JPH03212267A - Improved instrument for use in applying fillers to pulp canal prepared for intradental treatment - Google Patents

Abstract

PURPOSE: To provide an improved instrument for use in applying a filling material to a root canal by having distal and proximal portions, with the distal portion made from a material having high biological durability and having a spiral groove, and by having a handle part at the proximal part of a shaft. CONSTITUTION: This improved instrument 10 is used in applying a filling material to a root canal. The instrument 10 is made of a material with high biological durability, with a shaft 12 having a handle part 26 at a proximal end 14, and with a distal end 16 having a surface configuration adapted to hold the filling material. The root canal is filled with the filling material 28 up to the end region 36 of the tooth by insertion of the instrument, and, after the complete insertion of the instrument, torque is applied to the handle 26, and the shaft is cut at a decreased torque resistance region 22. The distal part of a support member is left in the tooth to reduce the influence of contraction of the filling material. Further, the use of a spiral groove 44 makes the instrument slightly rotatable so as to further compress and condense the filling material after the distal portion having the filling material thereon has been inserted into the root canal, and enables the instrument to be removed completely.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is based on a patent application for use in applying filling materials to endodontically prepared root canals, to William B. Johnson, published July 19, 1988. U.S. Pat. No. 4,758,156 entitled ``Tools for Providing Tools'', which application is incorporated herein by reference.

The present invention is summarized as an improved instrument for use in applying a filling material, such as Gutta Percha or the like, to an endodontically prepared root canal, which instrument has a high biological resistance. in the form of an elongated shaft made of a material having a handle portion at the proximal end and a distal end of the shaft having a surface suitable for retaining the formed filler material. The distal portion and the proximal portion of the shaft can be cut from each other, thereby leaving the distal portion and the filling material in the root canal. In a preferred embodiment, the surface of the distal portion of the shaft is defined by a helical groove.

Conventional techniques for performing dental ridge treatments are time consuming and often do not adequately ensure that the entire root canal system is filled with restorative material. Experience has shown that with current preparation techniques it is not possible to remove all pulp remnants and contaminants from the root canal. Dental ridge treatment will be successful if the pulp remnants and contaminants are completely embedded in the restorative material. If the pulp remnants and contaminants are not completely buried, there is a high possibility of failure of the dental ridge treatment. Complete implantation of pulp remnants and contaminants requires complete solidification of the root canal system. Experience has shown that failure to provide complete rigidity to the root canal system is a major cause of failure in dental ridge treatment.

The device of the present invention is in the form of a rigid support member having a proximal portion and a distal portion, the distal portion being covered with gutta percha or similar filler material.

The support member is a tapered elongated rod.

The support member can be constructed from a material that is sufficiently rigid and non-toxic when left in the root canal. One material that has been successfully used is stainless steel. Plastic or metallic materials with high biocompatibility can also be used successfully.

In the present invention, the instrument has distinctive proximal and distal ends, the distal end being positionable within the entire length of the root canal, and the handle portion extending above the crown of the tooth. ing. The distal and proximal portions of the instrument are configured such that they can be separated from each other after the distal portion is fully positioned within the root canal.

In some embodiments, the device has a prefit between the distal portion and the proximal portion. In another embodiment, the device has a distal portion and a proximal portion secured together by a bonding cement.

In yet another embodiment, the distal and proximal portions are arranged such that the device can be broken by moving the proximal portion back and forth relative to the distal portion to break the device in areas of reduced strength. separated by regions of reduced cross-sectional dimension.

In another embodiment, the distal and proximal portions do not have defined cutting points and the dentist cuts the instrument after the distal portion is well within the root canal.

According to a further refinement of the device of the invention, the cross-sectional shape of the device at least in the distal part is not circular, such as triangular, square, oval, etc. In a further different preferred embodiment, the distal part has a helical groove that serves to retain the filling material on its surface and compress it within the root canal. Another embodiment includes the use of a surface formed by integral projections that serve to retain the filler material in the distal portion.

A disc-shaped washer is incorporated into the shaft of the support member and acts as a stop at the coronal opening of the root canal, thus serving to prevent viscous flow of gutta percha from the root canal during the insertion process. Disk-shaped washers are also used for distance measurements.

The filling material is molded into the supporting member in a tapered or conical shape, with sufficient material to ensure the complete filling of the root canal and thus the complete solidification of the root canal. facilitates introduction into the taper part.

