INSTRUMENT TO BYPASS FRACTURED FRAGMENTS OF ENDODONTIC ROTARY FILE IN ROOT CANAL OF A TOOTH

Abstract

Instruments to bypass fragments of fractured endodontic rotary files are configured for bypassing fractured fragments of endodontic rotary files that have become lodged within a root canal of a tooth during a root canal treatment. An instrument can be an endodontic file having a handle and a working shaft. The active distal portion of which includes a flat, therefore inactive, lateral surface 3. The files have a dual design along the active distal portion with a safe side and a cutting side to ease the penetration of the instrument in the narrow space between the root canal wall and the broken fragment of a NiTi endodontic rotary file.

Claims

1. An instrument for bypassing a part of a broken endodontic tool retained in a root canal, the instrument comprising: an endodontic file having a working shaft having an active cutting length, the active distal portion of which includes a flat, therefore inactive, lateral surface.

2. The instrument, according to claim 1, wherein the inactive flat lateral surface has an inclination of 2° with respect to the main axis of the file.

3. The instrument, according to claim 1 wherein the inactive flat lateral surface extends over a length of at least 3 mm.

4. The instrument, according to claim 1, wherein the active length has a double tapered profile, the conicity being greater on the distal portion comprising the inactive flat lateral surface than on the rest of the active length.

5. The instrument, according to claim 1, wherein the distal portion ends with a tip in the form of an eccentric pyramid, the top of the pyramid being located between the axis of the working shaft and the flat lateral surface.

6. The instrument, according to claim 1, wherein the file has a diameter of 0.10 mm, and wherein the conicity of the active distal portion comprising the inactive flat lateral surface is 4%, while the conicity of the rest of the active length is 2%.

7. The instrument, according to claim 1, wherein the file is 0.15 mm in diameter, and that the conicity of the active distal portion comprising the inactive flat lateral surface is 3% while that the conicity of the rest of the active length is 2%.

8. A kit of instruments for the removal from a root canal of a part of broken endodontic tool retained in said root canal, the kit comprising: at least two instruments according to claim 1, having various dimensions and intended to be used successively.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0033] The detailed description, in conjunction with the accompanying drawings, provides a clear understanding of the invention. Persons skilled in the art will however appreciate that the hereinafter drawings only depict a possible embodiment of the invention. The invention is therefore not limited to the depicted example, and variations and/or combinations of the concepts and features of the invention disclosed hereinafter are also to be treated as a part of the present invention and disclosure.

[0034] FIG. 1 shows front and side elevation views of an instrument (file) to bypass fractured endodontic rotary file according to the invention.

[0035] FIG. 2 is a side elevation view of the handle of an instrument of the present invention.

[0036] FIG. 3 depicts a perspective view of such an instrument, including an enlarged perspective view of the active distal portion of the file.

[0037] FIG. 4 shows elevation views of the active length of the instrument.

[0038] FIG. 5 is a side elevation view of the active distal portion of the same instrument.

[0039] FIG. 6 depicts some cross-sectional or side views in several locations along the working or active length of the file, i.e. more particularly: [0040] Section A is a cross sectional view of the file at A in FIG. 4; [0041] Section B is a cross sectional view of the file at B in FIG. 5; [0042] Section C is a cross sectional view of the off-centered pyramid cutting tip, taken at C in FIG. 5; and [0043] Section D is the side view of the off-center pyramid cutting tip;

[0044] FIG. 7 is a cross sectional view of the instrument of the invention used in a human tooth root canal, showing the end portion of the file squeezed between the canal wall and the instrument.

[0045] FIG. 8 is an enlarged cross sectional view of the instruments in a human tooth root canal showing better a 1 mm insertion (penetration) of the file tip between the canal wall and the fractured part of the endodontic rotary file.

DETAILED DESCRIPTION OF THE INVENTION

[0046] The instrument according to the invention, provided for bypassing a fractured part 13 of a endodontic rotary file, for example made of NiTi, as may for instance be seen in FIGS. 7 and 8, has a dual taper or conicity, of for example namely 4% in the first 3 mm and then 2% for the rest of the active length 7 (see FIG. 4), in one of the possible embodiments, i.e. the one having the shortest length.

[0047] In a second embodiment, the instrument according to the invention has a conicity of 3% for the first 3 mm and then of 2% for the rest of the active length 7 of the tool (see FIG. 4), this applying to the instruments having the longest length. In the first 3 mm of the distal portion 9 of the file 1 (see in FIG. 5), near the tip 11 of the instrument, a flat (smooth) surface 3 is also provided, having a two degrees (2°) inclination 10 (see in FIG. 5) with respect of the longitudinal axis of the tool.

[0048] The instrument basically includes a handle 2 and a tool or working part 1 (see for instance in FIGS. 1 to 3). The tool part 1 (excluding the handle 2) includes an distal end portion 9 (see FIG. 5) provided with the flat surface 3, which is actually part of the more general active/cutting length 7. A perspective view of the distal end portion of the instrument is actually shown in the enlarged view depicted in FIG. 3, this enlarged view being referred to as 8 in FIG. 3 as well as in FIG. 4.

