In-office bleaching, which involves direct application of the whitening substance on the surface of the teeth by a dentist, generally provides the fastest results, explains WebMD. Lasers, special lights or heat may be used during the procedure. Unfortunately, this approach is typically the most expensive.
Because they contain mild abrasives, ordinary toothpastes also help keep teeth white, notes WebMD. However, their effectiveness is limited, as they can only remove stains on the surface of the teeth. The same limitation applies to whitening toothpastes, which contain specialized chemicals or polishing agents that help brighten teeth by about one shade.
Whitening strips produce results in a few days, and the effect lasts for about four months, explains WebMD. The strips, thin to the point of being invisible, are coated with a lightening gel formulated from peroxide and are applied on the teeth twice daily for two weeks. In contrast, whitening gels, which are also made from peroxide, are applied with a brush. The frequency and length of application depend on the strength of the formulation. Results start showing in a few days, and the whitening effect lasts for about four months.
Whitening mouth rinses typically include teeth-brightening ingredients such as hydrogen peroxide, states WebMD. They are used in a similar manner to normal mouthwashes and take up to 12 weeks to brighten teeth. Rinses take longer to show results because they tend to be in limited contact with teeth; they are used for about 60 seconds twice a day. In contrast, tray-based products can keep the whitening gel in contact with teeth for as long as necessary. The gel is placed in trays, which look like mouth guards and are worn for a number of hours every day.