The instrument is compatible with standard endotherapy files.
Can be manufactured in a variety of sizes.

In using the instrument of the present invention, the root canal is first prepared in a standard manner by drilling with an endotherapy file. Prepare an appropriately sized device with filling material. The filler material can be heated with a flame so that the filler material becomes thermoplastic. The heated instrument is then inserted into the root canal with positive tip force. The proximal portion of the instrument is separated from the distal portion, leaving the distal portion with the filling material within the root canal.

The proximal portion is then removed while the stopper or washer is held against the tooth, and the remainder of the gingival treatment is completed using conventional procedures.

In another aspect of the instrument, the shaft may have no defined means of cutting the proximal portion from the distal portion. In this embodiment, the distal portion with filler material is
It is inserted into the root canal to its full depth. Next, using a rotating burr or cutter pliers, the dentist cuts the proximal portion from the distal portion. Alternatively, the dentist can create a point of reduced strength by making a score in the shaft with a rotary bur or cutting pliers, and then move the proximal to distal portion by bending the shaft back and forth at the point of reduced strength. Parts can be separated. In this way, the instrument can be used without considering matching the length of the distal portion to the depth of the root canal.
Can be used at any depth in the root canal.

One of the advantages of leaving the distal part of the support member on the tooth according to the principles of the invention is that it greatly reduces the volume of filling material used, thus reducing the effects of shrinkage of the filling material. .

For more background material regarding the present invention, see the Journal, which describes a new gutta-percha technique in which gutta-percha is formed around an endotherapy file.
al of Endodontics, Volume 4, No. 6, June 1978, pages 184-188.

A better understanding of the invention may be had by reference to the following description and claims taken in conjunction with the accompanying drawings.

Referring initially to FIG. 1, the support member instrument is indicated generally by the numeral 10 and is formed as an elongated shaft 12 having a proximal end 14 and a distal end 16. As shown in FIG. The shaft can have a variety of cross-sectional shapes, but as will be described more specifically below, when the shaft is positioned within the root canal, it has a flared end ff1.
A preferred and simple shape is a circular cross-sectional shape so that 18 prevents rotation of the shaft. a plurality (three shown) of spaced apart enlarged cross-sectional sections 208-20;
C is formed integrally with the shaft.

When the shaft is preferably of circular cross-section, enlarged dimension portions 20A, 20B and 20C are also preferably of enlarged circular cross-sectional shape.

A reduced torque resistance region 22 is located between the enlarged diameter portion 2OA and the proximal end 14. This is in the form of a 10 groove formed around the shaft as shown. Between the groove 22 and the proximal end 14 is a cleat or washer 24 with an opening 24A that slidably receives the shaft 12.

At the proximal end 14, a handle portion 26 is attached to the shaft. The handle 26 is of a larger diameter than the shirt 12 and can be integral with the shaft or fixed to the shaft and made from a material such as plastic.

FIG. 2 shows an instrument ready for inserting a filling material into the root canal of an endodontically prepared tooth. FIG. 2 shows a filler material 28 formed in device 10 in cross section.

The filler material 28 can be a gutta percha or the like and can be formed by hand into the device IO. After formation, guttapelcha can be heated with a flame at the appropriate stage.

FIG. 3 shows a tooth 30 having root canals 32 and 34. FIG. The root canal 32 is endodontically prepared in standard techniques, such as by the use of a file, to remove the pulp and prepare the root canal as cleanly as possible. The instrument IO with the filling material 28 molded thereon is ready to be filled into the root canal 32. The apex of the root canal is indicated by 36 and the crown or coronal part is numbered 38.
is shown by.

4-6 show the stages of filling the root canal 32. Fourth
The figure shows the instrument inserted into the root canal 32.

The filling material 28 is forced out by insertion of the instrument and the root canal is filled up to the apical region 36 of the tooth. As shown in FIG. 4, after complete insertion of the instrument, rotational torque is applied to the handle 26.
is applied to cut the shaft in a region of reduced torque resistance 22, as shown in FIG. This is possible because the flared distal end 28 of the shaft prevents rotation relative to the teeth 30.

After the shaft is cut into two parts, the proximal part is withdrawn. Sliding washer 24 is used to retain filling material 28 within the root canal by holding the washer downward as the proximal end of shaft 12 is withdrawn.

Figure 6 shows the proximal portion of the instrument being withdrawn. The washer 24 is then removed, leaving the distal portion of the shaft in place within the root canal 32. Root canal 3
2 is filled more completely by applying additional filling material and by applying mechanical or hydraulic pressure on the filling material to force it into the root canal.

