KR20190006937A - Ni-Ti File for Root Canal Cleaning Process using Ultrasonic Wave - Google Patents

Abstract

According to an embodiment of the present invention, provided is a file, which can be used for cleaning a root cap by using ultrasonic energy. The file according to an embodiment of the present invention is made of a Ni-Ti alloy and is heat-treated to include an R-phase at a temperature range of 36 to 45 deg. C.

Description

[0001] The present invention relates to an ultrasonic canal cleaning apparatus,

The present invention relates to an ultrasonic root canal cleaning pile for use in root canal treatment, and more particularly, to a pile cleaning tool for improving the shape and characteristics of a pile made of a Ni-Ti alloy, which is a shape memory alloy, the present invention relates to an ultrasonic root canal cleaning file configured to more efficiently and stably clean the canal system.

[This study was carried out by the Ministry of Commerce, Industry and Energy and the Korea Institute of Industrial Technology (KIET), and was conducted as an ENCOURAGEMENT PROGRAM FOR THE INDUSTRIES OF ECONOMIC COOPERATION REGION.]

The teeth, which are the hardest tissues in the human body, have soft tissues that are different from the outer appearance and have internal nerves and blood vessels. The dimensions extend to the root, that is to the end of the root, and are connected to the blood vessels and nerves of the periodontal ligament in the gingival bone (alveolar bone) surrounding the root through a narrow hole (apical hole) at the root tip. It is the symptoms that the nerves of the dimension react to protect teeth from irritation when toothache or other stimuli feel it is sick.

In the case of weak stimuli, even if the dimensions are reacted easily, they can be restored without any special treatment. However, if the tooth is infected by severe caries or exposed to external injuries such as tooth fracture, And the dimensions are in an irreversible state, causing severe pain.

Dentists often perform endodontic treatment, often referred to as neurological treatment, in the event of such damage, since removing the teeth is a burden to restore later. Endodontic treatment refers to a treatment method that removes damaged teeth and removes only the soft tissues inside the teeth to prevent pain, while preserving teeth so that they function properly in place. In other words, endodontic treatment (neuropathy) is not a treatment to repair the nerve of a damaged or infected tooth but to remove the nerve tissue (dimension) of damaged or infected tooth to prevent pain or related complication.

Endodontic treatment is basically performed by physically and chemically removing the dental tissue and infectious source (mainly bacteria) inside the injured tooth and filling the inside of the root canal with a biocompatible and sealable substitute filling material.

Since the inside of the root canal is formed with a very complicated and curved anatomical structure, it is almost impossible to completely remove the infected size tissue deep inside the root canal by mechanical means. Therefore, in order to cleanly remove the residual dimensions present in the damaged tooth, it is necessary to chemically clean (disinfect) the inside of the root canal with the cleaning liquid. According to the reported studies, it is known that more than 70% more dimensional residues are left in the case of performing canal preparation only by mechanical method without cleaning.

NaOCl (sodium hypochlorite), EDTA (ethylenediaminetetraacetic acid), H ₂ O ₂ , citric acid and other chemical agents are mainly used for cleaning the root canal.

Among them, NaOCl has excellent ability to dissolve dimensional tissues, bacteria, viruses, spores, endotoxins, etc. [According to the reported studies, if root canal cleaning is performed with 0.5% NaOCl, root canal cleaning using physiological saline EDTA has a smear layer that is relatively inferior in the ability to dissolve the tissue, but does not remove NaOCl well. Because of the ability to expose a large number of ivory tubules surrounding the root canal, more recently, root canal rinses have been performed using NaOCl and EDTA.

In recent years, researches on a method of effectively improving the cleaning efficiency of a root canal by effectively transferring the cleaning liquid to a place deep inside the tooth having a complicated anatomical structure are progressing steadily.

As a conventional method for improving the cleaning efficiency, a cleaning liquid is injected into a nail portion existing at the root end of a tooth directly using a thin needle, and then the cleaning liquid injected using a small treatment padding or injection needle is agitated There is a method for increasing the fluidity and cleaning property of the cleaning liquid.

In recent years, a method has been proposed in which the ultrasonic vibration energy is transmitted to the cleaning liquid injected into the root canal, thereby significantly improving the fluidity of the cleaning liquid, thereby improving the cleaning efficiency by penetrating the cleaning liquid to deeper places.

