From what I can see, there's no control-group, so it's showing correlation, and not causation. I read that people who floss daily live longer too. It's not bec

From what I can see, there's no control-group, so it's showing correlation, and not causation. I read that people who floss daily live longer too. It's not because they floss, but the ones who floss are more likely to have healthier lifestyles in general. This study seems to fit into the same bracket.