The American Dental Association (ADA) has asked U.S. Food and Drug Administration (FDA) to establish appropriate classifications for tooth-whitening chemicals. Citing concern about the safety of whitening products that are often administered without the benefit of professional consultation or examination by a dentist, the ADA said that the application of chemically-based tooth whitening or bleaching agents can harm teeth, gums and other tissues in the mouth.The ADA pointed out that such conc...