Do home kits work?

Home whitening kits can only contain up to 0.1% peroxide by law, which won’t have much effect; dentists can use up to 0.6%. Trays not tailor-made will not fit as well, so there’s a higher chance that the bleach can leak onto the gums, causing sensitivity, warns Professor Damien Walmsley. However, his main concern is that over-thecounter kits have been found to contain substances that can damage teeth.