When FS+ bleaches, the discolorations are oxidized without releasing harmful molecules known as free radicals. These radicals are what damage the enamel and cause severe sensitivity. This means that during the whitening process there is no damage or erosion to the enamel, meaning that the outer layers of the tooth remain intact, and can continue to protect the nerves, while effectively whitening. FS+ the bleaching process is effective against many types of discolouration, which can both arise from internal and external influences', and it is clinically proven that results are seen immediately after 1 treatment.