There are some marked differences between whitening procedures done in a cosmetic dentist office, and those done at home. The first obvious difference is the effects that can be achieved. Things like whitening toothpaste can make your teeth lighter, but the toothpaste treatment will only make your teeth about a shade lighter over a period of some time. In contrast in office whitening can make your teeth many shades lighter, around 8 shades in fact.
Dental whitening gels can be purchased in your local supermarket, or at your local dentist office. The difference is the supervision of a trained professional, fitted trays that maximize the contact of the gel against the tooth, and use of the only gel that carries the ADA seal of approval. The gels themselves are quite different as explained by WebMD:
Over-the-counter home use products and dentist-supervised at-home products usually contain a lower strength-bleaching agent from 10% carbamide peroxide, which is equivalent to about 3% hydrogen peroxide, up to 22% carbamide peroxide. In-office, professionally applied tooth whitening products contain hydrogen peroxide in concentrations ranging from 15% to 43%.
Dentists also offer such options as “power bleaching” that can dramatically lower the shade of your teeth in a single treatment. Dentists also have been using laser treatments to enhance the effects of lightening techniques. Typically your dentist can offer you whitening methods that are faster, safer, and simply unavailable at home. In short, if you are looking for the fastest, most effective, and safest route for teeth whitening, your dentist is the best bet by far.