CNN – Hydrogen peroxide, the active ingredient in over-the-counter whitening strips, may be harmful to the layer under the enamel of teeth, according to research presented Tuesday at a scientific meeting.
Teeth are made up of three layers: the outer enamel, an underlying dentin layer and connective tissue that binds it to the gum.
The middle layer, dentin, is rich in proteins, of which collagen is the most abundant.
Most studies on the safety of hydrogen peroxide have focused on enamel.
The chemical is known to penetrate the enamel and reach the dentin, although in miniscule amounts, explained Dr. Edmond Hewlett, associate dean at the UCLA School of Dentistry and spokesman for the American Dental Association, who was not involved in the new study.
Kelly Keenan, senior author of the study and associate professor of chemistry at Stockton University in New Jersey, said in a statement that she and her colleagues “sought to further characterize what the hydrogen peroxide was doing to collagen.”