Teeth whitening is ideal for patients with healthy, un-restored teeth (no fillings) and healthy gums who would like a brighter smile. Patients with yellow tones on their teeth respond best, but this cosmetic procedure is not recommended for everyone.
Enamel, the first layer of tooth surface, is actually semi-translucent, or clear. The layer underneath the enamel, known as dentin, is typically yellow, but may be gray, brown or black. This hue is what is seen penetrating through the enamel.
In order to whiten the dentin, a peroxide solution is placed on the enamel. This process opens the pores of the enamel, allowing the solution to reach the layer of dentin. The solution will then begin to lighten the dentin, resulting in the appearance of whiter teeth.
Teeth whitening is not recommended or will be less successful in the following circumstances:
- Age and pregnancy issues. Bleaching is not recommended in children under the age of 16. This is because the pulp chamber, or nerve of the tooth, is enlarged until this age. Teeth whitening under this condition could irritate the pulp or cause it to become sensitive. Teeth whitening is also not recommended for pregnant or lactating women.
- Sensitive teeth and allergies to products. Individuals with sensitive teeth and gums, receding gums and/or defective restorations should consult with their dentist prior to using a tooth whitening system. Anyone allergic to peroxide (the whitening agent) should not use a bleaching product.
- Gum disease, worn enamel, cavities, and exposed roots. Individuals with gum disease or teeth with worn enamel are generally discouraged from undergoing a tooth whitening procedure. Cavities need to be treated before undergoing any whitening procedure. This is because the whitening solutions penetrate into any existing decay and the inner areas of the tooth, which can cause sensitivity. Also, whitening procedures will not work on exposed tooth roots because roots do not have an enamel layer.
- Fillings, crowns and other restorations. Tooth-colored fillings and resin composite materials used in dental restorations (crowns, veneers, bonding, bridges) do not whiten. Therefore, using a whitening agent on teeth that do and do not contain restorations will result in uneven tones. Any whitening procedure should be done prior to the placement of composite fillings, bonding, veneers, crowns, dentures, or porcelain restorations in order to best match the degree of whitening to your new tooth color. A minimum of two weeks following a whitening procedure should be allowed before crowns, bondings, or veneers are completed. This will allow enough time for the enamel to re-mineralize and optimize the bonding strength. Tooth-colored fillings will need to be replaced after the bleaching process is complete. Individuals with numerous restorations that would result in uneven whitening may be better off considering bonding, veneers or crowns rather than a tooth whitening system.
- Unrealistic expectations. Individuals who expect their teeth to turn “blinding white” may be disappointed with the results. Smokers need to be aware that the results may not be satisfactory unless they refrain from continued smoking, particularly during the bleaching process.
- Darkly stained teeth. Yellowish teeth respond well to bleaching, brownish-colored teeth do not, and grayish-hue or purple-stained teeth may not respond to bleaching at all. Bluish-gray staining caused by tetracycline is more difficult to lighten and may require up to 6 months of home treatments or several in-office appointments to successfully lighten. Teeth that have dark stains may be better candidates for other lightening options, such as veneers, bonding, or crowns.
It is important to have realistic expectations when evaluating your final results; it may take several treatments to achieve a whiter smile. With all types of bleaching procedures, the degree of brightness will vary with each individual, depending on the condition of the teeth, nature of the stain, the concentration of the bleach and the duration of time, and bleaching system used. Whitening results may not be permanent, as your teeth coloration will naturally be affected by certain foods and beverages or from tobacco use.
Remember to brush and floss daily, and visit your dentist for regular cleanings and examinations.