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

• US 9,155,597 B2
• Filed: 07/31/2008
• Issued: 10/13/2015
• Est. Priority Date: 07/10/1998
• Status: Expired due to Term

• Current Assignee: Ivoclar Vivadent AG
• Original Assignee: Ivoclar Vivadent AG
• Inventors: Brodkin, Dmitri G., Panzera, Carlino, Panzera, Paul
• Primary Examiner(s): Tentoni, Leo B
• Application Number:
  US12/183,594
• Publication Number:
  US 20080318189A1
• Time in Patent Office: 2,630 Days
• Field of Search: 264/16, 264/17, 264/19, 264/113, 264/317
• US Class Current: 1/1
• CPC Class Codes: A61C 13/0003 Making bridge-work, inlays, implants or the like
• CPC Class Codes: A61C 13/0004 Computer-assisted sizing or machining of dental prostheses
• CPC Class Codes: A61C 13/0019 using three dimensional printing
• CPC Class Codes: A61C 5/35 Pins; Mounting tools or dispensers therefor
• CPC Class Codes: A61C 5/77 Methods or devices for making crowns
• CPC Class Codes: A61K 6/802 comprising ceramics
• CPC Class Codes: A61K 6/807 comprising magnesium oxide
• CPC Class Codes: A61K 6/816 comprising titanium oxide
• CPC Class Codes: A61K 6/818 comprising zirconium oxide
• CPC Class Codes: A61K 6/822 comprising rare earth metal oxides
• CPC Class Codes: A61K 6/838 Phosphorus compounds, e.g. apatite
• CPC Class Codes: A61K 6/84 comprising metals or alloys
• CPC Class Codes: A61K 6/849 comprising inorganic cements
• CPC Class Codes: A61K 6/884 comprising natural or synthetic resins
• CPC Class Codes: A61K 6/887 Compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61K 6/891 Compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61K 6/893 Polyurethanes
• CPC Class Codes: B29C 64/153 using layers of powder being selectively joined, e.g. by selective laser sintering or melting
• CPC Class Codes: B29C 64/165 using a combination of solid and fluid materials, e.g. a powder selectively bound by a liquid binder, catalyst, inhibitor or energy absorber
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 80/00 : Products made by additive manufacturing
• CPC Class Codes: C08L 33/08 : Homopolymers or copolymers of acrylic acid esters
• CPC Class Codes: C08L 63/00 : Compositions of epoxy resins; Compositions of derivatives of epoxy resins
• CPC Class Codes: C08L 83/04 : Polysiloxanes

Abstract

Solid free form fabrication techniques such as fused deposition modeling and three-dimensional printing are used to create a dental restoration. Three-dimensional printing includes ink-jet printing a binder into selected areas of sequentially deposited layers of powder. Each layer is created by spreading a thin layer of powder over the surface of a powder bed. Instructions for each layer may be derived directly from a CAD representation of the restoration. The area to be printed is obtained by computing the area of intersection between the desired plane and the CAD representation of the object. All the layers required for an aesthetically sound restoration can be deposited concurrently slice after slice and sintered/cured simultaneously. The amount of green body oversize is equivalent to the amount of shrinkage which occurs during sintering or curing. While the layers become hardened or at least partially hardened as each of the layers is laid down, once the desired final shaped configuration is achieved and the layering process is complete, in some applications it may be desirable that the form and its contents be heated or cured at a suitably selected temperature to further promote binding of the powder particles.

Claims

1. A process for manufacturing dental restorations consisting essentially of:

(a) depositing a layer of a slurry of a ceramic material and a binder;

(b) curing the layer of the ceramic material and binder;

(c) repeating steps (a) and (b) a number of times by directly depositing a next layer of a slurry of a ceramic material onto a previous layer to produce a number of layers of ceramic material which are bonded to one another to form a shape of a dental restoration, wherein the layers vary by mechanical properties comprising strength, fracture toughness and wear, to provide a functionally gradient structure;

(d) hardening the shaped material to form the dental restoration.

