Provisionals provide a duplicate of the desired changes in esthetics/function which were established in the diagnostic wax-up. The provisional is also trial therapy to allow the patient to see and feel the expected changes. Pre-treatment shells are relined at the time of tooth preparation and are made from the design created by the diagnostic wax-up. They can be used for long-term temporary restorations and can be produced via a single layer or multilayer technique (2 different product levels).