[0049] Forming together the working part 1 of the instrument of the invention, in the continuation of the portion 7 and located between the internal end of it and the handle 2, is a cylindrical linking member provided with a groove 4, whose function is to mark the side of the working part where the flat surface 3 is situated. The opposite surface 6 of the said cylindrical portion is by contrast not provided with any kind of marking member.

[0050] The dual taper or conicity makes the file 1 stiffer, which makes easier the penetration of the file 1 between the root canal and the separated/fractured part 13 of the for instance made of NiTi rotary file, as depicted in FIGS. 7 and 8.

[0051] The instrument of the present invention has in fact an off-center pyramid shaped tip 11 (see FIGS. 5 and 6), as depicted in sections C and D of FIG. 6, this ensuring a better guided penetration of the instrument with less chances of creating iatrogenic problems like ledges or perforations.

[0052] Because of the above mentioned dual design along the distal end portion 9, with the first 3 mm provided with a flat surface (smooth) 3 without flutes, it becomes possible to squeeze more easily the instrument of the invention between the root canal space and the separated/fractured part 13 of the NiTi endodontic rotary file (see FIGS. 7 and 8). The flat surface 3 may be in contact with the fractured part 13 while the opposite working side provided with a cutting surface 5 has flutes which allows the cutting of dentin. The cutting action furthermore creates space for further cleaning and shaping of the root canal space.

[0053] The depth of the flutes on the working cutting side 5 (see for instance in the enlarged portion referred to as 8 in FIGS. 3 and 4) of the active distal portion 9 is shorter than those of regular endodontic files, which allows for more efficiency in cutting the dentin, and creates subsequently space within the root canal system. The dual design of the file 1, including simultaneously a smooth-side and a cutting-side in the portion 9 of the file 1 near the tip 11, is a new feature designed especially to ease the penetration of the instrument in the narrow space between the root canal wall and the fractured part 13 of a NiTi endodontic rotary file.

[0054] The manufacturing method of instruments in accordance with the invention has been especially adapted to be suitable for the anatomical needs resulting from the narrow root canal space, in the presence of a separated part 13 of NiTi endodontic rotary files. The device is especially designed to handle cases where NiTi endodontic rotary files break during root canal treatment (when extraction of the broken part 13 is not possible), thus it does not jeopardize the prognosis of the treatment at a later point of time.

[0055] The present invention embodies: [0056] a standard diameter at the tip 11 of the file 1, [0057] dual taper in its working area, i.e. the active length 7, [0058] a cutting edge 5 at the side of the active distal portion facing the root canal wall and a safe-side 3 (flat/smooth) facing the fractured part of the NiTi rotary endodontic file.

[0059] The goal of the newly invented instrument is to bypass broken/separated/fractured portions of NiTi endodontic rotary files in introducing an especially designed instrument that can complete the root canal treatment in an efficient way.

[0060] This invention is designed in consideration with the narrow root canal space due to the presence of a separated/fractured part of a NiTi rotary endodontic file. This instrument is designed to help the clinicians to perform complete root canal treatment without the risk of leaving uninstrumented/uncleaned root canal walls.

[0061] As an example of the way it can be utilized, the practitioner has first to determine the level and length of fractured portion of rotary NiTi file within the canal space in order to choose the appropriate instruments in term of file size, keeping in mind that he/she has to bypass the said broken portion.

[0062] FIGS. 7 and 8 illustrate a tooth having a root canal within which the fragment of an endodontic file 13 has been broken and become wedged within the root structure surrounding the root canal. As may be seen, the broken file fragment 13 may be located deep within the root canal of the tooth so that it cannot be easily visible or accessible to the practitioner using usual removal means, thus bypassing is the appropriate option.

[0063] Initially, a normal standard K-type file is inserted to determine the working length by testing the level of the separated portion of the rotary file with light apical pressure. Then the proposed invented file 1 is inserted making sure that the flat (smooth) surface 3 is facing the fragment 13 (using the groove 4 marking the suitable face) while the cutting surface 5 is adequately facing the dentinal wall. This dual feature is especially designed to ease the penetration of the instrument 1, in fact the active length 7 of it, in the narrow space between the root canal wall and the broken fragment 13 of the NiTi endodontic rotary file.

[0064] Furthermore, during the file 1 insertion between the said broken fragment 13 and canal wall the practitioner has to make sure to be away of the danger zone 14. The invented instruments are then used performing watch-winding hand motions. The winding motions are effected in a reciprocating way, going back and forth (clockwise/counterclockwise) when rotating the instrument.

[0065] A first light apical pressure is applied to move the file 1 deeper into the canal, reaching a further point between the fractured fragment 13 of the file and the canal wall, then watch-winding again, performing to this purpose the same action with hand motions at a level located 1 mm deeper.

[0066] This is followed by a withdrawal of the instrument, then the practitioner irrigates the root canal, resumes with a corresponding K-type file, and finally repeats the entire operation, resuming all the above mentioned steps 1 mm deeper than before until achieving the full working length of the root canal, including the remaining untouched portion 12 of the canal, i.e. the portion beyond the broken fragment 13 of the rotary file.

[0067] The invention is not limited to the depicted example, which shows only a possible example of instruments fulfilling the aim as set at the beginning of the specification.