Teeth Whitening- Teeth whitening done in a professional dental setting is a safe, effective way to brighten your smile. It's also perhaps the most economical cosmetic dental procedure. Depending on the whitening method you choose, results can be dramatic: in-office whitening, for example, can lighten teeth three to eight shades in a single hour. Professionally supervised whitening will work faster, and protect sensitive gums and tooth-root surfaces better, than over-the-counter whitening products. Having an oral exam before you begin any whitening process is an important first step to make sure your tooth discoloration is not the result of a dental condition in need of treatment.