Remember that if your gums or your tooth are being irritated or hypersensitive you can choose the lower grades but then the desired results will take longer to manifest. Conversely, higher concentration gives faster results if comfort is not an issue. Follow instructions and indications. Do not leave teeth whitening products whether gels and rinses, longer in the mouth than prescribed. These are clear gels that contain a good concentration of peroxide- that main ingredient that facilitates teeth whitening. 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. 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. And what are these limitations? Consider the list below, and be guided accordingly. These procedures are not best for those below 16 years of age. The dentist will begin with the minor cleaning procedure which will include the removal of existing plaque in the gum line. Once cleaned, a gel fortified with peroxide is then applied to the targeted teeth. This gel in question contains peroxide in just the right quantity that can ensure that the teeth will whiten. While superficial stains and discoloration could be removed by prophylactic cleaning and brushing, there are stains that are a little more stubborn and could accumulate between the spaces of the tiny cracks in the tooth that would need bleaching to remove the stains. When the stains are not effectively removed and stays on the teeth for a period of time, this could penetrate deeper into the dentin which could require more involved methods. For this set of bleaching agents, the usual recommendation is to use twice daily and the waiting time can reach two weeks before the effects can be realized. In terms of price, expect to pay $3 to $10 for teeth whitening toothpastes. And for other bleaching formulations, some over the counter products can fetch around $30.