The ingenious feature is the handle, which works like a cross between a syringe and a deodorant stick. Fill it up with toothpaste, then when you're ready to brush, twist the bottom a few notches and toothpaste squeezes out the bristles.
Nifty. I link to this here because it reminds me of something I created when I was nine. Each of us in my fourth-grade class was charged with coming up with an idea, any idea, that would make some task simpler or easier. I, being a seeker of efficiency even then, came up with the idea of taping together two toothbrushes back-to-back, so that you could brush your top and bottom teeth simultaneously.
I'm sure at the time I thought it was the greatest idea ever. Hell, I still think it's the greatest idea ever! (OK, fine, so I didn't think it through fully, and trying to brush the sides of your teeth was, well, comical at best.)
I remember a friend's invention from the same project: glow-in-the-dark dog bowls. It was needed because, obviously, dogs otherwise would starve.