Method of making thermoplastic dental impression tray

Claim 1

A method of making a thermoplastic dental impression tray which is capable of being molded in the mouth of a patient after reheating, said method comprising the steps of: (a) mixing 45-55% by weight of a methylmethacrylate liquid monomer and 45-55% by weight of a suitable liquid plasticizer to form a plasticized liquid monomer; (b) mixing said plasticized liquid monomer with methylymethacrylate polymer powder in a ratio of 1:3-3.5 parts by weight to form a mixture; (c) allowing the mixture to reach a doughy-like state; (d) placing said mixture into a mold conforming to the desired structure of the tray; (e) heating the mold at a temperature of about 145°-155° C. for about 4-8 minutes under pressure of about 1,000-2,000 p.s.i. to provide a tray that may be subsequently molded in the patient's mouth after heating it to above about 135° F., with the tray accurately maintaining its molded structure after removal from the mouth; and (f) removing the tray from the mold.

Claim 2

A method of making a thermoplastic dental impression tray which is capable of being molded in the mouth of a patient after reheating, said method comprising the steps of: (a) mixing 45-55% by weight of a methylmethacrylate liquid monomer and 45-55% by weight of a suitable liquid plasticizer to form a plasticized liquid monomer; (b) mixing said plasticized liquid monomer with methylymethacrylate polymer powder in a ratio of 1:3-3.5 parts by weight to form a mixture; (c) allowing the mixture to reach a doughy-like state; (d) placing said mixture into a mold conforming to the desired structure of the tray; (e) heating the mold at a temperature of about 145°-155° C. for about 4-8 minutes under pressure of about 1,000-2,000 p.s.i. to provide a tray that may be subsequently molded in the patient's mouth after heating it to above about 135° F., with the tray accurately maintaining its molded structure after removal from the mouth; and (f) removing the tray from the mold.

Claim 12

A method of making a thermoplastic dental impression tray capable of being molded in the mouth of a patient after reheating, said method comprising the steps: a. blending not more than about 55% by weight of a non-crosslinked liquid methylmethacrylate monomer with not less than about 45% by weight of suitable liquid plasticizer in a container; b. placing the container in a cooler at a temperature of about -10° F.; c. mixing the liquid blend with a methlymethacrylate polymer powder in the ratio of about 3.5 parts by weight polymer powder to one part by weight of the liquid blend; d. pouring the mixture into a shallow pan; e. allowing the mixture to reach a doughy-like consistency; f. cutting the mixture into a plurality of bars weighing between 0.03-0.04 lbs.; g. placing a bar into a mold made of brass beryllium; h. heating the mold at a temperature of about 150° C. for about 41/2 minutes at a pressure of about 1,000 psi to sufficiently polymerize the monomer to provide a tray that may be molded in a patient's mouth after heating to above 135° F., with the tray accurately maintaining its molded structure after removal from the mouth characterized by a recovery rate of less than about 2%; i. cooling the mold at a temperature of about 45°-60° C. at a pressure of about 1000 psi for about 41/2 minutes; and j. removing the tray from the mold.

Claim 13

A method of making a thermoplastic dental impression tray capable of being molded in the mouth of a patient after reheating, said method comprising the steps: a. blending not more than about 55% by weight of a non-crosslinked liquid methylmethacrylate monomer with not less than about 45% by weight of suitable liquid plasticizer in a container; b. placing the container in a cooler at a temperature of about -10° F.; c. mixing the liquid blend with a methlymethacrylate polymer powder in the ratio of about 3.5 parts by weight polymer powder to one part by weight of the liquid blend; d. pouring the mixture into a shallow pan; e. allowing the mixture to reach a doughy-like consistency; f. cutting the mixture into a plurality of bars weighing between 0.03-0.04 lbs.; g. placing a bar into a mold made of brass beryllium; h. heating the mold at a temperature of about 150° C. for about 41/2 minutes at a pressure of about 1,000 psi to sufficiently polymerize the monomer to provide a tray that may be molded in a patient's mouth after heating to above 135° F., with the tray accurately maintaining its molded structure after removal from the mouth characterized by a recovery rate of less than about 2%; i. cooling the mold at a temperature of about 45°-60° C. at a pressure of about 1000 psi for about 41/2 minutes; and j. removing the tray from the mold.