New evidence has linked poor brushing (and Gum Disease) with heart disease and strokes. One bacteria most recently incriminated is Streptococcus Gordonii which is one of many plaque bacteria. The mechanism is easy to understand. If your gums bleed when you brush then oral bacteria (plaque) can get into the blood stream. Once they are in, the body's defences make platelets clump around them and this little 'clot' is travelling around the body and can lodge in a heart or brain artery, occluding the vessel and killing the tissue it supplies.