How long should i leave 22% carbamide peroxide on my teeth before rinsing?

4 to 8 hrs: Take home trays are recommended over night independent of solution concentration, but if you have sensitive teeth then 4 to 5 hours are good enough. Wear the trays for 3 to 4 days. It all depends on how fast you want results. The longer you wear the faster the results.

1 hour: Most of the home bleaching solution are recommended for one hour, it is not necessary to wear them all night as the whitening gel will loose it's efficiency after one hour or so. If you want to rinse you can do it right away after you remove your trays, follow your dentist's recommendations.