features A teeth whitening pen is a plastic tube that’s small enough to comfortably fit in your hand. It resembles a pen but has whitening gel inside it which you can then “draw” onto your teeth. Usually, you can see the difference in whiteness right after using it. The main ingredient in teeth whitening gel pens is peroxide. According to the American Dental Association, carbamide peroxide breaks down into hydrogen peroxide, which then allows oxygen to get to your teeth enamel. How to use 1.Brush and floss your teeth. 2.Dry your teeth with a tissue. 3.Twist the bottom of the pen clockwise(to the right) until a little gel flows from the gel chamber on to the brush. For first use you may need more twisting. 4.Smile wide keeping lips away from your teeth. 5.Use even brush strokes to apply a thin layer of gel to each tooth. Do NOT apply gel to the gums. 6.Relax your lips after 30 seconds. 7.Avoid eating or drinking for 30 minutes after treatment.