US3922787A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Plastic orthodontic bracket
Assignee: Individual
•
Filing: 1974-05-07
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Granted: 1975-12-02
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Expires: 1994-05-07
Abstract
Abstract An all plastic orthodontic bracket is disclosed which is adapted to be attached directly to the labial surface of a tooth. The bracket has a quasi triangular shaped body as viewed from the facial view to minimize forces being applied to the bracket during mastication and occlusion. The apical section of the triangular shaped body is adapted to be attached to the incisal section of the tooth and the base of the triangular shaped body is adapted to be attached to the gingival section of the tooth. All surfaces of the bracket body extending from a ligature undercut over the front surface of the bracket body are smooth and convex with the exception of those surfaces defined by an archwire slot and a second slot which is perpendicular to the archwire slot. Smooth convex bracket body surfaces substantially lessen plastic fatigue commonly found in prior art plastic orthodontic brackets having sharp corners. The ligature undercut is of a depth which is substantially filled by a small gauge archwire or an elastic ring. The relatively shallow depth of the ligature undercut insures that maximum bracket bulk is distributed between the archwire slot and the ligature undercut to lessen the tendency for bracket body fatigue between these points.
Inventors
- 👤 Kenneth J Fischer
- 👤 Jan A Orlowski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:42
CPC Classifications
A; A61; A61C; A61C7/00; A61C7/12
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
85 words
A plastic orthodontic bracket comprising a base which is adapted to be attached to the labial surface of a tooth between the gingival and the incisal sections and a body which is joined to said base, said body having a quasi-triangular shaped front surface, an archwire slot cut in the front surface of said body, a ligature undercut extending completely around the periphery of the front surface of said body, and a smooth and convex surface extending from said ligature undercut to said archwire slot.
Claim 2
Dependent Claim
85 words
A plastic orthodontic bracket comprising a base which is adapted to be attached to the labial surface of a tooth between the gingival and the incisal sections and a body which is joined to said base, said body having a quasi-triangular shaped front surface, an archwire slot cut in the front surface of said body, a ligature undercut extending completely around the periphery of the front surface of said body, and a smooth and convex surface extending from said ligature undercut to said archwire slot.
Claim 3
Dependent Claim
42 words
In an orthodontic bracket as recited in claim 1 wherein said plastic is a filled polycarbonate having the following physical properties: shear strength ranging from 10,000 to 16,000 p.s.i. and deformation at 70*F under a 4,000 p.s.i. load being less than 0.1%.
Claim 4
Dependent Claim
42 words
In an orthodontic bracket as recited in claim 1 wherein said plastic is an unfilled polycarbonate having the following physical properties: shear strength ranging from 6,000 to 8,500 p.s.i. and deformation at 70*F under 4,000 p.s.i. load being from 0.1% to 0.3%.
Claim 5
Dependent Claim
39 words
A plastic orthodontic bracket as recited in claim 1 further comprising means cut in the front surface of said bracket body for use in applying mesial or dital rotational forces to a tooth to which the bracket is attached.
Claim 6
Dependent Claim
32 words
In an orthodontic bracket as recited in claim 4 wherein said means comprises a slot cut in the front surface of said bracket body, said slot being perpendicular to said archwire slot.
Claim 7
Dependent Claim
26 words
In an orthodontic bracket as recited in claim 1 wherein said ligature undercut is smooth and concave and has a maximum depth of 0.015mm or less.
Claim 8
Dependent Claim
105 words
A plastic orthodontic bracket comprising a base portion which is adapted to be attached to the labial surface of a tooth between the gingival and incisal sections and a body which is joined to said base, said body having a front surface which is quasi-triangular shaped for minimizing the forces exerted on said bracket during mastication and occlusion when said bracket is attached to said tooth so that the apex of said quasi-triangular shaped front surface is positioned closest to the incisal section of a tooth and the base of said quasi-triangular shaped front surface is positioned closest to the gingival section of the tooth.
Claim 9
Dependent Claim
105 words
A plastic orthodontic bracket comprising a base portion which is adapted to be attached to the labial surface of a tooth between the gingival and incisal sections and a body which is joined to said base, said body having a front surface which is quasi-triangular shaped for minimizing the forces exerted on said bracket during mastication and occlusion when said bracket is attached to said tooth so that the apex of said quasi-triangular shaped front surface is positioned closest to the incisal section of a tooth and the base of said quasi-triangular shaped front surface is positioned closest to the gingival section of the tooth.
Claim 10
Dependent Claim
51 words
In an orthodontic bracket as recited in claim 7 further comprising an archwire slot cut in the front surface of said bracket body and a ligature undercut extending completely around the periphery of said front surface, said ligature undercut being smooth and concave and having a depth of 0.015mm or less.
Claim 11
Dependent Claim
85 words
An orthodontic bracket as recited in claim 7 wherein said bracket body further comprises an archwire slot, means cut in the front surface of said bracket body for use in applying mesial or distal rotational forces to a tooth to which the bracket is attached, said slot being cut into the front surface of said bracket body, and a ligature undercut extending completely around the periphery of said bracket body, and a smooth and convex surface extending from said ligature undercut to said archwire slot.
Claim 12
Dependent Claim
32 words
In an orthodontic bracket as recited in claim 8 wherein said means comprises a slot cut in the front surface of said bracket body, said slot being perpendicular to said archwire slot.
Claim 13
Dependent Claim
47 words
An orthodontic bracket as defined in claim 3 wherein said base portion of said bracket extends away from the ligature undercut a distance sufficient to prevent adhesive used for attaching the base of the bracket to the labial surface of the tooth from occluding the ligature undercut.
Claim 14
Dependent Claim
23 words
An orthodontic bracket as recited in claim 5 wherein the base is extended away from the ligature undercut at least for 0.015 inch.
Claim 15
Dependent Claim
42 words
In an orthodontic bracket as recited in claim 7 wherein said plastic is a filled polycarbonate having the following physical properties: shear strength ranging from 10,000 to 16,000 p.s.i. and deformation at 70*F under a 4,000 p.s.i. load being less than 0.1%.
Claim 16
Dependent Claim
42 words
In an orthodontic bracket as recited in claim 7 wherein said plastic is an unfilled polycarbonate having the following physical properties: shear strength ranging from 6,000 to 8,500 p.s.i. and deformation at 70*F under 4,000 p.s.i. load being from 0.1% to 0.3%.
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) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |