To keep things simple throughout this blog, we will use the word “whitening” as a catch all term to describe any products that increase the whiteness of your teeth. However, tooth ‘whitening’ products and tooth ‘bleaching’ products do fundamentally different things.
Tooth Whitening Products
‘Whitening’ agents are not the same as true bleaching agents. They only affect stains embedded within the enamel pellicle (the protein skin of your teeth) and do not alter a tooth’s base color. They typically depend on abrasives and acids to remove stuck on tooth stains. These are things like whitening toothpastes, and those natural ‘whitening ads that you make have seen online with the strawberries and baking soda.
True Tooth Bleaching Products
Bleaching agents will also dissolve stains adherent to the outside of your tooth. However, unlike ‘whitening’ agents they will penetrate your tooth’s enamel and also produce alterations in the tooth’s color beyond its natural shade by affecting the dentin layer of your teeth. Their bleaching effect comes from either hydrogen peroxide or carbamide peroxide present as the active ingredient. Theoretically, the reactive hydrogen peroxide radicals attack the long-chained, dark-colored chromophore molecules and split them into smaller, less colored, and more diffusible molecules.
Due to the nature of the whitening produced by true bleaching agents you will get a more dramatic change with bleaching products, and longer color stability.
Where do Crest Whitestrips fit into all of this?
Crest Whitestrips have hydrogen peroxide as an active ingredient so they must be bleaching agents right…not exactly.
Based on their design and their acidic pH (~5.8), whitestrips still derive a lot of their whitening action from acidic disruption of the enamel pellicle to remove mainly staining compounds stuck to your tooth. True bleaching effects appear to have a secondary role. Depsite having a higher relative concentration of hydrogen peroxide (6% in the formulation tested) to traditional tray-whiteners, the effective peroxide dose to the tooth from whitestrips is a third of that of a tray with 10% carbamide peroxide gel .
Note: Hydrogen peroxide is the active form of carbamide peroxide,
and 10% carbamide peroxide = 3.5% hydrogen peroxide
To still achieve a similar level of whitening to tray whitening products with whitestrips, means that the dissolution of stuck on stains by hydrogen peroxide and acids is the primary mechanism of tooth whitening in Crest whitestrips. Ironically, to keep your teeth healthiest you do not want to expose your teeth to acids more than you have to, and you want to preserve your enamel pellicle for its acid resistant properties.
Even though whitestrips are acidic and will disrupt the pellicle, this does not mean that Whitestrips are all bad. In fact, using Crest Whitestrips is probably the most convenient way to whiten your teeth at home, and they won’t make your teeth as sensitive because less hydrogen peroxide gets into your teeth.
The take away points for using Whitestrips:
In case you are interested, here are the ingredients for Crest Whitestrips:
Active Ingredients: Hydrogen Peroxide gel (percentage concentration varies) on a polyethylene film
Inactive Ingredients: Purified water, glycerin, carbamol 956, sodium hydroxide, sodium acid pyrophosphate, sodium stannate and sodium saccharin