Solid free-form fabrication methods for the production of dental restorations

Abstract

Solid free form fabrication techniques can be utilized indirectly to manufacture substrates, dies, models, near-net shapes, shells, and wax-ups that are then used in the manufacture of dental articles. Digital light processing is the most preferred indirect method for the production of substrates. After the substrates are produced, various coating or deposition techniques such as gel casting, slip casting, slurry casting, pressure infiltration, dipping, colloidal spray deposition or electrophoretic deposition are used to manufacture the dental article.

1 . A process for manufacturing a dental article comprising: 
 obtaining digital data of a patient's tooth or teeth;    designing an enlarged die or mold based on the digital data of the patient's tooth or teeth;    rapid-prototyping the enlarged die or mold;    applying ceramic particulate material onto or into the enlarged die or mold;    sintering the ceramic particulate material to form the dental article.    
     
     
         2 . The process of  claim 1  wherein the step of obtaining digital data of a patient's tooth or teeth comprises scanning a master die, a working die, or a wax-up of a dental restoration, or intraorally scanning the patient's teeth.  
     
     
         3 . The process of  claim 1  wherein the enlarged die or mold is enlarged according to an amount the ceramic particulate material will shrink during the sintering step.  
     
     
         4 . The process of  claim 1  wherein the step of designing an enlarged die or mold comprises creating a virtual die or mold with the use of a computer.  
     
     
         5 . The process of  claim 1  further comprising preparing the enlarged die or mold after the step of rapid-prototyping the enlarged die or mold.  
     
     
         6 . The process of  claim 5  wherein the step of preparing the enlarged die or mold comprises trimming the die or mold or coating the die or mold with conductive paint.  
     
     
         7 . The process of  claim 1  wherein the step of applying ceramic particulate material onto the enlarged die or mold comprises gel casting, slip casting, slurry casting, pressure infiltration, pressure casting, direct coagulation, dipping, colloidal spray deposition, electrophoretic deposition.  
     
     
         8 . The process of  claim 1  wherein the step of applying ceramic particulate material into the enlarged die or mold comprises filling the mold by injection molding, extrusion, heat pressing, hot pressing, hot casting, centrifugal casting, gravity casting, pressure casting, gel casting, slip casting, slurry casting and slip pressing.  
     
     
         9 . The process of  claim 1  wherein the ceramic particulate material is in the form of a suspension, slurry, slip, gel, pellet or feedstock.  
     
     
         10 . The process of  claim 1  further comprising heat-treating the ceramic particulate material prior to sintering to release the die or mold and to eliminate organic ingredients from the ceramic particulate.  
     
     
         11 . The process of  claim 1  wherein the step of sintering the ceramic particulate material comprises sintering to full density.  
     
     
         12 . The process of  claim 1  further comprising finishing the dental article after the step of sintering the ceramic particulate material.  
     
     
         13 . The process of  claim 12  wherein finishing the dental article after the step of sintering the ceramic particulate comprises applying one or more layers of porcelain, glass, or glass-ceramic having a coefficient of thermal expansion (CTE) up to about ±2×10−6/C of the CTE of the sintered ceramic particulate material.  
     
     
         14 . The process of  claim 1  wherein the step of rapid-prototyping the enlarged die comprises rapid-prototyping by stereolithography, photo-stereolithography, digital light processing, selective area laser deposition, selective laser sintering (SLS), electrophoretic deposition(EPD), robocasting, fused deposition modeling (FDM), laminated object manufacturing (LOM), or 3D printing.  
     
     
         15 . The process of  claim 1  wherein the ceramic particulate material is selected from the group consisting of zirconia, ytrria, hafnia, alumina, ceria, magnesia, titania, silicon nitride, silicon carbide, silica-alumina-nitride, mullite, garnets, porcelain, or mixtures thereof.  
     
     
         16 . The process of  claim 15  wherein the ceramic particulate comprises a solid solution, agglomerates, complexes or mixtures thereof.  
     
