METHOD, BLANK, ASSORTMENT OF BLANKS, DENTAL DATABASE AND BLANK DATABASE COMPRISING PREFABRICATED PARTIAL END SURFACES OF PARTIAL DENTURES

• US 20090181346A1
• Filed: 05/08/2007
• Published: 07/16/2009
• Est. Priority Date: 05/08/2006
• Status: Active Grant

• Current Assignee: Sirona Dental Systems GmbH (Sirona Dental Systems Incorporated)
• Original Assignee: Sirona Dental Systems GmbH (Sirona Dental Systems Incorporated)
• Inventors: Orth, Ulrich
• Granted Patent: US 8,483,857 B2
• Time in Patent Office: Days
• US Class Current: 433/201.100
• CPC Class Codes: A61C 13/0004 Computer-assisted sizing or machining of dental prostheses
• CPC Class Codes: A61C 13/0022 Blanks or green, unfinished dental restoration parts
• CPC Class Codes: G16H 50/50 for simulation or modelling of medical disorders

Abstract

The invention relates to a process, a blank, an assortment of blanks, a tooth database, and a database of blanks, for the production of a dental prosthetic item. The method comprises the provision of a 3D model of a dental prosthetic item and the selection of a suitable blank from a plurality of possible blanks. The provision of the 3D model of the dental prosthetic item comprises the determination of an esthetically relevant designed subregion of the 3D model of the dental prosthetic item as part of an exterior surface of said dental prosthetic item, and a blank is specified from a plurality of blanks having a prefabricated esthetically relevant terminal subsurface of a surface of the tooth, the terminal subsurface of said blank being such that it at least approximates the thus specified designed subregion. The 3D model of said dental prosthetic item is carved from the selected blank such that the prefabricated terminal subsurface of said blank remains unmachined in at least a central region thereof.

Claims

1. The method for the production of a dental prosthetic item, comprising the provision of a 3D model of a dental prosthetic item and the selection of a suitable blank from a plurality of possible blanks, characterized in that the provision of a 3D model of the dental prosthetic item comprises the determination of an esthetically relevant designed subregion (7) of the 3D model of the dental prosthetic item (10, 30) as part of an exterior surface of said dental prosthetic item (10, 30), that a blank (1, 20) is specified from a plurality of blanks (1, 20) having a prefabricated esthetically relevant terminal subsurface (2) of a surface of the tooth, the terminal subsurface (2) of said blank being such as at least approximates the thus specified designed subregion (7), and that the 3D model of said dental prosthetic item (10, 30) is carved from the selected blank (1, 20) such that the prefabricated terminal subsurface (2) of said blank (10, 30) remains unmachined in at least a central region thereof.

2. The method as defined in claim 1, characterized in that the provision of the 3D model of the dental prosthetic item (10, 30) comprises the selection of a 3D model of a tooth matching the preparation site from a tooth database having a plurality of 3D models (60.1 to 60.3) of a tooth having at least one desired esthetically relevant terminal subsurface (2.1 to 2.3), wherein for each 3D model (60.1 to 60.3) of a tooth in the tooth database there is present, in a database of blanks, a 3D model (70.1 to 70.3) of a blank having a terminal subsurface (2.1 to 2.3) coinciding with the terminal subsurface (2.1 to 2.3) of the tooth and that the selected 3D model (60.1 to 60.3) of the tooth is changed for adaptation to the individual tooth situation at the preparation site, wherein the specified terminal subsurface (2.1 to 2.3) remains unchanged in at least a central region thereof, that an assortment of blanks matching the database of blanks exists, and that the 3D model of the dental prosthetic item (10, 30) is carved from the blank (80.1 to 80.3) corresponding to the 3D model of the tooth.

3. The method as defined in claim 1, characterized in that a designed subregion (7) on the 3D model of the planned dental prosthetic item (10, 30) is determined either interactively by the user using input means (52, 53) or automatically by a computer (50) with reference to specific parameters.

4. The method as defined in claim 3, characterized in that the selection of a blank (1, 20) having a terminal subsurface from a plurality of blanks (1, 20) having at least one prefabricated terminal subsurface (2) of a tooth surface is carried out automatically by the computer (50), the deviations between the specified designed subregion (7) on the 3D model of the dental prosthetic item (10, 30) and the prefabricated terminal subsurface (2) being minimized.

5. The method as defined in claim 3 or claim 4, characterized in that the 3D model of the dental prosthetic item (10, 30) is carved from the selected blank (1, 20) in such a manner that in the finished dental prosthetic item at least one subregion of the prefabricated terminal subsurface (2) of the blank takes the place of the selected designed subregion (7) of the 3D model of the dental prosthetic item.

6. The method as defined in any one of claims 3 to 5, characterized in that the minimization of the deviations is carried out in such a manner that the deviations are mainly located in the marginal area of the selected designed subregion (7).

7. The method as defined in any one of claims 3 to 6, characterized in that a positional relationship is determined between the specified designed subregion (7) of the 3D model of the dental prosthetic item and the prefabricated terminal subsurface of the blank.

8. The method as defined in any one of claims 3 to 7, characterized in that said positional relationship is used as the basis for the determination of a machining schedule for the selected blank.

9. The method as defined in any one of claims 1 to 8, characterized in that the blank is machined only in the marginal area of the terminal subsurface (2) and on the surfaces (6) requiring machining outside the terminal subsurface (2).

10. The method as defined in any one of claims 1 to 9, characterized in that the blank exhibits a translucent layer (3) and that the prefabricated terminal subsurface (2) is disposed on the translucent layer (3).