The method of using sound waves is relatively safe because it uses a smaller energy than the method using ultrasonic waves, but there is a problem that energy can not be efficiently transmitted from a curved root canal because of a long wave, and the effect of synergy of cleaning function is lowered due to low energy There is a disadvantage.

On the other hand, the ultrasonic method transmits vibrational energy while forming node and antinode, so it can transmit the vibration energy more effectively to the deep inside the complicated canal, which is recognized as the most efficient cleaning method have. In particular, when ultrasonic vibration is applied to the cleaning liquid, a vortex is formed in the cleaning liquid injected into the root canal, so that the physical effect of the cleaning liquid is increased, and fine bubbles are formed to more effectively remove contaminants attached to the root canal wall. The chemical efficiency is increased and the cleaning efficiency is greatly improved. In particular, when ultrasonic vibration is applied to NaOCl cleaning solution, which is widely used for root canal cleaning, fine bubbles and vortices are formed in the solution, and the temperature increases and the solubility of NaOCl increases.

Although the root canal cleaning using ultrasonic energy has various advantages as described above, there is a problem that a complicated requirement is required for manufacturing a treatment paddle (file) for reliably delivering ultrasonic energy to the root of the tooth.

Conventional endodontic treatment files are usually formed of stainless steel in most cases. However, since stainless steel has strong rigidity, when used for root canal cleaning using ultrasonic energy of high energy, the canal wall formed by the pile is damaged, or in the case of severe case, ledge or perforation is caused on the canal wall It can cause problems.

In order to solve this problem, it is possible to consider a method of forming a root canal cleaning pile using a shape memory alloy, Ni-Ti alloy. Ni-Ti alloys with superelasticity or pseudoelasticity have relatively low modulus of elasticity and are easy to insert deep into the curved root canal and have a relatively low risk of damaging or puncturing the root canal wall due to low elastic modulus, It has properties suitable for use as a treatment file. However, the use of Ni-Ti alloy is inevitably limited because of the problem that it is easily broken when subjected to ultrasonic vibration.

Ultrasonic generators used in dentistry mainly use frequencies from 10 kHz to 150 kHz, and 20 kHz to 40 kHz are mainly used for endodontic treatment. These ultrasonic vibrations, when transferred to a file, cause energy to be concentrated in a particular area of the file, and this energy concentration can cause the fracture of a Ni-Ti alloy pile having a relatively low stiffness. In particular, the energy concentration phenomenon is easily concentrated on the micro-cracks formed during the machining process of the pile, so that the possibility of fracture can be further increased in the case of Ni-Ti alloy, which is liable to cause microcracking during machining due to its low rigidity have. In addition, chlorine ions contained in the NaOCl solution, which is frequently used for root canal cleaning, may react with Ni contained in the Ni-Ti alloy to cause corrosion, which may serve as another cause of breaking the Ni-Ti alloy pile have.

In addition, although the Ni-Ti alloy has a low elastic modulus as compared with stainless steel, it still has a high elastic modulus in order to stably transmit the ultrasonic wave, which may easily break when it is used as a file for an ultrasonic wave transmission device. Specifically, as is known from Patent Document 1, the pile used for root canal cleaning should have a modulus of elasticity lower than 8 Msi, while the Ni-Ti alloy has an elastic modulus of 9 Msi or more, There is a problem that is not easy to use as a file of the device.

Therefore, in the field of dentistry, there is a constant demand for the development of a file that can more effectively and stably perform root canal cleaning in the root canal treatment process, particularly a file that can be used stably for root canal cleaning using ultrasound energy known in the most efficient manner In fact.

Patent Document 1: EP 1 977 716 A1

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide a method for cleaning a root canal using ultrasound vibration energy, It is intended to provide a file.

In order to accomplish the above-mentioned object, a representative configuration of the present invention is as follows.

According to one embodiment of the present invention, a file that can be used for root canal cleaning using ultrasonic energy is provided. A file according to an embodiment of the present invention is formed of a Ni-Ti alloy and is characterized in that it is heat-treated to include an R-phase at a temperature range of 36 to 45 ° C.

