We all know the expression “the eyes are the window to the soul.” As oral health professionals, we view the mouth as the window to the entire body. Studies have shown that good oral health correlates to better overall health. Contrarily, poor oral health has been linked to a long list of systemic diseases. A 2011 article in Diabetologia found a prominent link between oral health and diabetes.
How can a small cavity be linked to such serious illnesses? To understand this, we must consider the concept of a microbiome. A microbiome is a community of microbes, typically bacteria, that co-exist in a given environment. Microbiota exist in the mouth, skin, digestive tract and many other regions of the body. A 2013 article in Periodontology 2000 found that the oral cavity can contain up to 700 bacterial species. Many of these bacteria have unknown functions. Although, a few have been implicated in dental caries and gum disease. Certain bacteria are even beneficial, warding off disease by competing with pathogenic bacteria. Interestingly, many species work together for survival in the oral cavity.
The connection between oral health and systemic health relates to chronic inflammation. Chronic inflammation causes excessive damage to healthy tissue and promotes unregulated immune activity. Unregulated inflammation can lead to an increased risk of autoimmune disease. The process begins when oral bacteria gain entry to systemic circulation following injury or surgery. Bacteria in the blood stream may settle in various sites and induce an immune response (Periodontology 2000). The body produces inflammatory factors like IL-6 and TNF-alpha. These factors recruit immune cells to the site of bacterial entry and destroy infected tissues (Diabetologia). This process is non-specific, as healthy tissue is sacrificed along with infected tissue. The inflammatory immune response is beneficial in the short term. In chronic inflammation, the cells remain in the tissues for longer. As a consequence, the cells may inadvertently destroy increased amounts of normal tissue. This is a critical part of disease progression in both periodontitis and diabetes.
The Centers for Disease Control and Prevention (CDC) estimate that 30 million Americans have diabetes, while 65 million have periodontitis. Diabetes and periodontitis represent the two most prominent chronic inflammatory diseases (Periodontology 2000). There is a close correlation between periodontitis severity and diabetic complications. The mechanism behind this is the role of inflammation in creating advanced glycation end-products (AGEs). According to the CDC, AGEs are the result of excess blood sugar chemically reacting with proteins and other molecules. They are thought to be related to kidney failure, heart disease and nerve damage associated with untreated diabetes. Inflammatory diseases promote insulin resistance, enhance the effects of AGEs and lead to diabetes progression. Diabetics with severe periodontitis are three times more likely to die of kidney or heart disease. Fortunately, treatment of gingivitis lowers blood sugar and can help keep diabetes under control (Periodontology 2000). This indicates that maintaining oral health is important in controlling diabetes and reducing mortality.
Numerous studies have revealed correlations between oral health and systemic illnesses like diabetes. Unfortunately, a causal relationship has not yet been determined. By better understanding the systemic impact of oral diseases, we can provide more effective care.
~Parandis Nejati, Stony Brook ’20