11. The method as defined in claim 10, characterized in that the prefabricated terminal subsurface (2) of the blank (1, 20) comprises the designed subregion (7) of the dental prosthetic item (10, 30) and that the terminal subsurface (2) extending over the translucent layer (3) is machined down to the designed subregion (7) and that the machined edge of the translucent layer (3) is subsequently polished.

12. The method as defined in claim 10, characterized in that the designed subregion (7) of the dental prosthetic item (10, 30) comprises the prefabricated terminal subsurface (2) of the blank (1, 20) and that the remaining marginal area (40) between the prefabricated terminal subsurface (2) and the designed subregion (7), which initially exhibits no translucent layer (3), is subsequently veneered with a translucent layer (41) and polished.

13. The method as defined in any one of claims 1 to 12, characterized in that the surfaces (6) to be machined outside the terminal subsurface (2) of the blank (1, 20) exceed the size of the surface of the planned dental prosthetic item (10, 30) by at least 1 mm.

14. The method as defined in any one of claims 1 to 13, characterized in that the specified designed subregion (7) corresponds to a surface which is visible from outside the oral cavity after the dental prosthetic item (10, 30) has been placed in the oral cavity.

15. The method as defined in any one of claims 1 to 14, characterized in that the specified designed subregion (7) corresponds, in the case of incisors, to the labial surface (16) and preferably also to the incisor edge (12), or, in the case of premolars, to the buccal surface (21) and preferably also to the occlusal surface (22).

16. The method as defined in any one of claims 1 to 15, characterized in that the specified designed subregion (7) covers not more than 50% of the entire exterior surface of the 3D model of the dental prosthetic item.

17. The method as defined in any one of claims 1 to 16, characterized in that the blank (1, 20) is selected from a large number of blanks (1, 20), which have prefabricated terminal subsurfaces (2) showing deviating shapes and/or coloration and/or translucency attributes.

31. An assortment of blanks, comprising a plurality of blanks, characterized in that said assortment of blanks comprises at least blanks (1, 20) of the same type but differing from each other in size as defined in any one of claims 17 to 25.

18. A blank for the production of a dental prosthetic item and exhibiting a prefabricated terminal subsurface corresponding in geometry and surface attributes to the planned dental prosthetic item, characterized in that said blank exhibits surfaces (6) to be machined which are outside the prefabricated esthetically relevant terminal subsurface (2) and are of larger dimensions than the surface (8, 12, 13, 14, 15, 31, 32, 33, 34) of the planned dental prosthetic item (10, 30).

19. The blank as defined in claim 18, characterized in that the surfaces (6) of the blank (10, 30) which are to be machined outside the prefabricated esthetically relevant terminal subsurface (2) are oversized by at least 1 mm relative to the surface (8, 12, 13, 14, 15, 31, 32, 33, 34) of the planned dental prosthetic item (10, 30).

20. A blank as defined in claim 18 or claim 19, characterized in that the prefabricated terminal subsurface (2) covers not more than 50% of the entire surface of the blank.

21. The blank as defined in any one of claims 18 to 20, characterized in that the degree of oversize is at least 1 mm.

22. The blank as defined in any one of claims 18 to 21, characterized in that the blank exhibits a translucent layer (3) and that the prefabricated terminal subsurface (2) extends over the translucent layer (3).

23. The blank as defined in claim 22, characterized in that the translucent layer (3) has a thickness of from 0.3 mm to 1.5 mm and is preferably polished and has regions which differ in shape and/or translucency and/or color attributes.

24. The blank as defined in any one of claims 18 to 23, characterized in that the prefabricated esthetically relevant terminal subsurface (2) has color and translucency attributes which are similar to those of natural teeth.

25. The blank as defined in any one of claims 18 to 24, characterized in that the surfaces (6) to be machined on the blank form part of a basic geometrical shape, in particular a cone, a cylinder, a cube, a cuboid, or a pyramid.

26. The blank as defined in any one of claims 18 to 25, characterized in that the positional relationship of the surfaces (6) to be machined relative to each other, to the terminal subsurface (2), and to a holder (4) for the blank (1, 20) is known.

27. The blank as defined in any one of claims 18 to 26, characterized in that the surfaces (6) to be machined are embodied as reference surfaces for determination of position.

28. The blank as defined in any one of claims 18 to 27, characterized in that said blank (1, 20) is made of plastics material or ceramics and preferably feldspar ceramics.

29. The blank as defined in any one of claims 18 to 28, characterized in that said blank (1, 20) is composed of at least two layers (5) differing from each other as regards their color and/or translucency attributes.

30. The blank as defined in any one of claims 18 to 29, characterized in that the prefabricated terminal subsurface (2) corresponds, in the case of incisors, to the labial surface (16) and preferably also to the incisor edge (12) or, in the case of premolars, to the buccal surface (21) and preferably also to the occlusal surface (22).

32. A tooth database for the production of dental prosthetic items, comprising at least one 3D model of a dental prosthetic item, characterized in that said 3D model of the dental prosthetic item has at least one esthetically relevant terminal subsurface (2) having a specific border line.

33. The tooth database as defined in claim 32, characterized in that the 3D model (10, 30) can be changed only outside the border line of the terminal subsurface (2) for the purposes of designing the 3D model of the individual dental prosthetic item (10, 30), whilst a size-reducing adaptation may preferably be permitted in the marginal area of the terminal subsurface (2).

34. A database of blanks for the production of dental prosthetic items, comprising at least one 3D model of a blank, characterized in that said 3D model of the blank (1, 20) has at least one terminal subsurface (2) which is coincident with an esthetically relevant terminal subsurface (2) of a 3D model of a tooth in a tooth database with a defined border line.

35. A database of blanks as defined in claim 34, characterized in that each 3D model of the blank contains information concerning the machining border line of the terminal subsurface.