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How Whitening Works

Course Number: 657

Dose of Ingredients Used in Tooth Whitening

In 2000, Procter and Gamble created a step change in ‘at home’ whitening with their development of strip-based peroxide tooth whiteners.31 Consumers could achieve safe, significant whitening at home for a lower cost than professionally administered trays. The reason for the success of this innovation was related primarily to controlling of the dose of applied peroxide. The dose of applied bleach is the total quantity of the ingredient being used. It is described by the concentration of the bleach multiplied by the mass of the delivery vehicle used. The innovation of strips holding the finite dose of bleaching gel allowed concentrations of peroxide to be used in strips of over 10% in some applications without side effects of soft tissue irritation. By controlling the total dose of peroxide, strips use higher concentrations of peroxide due to this feature of dose control. By controlling dose and maintaining a low total dose per unit area, the higher concentrations do not lead to excessive tissue irritation as the amount delivered per unit area is well within the ability of the soft tissue to rapidly decompose the peroxide into oxygen and water. While the efficacy is largely driven by concentration, soft tissue tolerability is driven by the amount of peroxide applied per unit area. For example, a 12% composition applied at half the thickness of a 6% peroxide composition applies the same amount of peroxide per unit area even though the concentration is 2X. In this example, the 12% peroxide composition will whiten faster with the same soft tissue tolerability profile.