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US 6,484,791 B1Granted
Plunger for a pressing furnace
AssigneeJeneric/Pentron Incorporated
InventorPatricia E. Vidal
Life of this patent
Estimating the term…
Abstract
A disposable plunger for use in a pressing furnace for the fabrication of dental restorations. The plunger is fabricated of a partially sintered ceramic material. The plunger is fabricated by known casting methods. The mold used for making the plunger can be supplied by a manufacturer of molds or can be easily made by using an alumina or similar plunger as a model. Laborious cleaning and grinding are not required with plungers herein described. Cracking problems that occur with prior art plungers are decreased, if not completely eliminated.
Claims7
Method of making a dental restoration using a pressing furnace comprising:
- pushing an internal plunger onto an external plunger whereby the external plunger contacts a dental ceramic material and forces the dental ceramic material to flow into a mold cavity space to form the dental restoration;
- raising the internal plunger;
- and
- removing the external plunger from the pressing furnace and disposing of the external plunger;
- whereby the external plunger is fabricated of a second ceramic material having a coefficient of thermal expansion higher than the coefficient of thermal expansion of the dental ceramic material.
2 more elements
Dependencies are inferred from the claim text.