How chemical bleaching work?

The active ingredient found in most bleaching agents is hydrogen peroxide (HP), which can be delivered as HP or as carbamide peroxide (CP). CP is a stable compound which in contact with water will break down into HP and urea.

These peroxide-based whitening products work to remove the appearance of stain through a redox chemical reaction. Free radicals are produced when the oxidizing agent hydrogen peroxide (HP) breaks down. These free radicals are then available to react with organic molecules in enamel and dentine, breaking down the double bonds of the chromogens (colour causing agents). These new, simpler molecules reflect light differently resulting in the appearance of whiter teeth.