Question: how long should you leave on teeth whitening gel?
Answer: Lightly tap tray to adapt sides to teeth. Unless directed otherwise, wear Opalescence 10% for 8-10 hours or overnight, Opalescence 15% for 4-6 hours, Opalescence 20% for 2-4 hours, and Opalescence 35% for thirty minutes. Remove Excess gel with clean finger or soft toothbrush.