Some commercially available “whitening toothpastes” can be somewhat effective at removing stains and making teeth a few shades brighter. However, many of these products have abrasive substances that can actually wear away your tooth’s enamel.
Whitening agents are also ineffective on certain types of stains. For example, bleaching agents have a difficult time removing brownish or grayish stains.
Professional whitening is considered to be the most effective and safest method; done properly, tooth whitening can last as long as five years with no damage to the surface of your teeth.