Cardiovascular Disease (CVD)

      In 2008, several important studies confirmed that there was a correlation between Periodontal Disease and Cardiovascular Diseases (CVD), including Stroke and Coronary Heart Disease.  The most common cause of heart disease and stroke is Atherosclerosis.  Several studies have found that Periodontal Disease increases a number of blood proteins that circulated throughout the body.  One of these is called high sensitivity C-Reactive Protein (hs-CRP).   hs-CRP levels have been found to be more accurate predictors of heart attacks than cholesterol levels.

      Periodontal Disease can affect the risk of CVD both directly and indirectly.  When bacteria invade the gum tissues, they can also find their way into the blood supply.  This is called bacteremia.  Researchers examining the makeup of the atherosclerotic plaques that narrow arteries have found bacteria within the plaque.  Sometimes, these are the same bacteria found in the mouth and in periodontal disease!

    There is also an indirect effect.  When gum tissues are infected by bacteria, white blood cells are attracted to the area to fight the disease.  These cells release chemicals that destroy bacteria.  At the same time, the chemicals can cause the surrounding tissue to swell, become sore and red – we call this inflammation.  White blood cells also send out chemical messengers call cytokines.  Cytokines and messenger proteins like hs-CRP tell other cells and organs that there is an infection somewhere else in the body, and they should be armed and ready to fight should the infection reach them. 

      How does this affect blood vessels?  To understand what is happening here, we need to know a bit more about Cardiovascular Disease.  In CVD, affected blood vessels develop atherosclerotic plaques.  The lining of the blood vessels next to these plaques gets thin and can develop ulcer-like lesions.  When this occurs, the body reacts as it would anywhere else. Platelets arrive through blood vessels and form clot-like structures to try to keep the blood vessel from leaking.  Occasionally, these clots can break off, blocking off the blood vessel further down the line.  When this happens, it results in a stroke or a heart attack.

      Even when the result isn’t a blood clot, atherosclerosis can still be a problem.  If the width of the affected blood vessel gets too narrow, problems can also occur.  In the heart, reduced blood flow can cause angina (chest pain).  In the brain, reduced blood flow can cause problems ranging from dizziness and fatigue to confusion and impaired response.

      Let’s return to gum disease.  When bacteria invade the gum tissues, the body reacts by creating chemical messengers - cytokines - and sending them throughout the body.  In the presence of cytokines, the blood vessels in CVD become damaged more often.  This is because several of these cytokines can irritate the lining of major blood vessels.  At the same time, others can cause the clot that forms around damage blood vessels to form faster and get larger than they would otherwise.  Thus, the chance of a clot becoming large enough to cause serious problems is much greater in the presence of gum disease than it would be otherwise.

                                   

      Stroke/Cerebrovascular Accidents (CVA)

      Basis of Current Understanding: Numerous Prospective and Cross-Sectional Studies

      Strength of Statistical Evidence: Moderate

      Studies Link Periodontal Treatment to Reduction of Disease: Not Investigated

      Reported Risk:  90% to 180%

      There are two types of strokes and Periodontal Disease has been linked to both.  The first is due to rupture of a blood vessel in the brain. In medical circles, this is often referred to as a Cerebrovascular Accident or CVA  When a blood vessel ruptures, it deprives the area it supplies of oxygen, and so the tissues cannot function.  The blood from the wound also causes swelling, and this affects the surrounding brain cells.

      The most common condition underlying CVA strokes is high blood pressure (hypertension).   When a blood vessel becomes weak, it can burst, just due to the force of the blood flowing through.  When blood pressure becomes elevated, this makes it more likely to exceed the limits of the weakened vessel.

      Periodontal Disease can influence this situation.  We know that certain cytokines, especially Tumor Necrosis Factor-α (TNF-α) can cause irritation and thinning of blood vessel walls.  Several studies have shown that cytokines like TNF-α are elevated when gum disease is present.  Statistically, the incidence of CVA-type stoke is higher in study participants with periodontal problems.

      The second type of stroke is due to the blockage of one of the arteries in the brain.  The blocked artery stops supplying blood to an area of the brain and the cells can no longer function.  Blockage of the artery can be of local origin due to Atherosclerosis or can be of remote origin due to a clot, called an embolus, as it travels along the blood vessel.  In this situation, a blood clot breaks off “upstream” and gets stuck in a smaller blood vessel.  If the vessel is in the brain, we call it a Stroke.  Studies have provided evidence of direct and indirect mechanisms through which gum disease can influence the risk of atherosclerosis and stroke. 

      For a more complete discussion on the biological basis of gum disease and atherosclerosis, please see the general section on Cardiovascular Disease (CVD).

 

      Coronary Heart Disease (CHD)   

      Basis of Current Understanding: Numerous Prospective and Cross-Sectional Studies

      Strength of Statistical Evidence: Moderate

      Studies Link Periodontal Treatment to Reduction of Disease: Not Investigated

      Reported Risk:  115% to 360%

      Atherosclerotic Coronary Heart Disease (ACHD) is the most common of the Coronary Heart Diseases.  Included in this group are heart attacks, called Myocardial Infractions (MI’s) by the medical community, and Angina Pectoris (AP).  In Angina, one or more of the major blood vessels supplying the heart is narrowed due to atherosclerosis.  During times of activity, the heart cannot get enough oxygen to function properly, and this triggers a pain response.  Fortunately, in most cases, Angina can be alleviated with medicines before irreversible heart damage has been done.  However, Angina can be debilitating, limiting lifestyles severely.

      Unlike Angina, a Heart attack, or myocardial infarction, can occur even without signs or symptoms before hand.  This is because the blood vessel may have significant atherosclerosis, but still be open enough to allow the heart to operate without too little oxygen.  Everything seems to be OK until a blood clot or embolus breaks off from a wound in the artery wall and travels down stream until it gets lodged in the artery as it narrows.  When this happens, the tissues served by the artery cannot function and the heart can stop beating properly.  Several studies have provided evidence of a relationship between Periodontal Disease and Coronary Heart Disease, Myocardial Infarction and Angina Pectoris. 

      For a more complete discussion of the mechanisms thought to underlie this relationship, please see the general section on Cardiovascular Disease (CVD).