     
         17 . The process of  claim 15  wherein the porcelain comprises glass, leucite, lithium disilicate, mullite or mica.  
     
     
         18 . The process of  claim 15  wherein the zirconia comprises tetragonal zirconia.  
     
     
         19 . The process of  claim 1  wherein the enlarged die or mold is fabricated of die stone, clay, plaster of paris, gypsum, silica, leucite, zirconia, hafnia, zirconia, alumina, magnesia, zircon, aluminosilicate, cordierite, mica, silicon nitride, silicon carbide, silica-alumina-nitrides, mullite, garnet, or mixtures thereof.  
     
     
         20 . The process of  claim 19  wherein the silica comprises crystalline silica, amorphous silica, colloidal silica, or mixtures thereof.  
     
     
         21 . The process of  claim 1  wherein the die or mold thermally decomposes during the sintering step.  
     
     
         22 . The process of  claim 1  wherein the enlarged die or mold is fabricated of a wax, paraffin, rubber, plastic, polymeric material, thermoplastic material, thermosetting material or light curable resin or mixture thereof.  
     
     
         23 . The process of  claim 22  wherein the light curable resin is curable by visible or UV light.  
     
     
         24 . The process of  claim 22  wherein the light curable resin comprises acrylic, epoxy, silicone resins or monomers or mixtures thereof.  
     
     
         25 . The process of  claim 1  wherein dental article is in the shape of a coping, framework, pontic, denture teeth, a bridge, crown, space maintainers, tooth replacement appliance, orthodontic retainer, denture, post, jacket, inlay, onlay, facing, veneer, facet, implant, abutment, splint, partial crown, cylinder, pin, or connector.  
     
     
         26 . A dental article formed by the method comprising: 
 obtaining digital data of a patient's tooth or teeth;    designing an enlarged die or mold based on the digital data of the patient's tooth or teeth;    rapid-prototyping the enlarged die or mold;    applying ceramic particulate onto or into the enlarged die or mold; and    sintering the ceramic particulate material to form the dental article.    
     
     
         27 . A method for producing a dental article comprising: 
 obtaining three-dimensional digital data relating to a patient's dentition;    designing an enlarged virtual prosthesis for said dentition using the three-dimensional digital data;    transmitting digital data corresponding to the virtual prosthesis to an automated prototyping system;    producing an enlarged prototype of the dental prosthesis with the automated prototyping system;    applying a material that can be hardened or cured on the prototype;    allowing the material to harden partially or completely to form an enlarged shell around the prototype;    removing the prototype from within the shell to produce an enlarged die or mold for the dental prosthesis;    filling the enlarged mold with a ceramic particulate material to produce a green body in a shape of the dental article;    removing the enlarged mold; and    sintering the green body to produce the dental article.    
     
     
         28 . The method of  claim 27  wherein the prototype is fabricated of a wax, thermoplastic material, thermosetting material or light curable resin.  
     
     
         29 . The method of  claim 28  wherein the wax comprises paraffin wax, microcrystalline wax, synthetic hydrocarbon wax, oxidized polyethylene wax or a mixture thereof.  
     
     
         30 . The method of  claim 27  wherein the prototype is fabricated of thermally decomposable material.  
     
     
         31 . The method of  claim 27  wherein the mold is fabricated of a plastic material.  
     
     
         32 . The method of  claim 27  wherein the mold is fabricated of silicone rubber.  
     
     
         33 . The method of  claim 27  wherein the mold is fabricated of an investment material.  
     
     
         34 . The method of  claim 27  wherein the enlarged die or mold is fabricated of die stone, clay, plaster of paris, gypsum, silica, leucite, zirconia, hafnia, alumina, magnesia, zircon, aluminosilicate, cordierite, mica, silicon nitride, silicon carbide, silica-alumina-nitrides, mullite, garnet, or mixtures thereof.  
     
     
         35 . The method of  claim 27  wherein the step of applying a material on the prototype comprises injection molding, extrusion, heat pressing, hot pressing, hot casting, centrifugal casting, gravity casting, pressure casting, gel casting, slip casting, or slurry casting.  
     
