David E Sarfatti

US Patent:

41655621, Aug 28, 1979

Filed:

Aug 12, 1977

Appl. No.:

5/824158

Inventors:

David E. Sarfatti - Philadelphia PA

International Classification:

A61C 502

US Classification:

32 57

Abstract:

A precision endodontic file including a threaded base having an endodontic file projecting outwardly therefrom is disclosed. A threaded sleeve threadedly receives the base to facilitate precise longitudinal adjustment of the file relative to the sleeve. The bottom end of the sleeve is utilized as a stop which abuts the tooth to thereby limit the depth of file penetration. The threaded body incorporates at least one lock which is continuously biased to a locking position. The threaded sleeve is provided with one or more slots into which the lock can extend to prevent the threaded body from turning relative to the sleeve once the desired length adjustment has been preset. A plastic, transparent throw away type cap overfits the combination of the file and the sleeve and is imprinted with a plurality of graduations thereon to indicate the distance that the bottom of the file extends from the bottom of the sleeve. By measuring precisely the depth of desired penetration from an x-ray, the length can be precisely set on the instrument by turning the body relative to the sleeve until the bottom of the file aligns with the proper graduation on the cap. The plastic cap is then removed from the sleeve and discarded to expose the working portions of the instrument.