US4538989A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dental reamer
Assignee: Dentsply Sirona Inc
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Filing: 1980-09-16
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Granted: 1985-09-03
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Expires: 2000-09-16
Abstract
Abstract A dental reamer adapted for removing damaged nerve tissue and dead or injured cell material from the root canal of a tooth is formed with a tapered shank with at least two oppositely disposed continuous helical flutes formed along at least a part of its shank to define two oppositely disposed continuous helical upwardly facing cutting edges.
Inventors
- 👤 Jerry Apairo, Jr.
- 👤 Derek E. Heath
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:56
CPC Classifications
A; A61; A61C; A61C3/00; A61C3/02; A61C5/00; A61C5/40; A61C5/42
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
130 words
A dental reamer comprising a shank tapered along at least part of its length and terminating at a point; two oppositely disposed continuous helical flutes formed in said tapered shank defining two oppositely disposed continuous helical cutting edges, generally directed away from said point; the helix angle of each of said flutes uniformly decreasing over the fluted length of said shank and the pitch of each of said helical flutes being constant over the fluted length of said shank; each flute immediately adjacent said cutting edge being undercut to form a positive rake angle cutting edge; and the web defined between said at least two flutes immediately sloping away from said first and said second cutting edges so that there is virtually no outside circumferential land at said cutting edges.
Claim 2
Dependent Claim
130 words
A dental reamer comprising a shank tapered along at least part of its length and terminating at a point; two oppositely disposed continuous helical flutes formed in said tapered shank defining two oppositely disposed continuous helical cutting edges, generally directed away from said point; the helix angle of each of said flutes uniformly decreasing over the fluted length of said shank and the pitch of each of said helical flutes being constant over the fluted length of said shank; each flute immediately adjacent said cutting edge being undercut to form a positive rake angle cutting edge; and the web defined between said at least two flutes immediately sloping away from said first and said second cutting edges so that there is virtually no outside circumferential land at said cutting edges.
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) | 1988-09-02 | 1989-03-04 | 1989-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-02 | 1993-03-04 | 1993-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-02 | 1997-03-04 | 1997-09-03 | $7700.00 | Window Closed / Lapsed |