FINISHING ENDODONTIC FILE AND METHOD OF USE THEREOF

Abstract

The present invention relates to dentistry, and particularly, to a rotary endodontic finishing file used for root canal treatment. The endodontic finishing file comprises a shank for inserting in an endodontic motor handpiece, and a core of twisted metal braids secured in the shank, the said core being provided with an outer braid made of wire wound over the core. The length of the braid is less than the length of the core. At the braid-free end of the core, a brush of the core braids is formed. The winding of the wire of the outer braid is made in four layers, the winding of the first and third layers is made in the direction from the shank to the brush without a gap between the adjacent coils in each layer, the winding of the second and fourth layers is made in the opposite direction, providing the possibility of securing both ends of the braid wire in the shank. The winding pitch in the second and fourth layers is 8 to 10 times greater than the winding pitch in the first and third layers of the braid, the winding length of the third and fourth layers in the direction from the shank to the brush is less than the winding length of the first and second layers. The core is made of three twisted elastic tungsten wires, the open ends of which, located in the braid-free portion of the core, are of a cylindrical helix shape and curved in the form of a conical helix with an increasing pitch of turns for each strand of the core, whereby the curved ends of the brush wires are inserted into the canal separately and sequentially one after another with the motor turned off, each inserted wire being pressed against the walls of the canal during the insertion of the file. The proposed technical solution allows to provide high-quality and safe treatment, reduce the risk of injury during treatment, and also increase the service life of the endodontic file.

Claims

1. A finishing endodontic file comprising: a shank for inserting into an endodontic motor handpiece, and a core of twisted metal braids secured in the shank, wherein: the core is provided with an outer braid made of wire wound over the core, the length of the braid is less than the length of the core, at a braid-free end of the core, a brush of the core braids is formed, the outer braid comprises four layers of wire, wherein: the winding of the first and third layers is made in the direction from the shank to the brush without a gap between the adjacent coils in each layer, the winding of the second and fourth layers is made in the opposite direction, providing the possibility of securing both ends of the braid wire in the shank, the winding pitch in the second and fourth layers is 8 to 10 times greater than the winding pitch in the first and third layers of the braid, and the winding length of the third and fourth layers in the direction from the shank to the brush is less than the winding length of the first and second layers, and the core is made of three twisted elastic tungsten wires, the open ends of which, located in the braid-free portion of the core, are of a cylindrical helix shape and curved in the form of a conical helix with an increasing pitch of turns for each strand of the core.

2. The finishing endodontic file according to claim 1, wherein the winding length of the third and fourth layers in the direction from the shank to the brush is less than one-third of the winding length of the first and second layers.

3. The finishing endodontic file according to claim 1, wherein the winding of the second layer of the braid forms an encircling coil on the side adjacent to the brush to keep the brush wires from unwinding.

4. The finishing endodontic file according to claim 1, wherein each core wire has a diameter of 0.08 to 0.12 mm.

5. The finishing endodontic file according to claim 1, wherein the outer braid is made with tight winding.

6. The finishing endodontic file according to claim 1, wherein the file is designed to operate at a speed of 500 to 5500 rpm.

7. The finishing endodontic file according to claim 1, wherein the outer braid is made of tungsten wire.

8. A method for cleaning root canals using a finishing endodontic file according to claim 1, wherein the curved ends of the brush wires are inserted into the canal separately and sequentially one after another with the motor turned off, each inserted wire being pressed against the walls of the canal during the insertion of the file.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 is a general view of a finishing endofile;

[0035] FIG. 2 is a general view of an open end of a core of the endofile;

[0036] FIG. 3 is a general view of a closed end of a core of the endofile;

[0037] FIG. 4 is a general view of an exposed portion of the core strands;

[0038] FIG. 5 is a cross-sectional general view of the core and braid securement in a shank;

[0039] FIG. 6 is a general view of an assembled file with an endodontic motor handpiece.

