Method of making a dental crown for a dental preparation by means of a CAD-CAM system

• US 4,937,928 A
• Filed: 10/05/1988
• Issued: 07/03/1990
• Est. Priority Date: 10/07/1987
• Status: Expired due to Term

• Current Assignee: Elephant Edelmetaal BV Atoomweg 12 1627 Le Hoorn
• Original Assignee: Elephant Edelmetaal BV
• Inventors: van der Zel, Joseph M.
• Primary Examiner(s): Hall, Carl E.
• Assistant Examiner(s): Cuda, I.
• Application Number:
  US07/253,772
• Time in Patent Office: 636 Days
• Field of Search: 29/160.6, 409/79, 409/80, 409/82, 409/84, 433/202.1, 433/206, 433/207, 433/204, 433/205, 433/208, 433/213, 433/218, 433/223
• US Class Current: 29/896.1
• 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 5/73 Composite crowns
• CPC Class Codes: A61C 5/77 Methods or devices for making crowns
• CPC Class Codes: A61C 9/00 Impression cups, i.e. impression trays; Impression methods computer-assisted sizing A61C13/0004; instruments for determining occlusion A61C19/05
• CPC Class Codes: A61K 6/16 Refractive index
• CPC Class Codes: A61K 6/17 Particle size
• CPC Class Codes: A61K 6/20 Protective coatings for natural or artificial teeth, e.g. sealings, dye coatings or varnish
• CPC Class Codes: A61K 6/802 comprising ceramics
• CPC Class Codes: A61K 6/844 Noble metals
• CPC Class Codes: G05B 19/4099 Surface or curve machining, making 3D objects, e.g. desktop manufacturing
• CPC Class Codes: G05B 2219/45167 Dentist, dental manufacture
• CPC Class Codes: G05B 2219/49013 Deposit layers, cured by scanning laser, stereo lithography SLA, prototyping
• CPC Class Codes: Y10T 29/49567 Dental appliance making
• CPC Class Codes: Y10T 409/300896 with sensing of numerical information and regulation without mechanical connection between sensing means and regulated means [i.e., numerical control]

Abstract

A method of making a dental crown for a dental preparation by means of a CAD-CAM system. In the method, first a model of the dental preparation is made from a refractory material under the control of the CAD-CAM system. Subsequently, at least one layer of a material suitable for dental crowns is applied to the model. The layer is sintered during or after its application, and is then ground under the control of the CAD-CAM system until a predetermined shape is obtained. Finally the refractory material is removed.

Claims

1. A method of making a dental crown for a dental preparation by means of a CAD-CAM system wherein under the control of the CAD-CAM system a model of the dental preparation is made from a refractory material, to which model successively two or more layers of a material suitable for dental crowns are applied, each layer being sintered during or after its application and being ground after the sintering treatment and before the next layer is applied, which grinding treatments are effected under the control of said CAD-CAM system until a shape determined by said system is obtained, after which the refractory material is removed.

2. A method as claimed in claim 1, characterized in that the refractory material is MgO and that the model is cut under the control of the CAD-CAM system to obtain the shape of the dental preparation.

3. A method as claimed in claim 2, characterized in that the layers are applied by means of plasma jetting.

4. A method as claimed in claim 1, characterized in that four layers are applied to the model of the dental preparation, the first layer being a metal layer of a dental alloy, the second layer an opaque porcelain layer, the third layer a dentin porcelain layer and the fourth layer a cutting mass layer.

5. A method as claimed in claim 4, characterized in that the dental alloy is made up of a metal powder having a grain size smaller than 60 micrometers and a bulk density larger than 70% of the theoretical density of the alloy.

6. A method as claimed in claim 5, characterized in that the layers are applied by means of plasma jetting.

7. A method as claimed in claim 4, characterized in that the layers are applied by means of plasma jetting.

8. A method as claimed in claim 1, characterized in that the layers are applied by means of pneumatic spraying.

9. A method as claimed in claim 1, characterized in that the layers are applied by means of plasma jetting.

10. A method as claimed in claim 1, characterized in that the layers are applied by means of flame spraying.

11. A method as claimed in claim 1, characterized in that the layers are applied by means of laser sintering.