The Opalescence Whitening Gel is ideal for people who value convenience. You can wear Opalescence for as little as 30 minutes per day, or even overnight! Opalescence whitening gel allows you to get professional whitening results at your convenience in a safe, effective, and customized way! The sticky, viscous gel won't leak out of the tray onto your gums and Opalescence gels include potassium nitrate and fluoride (PF) which have been confirmed to actually help reduce cavities, minimize sensitivity, increase enamel hardness and improve the overall health of your teeth. Powerful, the professional-strength whitening gels are available with 10% and 16% carbamide peroxide concentrations. These whitening gels can provide results after just one treatment, though you should expect to see noticeable results in about a week. Featuring a customized bleaching tray, this customization is part of why Opalescence take-home whitening gels are so effective. You can further customize your experience with Opalescence take-home whitening gels by choosing from the various concentrations and flavors (Mint and Melon).