US4937928A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making a dental crown for a dental preparation by means of a CAD-CAM system
Assignee: Elephant Edelmetaal BV
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Filing: 1988-10-05
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Granted: 1990-07-03
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Expires: 2008-10-05
Abstract
Abstract A method of making a dental crown (5) for a dental preparation (1) by means of a CAD-CAM system. In said 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 (2) 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.
Inventors
- 👤 Joseph M. van der Zel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:11
CPC Classifications
A; A61; A61C; A61C13/00; A61C13/0003; A61C13/0004; A61C5/00; A61C5/70; A61C5/73; A61C5/77; A61C9/00; A61K; A61K6/00; A61K6/15; A61K6/16; A61K6/17; A61K6/20; A61K6/80; A61K6/802; A61K6/84; A61K6/844; G; G05; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/4097; G05B19/4099; G05B2219/00; G05B2219/30; G05B2219/45; G05B2219/45167; G05B2219/49; G05B2219/49013; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49567; Y10T409/00; Y10T409/30; Y10T409/30084; Y10T409/300896
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
105 words
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.
Claim 2
Independent Claim
105 words
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.
Claim 3
Dependent Claim
36 words
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.
Claim 4
Dependent Claim
19 words
A method as claimed in claim 2, characterized in that the layers are applied by means of plasma jetting.
Claim 5
Dependent Claim
54 words
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.
Claim 6
Dependent Claim
42 words
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.
Claim 7
Dependent Claim
19 words
A method as claimed in claim 5, characterized in that the layers are applied by means of plasma jetting.
Claim 8
Dependent Claim
19 words
A method as claimed in claim 4, characterized in that the layers are applied by means of plasma jetting.
Claim 9
Dependent Claim
19 words
A method as claimed in claim 1, characterized in that the layers are applied by means of pneumatic spraying.
Claim 10
Dependent Claim
19 words
A method as claimed in claim 1, characterized in that the layers are applied by means of plasma jetting.
Claim 11
Dependent Claim
19 words
A method as claimed in claim 1, characterized in that the layers are applied by means of flame spraying.
Claim 12
Dependent Claim
19 words
A method as claimed in claim 1, characterized in that the layers are applied by means of laser sintering.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-07-02 | 1994-01-01 | 1994-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-02 | 1998-01-01 | 1998-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-02 | 2002-01-01 | 2002-07-03 | $7700.00 | Window Closed / Lapsed |