The teeth are not expected to shade lighter than its natural cast. Following that, a retractor will be placed inside the mouth to expose the teeth in the zone visible when you smile. A protective rubber dam is them placed in the gum to protect it from irritation when the bleaching gel is applied. The bleaching gel is then applied to the teeth and then rinsed off after at least 15 minutes after which another application of the bleaching gel will be applied and kept in the mouth for approximately the same period of time. There are many cases where the staining is deep and for the meantime intractable. No amount of bleaching will be effective unless other procedures are conducted first. If ever, the stained tooth will only become more apparent while the surrounding teeth are bleaching white. In cases such as this, the dentist may recommend a home bleaching kit and recommend other alternatives to peroxide bleaching or an intensive home bleaching program. After this is done, the teeth will then be coated with the whitening formulation, and the coating will cover the surface of the teeth. And depending on the attending dentist, the formulation may contain the hydrogen peroxide or the carbamide peroxide. Either way, it can be expected that the whitening effect can be achieved. And if you are rushing into having your own sessions with your favorite dentist or you know someone who is planning to, it's best to hit the brakes first. These procedures are not for everybody; there are some restrictions and once you have checked these then you can always retry the services of teeth whitening. These products that are available here will often contain lesser amount of whitening agents. Or the concentration of hydrogen peroxide for these products is less than what the professionals use. In many counts, the concentration of the peroxide for these products varies from 3 to 6 percent. For this reason, the efficacy and the reliability can be questioned depending on the actual product. Over the years, the accumulation of the debris forms layer upon layer of film that show eventually as stain. The good thing is that while the staining agents worked its way through the pores in the rods, the whitening agents also use that access to free the teeth of the stains through oxidation reaction.