According to one embodiment of the present invention, the pile can be heat treated in a temperature range of 300 ° C to 400 ° C. More preferably, the file according to an embodiment of the present invention may be heat treated at a temperature range of 300 ° C or more and 350 ° C or less.

According to one embodiment of the present invention, the surface of the pile may be coated with a material comprising Ti. For example, the surface of the pile may be coated with a TiN or Ni-Ti film.

According to one embodiment of the present invention, the file includes a work part inserted into the root canal, and the working part of the file can be formed in a shape of 01 taper or more to 03 taper or less.

According to an embodiment of the present invention, the file may be formed to a thickness of ISO standard # 10 or more and less than # 25.

In addition to this, the ultrasonic canal cleaning file according to the present invention may further include other additional configurations as long as the technical idea of the present invention is not adversely affected.

The present invention relates to a file for endodontic treatment formed of a Ni-Ti alloy, which is a shape memory alloy, by (i) removing the crystal lattice defects formed inside the Ni-Ti alloy through heat treatment, (Ii) a coating layer containing a Ti component is formed on the surface of a Ni-Ti alloy pile to form a crack on the surface of the Ni-Ti alloy pile By removing defects and improving surface characteristics, it can be used for root canal cleaning using ultrasonic energy, so that it does not damage the formed canal and does not break easily, and it can transmit the ultrasonic vibration energy stably to the deep part of the apical root.

In addition, the present invention is configured to adjust the shape and thickness of a Ni-Ti alloy pile and to coat the surface of the Ni-Ti alloy pile so that the ultrasound energy transfer efficiency is prevented from being lowered by the alloy structure stretched by the heat treatment, This allows the high cleaning efficiency to be maintained.

FIG. 1 illustrates an exemplary perspective view of an ultrasonic transmitter according to an embodiment of the present invention.
Fig. 2 shows an exploded view of the ultrasonic transmitter shown in Fig.
Fig. 3 exemplarily shows the structure of a vise chuck of the ultrasonic wave transmission apparatus shown in Figs. 1 and 2. Fig.
FIG. 4 exemplarily shows the shape of a file which can be used in the ultrasonic wave transmission apparatus shown in FIGS. 1 to 3. FIG.
Figure 5 illustrates heat flow experimental data of a Ni-Ti alloy pile heat treated and surface treated in accordance with an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily carry out the present invention.

In order to clearly explain the present invention, a detailed description of parts that are not related to the present invention will be omitted, and the same constituent elements will be denoted by the same reference numerals throughout the entire specification. In addition, since the shapes and sizes of the respective components shown in the drawings are arbitrarily shown for convenience of explanation, the present invention is not necessarily limited to the illustrated shapes and sizes. That is, the specific shapes, structures, and characteristics described in the specification may be modified and embodied from one embodiment to another without departing from the spirit and scope of the present invention. Also, It is to be understood that changes may be made without departing from the spirit and scope of the invention. Therefore, the following detailed description is not intended to be construed in a limiting sense, and the scope of the present invention should be construed as encompassing the scope of the appended claims and all equivalents thereof.

The ultrasonic wave transmitting device for root canal cleaning according to one embodiment of the present invention

FIG. 1 and FIG. 2 illustrate an ultrasonic wave transmission apparatus 100 for cleaning a root canal according to an embodiment of the present invention. The ultrasound transducer 100 according to an embodiment of the present invention connects a treatment tool 200 inserted into a canal to an ultrasonic generator (not shown) to inject ultrasound energy generated in the ultrasonic generator into the canal To the cleaning liquid.

1 and 2, an ultrasonic transmitter 100 according to an embodiment of the present invention includes a hand 110 connected to an ultrasonic generator, a vise chuck 120 for holding a file 200, And a pin vise 130 for fixing the pins 200.

The hand 110 is connected to an ultrasonic generator (not shown) at one end to generate ultrasonic vibration energy, and transmits the ultrasonic vibration energy generated in the ultrasonic generator to the file 200 inserted into the canal of the patient do. The hand 110 can be formed in any shape using metal or various other materials.

