How do teeth whiteners work-and are any methods better than others?
Many studies have been conducted to test the effectiveness of teeth-whitening materials and techniques, says Dr. Gerard Kugel, D85, L93, professor of prosthodontics and operative dentistry and associate dean for research. By using carbamide peroxide, hydrogen peroxide or a combination of the two, teeth do become whiter, but exactly how that happens is still not completely understood. When applied to teeth, hydrogen peroxide diffuses through the enamel and dentin. It produces free radicals-atoms with unpaired electrons-which are “extremely unstable and attack most other organic molecules to achieve stability, generating other radicals,” says Kugel. What causes teeth to appear yellow are double-carbon bonds, which absorb light and trap chemicals that add color to molecules, says Kugel. When these double-bonds are broken by the radicals, single-carbon bonds are formed that reflect light, making the teeth appear brighter. Whitening toothpaste tends to work by removing superficial stains, h
