Whitening toothpastes contain an abrasive material that scrapes off stains on the surface of the teeth in order to polish them. While whitening toothpastes can prevent further staining, there is little evidence to suggest that they lighten teeth and the abrasive particles can wear away tooth enamel. Bleaching kits containing hydrogen peroxide which are worn overnight for up to two weeks are more effective than whitening toothpastes. In-surgery laser whitening is known to lighten teeth up to 11 shades and takes just 30 minutes to an hour to perform. During this procedure the dentist will apply a whitening gel containing hydrogen peroxide to your teeth. If the tooth enamel itself is stained or is discolored as a result of tetracycline use or a dead nerve, then laser whitening may not work and a veneer might be a better option. If you have fillings, crowns or veneers on the front teeth these will not change color and could look out of place if you whiten your teeth.