This type of tooth whitening usually requires two visits. At the first appointment, impressions (molds) will be made of your teeth to fabricate custom, clear plastic trays. At your second appointment, you will try on the trays for proper fit and adjustments will be made if necessary. The trays are worn with a special whitening solution either twice a day for 30 minutes or overnight for a couple of weeks, depending on the degree of staining and desired level of whitening. It is normal to experience tooth sensitivity during the time you are whitening your teeth, but it will subside shortly after you have stopped bleaching. You will receive care instructions for your teeth and trays, and be encouraged to visit your dentist regularly to help maintain a beautiful, healthy, white smile.