Whitening strip teeth bleaching products were first introduced to the over-the-counter marketplace with the debut of Crest Whitestrips ®. Whitening strips offer a means by which the teeth whitening process can be performed without the use of a rigid bleaching tray. The peroxide-based chemistry involved with the use of whitening strips is essentially the same as that employed by tray teeth whitening systems, but the whitener is held in contact with the tooth surface via the use of an adhesive plastic strip rather than by a tray.
( More about Crest Whitestrips ® / whitening strips... )
Crest Whitestrips is a registered trademark of the Proctor & Gamble Company.
Many of the over-the-counter teeth whitening kits available are "tray" whitening systems. These products come with a stock bleaching tray that the end-user customizes so it fits over their teeth. The tray is then filled with a carbamide peroxide teeth whitening gel and subsequently worn for that treatment time recommended by the product's instructions. Treatments are continued, per the product's instructions, over a period of days to weeks as the whitening effect is achieved.
( More information about tray-based teeth whitening... )
As their name implies, paint-on teeth whiteners don't make use of bleaching trays but instead are painted directly onto the surface of the teeth being bleached in similar fashion as polish is brushed onto nails. Colgate ® introduced this relatively inexpensive whitening technique to the over-the-counter marketplace in 2002 with the introduction of their Simply White ® product. Since then they have introduced another paint-on tooth whitener, this one named Colgate Simply White Night ®. Crest ® has also entered the field of paint-on teeth whitening with their product named Crest Night Effects ®.
( More about paint-on teeth whitening products... )
Colgate Simply White and Colgate Simply White Night are registered trademarks of the Colgate-Palmolive Company.
Crest Night Effects is a registered trademark of the Proctor & Gamble Company.
It seems likely that the majority of whitening products sold on an over-the-counter basis are teeth whitening toothpastes. Toothpaste manufacturers have been making whitening claims for decades. And while this type of product can serve a purpose their claims may not be based on the same definition of whitening as you might have expected.
( More about whitening toothpastes... )