Stroke

Cerebrovascular accident (CVA), commonly referred to as a stroke, occurs when brain cells die due to a lack of oxygen resulting from an artery in the brain becoming blocked (ischemic stroke) and/or rupturing (hemorrhagic stroke).³⁴ Of the two, ischemic strokes are the more common.⁵⁴ The common risk factors include hypertension, diabetes, smoking, obesity and drug use.⁵⁵ In a Japanese study conducted in 2016, researchers found that there was an increase (26%) of collagen binding protein, cnm- positive Streptococcus mutans in those with hemorrhagic stroke as compared to 6% in ischemic stroke.⁵⁶ In a more recent study, there was a correlation between C-reactive protein and moderate-severe periodontitis and ischemic stroke.⁵⁷ There has even been an association between S. mutans and several types of cerebrovascular events, such as hemorrhage and aneurysms.⁵⁸

The evidence for a causal or correlative relationship between oral bacteria and stroke is still emerging and does not appear to be as strong. However, because strokes represent vascular injury it can be postulated that inflammatory conditions, such as periodontitis, can have an impact on vascular integrity due to hypertension and atherosclerosis of weakened vessels.³⁵ Research is currently being undertaken to fully understand the role oral bacteria plays in cerebrovascular events, such as strokes, which are known to have multifactorial causes. It can be inferred that periodontitis may be a risk factor for strokes when combined with other more well described risk factors.