[msteinert]

Agreed! For the causation you'll have to read the extensive literature on periodontal disease.

[run4yourlives]

Which won't help much, given that the second line in your link is: While a cause-and-effect relationship has not yet been proven

[msteinert]

Agreed, the cause and effect between heart disease and periodontal disease is not well proven. However, the beneficial effects of flossing in preventing periodontal disease is well understood and you're welcome to read the literature yourself if you don't believe me. I believe this is exactly what I said in my original comment.