Oral hygiene practices have no correlation to oral cancer. However, statistics can be manipulated anyway that you like. There have been several studies published decades ago showing that people who practice unhealthy lifestyles, (which might include smoking, drinking, eating too much fat, not getting enough exercise, and on and on) have higher disease rates including cancer. Another study suggests that if you do not practice good oral hygiene you are probably lax in the other categories of taking care of yourself as well. While you could extrapolate between these studies a correlation between poor oral health and increased cancer risk, it would require a couple of leaps of logic, that are not considered in the studies. That a hospital would put out an old wives tale does not surprise me much, I see it all the time, and the web is full of it. We are all the architects of our own situations, whether by choices or by genetic make up, or some combination of the two. The best that you can do in life is try to avoid those things that are KNOWN to have severe health risks, and then hope that your genetic make up will take care of the rest. Surely if you eat a diet high in saturated fat you are going to clog your arteries, and have a high chance of getting a heart attack or stroke. If you smoke or chew tobacco you are exposing yourself to over 400 carcinogens