At-home
Commercial whitening products intended for home use include gels, chewing gums, rinses, toothpastes, among others. The ADA has published a list of accepted over-the-counter whitening products to help people choose appropriate whitening products.
High-concentration home bleaching uses carbamide peroxide. Whitening is performed by applying a high concentration of oxidizing agent to the teeth with thin plastic trays for a short period of time, which produces quick results. The application trays ideally should be well-fitted to retain the bleaching gel, ensuring even and full tooth exposure to the gel. Trays will typically stay on the teeth for about 15–20 minutes. Trays are then removed and the procedure is repeated up to two more times.
Low-concentration whitening is far less effective. Low-concentration whitening involves purchasing a thin mouthguard or strip that holds a relatively low concentration of oxidizing agent next to the teeth for as long as several hours a day for a period of 5 to 14 days. Results can vary, depending on which application is chosen, with some people achieving whiter teeth in a few days, and others seeing very little results or no results at all. Dentists as well as some dental laboratories can make custom fitted whitening trays that will greatly improve the results achieved with an over-the-counter whitening method.
Read more about this topic: Tooth Bleaching, Methods