Glo Brilliant Smile Whitening System, a gizmo being launched by New York cosmetic dentist Jonathan B. Levine, sheds new light on at-home teeth whitening. The device employs an LED to accelerate the bleaching properties of hydrogen peroxide gel and promises significant smile brightening without sensitivity or pain. Four eight-minute sessions a day for three to five days is enough to see improvement. (Stubborn discolorations may need up to 10 days.) And Levine stresses the importance of monthly touch-ups. “Three months after a professional whitening, 20 percent of the benefits are gone,” he says. “With your own teeth-whitening device, you can maintain the results” (gloscience.com, and starting in March at Sephora; $275).