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How Whitening Works

Course Number: 657


An emulsion is the combination of a two-phase system where one phase is insoluble to the other. In the case of Whitening Emulsions™, a hydrophobic carrier (water repelling) contains microdroplets of peroxide which are hydrophilic (water attracting). The Procter & Gamble Company has developed Whitening Emulsions™ as a breakthrough innovation to the market. While the professional applied and prescribed systems represent variations on concepts associated with the design of effective tooth whiteners, this new technology is a new delivery system leave-on whitening technology using chemistry to provide the hydrogen peroxide with its own protective barrier.

This new on the go, leave-on technology has recently been introduced, which uses a novel emulsion-based vehicle to facilitate peroxide delivery while minimizing dehydration. In this emulsion, a petrolatum base which is hydrophobic suspends microdroplets of the hydrogen peroxide until they come in contact with the tooth surface. The tooth surface is hydrophilic, as are the peroxide microdroplets (~25 microns), therefore the peroxide is drawn out of suspension to the tooth surface where it creates a diffusion layer to begin the diffusion process through the enamel. The petrolatum base protects the microdroplets and renders them 100% available; there is no inhibition of peroxide droplets to diffuse, like in prior delivery systems. In addition, the hydrophobic carrier ensures the peroxide isn’t washed away via saliva allowing additional contact time.

Another distinction from traditional peroxide gels is that because there are no thickening or adhesive agents which can chemically bond to the peroxide, the peroxide delivery in an emulsion is uninhibited and available toward the hydrophilic surface.