Reports have emerged that a new study claims that teeth whitening products could actually be doing harm to our teeth.
The study by scientists at Stockton University in the US has found that hydrogen peroxide, the active ingredient in over-the-counter whitening strips and products, can damage the protein-rich dentin tissue found beneath the tooth’s protective enamel.
According to scientists, the tooth is made of three layers: the outer tooth enamel, an underlying dentin layer and connective tissue that binds the roots to the gum. Most studies of whitening strips have focused on tooth enamel, which contains very little protein. The team focused on dentin, which makes up most of the tooth and has high levels of protein, most of which is collagen.
It is well established that hydrogen peroxide can penetrate the enamel and dentin. Previous work by the researchers showed that collagen in the dentin layer decreased when teeth were treated with whitening strips.
The researchers demonstrated that the major protein in the dentin is converted to smaller fragments when treated with hydrogen peroxide.
In additional experiments, they treated pure collagen with hydrogen peroxide and then analysed the protein using a gel electrophoresis laboratory technique that allows the protein to be visualised.
The researchers point out that their experiments did not address whether collagen and other proteins in the teeth can be regenerated, so it is unknown if the tooth damage is permanent.
Next, they plan to further characterize the protein fragments released when collagen is treated with hydrogen peroxide and determine if hydrogen peroxide has the same impact on other proteins in the teeth.