A vise chuck 120 may be provided at the opposite end of the hand 110. The vise chuck 120 serves to grip and fix the file 200. The vise chuck 120 may be formed in a similar structure and shape to a drill mounting portion of a conventional electric drill. 2 and 3, the vise chuck 120 has an insertion hole 122 into which a pile 200 can be inserted at a central portion of one side end, The inner diameter of the insertion hole 122 is reduced to securely hold the pile 200 when the vise chuck 120 is coupled to a pin vise 130 described below. Meanwhile, the coupling between the vise chuck 120 and the pin vise 130 can be realized by various known coupling methods including screw coupling through the threaded portion as shown in FIGS.

The pin vise 130 is a component corresponding to the vise chuck 120. The pin vise 130 reduces the insertion hole 122 of the vise chuck 120 mounted on the pile 200 and guides the pile 200 to the vise chuck 120 And to fix it. To this end, the pin vise 130 may have an internal structure that has a passage through which the pile 200 can pass at its center and is coupled to the vise chuck 120 to tighten the vise chuck 120. For example, the inside of the pin vise 130 may be formed to have a gradually narrowed structure so that the vise chuck 120 can be tightened. In this case, the pin vise 130 is fixed to the vise chuck 120 by tightening the pile 200 of the vise chuck 120 through the internal structure gradually narrowed in the process of being coupled to the vise chuck 120, (122).

In an embodiment of the present invention, the ultrasonic canal cleaning file

Next, the ultrasound canal cleaning file 200, which is a characteristic feature of the present invention, will be described in detail.

As shown in FIG. 4, the file 200 is formed in an elongated shape so as to be deeply inserted into a root apex, and is connected to an ultrasonic generator (not shown) through an ultrasonic transmitter 100 as shown in FIGS. And transmits the ultrasonic vibration generated from the ultrasonic wave generating device to the cleaning liquid injected into the root canal to generate micro flow in the cleaning liquid, thereby improving the cleaning function.

According to an embodiment of the present invention, the file 200 may be formed of a Ni-Ti material, which is a shape memory alloy, and includes a working portion 210 inserted into a root canal of a patient as shown in FIG. 4, And a shank portion 220 coupled to the apparatus 100. The working portion 210 of the file 200 may have a structure such as a thread on its surface as shown in Fig. 4, or may be formed as a smooth surface without such a structure. [A product having a shape such as a thread on a surface is referred to as a file, and a product formed of a smooth surface may be referred to as a tip. However, in the present specification, The case where it is formed or the case where it is formed with a smooth surface without any structure is collectively referred to as a file)

The file 200 according to one embodiment of the present invention is configured to have the following shape and characteristics to improve the efficiency and stability of root canal cleaning.

(a) Heat treatment

When the disinfectant is injected into the root canal and root canal of the tooth, the disinfectant rises to a temperature similar to the body temperature. Further, when the ultrasonic vibration is applied to the disinfectant in this state, the disinfectant rises to a higher temperature. The purging file experiences a sudden temperature change during clinical use. These temperature changes can act as a cause of Ni-Ti pile fracture. Therefore, in order to form pile cleaning pads with Ni-Ti alloy, the elastic modulus of Ni-Ti alloy is lowered and fatigue fracture resistance is increased to reduce the risk of fracture .

In order to achieve this object, the file 200 according to an embodiment of the present invention can be configured to improve the texture characteristics of the Ni-Ti alloy through heat treatment. In detail, the file 200 according to an embodiment of the present invention removes the internal strain generated inside the Ni-Ti alloy during the manufacturing process of the pile through heat treatment, uniformizes the crystal grains, And at the same time reduce the elastic modulus by reducing the superelastic properties of the Ni-Ti alloy material.

