US4431419A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Denture magnetic retention unit
Assignee: Zest Anchors Inc
•
Filing: 1983-03-01
•
Granted: 1984-02-14
•
Expires: 2003-03-01
Abstract
Abstract A closed field magnetic denture retention unit which includes a ferromagnetic cup containing a cylindrical permanent magnet which is displaced down from the top of the cup, the cup and magnet being embedded in the denture; and a magnetic keeper which is embedded in an exposed tooth root in the mouth of a patient and extends across the top of the cup in contact with the peripheral edge of the cup but not with the magnet, the keeper serving to close the cup when the denture is in place to retain the denture in place by magnetic attraction, the keeper forming a closed magnetic field so that there is no external magnetic field in the mouth of the patient.
Inventors
- 👤 Leonard L. Portnoy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 04:39
CPC Classifications
A; A61; A61C; A61C13/00; A61C13/225; A61C13/235
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
131 words
A denture magnetic retention unit comprising: a first component in the form of a cup-shaped member of low coercivity magnetic material having an open top, and a disc-shaped permanent magnet with magnetic poles on the opposite sides thereof retained within said cup-shaped member with one side of said disc-shaped permanent magnet contacting the bottom of the cup-shaped member; and a second component in the form of a keeper of low coercivity magnetic material positioned to extend across the open top of said cup-shaped member completely to enclose said permanent magnet within said cup-shaped member, said cup-shaped member and said keeper forming a low reluctance magnetic path for the magnetic field of the permanent magnet and serving to close the magnetic field of the permanent magnet when the denture is in place.
Claim 2
Dependent Claim
131 words
A denture magnetic retention unit comprising: a first component in the form of a cup-shaped member of low coercivity magnetic material having an open top, and a disc-shaped permanent magnet with magnetic poles on the opposite sides thereof retained within said cup-shaped member with one side of said disc-shaped permanent magnet contacting the bottom of the cup-shaped member; and a second component in the form of a keeper of low coercivity magnetic material positioned to extend across the open top of said cup-shaped member completely to enclose said permanent magnet within said cup-shaped member, said cup-shaped member and said keeper forming a low reluctance magnetic path for the magnetic field of the permanent magnet and serving to close the magnetic field of the permanent magnet when the denture is in place.
Claim 3
Dependent Claim
44 words
The denture magnetic retention unit defined in claim 1, in which said first component is adapted to be embedded in the denture, and said second component is adapted to be embedded in an exposed root of a tooth in the mouth of a patient.
Claim 4
Dependent Claim
24 words
The denture magnetic retention unit defined in claim 2, in which said cup-shaped member and said keeper are formed of a ferromagnetic stainless steel.
Claim 5
Dependent Claim
30 words
The denture magnetic retention unit defined in claim 1, in which the other side of the disc-shaped permanent magnet is displaced inwardly from the open top of said cup-shaped member.
Claim 6
Dependent Claim
18 words
The denture magnetic retention unit defined in claim 1, in which the permanent magnet is a cobalt/samarium alloy.
Claim 7
Dependent Claim
34 words
The denture magnetic retention unit defined in claim 1, in which the peripheral edge of said disc-shaped permanent magnet is spaced and insulated from the inner surface of the side of said cup-shaped member.
Claim 8
Dependent Claim
26 words
The denture magnetic retention unit defined in claim 4, in which the open top of the cup-shaped member is filled with a sealant of nonmagnetic material.
References Cited (Backward Citations)
US3646676A
Cited
US4302189A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-02-13 | 1987-08-15 | 1988-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-13 | 1991-08-15 | 1992-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-13 | 1995-08-15 | 1996-02-14 | $7700.00 | Window Closed / Lapsed |