Abstract: A preform consisting of a planar section of a thermoplastic having a glass transition temperature a few degrees above body temperature and a softening point below about 160.degree. F. is used to form custom, quadrant, dental impression trays. The preform is of uniform thickness except for a raised ridge, extending across both sides of the sheet, terminating in an elongated handle at one end, and dividing the preform into a pair of asymmetrical sections shaped to fit the buccal and the lingual musculature along a dental arch. The tray may be heated above its softening point and the side sections bent in a common direction about the central ridge so that their ends extend substantially parallel with one another to form a trough having a U-shaped cross-section.

Abstract: A method of making a thermoplastic dental impression tray which can be heated, placed into the patient's mouth where it can be intimately molded to approximate the patient's tissues and characterized in that the tray will maintain its molded structure to a high degree of accuracy. Methyl methacrylate monomer liquid and polymer powder are mixed together and the mixture is allowed to reach a doughy state. The mixture is placed into a mold conforming to the desired structure of the tray. The mold is then heated for a sufficient time under pressure to polymerize the monomer to provide a tray characterized in that when heated to above 135.degree. F. it wil become soft enough so that it can be placed into the patient's mouth for intimate molding therein and which will become so hard when cooled in the mouth that it will exhibit a recovery rate of less than 2% after removal from the mouth so that the precision of the impression is accurately maintained.

Abstract: Dental impression trays, full, quadrant and anterior, shaped to closely conform to either the maxillary or mandibular ridges for either dentulous or edentulous cases have sections which anatomically approximate surrounding tissue areas with peripheral border relief for muscle attachments and contiguous tissue areas. The trays are formed of an acrylic having a glass transition temperature slightly above body temperature so that they may be heated above their softening temperature exteriorly of the oral cavity, positioned over the oral area of which an impression is to be made, and then manually molded to approximate intimate conformity to the desired oral structures before they harden. A pleat formed in the central vault of a maxillary tray accommodates transverse adjustment. When the tray cools and hardens it is removed, allowing a custom final impression to be thus formed in a single procedure.