Such an effect can be obtained, for example, in a temperature range of from 300 DEG C to 400 DEG C, more preferably from 300 DEG C to 350 DEG C, which is not the temperature range of 400 to 450 DEG C conventionally used for heat treatment of the Ni-Ti alloy, Ti < / RTI > When heat treatment is performed in this temperature range, the actual clinical use temperature range in which the ultrasonic vibration is transmitted [the temperature range of approximately 36 to 45 ° C; When NaOCl is injected at the deep root of tooth root in clinical practice, NaOCl increases to the temperature similar to body temperature and then ultrasonic vibration is applied to NaOCl, the temperature of NaOCl inside root canal increases rapidly from apical (Austenite phase or martensite phase B? 19) is added to the Ni-Ti alloy at a temperature of about 36 to 45 占 폚 for about 20 seconds during which ultrasonic waves are applied) And the R-phase is formed, thereby making it possible to lower the modulus of elasticity of the alloy. For example, as can be seen from the experimental data of FIG. 5 (DSC analysis data of a Ni-Ti alloy file annealed at 325 ° C), a Ni-Ti alloy file according to an embodiment of the present invention has an R- Phase start temperature Rs is set at a temperature lower than the clinical use temperature (lower than 36 占 폚), and the austenite end temperature Af at which the phase of the alloy is changed to the austenite structure, Because it is formed at a higher temperature (higher than 45 ° C), the R-phase is structured within the tissue at the actual clinical use temperature range of 36-45. Of course, even if a martensite phase having a monoclinic structure is imparted, the elastic modulus of the Ni-Ti pile can be lowered and the fracture resistance can be increased. However, in this case, the ultrasonic vibration becomes too weak, There may be a problem of deterioration. On the other hand, when the Ni-Ti pile is formed to include the R-phase in the Ni-Ti pile according to the present invention, the Ni- It is possible to effectively prevent the deterioration of the ultrasonic vibration transmission force while increasing the resistance.

That is, the Ni-Ti alloy pile 200 according to an embodiment of the present invention not only has high fracture resistance in a temperature range used in clinical use, but also can be smoothly inserted into the root canal, And it is possible to provide the effect of minimizing the damage of the root canal wall when the ultrasonic vibration is transmitted by being inserted into the formed root canal.

(b) Surface coating

The file 200 according to an embodiment of the present invention can be configured to coat a surface of a file formed of a Ni-Ti alloy with a component including Ti (TiN, TiCN, TiNi, TiCNi, etc.). The surface coating of the Ti component can function to reduce the possibility of fracture of the pile by offsetting cracks or defects formed on the surface of the pile 200 during the machining process. In addition, the coating formed on the surface of the pile 200 may increase the surface hardness of the pile, thereby making the Ni-Ti alloy excessively softened by the heat treatment to prevent the ultrasound energy transfer efficiency from being excessively lowered.

For example, the surface coating of the pile 200 according to an embodiment of the present invention may be performed with a TiN coating. Since the TiN coating can perform the coating at a relatively low temperature of 300 or less, there is no problem of hardness reduction or dimensional deformation in the coating process, a high hard coating film can be easily obtained, and a coefficient of friction And the risk of damaging the shaped root canal is lowered.

Another coating method is to form a thin film of Ni-Ti alloy on the surface of the Ni-Ti alloy to remove cracks or defects formed in the machining process. The Ni-Ti thin film can be deposited on the surface of Ni-Ti alloy by vacuum deposition of titanium (Ti) and nickel (Ni).

(c)

The file 200 according to an embodiment of the present invention may be formed in a tapered shape in the work unit 210 as shown in FIG.

In root canal cleaning using ultrasonic energy, heat, micro-streaming and cavitation generated by ultrasonic vibration play an important role in cleaning. Particularly, in order to apply the cleaning liquid to the area deep within the apical root, the vapor lock of the apical region must be removed, and the cavitation caused by the pile 200 serves to stably remove the vapor lock .

When the working part 210 of the file 200 is formed into a straight line without being tapered, cavitation of similar size as a whole is regularly generated in the working part 210 of the file. On the contrary, when the working unit 210 of the file 200 is formed in a tapered shape as in the present invention, cavitation is concentrated on the tip portion of the file 200.

A disadvantage that can be caused when the pile 200 formed of a Ni-Ti alloy is annealed to reduce the superelastic characteristics of the alloy and to introduce the R-phase to soften the alloy, as in the present invention, It is a point that can be made. Therefore, in the case of the file 200 formed of the Ni-Ti alloy including the R-phase like the file 200 according to the present invention, the cavitation is concentrated on the tip of the file 200, So that it can be efficiently delivered to the deep portion in the cleaning liquid. For this reason, the file 200 according to an embodiment of the present invention is configured such that the working unit 210 is formed in an inclined shape so that cavitation can be concentrated in the tip end portion.

