Maintaining Good Oral Hygiene is one step to prevent Strokes; a recent study has found mouth bacteria in brain clots. Researchers from Tampere University, Finland found bacteria in blood clots of the person who received a heart stroke. The researchers found that 79% of them bore DNA from a common oral bacteria. Most of the bacteria were of the Streptococcus mitis type, which belong to a group that scientists call viridians streptococci. Using DNA evidence, scientists have shown that brain clot samples from people who have had ischemic stroke often contain mouth bacteria. According to the research, higher levels of oral bacteria were found in blood clot samples.