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: An orientation guide for adjustment of the occlusal plane of a set of dentures relative to the cranial anatomy of a patient includes a flat plate having a curved bite piece and a pair of laterally and distally extending wing sections projecting in opposed directions from the proximal end of the bite piece. A pair of wire guide extensions are supported in the distal ends of each of the wings and include end sections adjustably supported parallel to and above the wings and adapted to be aligned with the patient's ala-tragal line to facilitate parallelism of the occlusal plane to that line.

Abstract: A toothbrush having a handle formed of a thermoplastic material with a glass transition temperature in the range of about 110.degree.-140.degree. F. The handle is heated to soften the plastic shaped to a desired configuration while pliable, then allowed to cool so as to retain the desired configuration when it hardens. The brush bristles may be detached from the handle when worn and replaced by a fresh set.