Usually made from plastic or metal, dental impression trays hold the impression material while the impression is being created intraorally, and then provide a firm backing to make sure the impression is free of distortions as it finishes setting. Some impression trays are designed to be reused while others essentially become a part of the impression when it is sent to the dental laboratory. Available in various sizes, trays are designed to capture a specific part of the patient’s anatomy such as a full arch, a quadrant or opposing dentition. Because different restorative situations require the use of different types of trays, it can be helpful to have a variety of tray sizes and styles on hand.