Researchers at the Harvard School of Dental Medicine in Boston, Massachusetts , followed the heart and dental health of 41,380 men between the ages of 40 and 75 for 12 years.
They had no sign of heart disease or diabetes at the start of the study.
Men who had 24 teeth or less at the start of the study were found to have a 57 per cent increase in their risk for having an ischemic stroke compared to men who had 25+ teeth. Adults typically have a full set of 32 teeth.
Tooth loss in most cases was due to gum disease or cavities.
In the past, scientists have speculated that over time, oral bacteria may slip into the blood stream and trigger inflammation in the blood vessels that feed the heart and brain.
Some, but not all, studies on the topic have suggested a history of gum disease increases the risk of heart attack or stroke.