The Shiken Company of Japan is making a prototype solar-powered toothbrush, which causes a chemical reaction in your mouth, with the hopes of improving the elimination of harmful plaque and bacteria.
Dr. Komiyama designed the first model of this type of toothbrush more than 15 years ago: It contained a titanium dioxide rod in the neck of the brush, just below the nylon bristles. Any light falling on the wet rod would release electrons, which would react to the acid typically found in the mouth, helping break down plaque.
The latest model, the Soladey-J3X, works in much in the same way, except that it's twice as powerful.
The brush also has a solar panel at the base, which transmits electrons to the top of the toothbrush through a wire.