While using teeth-whitening products can make your smile brighter they might also lead to tooth damage researchers have warned. The study led by researchers from the Stockton University in the US found that hydrogen peroxide -- the active ingredient in whitening strips -- can damage the protein-rich dentin tissue found beneath the tooth's protective enamel. Human teeth is made up of three layers -- the outer tooth enamel an underlying dentin layer and connective tissue that binds the roots to the gum. Unlike most studies which have focused on tooth enamel the new study focused on dentin which makes up
