Chronic oral infection: An emerging risk factor of cerebral small vessel disease

Chronic oral infections (gingivitis/periodontitis) have been associated with age-related diseases such as diabetes, coronary heart disease, and acute ischemic stroke. In addition, imaging surrogates of cerebrovascular ischemia beyond acute ischemic stroke (i.e., silent strokes and brain white matter hyperintensities) may also be associated with chronic oral infections. The pathology underlying lacunar strokes and brain white matter hyperintensities (WMH) relates to small vessel disease in the brain. In this review, we highlight recent progress in exploring potential associations of oral infections with cerebral small vessel disease and its surrogates (silent strokes, white matter hyperintensities) and clinical sequelae (i.e., vascular dementia). Recent evidence suggests that periodontitis aggravates cerebral small vessel disease and increases lacunar stroke risk. Moreover, periodontitis interacts with Alzheimer's disease to increase the severity of clinical dementia and to accelerate its manifestations. The results suggest that periodontitis may be an emerging risk factor of small vessel disease-associated cerebrovascular disorders and that the risk increase may be mediated by the systemic inflammation resulting from chronic oral infections. Large cohort studies employing state-of-the-art magnetic resonance techniques to identify specific cerebral pathologies as a function of time, oral health status, and systemic inflammation are needed to further substantiate the hypothesis.