2. The method of claim 1 wherein hardening comprises sintering or curing the shaped material.

3. The process of claim 1 further comprising burning out the binder prior to hardening step (d).

4. The process of claim 3 wherein the binder is removed during the hardening step (d).

5. The process of claim 1 wherein the hardening step comprises sintering the shaped material to full density.

6. The process of claim 1 wherein the ceramic material comprises alumina, zirconia, mullite, silica, spinel, tricalcium phosphate, apatite, fluoroapatite, hydroxyapatite, or mixtures thereof.

7. The process of claim 1 wherein the layers of ceramic material form a selected pattern.

8. The process of claim 7 wherein the selected pattern is based on a computer assisted design.

9. The process of claim 1 wherein pigments, opacifiers, and/or fluorescing agents are added to the ceramic material prior to deposition thereof.

10. The process of claim 1 wherein pigments, opacifiers, and/or fluorescing agents are added to the ceramic material after deposition thereof.

11. The process of claim 1 wherein pigments, opacifiers, and/or fluorescing agents are added to the ceramic material during deposition thereof.

12. The process of claim 1 wherein the binder comprises an inorganic or an organic material.

13. The process of claim 1 wherein the binder comprises a molten thermoplastic material or a wax-containing material.

14. The process of claim 1 wherein the binder comprises polycarbosilazane or tetraethylorthosilicate.

15. The process of claim 1 wherein the dental restoration comprises denture teeth, bridges, crowns, space maintainers, tooth replacement appliances, orthodontic parts, orthodontic retainers, dentures, posts, jackets, inlays, onlays, facings, veneers, facets, implants, abutments, splints, partial crowns, teeth, cylinders, pins, and connectors.

16. A process for producing a dental restoration consisting essentially of:

providing a mixture of ceramic powder material dispersed in a binder; and

dispensing the mixture from a dispensing apparatus onto a platform to build a free-standing three dimensional dental restoration layer by layer, wherein each layer is deposited directly onto a previous layer by the dispensing apparatus, and wherein each layer can vary by mechanical properties comprising strength, fracture toughness and wear, to provide a functionally gradient structure.

17. The process of claim 16 comprising curing a layer before dispensing the next layer.

18. The process of claim 16 further comprising hardening the free-standing three dimensional dental restoration.

19. The method of claim 18 wherein hardening comprises curing or sintering the free-standing three dimensional dental restoration.

20. The process of claim 16 further comprising burning out the binder prior to hardening the free-standing three dimensional dental restoration.

21. The process of claim 18 wherein the binder is removed during hardening the free-standing three dimensional dental restoration.

22. The process of claim 18 wherein the hardening step comprises sintering the free-standing three dimensional dental restoration to full density.

23. The process of claim 16 wherein the dispensing apparatus comprises a continuous stream print head or drop-on-demand stream print head.

24. The process of claim 16 wherein the mixture is dispensed in the form of a bead, stream, or droplet.

25. The process of claim 24 wherein the bead, stream or droplet comprises a slurry or a liquified filament.

26. The process of claim 25 wherein the slurry comprises a ceramic powder and a binder.

27. The process of claim 25 wherein the liquified filament comprises ceramic powder and a binder.

28. The process of claim 16 wherein the binder comprises an inorganic or an organic material.

29. The process of claim 16 wherein the binder comprises a molten thermoplastic material or a wax-containing material.

30. The process of claim 16 wherein the binder comprises polycarbosilazane or tetraethylorthosilicate.

31. The process of claim 16 wherein pigments, opacifiers, and/or fluorescing agents are added to the ceramic powder material during, after or before dispensing thereof.

32. The process of claim 16 wherein the dental restoration comprises denture teeth, bridges, crowns, space maintainers, tooth replacement appliances, orthodontic parts, orthodontic retainers, dentures, posts, jackets, inlays, onlays, facings, veneers, facets, implants, abutments, splints, partial crowns, teeth, cylinders, pins, and connectors.