     
         36 . The method of  claim 27  wherein the ceramic particulate material is in the form of a suspension, slurry, slip, gel, pellet or feedstock.  
     
     
         37 . The method of  claim 27  wherein the dental article is in the shape of a coping, framework, pontic, denture teeth, a bridge, crown, space maintainers, tooth replacement appliance, orthodontic retainer, denture, post, jacket, inlay, onlay, facing, veneer, facet, implant, abutment, splint, partial crown, cylinder, pin, or connector.  
     
     
         38 . A dental article formed by the method comprising: 
 obtaining three-dimensional digital data relating to a patient's dentition;    designing an enlarged virtual prosthesis for said dentition using the three-dimensional digital data;    transmitting digital data corresponding to the virtual prosthesis to an automated prototyping system;    producing an enlarged prototype of the dental prosthesis with the automated prototyping system;    applying a material that can be hardened or cured on the prototype;    allowing the material to harden partially or completely to form a shell around the prototype;    removing the prototype from within the shell to produce a mold for the dental article;    filling the mold with a ceramic particulate material to produce a green body in a shape of a dental article;    removing the mold material; and    sintering the green body to produce the dental article.    
     
     
         39 . The dental article of  claim 38  formed by the method further comprising: 
 finishing the dental article after the step of sintering the green body, wherein the finishing step comprises applying one or more layers of porcelain, glass, or glass-ceramic having a coefficient of thermal expansion (CTE) up to about ±2×10−6/C of the CTE of the sintered dental article.    
     
     
         40 . A process for the mass production dental articles comprising: 
 obtaining digital data of a number of patients' tooth or teeth;    designing enlarged substrates, dies or molds based on the digital data of the patients' tooth or teeth;    concurrently rapid-prototyping a multiplicity of the enlarged substrates, dies or molds;    preparing the enlarged substrates, dies or molds for coating, deposition, casting, pressing or a molding process;    simultaneously applying ceramic particulate material onto a multiplicity of the substrates or into a multiplicity of the enlarged dies or molds;    sintering a multiplicity of green bodies to form the dental articles.    
     
     
         41 . The process of  claim 40  wherein simultaneously applying ceramic particulate onto a multiplicity of the substrates or into a multiplicity of the enlarged dies or molds comprises casting, pressing, molding or investing.  
     
     
         42 . The process of  claim 40  wherein the step of obtaining digital data of a patient's tooth or teeth comprises scanning a master die, a working die, or a wax-up of a dental article, or intraorally scanning the patient's teeth.  
     
     
         43 . The process of  claim 40  wherein the enlarged substrates, dies or molds is enlarged according to an amount the ceramic particulate will shrink during the sintering step.  
     
     
         44 . The process of  claim 40  wherein the step of designing enlarged substrates, dies or molds comprises creating virtual substrates, dies or molds with the use of a computer.  
     
     
         45 . The process of  claim 40  further comprising preparing the enlarged substrates, dies or molds after the step of rapid-prototyping the enlarged substrates, dies or molds.  
     
     
         46 . The process of  claim 42  wherein the step of preparing the enlarged substrates, dies or molds comprises trimming the substrates, dies or molds or coating the substrates, dies or molds with conductive paint.  
     
     
         47 . The process of  claim 40  wherein the step of applying ceramic particulate material onto the enlarged substrates, dies or molds comprises gel casting, slip casting, slurry casting, pressure infiltration, pressure casting, direct coagulation, dipping, colloidal spray deposition, electrophoretic deposition.  
     
     
         48 . The process of  claim 40  wherein the step of applying ceramic particulate material into the enlarged substrates, dies or molds comprises filling the mold by injection molding, extrusion, heat pressing, hot pressing, hot casting, centrifugal casting, gravity casting, pressure casting, gel casting, slip casting, slurry casting and slip pressing.  
     
