They're supposed to prevent cavities, not make them

from here and here

I can only assume that when these two felons were planning their escape from prison they spent a little too much time fantasizing about what the first thing they'd do when they got out was and not enough time planning how to stay out. I like pancakes as much as anyone, but not enough to go back to jail for.

Don't bring a toothbrush to a missile fight

from here and here (image source)

I suppose it's possible that if you throw one of these at someone it might be classified a missile, but I like to think the more probable explanation for Trump's repeated mistake is that he takes his toothbrush into the bath with him for naval play-time.