The coronal region of the tooth can be filled in the usual manner.

The description of the tooth 30 in FIGS. 3-6 is merely illustrative, as the tooth is individual, and the drawings represent the stages involved rather than providing an accurate pictorial representation of the appearance of the tooth or root canal. It is intended to be illustrative.

The device of the present invention thus provides a unique and highly effective method of delivering filling materials such as gutta percha into endodontically prepared root canals. The prior art teaches the use of files as carriers for filler materials, but while this known method works successfully for its intended purpose,
There are limitations and problems that are overcome by the present invention.

3 FIG. 7 shows an alternative embodiment of the invention, in which:
Instrument IO includes a shaft whose proximal portion 40 and distal portion 42 are integral with each other. The distal portion is tapered and includes a helical groove 44. Groove 44 has a generally flat outer edge. That is, the groove 44 is for the purpose of retaining the filling material in the distal portion. Additionally, the use of the helical groove 44 allows the instrument to be rotated slightly to further compress and condense the filling material after the distal portion with the filling material thereon is inserted into the root canal. has advantages.

When using the instrument of FIG. 7, the dentist inserts the instrument with the filling material into the endodontically prepared root canal and then, as previously described, rather than leaving the distal portion in the root canal. , the instrument can be completely removed. This technique is achieved in the following way. First, the distal end 42 of the instrument with the filling material thereon is inserted into the root canal, as shown in FIGS. 2 and 3. The dentist then rotates the instrument by the handle portion 264 in a counterclockwise direction while applying a slight force toward the tooth. The distal portion 42 can thus be completely retracted from the root canal, leaving the filling material within the root canal. As the distal portion advances away from the root canal, the helical cone action of the helical groove 44 compresses the filling material within the root canal.

In another technique, the dentist rotates the instrument 1/2 in a counterclockwise direction.
Rotate 2 to 1 revolution, stop rotation, apply pressure toward the tooth, rotate again 1/2 to 1 revolution, stop, and apply pressure toward the tooth, distal portion 42 This step is repeated sequentially until the tooth is completely removed from the root canal. This procedure of compression followed by rotation uses the helical-cone nature of the helical groove 44 to achieve effective filling of the root canal with the filling material.

The helical groove 44 in the distal portion 42 is formed to achieve a helical cone action and suppress drilling action.

That is, the flared portion is formed with a symmetrical outer edge so that it does not cut into the tooth on which the instrument is located and which is rotated for the purpose of helical drilling.

5- Thus, the embodiment of FIG. 7 can be used in techniques where the distal portion of the instrument is removed from the root canal or is completely removed.

A further advantage of the embodiment of FIG. 7 is that the provision of the helical groove 44 makes the distal portion of the instrument more flexible so that it easily adapts to the shape of a non-linear root canal. be.

It should be noted that in FIG. 7, the instrument does not include a cutting point. The instrument of FIG. 7 is illustrative of any use of the instrument shown herein, does not include a preselected cutting point, and is not provided with a cutting point.

In use of the instrument in FIG. 7, after inserting the distal portion 42 into the tooth, the dentist can cut the shaft with the use of a high speed burr or with cutting pliers. Cutting can be done simply to form a point of reduced strength, and then by moving the proximal section back and forth until it is cut, or with a high speed bur or cutting pliers or by cutting the two parts completely. The proximal portion is separated from the distal portion by the use of other means for. The shaft 6 is located below the crown region 38, i.e. when the root canal and the drilled portion of the crown region are completely filled, the distal portion 42 is removed, as seen in FIG. The cut should be made within the internal area of the tooth so that the white is completely retained.

In the method of implementing the embodiment of FIG. 7 in which a preselected separation point between the distal and proximal portions is not used, filling the gingivally prepared root canal first comprises:
A filler material is formed at the distal end of the elongated slender shaft formed from a material having high biological resistance.

The shaft with the filling material thereon is then positioned within the root canal using a handle portion secured to the proximal portion of the shaft. The final step is to cut the proximal portion of the shaft from the distal portion, leaving the distal portion and the filling material retained therein within the root canal.

Cutting the proximal portion from the distal portion may be performed by operation of a cutting means carried on the shaft. This cutting means may be a peripheral groove or weakened area 22, as described with reference to FIG. 1, or another means as described hereinafter. Cutting the proximal portion of the shaft from the distal portion includes applying a cutting force to the shaft with a high speed rotating bar or by use of cutting pliers or similar mechanical means.

