Let's look at the current predominant theory about the association between periodontal disease and coronary heart disease. In one word, the link boils down to this: Inflammation.
Inflammation happens when the immune system kicks in to fight off something foreign such as a virus or bacteria. It's supposed to do that, and it helps to keep us healthy. Sometimes, though, the immune system overreacts, and when this is chronic it can cause problems such as allergies, asthma, rheumatoid arthritis, and other autoinflammatory and autoimmune diseases. Inflammation may also be responsible for other chronic conditions, such as depression, cancer, diabetes and heart disease, among others.
Inflammation is linked to atherosclerosis, a form of heart disease characterized by a hardening of the arteries, but it remains unclear whether or not the inflammation is systemic (throughout the whole body) or local. Inflammation's role in periodontal disease is still unfolding, but studies have shown that when plaque isn't frequently removed from the surface of the teeth and the gumline, the bacteria in it releases toxins that cause infection and inflammation in the gums -- inflammation that can become chronic and systemic if not treated. Researchers have found that the same bacteria present in gum disease is also present in the fatty plaques that cause growth of blood vessel walls and harden carotid arteries, suggesting a link between the two diseases. According to the American Academy of Periodontology, research has also found that people with periodontal disease are almost twice as likely to have heart disease, when compared to people with healthy, firm, pink gums [source: Griffin].
Proper brushing and flossing in addition to semi-annual visits to the dentist are your best defense against developing gum disease. And while you can't know for sure if the bacteria responsible for your periodontal disease caused your atherosclerosis or vice versa, you can ask your doctor to test the level of inflammation present in your body. The body normally makes a protein called C-reactive protein (CRP) and the level of that protein increases if there is swelling anywhere in the body. The test is able to assess if CRP levels are higher-than-average in your blood, and while it isn't a diagnosis, it can be an indication that you need follow-up screenings.