Chemicals in tooth whitening products

True tooth whitening involves the modification of stain molecules deep within the tooth as well as modification of the tooth surface. While some products claim that they "whiten" teeth, they may only help remove surface stains. For a deeper whitening effect, one or a combination of special chemicals should be found in a product.
Hydrogen Peroxide and Carbamide Peroxide
Hydrogen peroxide is often the main ingredient in in-office and at-home whitening products. It travels inside the tooth and chemically alters the stain molecules to become invisible. Thus the stain is not removed from the teeth, but rather it is made transparent. Carbamide peroxide is breaks down in the tooth into hydrogen peroxide and byproducts, so it ultimately works in the same fashion but is more gentle. In-office whitening systems use the highest concentrations of hydrogen peroxide (up to 38%) since they are carefully applied and monitored by dental staff. For home use, dentists typically provide concentrations of up to 35% carbamide peroxide in gels for bleaching trays. Over-the-counter whitening products such as strips usually contain lower amount of carbamide peroxide.
Potassium Nitrate
This compound is not a whitening agent, but rather serves to decrease tooth sensitivity. Potassium nitrate is used in toothpastes that are designed for patients who normally have sensitive teeth. It works by blocking the painful nerve signals from being sent to the brain.
DID YOU KNOW?
A high dose of fluoride in a gel or special toothpaste can be used prior to treatment to reduce sensitivity. It can also be incorporated directly in whitening products.
Amorphous Calcium Phosphate (ACP)
ACP is believed to serve a couple of roles in whitening products. First, it helps decrease sensitivity by bathing the teeth in helpful minerals. Research has shown that tooth sensitivity is decreased when ACP is incorporated into the whitening product. Second, ACP improves the surface shine of the teeth. Teeth can appear dark if they have numerous microscopic scratches in the outer layer. Light rays hitting the tooth bounce around the small cracks and make the tooth look more dull. ACP helps fill in the cracks so that light scatters when it hits the tooth surface, resulting in a shining effect.
Whitening products that truly lighten the teeth have special chemicals that exert various effects. Chemicals like hydrogen peroxide penetrate into the tooth to break up stain molecules. On the other hand, ACP can fill in microscopic cracks in the surface and make it appear more shiny. People interested in whitening should check the active ingredients in the products to make sure they are safe and effective.