US 3924334 A
A root canal implement for accepting and holding root canal files and reamers of various sizes includes a threaded knob on one end of the file or reamer wire. The threaded knob is received in the threaded bore of a split chuck handle, wherein threading the knob into the bore determines the length of the exposed file or reamer wire. A locking ring positioned over the split chuck handle constricts the chuck about the knob to prevent the knob and therefore, the wire from turning during clinical use.
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Description (OCR text may contain errors)
United States Patent Lentine et al. Dec. 9, 1975 ROOT CANAL IMPLEMENT 781,617 1/1905 Price 32/59 Inventors: Frank ol s e y o 3,330,040 7/1967 Kahn 32/57 y g gg iz Keller Primary Examiner-Russell R. Kinsey Assistant ExaminerJ. Q. Lever  Assignee: Sybron Corporation, Rochester, Attorney, Agent, or Firm-Theodore B. Roessel; Roger N.Y. Aceto  Filed. June 21, 1974 ABSTRACT  Appl' No; 481524 A root canal implement for accepting and holding root canal files and reamers of various sizes includes a 52 US. Cl 32/57; 279/43 tbreaded knob on one end of the file er reemer Wire- 51 1m. (:1. A61C 5/02 The threaded knob is received in the threaded here of 5 Fidd f Search H 32 57 53 59; 279 02 a split chuck handle, wherein threading the knob into 279/103 43 50 57 the bore determines the length of the exposed file or reamer wire. A locking ring positioned over the split  References Cited chuck handle constricts the chuck about the knob to UNITED STATES PATENTS prevent the knob and therefore, the wire from turning during clinical use. 428,019 5/1890 Pugh 32/59 761,501 5/ 1904 Kimball et a]. 279/103 X 3 Claims, 1 Drawing Figure The present invention relates generally to a dental instrument for root canal preparations and more specifically to a universal chuck handle capable of holding file or reamer wires of various sizes and for adjusting the operable length of the wire.
In the preparation of root canals, the present dental practice is to utilize a file or reamer wire to file or ream the root canal of a tooth. Files or reamers of various diameters and sizes may be employed. Because of the relative small diameter of the wire, the present practice is to provide a precision made handle and collar for each size wire. It is also important in the preparation of a root canal to control the length of the wire in order to limit the depth of penetration of the file or reamer and avoid injury. For this purpose, the prior art uses a variety of means including a stop movable along the length of the wire.
In the root canal instrument of the present invention, the design is such that the handle portion can accommodate wires of various sizes and has an infinite linear adjustment capability over the entire adjustment range of the wire.
SUMMARY OF THE INVENTION The present invention may be characterized in one aspect thereof by the provision of a dental instrument for root canal uses including a file or reamer wire having one end insert molded into a threaded knob; a split chuck handle portion having a threaded bore for receiving the knob and presenting the operable end of the wire extending outwardly from one end of the handle, the threaded connection also acting as an infinite adjusting means to vary the length of the file wire extending from the handle portion; and a lock ring positionable about the handle to constrict the split portions of the split chuck handle about the knob to fix the knob and therefore the wire against both longitudinal and rotational movement.
OBJECTS OF THE INVENTION One object of the present invention is to provide a root canal instrument wherein the handle portion of the instrument can readily accommodate all sizes of file and reamer wires.
Another object of the present invention is to provide a root canal instrument wherein file or reamer wires of different sizes may be readily attached or detached from the handle portion of the instrument.
A further object of the present invention is to provide a root canal instrument wherein the length of the file or reamer wire is infinitely adjustable over the entire range of adjustment.
Still another object of the present invention is to provide a root canal instrument having an handle portion adapted to accommodate file or reamer wires of various sizes, the means for retaining the wire fixed in the handle portion being actuated automatically during normal use of the instrument.
These and other objects, advantages and characterizing features of the present invention will become more apparent upon consideration of the following detailed description thereof when taken in connection with the accompanying drawings depicting the same.
DESCRIPTION or THE DRAWINGS The sole FIGURE is a side view of the root canal instrument partly broken away and in section.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawing, the FIGURE shows the root canal instrument of the present invention to include a chuck handle generally indicated at 10 and a file or reamer wire assembly generally indicated at 12. The wire assembly includes a file or reamer wire 14, for fil ing or reaming the root canal, rigidly bonded at one end to a threaded cylindrical knob 16, so that the wire extends axially of the knob. The rigid bonding can be accomplished by any suitable means, preferably, however, the wire is insert molded into the knob. A wide range of file and reamer wire sizes are employed for root canal work so that while the diameter of wire 14 may vary, the size of the threaded knob will remain constant. The length of wire 14 protruding from the threaded knob will also be varied to provide any convenient length.
