Abstract: A thermoformed plastic dental retainer and method of construction including rapid cooling of the retainer, typically using a refrigerant coolant, as the retainer sets on a dental impression cast. The dental retainer is constructed by first forming an impression of a patient's upper or lower dentition and constructing the cast from the impression The retainer is vacuum-thermoformed over the cast using a sheet, plate or disc of thermoformable plastic and a vacuum or pressure thermoforming machine. As the thermoformed plastic retainer sets on the cast, the retainer is rapidly cooled typically by spraying a refrigerant coolant on the retainer.

Abstract: A thermoformed plastic dental retainer and method of selectively straightening crooked or maloccluded teeth and retaining the straightened teeth using the retainer. The dental retainer is constructed by first forming an impression of a patient's upper or lower dentition and constructing a cast from the impression. The retainer is vacuum thermoformed over the cast using a sheet, plate or disc of thermoformable plastic and a vacuum or pressure thermoforming machine. A protrusion or divot is formed in the retainer on the labial or lingual side of each tooth which is to be repositioned lingually or labially, respectively, and a gap, opening or window is formed in the retainer on the opposite side of the divot to accommodate unhindered tooth repositioning movement. As the retainer is worn on the patient's dentition over a period of days or weeks, the projecting divots apply pressure to the respective teeth and push the teeth into the gap or window of the retainer to a straightened position.