There are so many formulations of whitening and bleaching products on the market today it can be confusing. Not only do we have to understand which active ingredient to use, Carbamide Peroxide or Hydrogen Peroxide, but also the strength. Both of these chemicals are oxidizing agents, meaning they liberate oxygen and actually lighten the color of the dentin structure of teeth. This is by ADA definition what distinguishes a “bleaching”agent from a “whitening” agent, as whitening is the removal of extrinsic surface stain only.
Carbamide peroxide is commonly the active ingredient in take home products for tray bleaching, Custom trays are fabricated and dispensed along with varying strengths of gel for patients to apply on their own. The first refereed paper on Carbamide Peroxide was written in 1988 by Van Haywood and Harold Heymann. The reference to it’s ability to lighten teeth goes back to the 1960’s when it was used as the active ingredient in Gly-Oxide, which was dispensed to treat periodontal disease. Carbamide peroxide breaks down into Hydrogen peroxide in the presence of water. It is the Hydrogen Peroxide that is taken up into the porosities in the enamel rods and then enters the dentinal tubules and lightens teeth.
Carbamide peroxide is a third as strong as Hydrogen Peroxide, so a 30% solution is equivalent to a 10% solution of Hydrogen peroxide. Hydrogen Peroxide is typically he active ingredient in office bleaching systems. These are applied to create more active, rapid bleaching effect after the application of a liquid dam to protect the gum tissue. In studies comparing the effectiveness, the two products have been shown to be equally effective over time at lightening teeth.