What exactly does the laser for teeth whitening do?

Whitens the teeth: Your dentist applies a teeth whitening gel and points the laser at the teeth, the light removes the yellow stains.The laser light is used to enhance the penetration of the whitening gel into your teeth enamel, thus improving the result if the tooth bleaching.In most cases , you do not need further treatments.

Not much: There are effective techniques that do not use the laser or light, and yield fantastic results! in my experience, they add to the likelihood of post treatment sensitivity and dry out the teeth.

Not laser: Usually it is not a laser that is used for in-office whitening, but a light source such as gas plasma, plasma arc or led light sources that activate the ingredient in the gel for a more rapid result (think britesmile, rembrandt or zoom). While lasers were used more when whitening first started, it is more time consuming and done one tooth at a time with laser.

Questionable...: The lasers may activate the whitening gels. However, to be honest, the use of lights and lasers for gel activation is losing favor. It seems the gels activate just fine on their own. The gels without lasers nor lights are very safe and effective when properly used.