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US4988293A
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Toughness coating for crystalline orthodontic brackets
Assignee: Union Carbide Chemicals and Plastics Technology LLC
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Filing: 1988-11-07
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Granted: 1991-01-29
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Expires: 2008-11-07
Abstract
Abstract A single crystal orthodontic bracket is disclosed which is provided with an outer protective layer of a polycrystalline material so as to provide fracture toughness of the orthodontic bracket.
Inventors
- 👤 Paul R. Collins
- 👤 Larry R. Rothrock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:31
CPC Classifications
A; A61; A61C; A61C7/00; A61C7/12; A61C7/14; A61C7/141
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
79 words
An orthodontic bracket comprising a body comprising a single crystalline oxide material having a base face intended to face a tooth and an opposing front face defining a longitudinal arch wire groove, and having a polycrystalline outer coating layer on at least a portion of the bracket, said polycrystalline outer coating layer being a material selected from the group consisting of alpha-alumina, zirconia, yttria, magnesia, titania, strontium titanate, rare earth oxides, Al 2 O x (x=2-3), and combinations thereof.
Claim 2
Dependent Claim
79 words
An orthodontic bracket comprising a body comprising a single crystalline oxide material having a base face intended to face a tooth and an opposing front face defining a longitudinal arch wire groove, and having a polycrystalline outer coating layer on at least a portion of the bracket, said polycrystalline outer coating layer being a material selected from the group consisting of alpha-alumina, zirconia, yttria, magnesia, titania, strontium titanate, rare earth oxides, Al 2 O x (x=2-3), and combinations thereof.
Claim 3
Dependent Claim
27 words
The orthodontic bracket of claim 1, wherein the single crystal oxide material is selected from the group consisting of alpha-alumina, zirconia, yttria, magnesia, titania and strontium titanate.
Claim 4
Dependent Claim
19 words
The orthodontic bracket of claim 1, wherein the single crystal oxide bracket material is made entirely of crystalline alpha-alumina.
Claim 5
Dependent Claim
12 words
The orthodontic bracket of claim 3, wherein the crystalline alpha-alumina is sapphire.
Claim 6
Dependent Claim
18 words
The orthodontic bracket of claim 1, wherein the single crystal oxide bracket material is made entirely of zirconia.
Claim 7
Dependent Claim
18 words
The orthodontic bracket of claim 1, wherein the single crystalline oxide bracket material is made entirely of yttria.
Claim 8
Dependent Claim
26 words
The orthodontic bracket of claim 1, wherein the thickness of the polycrystalline outer coating layer is in the range of from about 1,000 to 50,000 Angstroms.
Claim 9
Dependent Claim
17 words
The orthodontic bracket of claim 1, wherein the polycrystalline outer coating layer coats the arch wire groove.
Claim 10
Dependent Claim
16 words
The orthodontic bracket of claim 1, wherein the polycrystalline outer coating layer coats the entire bracket.
Claim 11
Dependent Claim
24 words
The orthodontic bracket of claim 1, wherein the arch wire groove is oriented essentially parallel to the top and bottom faces of the bracket.
Claim 12
Dependent Claim
23 words
The orthodontic bracket of claim 1, wherein the bracket has a rhomboidal configuration when viewed looking directly at the front of the bracket.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-01-28 | 1994-07-30 | 1995-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-28 | 1998-07-30 | 1999-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-28 | 2002-07-30 | 2003-01-29 | $7700.00 | Window Closed / Lapsed |