Tooth whitening can be a very effective way of lightening the natural colour of your teeth without removing any of the tooth surfaces. It cannot make a complete colour change, but it may lighten the existing shade.
Professional bleaching is the most usual method of tooth whitening. Your dentist will be able to tell you if you are suitable for the treatment, and will supervise it if you are.
The ‘active ingredient’ in the product is usually hydrogen peroxide or carbamide peroxide. As the active ingredient is broken down, oxygen gets into the enamel on the teeth and the tooth colour is made lighter.