Preferably, the taper formed on the working portion 210 of the file 200 is formed to be 01 or more and 03 or less. Here, when the taper is formed as x, the thickness of the file (specifically, the thickness of the working portion 210) is 0.0 mm mm thick when proceeding from the end of the file toward the shank portion 220 in the longitudinal direction by 1 mm It means to lose. That is, when the file formed by the 01 taper is increased by 1 mm in the direction of the shank portion 220, the thickness of the working portion 210 is increased by 0.01 mm, and when the file formed by the 02 taper is 1 mm in the direction of the shank portion 220 The thickness of the portion 210 becomes 0.02 mm thick.

When the taper is formed to be less than 01, the degree of energy concentration at the end portion of the pile 200 is weak, so that the cleaning may not be performed well. On the other hand, when the taper is formed in excess of 03, the length of the working part 210 of the file 200 becomes too short and the shank part 220 becomes long, and the amplitudes of the ultrasonic wave energy are small There is a possibility that the possibility of the file 200 being broken becomes high.

(d) Thickness

The thickness of the file 200 can have a significant impact on the probability of the file being broken, which carries the ultrasonic energy of the file. When the thickness of the file is increased, the vibration width becomes smaller, so that the ultrasonic wave energy becomes difficult to be dispersed, so that the file 200 is easily broken. [For example, in a 02 taper file, an ISO specification # 10 file has a larger amplitude than an ISO specification # 30 file. Increasing the intensity of bold files such as # 30 files has little increase in amplitude, but files going with # 10 files will increase in amplitude as the intensity increases.

According to one embodiment of the present invention, the file 200 preferably uses a thickness of ISO standard # 10 or more and ISO standard # 25 or less. If the thickness of the file is thinner than the ISO standard # 10, the amplitude is excessively increased, and the file may not be able to sustain the concentrated energy and may easily wear or fracture. If the thickness of the file becomes thicker than the ISO standard # 25, Since it is difficult to move the file in the root canal, the transmission of ultrasonic energy may become difficult and the efficiency may be reduced.

As described above, according to the embodiment of the present invention, the R-phase is included in the Ni-Ti alloy structure in the temperature range of 36 to 45, which is the temperature range actually used in clinical practice through the heat treatment, By including surface coatings to eliminate cracks and defects on the surface during machining, it is possible to minimize the damage of the root canal wall while greatly reducing the possibility of file fracture and to achieve high cleaning efficiency by efficiently delivering ultrasonic vibration to the cleaning liquid .

In addition, the file according to an embodiment of the present invention adjusts the shape and thickness of the file and performs coating on the surface, and there is a disadvantage (energy) that may occur in the process of introducing the R-phase into the Ni-Ti alloy file through heat treatment The reduction of the delivery force and the increase of the possibility of fracture) are solved, thereby maximizing the efficiency and stability of the root canal treatment.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Therefore, the spirit of the present invention should not be construed as being limited to the above-described embodiments, and all the equivalents or equivalents of the claims are to be construed as falling within the scope of the present invention.

100: (for root canal cleaning) Ultrasonic transmitter
110: Hand
120: Vice Chuck
122: Insertion ball
124:
130: pin vise
200: (for ultrasonic canal cleaning) file
210:
220: Shank portion

Claims (7)

A file (200) used for root canal cleaning using ultrasonic energy,
Ni-Ti alloy,
Characterized in that it is heat-treated to include R-phase at a temperature range of 36 to 45 占 폚, which is a clinical use temperature range in which ultrasound vibration is transmitted during root canal treatment.
file. The method according to claim 1,
The file (200) is heat treated in a temperature range of 300 ° C to 400 ° C,
file. 3. The method of claim 2,
The file (200) is heat treated in a temperature range of 300 ° C or more and 350 ° C or less,
file. The method of claim 3,
The surface of the pile 200 is coated with a material containing Ti,
file. 5. The method of claim 4,
The surface of the pile 200 is coated with a TiN or Ni-Ti thin film,
file. The method according to claim 1,
The file (200) includes a work part (210) inserted into a canal,
The working part 210 is formed in a shape of 01 taper or more to 03 taper or less,
file. The method according to claim 6,
The file 200 is formed in a thickness of less than or equal to ISO standard # 10 and # 25 or less,
file.

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