These gels are often applied to the surface of the teeth with the use of a small brush. Most of the gels that are available in the market will call for you to apply these gels at least twice a day and this should go on for the next 2 weeks. The results can be realized after a few days, and the white color of the teeth can be maintained for months provided of course that proper maintenance is made. Expect to pay from $300 to $600 and this will include all the bleaching materials. What about laser whitening Laser whitening is done on the office or the clinic of the attending dentist. And in order to get the results, you may need to have one to four treatments. For this approach, gels are used and these gels do contain some peroxide-based formulations. While a temporary tooth may be sparkling white, the teeth replacing it may be not. As a person grows older, the teeth darken in shade, no matter how healthy and no matter how clean. But a clean white and shiny teeth is so important, very much so that even in ancient times royalties and people who can afford it applies whitening powder to their teeth even when it has proven to accelerate teeth rotting. While hydrogen peroxide acts faster, carbamide peroxide when left in the mouth for a time divides into urea and hydrogen peroxide that acts on the stains by the oxidation process. It gets into the spaces of the rods in the enamel of the tooth, lifts the stains and drains the stain out. Several repetitions of this and the teeth become as white as its original color. Even if you do not have these issues, you may still need a mouth exam and an assessment of your gums. Your dentist is also in the best position to seek advice regarding over-the-counter system that could be used. Remember that teeth darken with age and there are 16 teeth shades and the color differs from one person to another. Following are some of the risks that are frequently encountered. Increased teeth sensitivity This is more likely to happen when the treatment is done in a clinic or a health spa because bleaching agents that are used are more concentrated than home bleaching kits. More concentration of the bleaching agents however means faster results compared to home treatment methods that are very much "watered down" to insure safety.