Teeth whitening consists of a thorough cleaning and polishing of the teeth, with all debris carefully removed. Your dentist will then protect your gums before applying a whitening agent to the surface of your teeth. The product will be activated and left on the teeth for several minutes before being washed off with water. Your results will vary according to the natural shade of your teeth and degree of discoloration, but it is normal for patients to experience a lightening of several shades in a single visit.