And when used under the dentist-supervised procedure, this form of bleaching is used as complemented by a special light or the laser. In many cases, in just one visit the expected results can be seen immediately. But if the intent is to get that dramatic results in the form of shiny white teeth, then the person will need a number of visits to the dentist. Even as professionally supervised teeth whitening treatments contain hydrogen peroxide as its active bleaching agent that is safe enough even for home use, over the counter preparations contain carbamide peroxide which is even safer and milder. The effects are the same. 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. The dentist will always give the best advice, treatment and service, and it is recommended that even for simple cosmetic enhancements there must at least be a professional consultation. After the initial consultation, the process of getting an appointment, finding the time and actually sitting in the dentist's chair is not always convenient besides there are a lot of conditions where it is actually more practical to get a teeth whitening kit and apply it at home where the person could save enormously on fees and time. And these products will always contain chemicals. And it is the role of these chemicals to break down the stains taken down by the abrasives. Half of the reason why this product works can be linked to the proper use and application. It is recommended by oral health practitioners that this should be used twice a day. 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. Extrinsic staining and intrinsic staining are the two basic types at which the teeth develop stains and discoloration. Extrinsic stains are developed in the surface of the teeth that resulted from the accumulation of food debris and color. 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.