Does flossing prevent heart disease?
No, although flossing is still a good idea. Over the last century there have been some scientific papers casually linking poor dental hygiene to heart disease; these have since been refuted and are not considered part of the standard of practice for medical personnel.
Heart disease is thought to be caused by several factors - insufficient muscle tone of the heart (generally due to lack of exercise), improper diet and increase pro-inflammatory states in the body. Flossing has very little to do with any of this.
However, flossing on a regular basis can help keep your teeth healthy and reduce the risk of periodontal disease, tooth loss and gum disease.