Following in-office whitening treatment, a Lumibrite take-home whitening kit is recommended for maximum whitening and maintenance. Whitening trays, created from impressions taken by your dentist, are used to apply the whitening gel to your teeth at your convenience.Treatment time for take-home whitening kits varies depending upon the formulation, as well as the desired results. The 32-percent formulation requires a mere three-minute treatment each day for a period of two weeks. The 16-percent and 22-percent formulations require one or two treatments, applied for one or two hours a day, for two weeks.