What exactly does the laser for teeth whitening do?

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.
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.
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.
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.

Related Questions

What causes the sensitive teeth after laser teeth whitening? After I have it done, my teeth are always a bit sensitive for a day or so. It doesn't really bother me, but I'm curious about what exactly is happening that causes it..

The . The nerves in the teeth being bleached are sensitized by the bleaching gel which is a very strong peroxide, and the heat from the light. As you have discovered, the sensitivity is transient. Read more...
It's . It's a dehydration ilssue. Once the teeth rehydrate they lose the sensitivity. That's why some manufacturers of bleach gels include potassium nitrate in their formula ( & other formulas ) to safeguard agalnst this. If you want to become a little more knowledgeable about the matter (which i expect you do), i refer you to this article/link & see what a well known bleaching expert dr. Rod kurthy has to say. http://www.teethwhiteningreviews.com/artman/publish/teeth-whitening-sensitivity.php. Read more...
Dehydration. When you whiten your teeth they can become dehydrated resulting in pain. The discomfort is temporary as you have experienced but none the less it can hurt! an easy way to avoid this is to use Fluoride gel immediately after the procedure. I think you will find this to ease the discomfort! Read more...
Dessication. Laser whitening and any tooth bleaching system will cause your teeth to dry out due to a differential in osmotic pressure. This dessication causes the teeth to be hypersensitive. Read more...