This study (from Norway) involved more than 1,000 men; nearly half of which had heart attacks. The men ranged in ages from 48 to 77.
During the study it appeared that men who had a history of heart attack were more likely to have had teeth pulled because of infection (because of gum disease, or a tooth infection.)
"When a tooth is extracted because of an infection, the bacteria get into the bloodstream. This is called a "bacteremia." The body's inflammatory response to infections may help lead to increased plaque in arteries near the heart, which can increase risk of heart attack."
Each of the men in the study was given a number. The numbers were arranged to account for factors known to increase the risk of heart attack, which included smoking, high cholesterol, high blood pressure and excess weight. Even taking into consideration these additional factors, the study claims that "men who had heart attacks were more likely to have had teeth pulled due to infection."
Source: "Community Dentistry and Oral Epidemiology" Journal