Method for making custom dental impression trays

Claim 1

The method for making, on a study model of the patient's jaw ridge portion, a custom dental impression tray used for taking a precise final impression of at least that portion of a jaw ridge of a patient to receive a dental prosthesis, which method comprises precutting a flat sheet of thermoplastic material to form a flat sheet blank of a thickness 1/16 inch (1.6 mm) to 3/16 inch (4.8 mm) having a generally arcuate outer periphery and being of a width great enough to overhang the opposite outer lateral margins of the jaw ridge portion of the study model, building up the study model of the jaw ridge portion by packing successive overlying layers of thin tissue paper spacing material onto the model and thereby forming a composite layer having a total thickness of about 1 mm, to 3 mm, approximately equal to the desired thickness of final impression material to be used in the tray in taking the jaw ridge final impression, heating the flat sheet blank of thermoplastic material hard and tough at ambient temperatures until it reaches a deformable, nonresilient, nonliquid condition, manually shaping the heated flat sheet blank into a tray by deforming it onto the built-up study model so as to form a through closely complemental to the shape of at least a portion of the jaw ridge portion of the built-up study model but spaced from the model by the composite packing layer built up on it, and cooling the shaped tray sufficiently that the thermoplastic material returns to its hard and tough condition to preserve its shaped form for use as a custom dental impression tray.

Claim 2

The method for making, on a study model of the patient's jaw ridge portion, a custom dental impression tray used for taking a precise final impression of at least that portion of a jaw ridge of a patient to receive a dental prosthesis, which method comprises precutting a flat sheet of thermoplastic material to form a flat sheet blank of a thickness 1/16 inch (1.6 mm) to 3/16 inch (4.8 mm) having a generally arcuate outer periphery and being of a width great enough to overhang the opposite outer lateral margins of the jaw ridge portion of the study model, building up the study model of the jaw ridge portion by packing successive overlying layers of thin tissue paper spacing material onto the model and thereby forming a composite layer having a total thickness of about 1 mm, to 3 mm, approximately equal to the desired thickness of final impression material to be used in the tray in taking the jaw ridge final impression, heating the flat sheet blank of thermoplastic material hard and tough at ambient temperatures until it reaches a deformable, nonresilient, nonliquid condition, manually shaping the heated flat sheet blank into a tray by deforming it onto the built-up study model so as to form a through closely complemental to the shape of at least a portion of the jaw ridge portion of the built-up study model but spaced from the model by the composite packing layer built up on it, and cooling the shaped tray sufficiently that the thermoplastic material returns to its hard and tough condition to preserve its shaped form for use as a custom dental impression tray.