FIG. 8 shows a further alternative embodiment of the invention, which can be used either with or without cutting means, but includes an optional cutting point 22. The distal portion 42 includes an integral burr 4 extending from the surface.
6 to help support the filling material in the distal portion.

FIG. 9 shows an embodiment with an optional cut point 22, in which the distal portion 42 has a non-circular cross-sectional shape.

Figures 12A, 12B and 12c show examples of such non-circular cross-sectional shapes. FIG. 12A shows the distal portion 4
2 shows an embodiment in which the cross section is triangular.

Figure 12B shows an oval cross-sectional shape. FIG. 12C shows a square cross-sectional shape. Such a non-circular cross-sectional shape enhances retention of filler material in the distal portion.

The first (l) shows another embodiment of the invention that includes a defined separation point. In FIG. 1O, the distal portion 42 has a recess 48 at the upper end 42A. , has an enlarged portion 50 of reduced outer diameter that may be nested within recess 48. In this manner, distal portion 42 and proximal portion 40 are held in axial alignment while filling material 28 is fixed to the distal part, and the distal part with the filling material is inserted into the root canal.

The proximal portion 40 can then be easily separated from the distal portion.

FIG. 11 shows a further different means of achieving separation. In this embodiment, the upper end 42A of the distal section is secured to the end 40A of the proximal section by adhesive 52.

The adhesive is used to hold distal portion 42 and proximal portion 40 in axial alignment while filling material 28 is applied and the distal portion with attached filling material is inserted into the root canal. Although sufficient, bending 19 the proximal portion relative to the distal portion breaks the adhesive 52 and separates the portions.

Thus, Figures 7-11 first illustrate various means of improving retention of filler material in the distal portion of the shaft.

Second, they show two ways of implementing the invention, one is without a preselected separation portion and the dentist inserts the distal portion into the root canal, as shown in FIG. In Figures 8 to 11, the separation is performed after
Various types of embodiments are provided for preselected separation points. The embodiment of Figure 7 has the advantage of being able to design an instrument in which the main consideration is not to the depth of the root canal but rather to the diameter of the root canal, whereas the embodiment of Figures 8 to 11 , the appliance is preferably pre-designed to accommodate the root canal depth as well as the root canal diameter. Adaptation to the diameter of the root canal allows the dentist to easily select the maximum diameter that can be easily accommodated in the gingivally prepared root canal, thereby reducing the amount of filling material. 0, which means that it is possible to manufacture instruments of a wide variety of diameters, but is limited as there is no essential requirement that the diameter of the distal part of the instrument closely match the diameter of the root canal. This means that you only need a few diameters.

Although FIGS. 7, 8, and 9 show a device IO having a filler material formed in the distal portion 42, such devices typically have a filler material formed in FIGS. 10 and 11. It will be appreciated that it may be supplied to the dentist with the distal portion preformed as shown.

As previously mentioned, the filling material used to provide solidity to the gingivally prepared root canal can be gutta percha or the like. Gutta percha has been the most commonly used filler material for such purposes since its introduction 100 years ago. Gutta percha is obtained from the latex of Acatellaceae trees and is a trans isomer of polyisoprene, which differs from natural rubber by its crystal structure.

Gutta percha in raw form aI is in the alpha j crystalline form, but when heated above 65° it becomes amorphous and melts. , returning to the "beta" crystalline state. Thus, it is the "beta" crystalline form that is commonly used in gingival medicine. Additionally, gutta percha materials prepared commercially for gingival therapeutics are typically a mixture of the beta crystalline form of gutta percha and fillers such as zinc oxide to achieve the desired properties of the final product. It also has other minor components including heavy metal sulfates, waxes or resins.

Additionally, gutta percha is sometimes mechanically treated to change its physical properties for use in gingival therapy. US Pat. No. 4,632,977 teaches a method of plasticizing a thermoplastic polymer containing gutta percha to change its physical properties.

The present invention contemplates the use of a filling material of a physically and biologically resistant composition or formulation suitable for use in imparting solidity to a root canal. As used herein, the term "filling material" includes gutta percha in either the alpha or beta crystalline state, and also includes mixtures of gutta percha and other materials, or otherwise contains gutta percha in a therapeutically prepared root canal. Includes other filler materials with similar properties used during filling.

