What To Expect
At a dentist's office, a high concentration of peroxide is applied to the teeth, which has a stronger and faster effect than at-home whitening.
More advanced versions of this procedure include the use of custom-fitted trays, which can carefully deliver high doses of peroxide over time.
Who should do it: Licensing requirements vary from state to state. In some states, only a licensed dentist may perform bleaching with a high concentration of peroxide.
In other states, the rules are more lax, which explains the existence of tooth-whitening mall kiosks.
Duration: If you're having professional teeth bleaching, the peroxide solution will soak into your teeth for 20 minutes at a time, up to three times an appointment. If you have sensitive teeth, speak up—you'll want to cut back to shorter intervals.
How Painful Is It?
Hydrogen or carbamide peroxide can leave the teeth sensitive for up to 24 hours. "Zingers"—quick, sharp stabs of pain—are a common complaint, though not everyone experiences them.