Advertised as the most effective and safest system offered in dentists' offices, Opalescence Tooth Whitening System is consist of a package of four syringes pre-filled with melon flavored dispensing tips. There is minimal salivary flow as the patented, sticky and highly vicious formula of this system that stay in the tray and on the teeth. The significant water in this whitening system formula minimizes dehydration of the teeth. The Opalescence Tooth Whitening System contains everything needed to whiten teeth. It safely bleaches teeth to lighten the discoloration caused by food, coffee, tobacco, and aging. This system is designed to be worn for about 30 minutes a day, but can be worn all night for night bleaching. The whitening gel used has to be dispensed by a dentist. It can be applied at home using a clear and inconspicuous custom fitted tray. However, an all-natural teeth whitener can be the best alternative for Opalescence Tooth Whitening System which also requires wearing fitted trays filled with a whitening gel for only 15 to 30 minutes a day, and is also less expensive.