Tooth whitening: From the established treatments to novel approaches to prevent side effects

OBJECTIVE: The aim is to review the most important aspects about tooth whitening treatments, their side effects, and the new emerging approaches to overcome them. OVERVIEW: This review is focused on origin of tooth stains, the whitening systems and their chemistry, their side effects, and the new approaches. The search of bibliography of the period 1965-2018 has been analyzed. CONCLUSIONS: Tooth whitening has become one of the most requested dental treatments by the public. Tooth stains are classified according to their origin into two categories: intrinsic and extrinsic. The whitening systems are generally organized into two classes: in-office and at-home products. Most of the whitening systems use hydrogen peroxide as the active oxidative agent to degrade the organic compounds that cause stains. The concentration ranges depending on the treatment, and it may be applied directly or produced in a chemical reaction from carbamide peroxide that is more stable. Besides its popularity, tooth whitening still has some side effects being tooth hypersensitivity the most common. In order to decrease these side effects, new treatments are constantly in renewal processes. CLINICAL SIGNIFICANCE: Despite all the data and new strategies known about tooth whitening, there are many aspects that are not totally fully understood and methodologies that are not completely effective. Therefore, the development of effective, efficient, and long-lasting whitening treatments is still necessary.