There are many ways to whiten teeth. This is what I have been investigating for a long time. The over the counter options are usually limited due to the strength of the bleach. Most dentist prescribed whiteners are 10 -20% Carbamide Peroxide, while chemist bought bleaches are usually 1-2%. Whitening toothpastes are not of sufficient strength and are only in the mouth for a minute or two so there is a negligable effect with these.
The key is to get a strong enough bleach on the tooth for a long enough time. We have started using a sopisticated system to make the best fitting home bleach trays EVER! I imported the technique from The States in December and now have bleaching trays that fit beautifully. This means the gel stays on the teeth, and saliva can’t dilute it. The results have been amazing.
The icing on the cake is to try deep bleaching – a specific technique using in surgery bleaching combined with at home bleaching. I have just started a few cases and have been really impressed to finally get some predictable results.