Lung health may be related to having healthy teeth and gums. Perhaps it seems odd that, even in a healthy mouth, there are bacteria. However, the harmful bacteria are usually kept in check by an equal level of beneficial bacteria. 

But when the level of negative bacteria outgrows the level of beneficial bacteria, or some other pathogen gets in, the teeth, gums, and lungs can suffer. Not only can tooth decay, inflamed and bleeding gums, and other problems be blamed on an overgrowth of bad bacteria in the mouth, but also some respiratory conditions and unexplained coughs.

How Is Dental Health Related to Lung Health?

The biological mechanisms are still not entirely understood, and the relationship is not yet completely confirmed; however, research has explored the possible association between oral conditions and respiratory diseases¹. These potential methods of mouth disease spreading to the lungs include:

• Some oral bacteria can penetrate the lungs directly
• Salivary enzymes produced during periodontal disease affect the respiratory system’s lining to make it easier for infection to set in
• Hydrolytic enzymes from the bacteria that cause mouth disease reduce saliva’s ability to bind to pathogens that can cause lung disease (these normally destroyed in the stomach after swallowing), making then more likely to be aspirated into the lungs
• During tooth infection, saliva contains higher levels of inflammatory chemicals and certain types of blood cell than normal, and these may alter the respiratory tract and encourage respiratory pathogen uptake and subsequent infection

Long-term cardiac diseases have been linked to the bacteria that cause gum disease (periodontitis)². Research suggests that they enter the bloodstream through the soft tissue in the mouth and move toward the heart. This would explain why some dental plaque microorganisms frequently appear in heart valves and heart muscles. The dispersion of oral bacteria from the mouth to the lungs can be held responsible for some long-term respiratory conditions, such as emphysema (air-filled spaces in the lungs). 

The Effect of Dental Health on Lungs

Several studies have established a connection between good oral hygiene and both acute and chronic respiratory conditions, such as pneumonia, COPD, and asthma³.

Asthma 

Asthma is a common lung disease that causes inflammation and swelling in the airways. Sometimes, the production of extra mucus is also seen. It is characterized by shortness of breath, wheezing, coughing, usually in the nighttime, and tightness of the chest. 

In a systematic review, 21 research studies published between 1979 and 2017 were analyzed to investigate any link between dental health and asthma. Interestingly, this revealed two significant correlations: that asthmatics are more likely to have gingivitis and periodontitis than non-asthmatics and that the levels of gingival hemorrhage and plaque are higher in asthmatics. It was concluded that there is a link between asthma and periodontal disease⁴.

COPD

Chronic obstructive pulmonary disease (COPD) refers to illnesses that result in an inflammatory response and long-term lung damage in patients. For example, it includes emphysema and chronic bronchitis.

A study⁵ in the Journal of Periodontology suggests that COPD patients with periodontal disease may be more susceptible to respiratory infections like pneumonia. This illness results in the alveoli (tiny air sacs in the lungs) becoming filled with fluid, which produces a persistent cough and breathlessness.

Pneumonia

Pneumonia refers to the inflammation in tissues of one or both lungs caused by microorganisms such as fungi, bacteria, or viruses; the condition may vary from mild to severe.

A 2020 study⁶ suggests that tooth decay and tooth loss are on the rise, along with the prevalence of pneumonia. A lower incidence of pneumonia was linked to better oral hygiene practices, such as routine professional dental cleanings and frequent teeth brushing.

Pulmonary Actinomycosis

Pulmonary actinomycosis⁷ is a rare lung infection from bacteria typically found in the mouth and gastrointestinal system. Although these microorganisms frequently do no harm, a tooth abscess or poor dental hygiene can raise your chance of developing a lung infection brought on by these germs.

The Effects of Respiratory Diseases on Dental Health

There is a bidirectional relationship between dental health and lung health – treatment for some of the most prevalent respiratory conditions, including asthma, COPD, and sleep apnea, can impact your oral cavity and overall oral hygiene.

Lung/Throat Cancer and Taste/Smell Changes

Dysgeusia is an alteration in the body's taste sensitivity. One potential cause is cancer. Both throat and lung cancer have been linked to changes in taste and smell pre-treatment, although the particulars of the change vary: 

• Increased sensitivity to sweetness⁸, saltiness⁹, and bitterness¹⁰
• Increased sense of smell¹¹ 
• Decreased sensitivity for bitterness¹² and sourness¹³
• Decreased sense of smell¹⁴
• Aversion to certain foods (roast beef¹⁵; high-protein food, cereals, and sweet food¹⁶)

Such changes may be more pronounced if the cancer is more advanced¹⁷. 

However, not all patients with lung or throat cancer report changes in taste or smell¹⁸¹⁹²⁰, and not everyone who experiences taste and smell changes has cancer²¹.

COVID-19 and Loss of Smell/Taste

The loss of smell and/or taste is a widely reported symptom of various strains of COVID-19 all over the world²²,²³,²⁴. One meta-analysis of multiple studies found that, on average, half of COVID-19 patients in 2020 reported a sudden loss of smell or taste²⁵, and between 2020 and 2021 around 40% reported loss of taste²⁶. While normally short-lived, loss of smell or taste due to COVID-19 can last for at least seven months post-infection²⁷.

The Effect of Lung Condition Medications on Dental Health

Dry Mouth (Xerostomia)

Saliva is a barrier against microbes in the oral cavity. Some medical equipment and drugs used to treat lung ailments decrease saliva production, weakening this barrier. Since saliva helps protect teeth from microorganisms, a dry mouth might make it easier to develop cavities and gum disease.

