The main purposes of dental bridge are restoring function and esthetics. To achieve these aims, the dentist must make careful selection of impression materials to be used. Depending of specific patient needs, the dental bridge can be constructed using metal alloys, ceramic or plastic materials or a combination. Regardless of the materials selected, the dentist must obtain an accurate replica of the patient’s dentate arches and of the prepared abutment teeth.
Transfer to the laboratory of the precise relationship of adjacent and opposite oral structures is also critical. These procedures entail obtaining a negative copy of tissue surfaces by impressing mouldable material, usually contained in impression tray, into contact with oral tissue surfaces and allowing it to harden, or become elastic. The entire impression material and tray assembly can be removed from the contact without significant harm to the tissues or to the impression material.