$300 smart toothbrush does all your teeth at once

The Feno Smartbrush

Kyle Barr reports that the $300 Feno smart toothbrush is "the worst thing I've ever shoved in my mouth." The gob-filling mouthpiece cleans every one of your chompers simultaneously. He says it works, but he didn't like the experience one bit: it "made my entire head shake like a marionette piloted by a mad puppeteer."

It has technicall…