Tooth whitening at home and preparing the bleaching rail requires an exactly fitting impression made of the teeth, leading to the preparation of a soft plastic rail and made in the dental lab that fits precisely.  It is very important to fit the rail correctly, as the gelatin shall only come into contact with the teeth, but not the gum. The whitening gel shall be inserted into this flexible rail and shall be placed onto the denture. It is advisable to use it at night, as it is important that it remains in place for at least 3-4 hours.