Subtle Innovation: The Brush & Rinse Toothbrush
Amron Experimental's Brush & Rinse Toothbrush is pretty much like any other toothbrush out there, except it has a slightly grooved back that redirects water from a running faucet into an easy to sip arch of water. That's it. Simple perhaps, but it does beat using your hands, or a glass to grab water after brushing your teeth.
Will the world be dramatically changed because of the Brush & Rinse toothbrush? Definitely not. But it is an interesting tiny tweak that adds functionality to the device in a subtle way.