Methods of producing dental restorations using CAD/CAM and manufactures thereof
View Patent ↗Ceramic precursor powders are combined with a binder and pressed into blocks or similar shapes to form green bodies. The ceramic powders consist of fairly uniform particles thoroughly dispersed to be essentially free of agglomerates such that it will sinter predictably and isotropically without appreciable distortion. The green bodies may be soft-sintered to a bisque density less than about eighty five percent of the final density. The soft-sintered blocks are then milled to a desired shape and sintered to a final density rendering a high strength dental restorative material. The material may be aluminum oxide, partially stabilized zirconium oxide, mixtures of the two, mullite or any suitable oxide that may be sintered to high strength (i.e., greater than 250 MPa).
1. A method of manufacturing a dental restoration comprising:
fabricating a die for the dental restoration, wherein the die is oversized and wherein the die is partially sintered prior to application of the powder thereon;
applying powder selected from ceramic, glass ceramic powder and mixtures thereof onto the die in the shape of the dental restoration;
sintering the powder to form the dental restoration.
2. The method of claim 1 wherein the die is oversized in an amount to account for proper shrinkage of the powder after sintering.
3. The method of claim 1 wherein fabricating the die comprises machining the die from a block of material.
4. The method of claim 3 wherein the machined die is machined from data taken from a patient's mouth.
5. The method of claim 3 wherein the machined die is machined from data taken from an impression of a patient's mouth.
6. The method of claim 1 wherein the die is removed from the shaped powder prior to sintering.
7. The method of claim 1 wherein the dental material is sintered in the range of about 1400 to about 1500° C. for a time ranging from about one to about four hours.
8. The method of claim 1 wherein the ceramic powder linearly shrinks isotropically about 8 to about 25% during sintering.
9. The method of claim 1 wherein the powder comprises a material that may be sintered to a strength of greater than about 250 MPa.
10. The method of claim 1 wherein the powder comprises aluminum oxide, partially stabilized zirconium oxide, mullite, or mixtures thereof.
11. The method of claim 1 wherein the die is fabricated of a porous material.
12. The method of claim 11 wherein the porous material comprises gypsum.
13. The method of claim 1 wherein applying the powder comprises pressing, extrusion, slip casting, gel casting or injection molding.
14. The method of claim 13 wherein the dental restoration is pressed at 50,000 psi at about ambient temperature.
15. The method of claim 1 wherein one or more binders is mixed with the powder prior to application to the die.
16. The method of claim 1 wherein the powder is of uniform particle size.
17. The method of claim 16 wherein the particle size is in the range between about 1 and about 3 microns.
18. The method of claim 1 wherein the dental restoration is an orthodontic appliance, bridge, space maintainer, tooth replacement appliance, splint, crown, partial crown, denture, post, tooth, jacket, inlay, onlay, facing, veneer, facet, implant, abutment, cylinder, or connector.
19. The method of claim 1 wherein the powder is substantially homogeneous.