     
         49 . The process of  claim 40  wherein the ceramic particulate material is in the form of a suspension, slurry, slip, gel, pellet or feedstock.  
     
     
         50 . The process of  claim 40  further comprising heat-treating the ceramic particulate material prior to sintering to release the substrates, dies or molds and to eliminate organic ingredients from the ceramic particulate.  
     
     
         51 . The process of  claim 40  wherein the step of sintering the ceramic particulate material comprises sintering to full density.  
     
     
         52 . The process of  claim 40  further comprising finishing the dental article after the step of sintering the ceramic particulate material.  
     
     
         53 . The process of  claim 52  wherein finishing the dental article after the step of sintering the ceramic particulate comprises applying one or more layers of porcelain, glass, or glass-ceramic having a coefficient of thermal expansion (CTE) up to about ±2×10−6/C of the CTE of the sintered ceramic particulate material.  
     
     
         54 . The process of  claim 40  wherein the step of rapid-prototyping the multiplicity of the enlarged substrates, dies or molds comprises rapid-prototyping by stereolithography, photo-stereolithography, digital light processing (DLP), selective area laser deposition, selective laser sintering (SLS), electrophoretic deposition (EPD), robocasting, fused deposition modeling (FDM), laminated object manufacturing (LOM), or 3D printing.  
     
     
         55 . The process of  claim 40  wherein the ceramic particulate material is selected from the group consisting of zirconia, ytrria, hafnia, alumina, ceria, magnesia, titania, silicon nitride, silicon carbide, silica-alumina-nitride, mullite, garnets, porcelain, or mixtures thereof.  
     
     
         56 . The process of  claim 55  wherein the ceramic particulate material comprises a solid solution, agglomerates, complexes or mixtures thereof.  
     
     
         57 . The process of  claim 55  wherein the porcelain comprises glass, leucite, lithium disilicate, mullite or mica.  
     
     
         58 . The process of  claim 55  wherein the zirconia comprises tetragonal zirconia.  
     
     
         59 . The process of  claim 40  wherein the enlarged substrates, dies or molds are fabricated of die stone, clay, plaster of paris, gypsum, silica, leucite, zirconia, hafnia, zirconia, alumina, magnesia, zircon, aluminosilicate, cordierite, mica, silicon nitride, silicon carbide, silica-alumina-nitrides, mullite, garnet, or mixtures thereof.  
     
     
         60 . The process of  claim 59  wherein the silica comprises crystalline silica, amorphous silica, colloidal silica, or mixtures thereof.  
     
     
         61 . The process of  claim 40  wherein the substrates, dies or molds thermally decompose during the sintering step.  
     
     
         62 . The process of  claim 40  wherein the enlarged substrates, dies or molds are fabricated of a wax, paraffin, rubber, plastic, polymeric material, thermoplastic material, thermosetting material or light curable resin or mixture thereof.  
     
     
         63 . The process of  claim 62  wherein the light curable resin is curable by visible or UV light.  
     
     
         64 . The process of  claim 62  wherein the light curable resin comprises acrylic, epoxy, silicone resins, or monomers or mixtures thereof.  
     
     
         65 . The process of  claim 40  wherein the dental article is in the shape of a coping, framework, pontic, denture teeth, a bridge, crown, space maintainers, tooth replacement appliance, orthodontic retainer, denture, post, jacket, inlay, onlay, facing, veneer, facet, implant, abutment, splint, partial crown, cylinder, pin, or connector.  
     
     
         66 . Dental articles formed by the method comprising: 
 obtaining digital data of a number of patients' tooth or teeth;    designing enlarged substrates, dies or molds based on the digital data of the patients' tooth or teeth;    concurrently rapid-prototyping a multiplicity of the enlarged substrates, dies or molds;    preparing the enlarged substrates, dies or molds for coating, deposition, casting, pressing or a molding process;    simultaneously applying ceramic particulate onto a multiplicity of the substrates or into a multiplicity of the enlarged dies or molds;    sintering a multiplicity of green bodies to form the dental articles.