If these are present in the range that show when a person smiles, chances are whitening the teeth through the do it yourself regimen will result to uneven teeth color. Professional supervision is needed in such cases. Finally, see your dentist first. This is especially true if you have suffered teeth trauma in the past and have gums that are easily irritated. Since teeth whitening and bleaching are among the simplest cosmetic procedures and provided you do not have cracks crowns porcelain veneers, special teeth and gum conditions, home kits are advisable provided you start with a low mixture of bleaching agents and water. Peroxides that are sold over the counter have indications and recommendations for the mixture which you could use. For example there are specialize whitening centers that are present in major cities. And these special centers will have dentists that will check first the oral condition of the person before the whitening treatment can be suggested or performed. If for example there are other serious concerns relating to the oral health condition, then the practitioner will not recommend outright teeth whitening procedure. Extrinsic tooth stains forms in the enamel while for the most part, intrinsic stains that show trough the enamel occur in the dentin. First, the tooth enamel is a highly mineralized very hard part of the tooth composed of strand of rod-like crystalline materials. These rods while very tightly packed have microscopic gaps in between them. The front teeth most especially are very thin and gets more and more transparent with age. For this a different procedure may be taken. Aside from those mentioned above, in-office whitening could be conducted with basically the same procedure. The teeth will be prepped by cleaning away the debris, dirt and plaque that have accumulated in-between and on the teeth. The enamel deteriorates over time and this can be expected. In order to cover the wear and the deterioration, then the porcelain veneers can be used. Also the use of these veneers is best for wear and tear. As people age, the teeth also suffers considerably. The teeth will crack or will have chips. And the veneers can be used to address this concern.