It is preferred that the material of threaded knob 16 be such that normal sterilization techniques and solutions will not effect the physical properties of the knob. It is further preferred that the material of the knob be tinted or otherwise color coded for ease of recognition of the particular size of the wire, wherein the particular color coding of the knob is related to the wire size.
Chuck handle 10 is generally cylindrical and consists of a forward portion 18, rearward portion 20 and a intermediate portion 22. The intermediate portion is provided with a tapered surface 24 for purposes set out herein below.
Chuck handle 10 is also provided with a threaded, axial bore 26 adapted to receive threaded knob 16. A slot 28 which extends inward from the rear portion and through the intermediate portion of the chuck handle allows the handle to function as a split chuck wherein the upper and lower portions 30, 32 of the chuck handle, formed by the slot, can be constricted or clamped together about knob 16. The clamping is accomplished with a lock ring 34 which is positionable about intermediate portion 22. The internal diameter of the lock ring is less thaneither the forward or rearward positions 18, 20 and is such that as the ring moves toward the forward portion, the ring will engage in an interference fit with the tapered surface, so as to constrict the upper and lower portions of the chuck handle together.
In operation, the upper and lower portions of the chuck handle are squeezed together to permit passage of locking ring 34 over rear portion 20 and on to the intermediate portion. The appropriate size file or reamer wire is then selected and its knob 16 threaded into bore 26. A slot or keyway 36 on the end of knob 16 provides a gripping surface for threading the knob the desired distance into the chuck handle. A suitable tool such as a screw driver is simply inserted into slot 36 and turned until the desired length of file wire 14 extends beyond the forward end surface 38 of the chuck handle; surface 38 representing a datum surface for the desired length measurement of file wire 14.
Locking ring 34 is then moved toward forward portion 18 and rotated slightly to engage the locking ring against tapered surface 24. This constricts the upper and lower portions 30, 32 of the chuck handle tightly about threaded knob 16 to lock the knob securely 3 therein. This locking action will prevent rotation of knob 16 while the engagement of the threads on the knob and chuck handle will prevent axially movement of the knob.
It is customary to use a root canal instrument by inserting the operative end of the instrument into a root canal to a given depth, twisting the instrument approximately 45 clockwise and then pulling the instrument out. 'In the present invention, the locking action is enhanced by this normal clinical procedure in that the operators fingers during use, are placed on or adjacent to the locking ring 34, so that when normal pressure is applied to use the instrument, the lock ring is forced toward the forward portion of the chuck handle.
Thus, it should be appreciated that the present invention accomplishes its intended objects in providing a dental instrument for root canal procedures wherein a single chuck handle is capable of accommodating various sizes of file or reamer wires used in root canal procedures. The chuck handle provides a means for securely holding the wire wherein the procedure for using the instrument enhances the locking of the handle to the file wire.
Having thus described the invention is detail, what is claimed as new is:
l. A root canal instrument comprising:
a. a wire to be used in filing the root canal of a tooth;
b. an externally threaded knob on one end of said wire;
c. a generally cylindrical handle having a threaded bore extending therethrough for receiving said threaded knob with said wire projecting outward from a forward end surface of said handle;
d. said handle having a forward portion, a rear portion and an intermediate portion tapering outwardly from said rear portion to said forward portion, the smaller diameter of said tapered intermediate portion being less than the diameter of said rear portion, and said handle having a longitudinal slot extending from a rearward end surface thereof through said rear portion and into said tapered intermediate portion, said slot allowing said handle to function as a split chuck; and
e. a lock ring positionable on said handle and about said intermediate portion, the inner diameter of said ring being smaller than the diameter of either said forward or rear portions so that said ring will interfere with said tapered surface upon axial movement forward for constricting and locking the rear and intermediate portions of said handle about said knob and will abut said rear portion when moved axially rearward.
2. A dental instrument as set forth in claim 1, wherein said knob is cylindrical and said threads extend for substantially the full length thereof.
3. A dental instrument as set forth in claim 1, wherein said knob has a transverse slot in the end thereof adapted to receive a tool for threading said knob through said bore.