DIFFRENT METHODS OF TOOTH-WHITENING
Professional:
In-Office

In-Office bleaching is the most effective tooth-whitening method. Dentists are able to use agents with much higher concentrations of bleach than are found in over-the-counter products. You will see results after your first time, but can do a few more sessions for more dramatic results. Although this method is the most effective, it is also the most expensive. However, as this procedure has gained popularity, many dentists have begun to offer the service at discounted prices.
At-Home:
Strips and Gels

Over-the-counter whitening strips and gels are the most effective at-home method. These have the highest level of bleach other than professional in-office whitening products. Whitening strips are thin strips coated with a bleaching agent that you put on your teeth twice a day for 14 days. Also available, are whitening trays. These also use a bleaching agent, but come with a dental tray that fits onto your teeth.
Whitening Rinses

Whitening rinses are similar to regular mouthwash, but they include whitening agents, like hydrogen peroxide. Although rinses can be effective, results will take considerably longer to appear since they have contact with your teeth for a lot less time.
Whitening Toothpastes

Whitening toothpastes are the least effective tooth-whitening method, because they do not contain bleach. They will clean the top layer of your teeth, but they can’t get deep into the tooth to attack long-term staining. They will usually only whiten your teeth by one shade.