Opalescence Teeth Whitening Systems instructions September 26, 2015 webadmin ⋅ Teeth Whitening ⋅ Opalescence Tooth Whitening Systems has 20% Carbamide Peroxide. To get refills of the Syringe with gel i found it cheaper on Amazon. So after i finish with the Doctor supply i will be purchasing my re Like 0 Thanks! You've already liked this « Crest 3D WhiteStrips and Crest 3D Vivid Toothpaste- Double Brighten/Whiten Your Smile! ;) » All About Teeth Whitening | How to Whiten Your Teeth At Home!