The claims and detailed description describe the invention as presented, and the terms used in the claims derive their meanings from the use of such terms in the detailed description. . The same terms used in the prior art will have a broader meaning than specifically used herein. When there is a conflict between the broad definition of such a term as used in the prior art and the specific use of the term herein, the specific meaning is intended.

Although the invention has been described with certain specificity, it will be apparent that numerous modifications may be made in the details of construction and aspects of the components without departing from the spirit and scope of the invention disclosure. It is.

It will be understood that the invention is not limited to the embodiments presented by way of illustration, but that each element includes the full scope of individuality with which it is associated, and is limited only by the scope of the claims.

The main features and aspects of the invention are as follows.

1. An instrument for applying a filling material, such as gutta percha or the like, to a therapeutically prepared root canal, the instrument comprising: (a) a distal portion and a proximal portion, the distal portion being a root canal; an elongate shaft, wherein at least a distal portion is made of a highly biologically resistant material, and the distal portion is made of a material having a high biological resistance; It has a spiral groove formed in the
(b) a filling material formed in the distal portion, wherein the helical groove improves retention of the filling material and retains the filling material when the instrument is retracted after insertion into the root canal; (c) a nodule portion in a proximal portion of said shaft;

24 2. The distal portion of the shaft is secured to the proximal portion of the shaft by a telescoping fit forming a means for disconnecting the proximal portion of the shaft from the distal portion of the shaft. utensils.

3. The device of claim 1, wherein the distal portion of the shaft is secured to the proximal portion of the shaft by a bonding adhesive forming a means for cutting the proximal portion of the shaft from the distal portion of the shaft.

4. The shaft includes a reduced cross-sectional area portion between the distal and proximal portions of the shaft forming a means for disconnecting the proximal portion of the shaft from the distal portion of the shaft. utensils.

5. The instrument according to item 1 above, wherein the proximal portion is severed from the distal portion by applying a cutting force after the distal portion has been inserted into the root canal.

6. An instrument for applying a filling material, such as gutta percha or the like, to a therapeutically prepared root canal, comprising: (a) made from a material with high biological resistance;
a shaft having a length extending at least substantially the entire depth of the root canal, having an outer surface suitable for receiving a filling material, and having a first end and a second end; (b) forming a handle portion, a first end and a second distal portion; (b) forming a handle portion;
a proximal portion of the shaft having an end thereof, wherein the second end of the proximal portion of the shaft has a recess therein, and the proximal portion of the shaft is nested within the recess of the distal portion. (c) a filler material formed in a distal portion of the shaft; and (c) a filler material formed in a distal portion of the shaft.

7. The device of claim 6, wherein the proximal and distal portions of the shaft are substantially aligned when the reduced cross-sectional area portion is fully received within the recess.

8. The first end of the proximal portion of the shaft has a recess therein, and the first end of the distal portion of the shaft is removably inserted into the recess of the proximal portion. 6 above with a reduced diameter end that can be accommodated in
Equipment described in.

9. The device of claim 8, wherein the proximal and distal portions of the shaft are substantially aligned when the reduced cross-sectional area portion is fully received within the recess.

10. The device of claim 6, wherein the distal portion of the shaft is triangular in cross section.

11. The device of claim 6, wherein the distal portion of the shaft is oval in cross section.

12. The device of claim 6, wherein the distal portion of the shaft is square in cross section.

13. The device of claim 6, wherein the distal portion of the shaft has a helical groove on its outer surface.

14. The device of claim 6, wherein the distal portion of the shaft has an integral protrusion extending from an outer surface.

15. An instrument used for applying a filling material, such as gutta percha or the like, to a gingivally prepared root canal, 27 (a) made of a material with high biological resistance;
a first portion of the shaft having a length extending at least substantially the entire depth of the root canal, having an outer surface suitable for receiving a filling material, and having a first end and a second end; (b) forming a handle portion, a first end and a second end;
a second end of the distal end of the shaft and a first end of the proximal portion of the shaft;
(c) a severable bonding material between mating surfaces of said shaft portion; and (d) formed on a distal portion of said shaft. A device comprising: a filling material;

16, the proximal and distal portions of the shaft are substantially aligned when a second end of the distal portion is secured to the first end of the proximal portion by the bonding material; 16. The device according to 15 above.

