Would you like to use a light-powered toothbrush which needs no toothpaste and no batteries? It’s already available in Japan and North America and it costs about $30. Its rod contains titanium dioxide that generates a plaque-removing electrochemical reaction. This ’solar’ toothbrush of the future ‘works by releasing electrons that then react with the saliva in the mouth and help to breakdown plaque.’ It just needs some light — so you’ll be able to wash your teeth in your garden or on your balcony. And as it has no batteries, this is a very eco-friendly device. It is currently tested today by 120 students at the University of Saskatchewan, Canada, but it’s already available online.