whitening can be a very effective way of lightening the natural colour of your teeth without removing any of the tooth surface. When it comes to tooth-whitening, you’ve got two options: in-office-based teeth bleaching, or at-home care. Both tooth-whitening options use peroxide-based bleaching agents. At-home systems contain from 3% to 20% peroxide (carbamide or hydrogen peroxides). In-office systems contain from 15% to 43% peroxide.