[Brief explanation of drawings]

28 FIG. 1 is an enlarged front view of a device or support member of the present invention including a slideable stop or washer shown in cross section. FIG. 2 shows the lower part of the first instrument enclosed by a conically shaped volume of filling material, such as gutta percha, ready for use for filling a gingivally prepared root canal; Front view similar to figure. FIG. 3 shows a cross-section of a gingivally prepared tooth and the instrument of the invention on a reduced scale being used to apply filling material to one of the gingivally prepared root canals. Figure shown. FIG. 4 is a cross-sectional view of the tooth similar to FIG. 3 showing the instrument inserted into the root canal. FIG. 5 shows the next step in the procedure for applying filling material to a root canal, in which the instrument has been rotated to cut the proximal portion from the distal portion. FIG. 6 shows the distal portion being retained in the root canal with the filling material and the proximal portion of the instrument being removed. =29- FIG. 7 shows an alternative embodiment of the present invention in which the distal portion of the device is formed with a helical groove for improved retention of filler material; There is no preselected point to cut or separate the distal end from the proximal end; instead, the dentist uses a rotary bur or cutter after the distal end is fully inserted into the root canal. At least a point of weakness is formed to be separated by cutting the proximal portion using pliers or moving the proximal end back and forth. FIG. 8 is a front view of a device similar to FIG. 7, with an integral protrusion on the distal portion that serves to enhance retention of filler material; FIG. 9 shows an embodiment of an instrument similar to FIGS. 7 and 8 in which the distal portion has a non-circular cross-sectional shape. Figure 1 theta shows how the distal part can be severed from the proximal part by a telescoping internal connection between the distal part and the proximal part, once showing the filler material secured to the distal part. Front view of the instrument. 0 FIG. 11 is a front view similar to FIG. 10 showing an arrangement in which the distal portion is secured to the proximal portion by bonding cement. FIG. 12A is a cross-sectional view of FIG. 9 showing an embodiment in which the non-circular cross-sectional shape of the distal portion is triangular. FIG. 12B is a cross-sectional view of FIG. 9 in which the distal portion has an oval cross-sectional shape. FIG. 12c is a cross-sectional view of FIG. 9 in which the distal portion has a square cross-sectional shape. FIG. 13 shows the helical grooves in the outer surface of the seventh
FIG. 3 is a cross-sectional view of the distal portion of the device shown. In the figure, 10... instrument, 12... shaft, 14...
- Proximal end, 16... Distal end, 20A to 20C...
・Enlarged cross-sectional portion, 22...Groove, 24...Washer, 26
...Handle part, 28...Filling material, 30...
Teeth, 40... Proximal part, 42... Distal part, 44.
...Spiral groove, 46 ... Cone, 48 ... Recess, 50
. . . Enlarged portion, 52 . . . Adhesive. 1

Claims (1)

Claims: 1. An instrument for applying a filling material, such as gutta percha or the like, to an endodontically prepared root canal, comprising: (a) a distal portion and a proximal portion; an elongate shaft, the distal portion being of a length positionable within at least substantially the entire length of the root canal; (b) a filler material formed in the distal portion, the helical groove improving retention of the filler material; and (c) a handle portion in a proximal portion of said shaft; and (c) a handle portion on a proximal portion of said shaft, the device serving to force filling material into the root canal when the device is retracted after insertion into the root canal. 2. An instrument for applying a filling material, such as gutta-percha or the like, to an endodontically prepared root canal, comprising: (a) made from a material with high biological resistance; a first distal portion of the shaft extending at least substantially the entire depth, having an outer surface suitable for receiving filler material, and having a first end and a second end; (b) a proximal portion of the shaft forming a handle portion and having a first end and a second end, wherein the second end of the proximal portion of the shaft has a recess therein; and (c) the proximal portion of the shaft has an integral portion of reduced cross-sectional area that can be nested and removably received in a recess in the distal portion; (c) formed in the distal portion of the shaft; A device comprising: a filling material; 3. An instrument used for applying a filling material, such as gutta percha or the like, to an endodontically prepared root canal, the instrument comprising: (a) made from a material with high biological resistance; a first portion of the shaft having a length extending at least substantially the entire depth of the root canal, having an outer surface suitable for receiving a filling material, and having a first end and a second end; (b) a proximal portion of the shaft forming a handle portion and having a first end and a second end, wherein a second end of the distal end of the shaft; the first ends of the proximal portions of the shaft are shaped for mating engagement with each other; (c) a severable bonding material between mating surfaces of the shaft portions; and (d) the shaft. a filling material formed in a distal portion of the device.