used 2hour white after professional bleaching with dentist. i used the 2 hour white NOT as directed....i placed gel in trays from professional whitening and kept gel in over night. i use the gel once every 4 to 6 months as a touch-up when the white from professional whitening begins to dull. the rembrandt product works GREAT to restore the bright white from before. definitely a deal for the price! i definitely wont go back to the $400+ whitening at the dentist!