It's true that correlation does not imply causation, but you're still wrong from my experience with hygienists and dentists.

They definitely and easily see a difference seen between those who floss and brush and those who just brush.

Also, those who use Sonicare, especially when used properly around the gumlines, also tend to have healthier mouths than those who brush with an old brush.

The one thing that can throw a wrench in this whole thing is smoking. Smokers' mouths are disgusting basically no matter what.

Point being, I love research, but I trust those who put their hands in tens of thousands of mouths more than skeptics on ArsTechnica article comments.

They look in your mouth and make assumptions that fit their preconceived notions. ie: "These teeth are in good shape, this person must've followed my advice on brushing and flossing!"

You can brush your teeth like a moron 24/7, but you still won't reach between them and remove the long-term unhealthy plaque with it - it doesn't have to do anything with a profession, but it's a physical fact. Not to mention that brushing teeth ain't proper brushing as itself, since you can easily irreversibly damage and remove the gum if using wrong technique, pressure and hard brush.