Opalescence gel is applied to a mouth guard or retainer before being worn over teeth:

• Brush and floss your teeth
• Place a small amount of gel in each tooth compartment of the tray before applying the retainer to your teeth. Remove any excess gel on gums with your finger or a dry toothbrush.
• Wear time varies by strength. See chart here.

Once the desired shade has been reached, continue to apply Opalescence once every two weeks to maintain your white teeth.

Please find full instructions here.