After a thorough exam of your teeth, gums and supporting bone structure, your Dentist will advise you whether tooth whitening is a safe option for your smile. If the agreed-upon treatment is an in-office, Dentist-supervised treatment, your Clinician will:Prepare your mouth by covering your lips and gums so that only your teeth are exposed. Apply a professional-strength whitening gel to your teeth. Expose your teeth to a special light for 15 minutes to help the gel penetrate and whiten your teeth. Invite you to watch TV or listen to music as you relax in the chair. Reapply the gel and light treatment two more time.