There are more than 400 drugs that have been linked to dry mouth, including those for respiratory disorders like antihistamines, certain blood pressure and heart drugs, bronchodilators, and anti-inflammatory inhalants²⁸.

Tooth Loss

A 2020 study published²⁹ in The Journal of the American Dental Association enrolled two groups. The first group had participants suffering from COPD and asthma and the second group comprised people with generally good health. The researchers concluded that the participants with asthma or COPD had a higher odds of tooth loss of six or more teeth. This may have been due to participants with asthma or COPD being less likely to regularly visit a dentist, indicating how behavioral changes due to respiratory conditions can affect oral health.

Damage to the Enamel

Due to decreased salivary defense against extrinsic or intrinsic acids, asthma medicines can increase the risk of dental erosion³⁰ in patients. One of the higher-risk groups for dental erosion is people with asthma, due to the regular use of bronchodilators, corticosteroids and anticholinergic drugs over an extended period, which can damage teeth enamel. 

Fungal Infections

There is evidence that some respiratory medicines are associated with worsened fungus infections. Candida (oral thrush) and other fungi can spread throughout the mouth, disrupting the usual flora. For instance, one study found that asthmatics receiving corticosteroid treatment had higher levels of Aspergillus fungi than those not without asthma or not receiving steroid treatment³¹, and another found that COPD patients being treated with inhaled corticosteroids and/or long-acting beta agonists (LABAs) were more likely to develop oral thrush than those only prescribed long-acting bronchodilators³². This may be due to corticosteroids suppressing the immune system, as fungal infections, including Candida and Aspergillus³³, present more often in immunocsuppressed or immunocompromised people 

The following are examples of thrush (fungal infection) symptoms:

• Red lesions
• White patches (around the tongue, cheeks, palate (roof of the mouth), and throat.
• Pain while eating
• Corners of the mouth crack

These diseases are managed with antifungal medications, although a little infection may resolve on its own in a few days.

The Effect of Other Medications on Dental Health

Swollen Gums (Gingival Overgrowth)

Gingival overgrowth is where the gums swell or grow, and can start to overgrow the teeth. This is similar to, but different from, periodontitis³⁴ (gum disease). It can be caused by multiple factors, but when drugs cause this growth, it is called drug induced gingival overgrowth (DIGO). It makes it difficult to brush the teeth, leading to a build-up of plaque and potentially more dental health problems.

Certain blood pressure medications, immune suppressants, and anti-seizure drugs can all induce gum swelling³⁵. The best treatment is changing to a different drug that doesn’t cause DIGO; otherwise, even after surgery, the gums may continue to enlarge³⁶.

Mouth Ulcers or Sores

Unpleasant mouth sores, called oral mucositis, can be brought on by chemotherapy medications or radiotherapy for cancer³⁷. This unfortunate side effect of important medical treatment can be difficult to treat and affect the cancer therapy’s outcomes³⁸, although there are some treatments that show positive effects³⁹.

Mouth ulcers can also be caused by the much-more-common NSAIDs aspirin and ibuprofen. Asprin, in conjunction with certain microbes in the digestive system, is a known contributor to stomach and other digestive system ulcers when taken long-term⁴⁰, including mouth ulcers. Similarly, there some evidence that ibuprofen also contributes to developing ulcers in the upper digestive system, which includes the mouth, when taken long-term⁴¹.

Luckily, combining specific other medications with aspirin⁴² or ibruprofen⁴³⁴⁴ reduces the development of such ulcers.

How Can I Keep Problems With My Oral Health From Affecting My Respiratory Health?

A strong immune system helps prevent pathogens that cause inflammation in the respiratory tract. Periodontal disease (infection of bones and gums that hold the teeth) may worsen already present respiratory disorders such as asthma, chronic obstructive pulmonary disease, pneumonia, and others.

Regular dental hygiene can benefit both teeth and lungs. To prevent bacteria from spreading to the lungs, you must take care of the bacteria on your teeth and gums. Here are some ways to do that:

• Practice good oral hygiene – At least twice every day, spend two minutes brushing your teeth
• Every day, use an interdental brush, floss, or water flosser to clean in between your teeth
• Make routine appointments for dental hygiene and examinations

Ask your doctor for a different medicine if the one you're taking makes you have a dry mouth. If dry mouth cannot be prevented:

• Drink water – Water flushes food particles from between your teeth, avoids dry mouth, and can neutralize acids that corrode and wear down your teeth.
• Chew sugarless gum to promote a steady flow of saliva
• Avoid alcohol and fizzy drinks as they are highly acidic and can erode tooth enamel
• Quit smoking

Adequate oral hygiene can greatly reduce your risk of developing gum disease and cavities⁴⁵ and improve your lung health. Always discuss your respiratory problems with the dentist during the visit. Your dentist will advise you about your dental health regime according to your respiratory health condition. 

Conclusion

To sum up, our mouth carries certain microbes and bacteria, which should be cleaned often. Otherwise, debris starts accumulating in the form of a thin film. This microbial film can then lead to bad breath and infections. Oral infections can be hazardous for the lungs and especially for immunocompromised people. 

As such, one must take oral health seriously as it's a long-term commitment to have good dental hygiene. By contrast, it takes few days to destroy it when you do not follow a proper regime as suggested by the experts. Therefore, regular visits to your dentist can play a vital role in improving dental health and lung health.

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