EMBODIMENT OF THE INVENTION

[0040] An endodontic file comprises a shank 1 for inserting in an endodontic motor handpiece 2, a core 3 of twisted metal strands 4 and an outer braid 5 of the core 3 made of wire wound over the core 3, the core and the braid being secured in the shank. The strands of the core and the braid wire wound on the core may be secured in the shank by pressing or adhesive bonding. The shank 1 is made of a hard material (for example, steel or brass) and is fixed in the handpiece of the endodontic motor by means of a tight detachable connection 6, for example, a collet, a lock or other device that provides a tight fixation of the shank in the handpiece. The length of the braid 5 is less than the length of the core 3, the braid itself is made of wire wound in four layers, whereby the first and third layers are wound in the direction from the shank to the brush without a gap between adjacent coils in each layer, the second and fourth layers being wound in the opposite direction, which allows both ends of the braid wire to be secured in the shank. The winding pitch in the second and fourth layers is 8 to 10 times greater than the winding pitch in the first and third layers of the braid, the winding length of the third and fourth layers in the direction from the shank to the brush is less than the winding length of the first and second layers and may be about one-third of its length. The core 3 is made of three twisted elastic tungsten wires 4, the open ends of which being located in the braid-free portion of the core, form a brush 7. Whereby, the ends of the wires that form the brush, are given a shape of a cylindrical helix 8, which is curved in the form of a conical helix 9 with an increasing pitch of turns for each strand of the core. The winding of the second layer of the braid forms an encircling coil 10 on the side adjacent to the brush 7 to keep the brush wires from unwinding. Each core wire has a diameter of 0.08 to 0.12 mm. The outer braid is made with tight winding on the core, and the diameter of the braid is 0.4 to 1.05 mm. The braid may be made of tungsten or another metal that provides the necessary stiffness characteristics, with a wire diameter of 0.08 to 0.12 mm. The endodontic file is designed to operate at a rotation speed of 500 to 5500 rpm.

[0041] Whereby, the choice of tungsten as a material for the manufacture of the core strands and providing a given shape of the brush wires is determined by the high stiffness requirements for the brush wires of the finishing endodontic file, which must effectively clean any tooth root canals. At the same time, during operation, each brush wire is subject to multiple flexing loads, since the number of its flexes during the treatment of one root canal, even at a relatively low file rotation speed of 5500 rpm, is about 10,000 times. Given that the largest tooth has four channels, each brush wire will be flexed about 40,000 times at an angle of 60-90 degrees to treat it. The materials currently used for the manufacture of similar devices, stainless steel, nitinol, etc., are not able to withstand such a load for a long time due to cyclic fatigue and excessive torsional force. To prevent their destruction, it is necessary to use other materials with higher mechanical properties. Such a material, as found by the authors of the claimed invention, is tungsten. The peculiarity of the use of tungsten is that it provides flexibility and resource capacity in small-diameter products, which is confirmed by experimental studies of the claimed finishing endodontic file.

[0042] Formation of the exposed portion of the core in a brush form, each wire of which has a structure pattern of a double helix (cylindrical and conical), in which the bends are offset relative to each other, prevents the brush from twisting into a single cable and allows to maintain its alignment with the longitudinal axis of the root canal during rotation in any direction, creating a web-like pattern. In doing so, regardless of the force, speed and direction of rotation, the brush always remains unwound.

[0043] Finishing endodontic file (brush), as a rule, can be operated in three modes: disinfection, activation and retreatment.

[0044] In all modes, after the file is inserted in the endodontic motor handpiece with the motor turned off, the curved ends of the brush wires are inserted separately and sequentially one after another into the tooth canal with each inserted wire being pressed against the canal walls during the file insertion after which another portion of the core is inserted into the channel to the working length. Then, in the modes of disinfection and activation, the tooth canal is filled with an active chemical, mainly sodium hypochlorite, and a structure formed from the brush wires. Rotating inside the channel at a speed of 500 to 5500 rpm, the exposed end of the file acts as a brush. In doing so, the bends of the brush wires form a stable structure that can follow the anatomical structure of the tooth root, regardless of the profile of the walls of the tooth canal and its shape. Intensively rotating, the wires (brushes) clean off the smeared layer from the walls of the root canal, which usually consists of dentin particles, remnants of the vital or necrotic pulp, bacteria and traces of irrigation solutions. In addition, active mixing of the solution contributes to its activation, i.e. acceleration of the chemical process.

[0045] When operated in the retreatment mode, the brush wires, rotating, first scrape off the old filling material from the walls of the canal of the tooth, after which the canal is filled with an active chemical substance, for example, a gutta-percha solvent of the solvadent type. The proposed technical solution allows to provide high-quality and safe treatment, reduce the risk of injury during treatment, and also increase the service life of the endodontic file.

REFERENCE NUMERALS

[0046] 1shank; [0047] 2endodontic motor handpiece; [0048] 3core; [0049] 4metal braids; [0050] 5outer braid of a core; [0051] 6tight detachable connection; [0052] 7brush; [0053] 8cylindrical helix; [0054] 9conical helix; [0055] 10encircling coil.