Patent US3290037A successfully refreshed from Google Patents.
Patent US4299571A successfully refreshed from Google Patents.
US4299571A
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US
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Dental file
Assignee: Dentsply Sirona Inc
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Filing: 1979-08-03
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Granted: 1981-11-10
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Expires: 1999-08-03
Abstract
Abstract Disclosed is a dental file for use in cleaning out or extirpating root canals, particularly those which are curved, wherein the file which conventionally is provided with cutting or abrading flutes, typically in a spiraled manner, is also provided with a smooth, non-abrading pilot end which rides on the deep inner portion of the root canal wall and prevents the file from straightening out and causing the end thereof to "zip" or slice into the canal wall in an uncontrolled manner.
Inventors
- 👤 John T. McSpadden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:53
CPC Classifications
A; A61; A61C; A61C5/00; A61C5/40; A61C5/42; A61C1/00; A61C1/0007; A61C1/0015; A61C1/003
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
66 words
A root canal file comprising an elongated body having a shank portion and a working portion, cutting shoulder means on said working portion circumscribing said body in a continuous manner and numbering from about 0.1 to about 5.0 per millimeter of body length, and a smooth pilot end of from greater than about 1.0 millimeters to about 3.0 millimeters in length extending from said working portion.
Claim 2
Dependent Claim
66 words
A root canal file comprising an elongated body having a shank portion and a working portion, cutting shoulder means on said working portion circumscribing said body in a continuous manner and numbering from about 0.1 to about 5.0 per millimeter of body length, and a smooth pilot end of from greater than about 1.0 millimeters to about 3.0 millimeters in length extending from said working portion.
Claim 3
Dependent Claim
23 words
The tool of claim 1 wherein the diameter of the shoulder means is progressively diminished toward said pilot end to provide a taper.
Claim 4
Dependent Claim
16 words
The tool of claim 1 wherein the shoulder means are combined into a screw-like continuous surface.
Claim 5
Dependent Claim
22 words
The tool of claim 1 wherein the cutting shoulder means number from about 0.1 to about 5.0 per millimeter of tool length.
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) | 1984-11-09 | 1985-05-11 | 1985-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-09 | 1989-05-11 | 1989-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-09 | 1993-05-11 | 1993-11-10 | $7700.00 | Window Closed / Lapsed |