Discoloration on teeth appears naturally and as a result of food, smoking, coffee or wine. Such discolorations cannot be removed by brushing the teeth but need bleaching. There are different methods, but home bleaching with custom made trays often is the most effective and lasting method. The treatment time can vary between patients, but takes normally 2 to 3 weeks. The trays can also be used for fluoride-application or for some additional bleaching after several years.