hand, radical solutions are not always necessary before surgery. A transplant patient’s treatment plan is individual and influenced by the patient’s own motivation to maintain good oral health. If the transplant is not planned for many years, more tooth-preserving and restorative treatments are possible, and tooth extractions can be avoided.

“The basic idea is, of course, that the mouth and teeth should have always been kept in good condition by careful and regular oral hygiene practices, rather than reacting only when there is a need for radical treatments,” says Dr. Meurman.

You may also be interested in … Oral-systemic health link: Tips for a healthy body and a happy smile

Deep gum pockets are nests for bacteria

“In addition to health and general well-being, maintaining good oral health also affects the patient’s quality of life. A painful mouth, dental problems, and other oral health issues can reduce quality of life and increase stress, which in turn can have a negative impact on general health and treatment outcomes for an underlying disease,” Dr. Meurman adds.

Regular dental checkups and careful oral hygiene practices are an important part of comprehensive health care for people with kidney and liver diseases. Taking care of oral health and working closely with dental professionals is particularly important for patients taking immunosuppressive drugs, which weaken the immune system’s ability to fight bacteria in the mouth and increase the risk of oral infections such as gingivitis and periodontitis. Immunosuppressive medicines can also cause changes to the mucous membranes, such as mouth ulcers and xerostomia, increasing the risk of caries.

Periodontal disease is a persistent companion

Signs of periodontal disease include reddened and bleeding gums and bad breath. In people with periodontal disease, the fibers that attach to the tooth are destroyed. A pocket begins to form between the gum and the tooth and can extend around the entire tooth. Gradually, inflammation begins to destroy more of the tissues that attach the teeth and eventually spreads into the jawbone. Once established, periodontitis is a tenacious companion that will progress if not treated carefully. Daily oral home care plays an important role in periodontitis and oral health in general. Regular dental checkups, daily toothbrushing and cleaning of the interdental spaces, and maintaining oral moisture balance are important measures to maintain oral health.

But traditional oral hygiene methods are not always enough to keep the mouth healthy. Flossing or brushing may be difficult due to age or disability, leaving the spaces between the teeth uncleaned. Even if brushing is successful, studies have shown that an effective electric toothbrush only removes about 65% of the harmful bacteria in the mouth.6

To tackle this residual plaque, which is invisible to the naked eye, Finnish researchers have developed an antibacterial teeth cleaning method based on antibacterial photodynamic therapy. The method kills both bacteria causing tooth decay and bacteria that cause gingivitis. The device has been recommended by the Finnish Association of Oral Hygienists, but it is not yet available in the US.7

More about Dr. Jukka Meurman

Dr. Meurman is professor emeritus of oral infectious diseases at the University of Helsinki and head physician in the department of oral and maxillofacial diseases at the University of Helsinki and Helsinki University Hospital in Finland. He is the author or coauthor of hundreds of peer-reviewed original research publications and several textbooks and textbook chapters focusing on the various aspects of oral and systemic health and oral microbiology. Dr. Meurman has a special interest in probiotics, a new research area he pioneered in the early 1990s, and in Candida infections.

Editor’s note: This article first appeared in Clinical Insights newsletter, a publication of the Endeavor Business Media Dental Group. Read more articles and subscribe.

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Nina Garlo-Melkas, MSc, is a health and science journalist who works as communications manager at Koite Health Ltd., a quickly growing health technology company and innovator in light-activated antibacterial solutions for treating and preventing oral diseases.

About the Author

Nina Garlo-Melkas, MSc

Nina Garlo-Melkas, MSc, is a health and science journalist who works as communications manager at Koite Health Ltd., a quickly growing health technology company and innovator in light-activated antibacterial solutions for treating and preventing oral diseases.