OJ Worse for Teeth than Whitening, Researchers Say (PhysOrg) Eastman Institute’s YanFang Ren, DDS, PhD, and his team determined that the effects of 6 percent hydrogen peroxide, the common ingredient in professional and over-the-counter whitening products, are insignificant compared to acidic fruit juices. Orange juice markedly decreased hardness and increased roughness of tooth enamel. Unlike …