A common question patients ask who are considering professional tooth whitening/bleaching is whether it damages the teeth. The answer is a resounding NO. The active ingredient in professional tooth bleaching products is either Carbamide Peroxide or Hydrogen Peroxide. It is the oxygen molecules that actually lighten the color of your teeth by both removing stain on the outside and lightening the internal color of the tooth.
The bleaching chemical is absorbed into your tooth and liberates oxygen which bleaches the tooth structure on the inside. This same chemical is also used to treat gum disease as it kills some of the bacteria that cause gingivitis and periodontal disease. It can even help prevent cavities. So contrary to hurting your teeth, it is actually beneficial to your overall dental health.
Excessive bleaching, which is the use of at home trays continuously over extended months or years can cause minor pitting to the enamel, but even this has been shown to be minor and easily reversible once bleaching is discontinued.
Tooth bleaching is not recommended for women who are pregnant or nursing. At this tine we do not have enough information to confirm it is safe.