Oral-B 3DWhite Whitestrips use the same enamel-safe whitening ingredient used by dentist. They are thin, flexible strips that are coated with a tooth-whitening gel containing peroxide. Once you unwrap them and place them across both upper and lower sets of teeth, they stay on until it's time to remove them. The recommended use is to keep on the surface of your teeth for 60 minutes once a day to remove stain build-up both on and below the tooth's surface