Question: how long do you use teeth whitening trays?
Answer: Use no more than 1/3 to ½ of the syringe, or one bulb per tray. Brush teeth before inserting tray. 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.