FACTS ABOUT IN-OFFICE TOOTH WHITENING
The procedure utilizes bleaching agents in the hydrogen peroxide family with a concentration ranging between 15% and 50%. Such high concentrations require some form of effective soft tissue protection against the caustic action of the peroxide. High concentrations may result in transient tooth sensitivity.
That is why some in-office whitening agents have a desenzitiser incorporated in their formula.
Light/heat activation delivered by a curing light or laser is used to speed the chemical reaction.
In-office bleaching can take two to six appointments of 45 min. to 1hr. each, scheduled usually one week apart. The number of applications to bring about the desired results is not predictable. Some discol-orations (eg. tetracycline stains) are known to be more tenacious.
In-office bleaching can be used alone or in combination with at-home whitening as an adjunctive procedure.

LASER-ASSISTED WHITENING
Claim to fame:
The laser provides a powerful energy source to enhance the action of the peroxide.
Concerns raised over the safety of lasers: The temperature created can be great and it varies with the type of laser used. The Argon laser can generate very little temperature rise in the tooth. The Carbon Dioxide laser can cause pulpal (nerve) irritation or even necrosis. The American Dental Association does not recommend the use of CO2 laser for bleaching.
Studies of laser bleaching to date have not indicated any better results than with other in-office techniques, and results possibly not as good as those obtained with at-home bleaching.

Source: Dentistry today, December 2002; Fundamentals of operative dentistry, second edition.