JP2004166953A - Production method for dental root canal treating appliance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve precision without greatly increasing a cost when manufacturing a dental root canal treating appliance having a working part tapered toward the tip and represented by a file and a reamer. <P>SOLUTION: This manufacturing method for manufacturing the dental root canal treating appliance (the file A) having the working part tapered toward the tip is as follows. A material 10 ground into a prescribed cross section is twisted, its tip 4 is ground by a grinding wheel 21 to be worked into the tapered work part 2 and the work part 2 is retained in a tapered state by a measuring element 31 comprising a fixing element 31a and a moving element 31b, which are disposed along the tapered face of the work part, and measured its diameter. The tip part is ground again based on the measured value and finished into a prescribed diameter corresponding to a preset size. <P>COPYRIGHT: (C)2004,JPO

Description

となる。
【００７１】
従って、中間材１１の作業部２に於ける位置６を測定して測定値Ｄ３を得たとき、この測定値Ｄ３が上記値以下である場合には、再研削しても良品とすることが出来ず、測定段階で排除することが可能となる。
【００７２】
本実施例に於いて、作業部２の長さは必ずしも一定値を有する必要はなく、個々の中間材１１毎に測定することで、再研削長さＬを演算しても良い。この場合、作業部２の長さを個々の中間材１１毎に把握することによって、個々の中間材１１に対し正確に再研削可能長さＬを演算して精度の高いファイルＡを製造することが可能である。
【００７３】
上記の如く、再研削することによって良品となり得る中間材１１に対して砥石２１による再研削を行い、再度所定位置を測定して良品となった中間材１１は図示しない次工程以下の工程を経て精度の高いファイルＡとして製造される。尚、上記実施例においては作業部をねじり加工によって形成する根管治療器具について説明しているが、上記根管治療器具に限定するものではなく、先細テーパ状であり、作業部の先端部分を再研削することで良品にし得るものであれば、目的の異なる器具であっても適用することが可能である。
【００７４】
【発明の効果】
以上詳細に説明したように本発明に係る根管治療器具の製造方法では、作業部をテーパ状に把持して測定する測定子によって作業部の所定位置の径を測定し、このときの測定結果を利用して作業部の先端部分を再研削することで、サイズの基準となる部位を作業部の太い方向に追い込むことで太くすることが出来る。
【００７５】
このため、加工された作業部の基準となる部位が目的のサイズの径よりも細い場合、再加工によって良品とすることが出来、不良品を低減させて歩留りの向上をはかることが出来る。従って、作業部を再研削する手数がかかるものの、不良品が減少することから、コストを削減することが出来る。
【図面の簡単な説明】
【図１】根管治療器具の例としてのファイルの構成を説明する図である。
【図２】作業部の断面形状を説明する図である。
【図３】ファイルを製造する工程を説明する図である。
【図４】ねじり加工が施された作業部の径を測定する際の測定位置を説明する図である。
【図５】作業部の径を測定する測定子の構造を説明する図である。
【符号の説明】
Ａ ファイル
Ｂ 測定具
Ｓ 基部の径
Ｓ３ 正規の径
Ｄ３ 尖端から３ｍｍの位置の測定値
Ｄ３ｄ 良品に再研削し得る下限値
Ｄ１３ 尖端から１３ｍｍの位置の測定値
１ シャフト部
２ 作業部
２ａ 鋭角
２ｂ 鈍角
３ ハンドル
４ 尖端
５ 基部
１０ 素材
１１ 中間材
２１ 砥石
３１ 測定子
３１ａ 固定子
３１ｂ 移動子
３１ｃ，３１ｄ 面
３２ 表示部
３３ ガイド部材
３３ａ 溝
３４ ストッパー[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a dental root canal treatment instrument having a tapered working portion for performing root canal treatment.
[0002]
[Prior art]
In dental treatment, a new surface of the root canal wall can be exposed to form a root canal by cutting the surface of the calcified root canal wall and removing cutting debris and contents filled in the root canal. Done. As a device for forming the root canal, a dental root canal treatment device including a file, a reamer, and the like in which a plurality of sizes are set according to the thickness is provided.
[0003]
For example, the file has a spirally formed working part with a relatively small pitch, and is mainly operated by pushing and pulling to cut the root canal wall and to remove cutting chips and contents. Have The reamer has a helically formed working part with a relatively large pitch, and has the function of mainly rotating and cutting the root canal wall and removing cutting chips and contents. is there.
[0004]
The root canal has a shape that gradually narrows and curves toward the apex, and since this curved shape has a large individual difference, the working portion of the dental root canal treatment instrument is formed into a tapered taper shape and has a distal end. A plurality of sizes are set according to the size of the diameter. When performing root canal treatment, a dental root canal treatment instrument with a large size should be used each time the cutting depth reaches a certain depth (the cutting diameter increases) due to the push-pull operation or the rotation operation. The root canal treatment ends when the cutting diameter reaches the target size.
[0005]
As a method of manufacturing the file or the reamer, there is a technique of performing a spiral processing by twisting a columnar body having a triangular or quadrangular cross-sectional shape in advance while crushing a blade edge portion (for example, see Patent Document 1). In this technique, a columnar body is formed by grinding the shape (diameter and taper) in the length direction so as to be crushed and reduced by a small amount, and the columnar body is inserted into a forming die and twisted to obtain an object. Manufactures files and reamers.
[0006]
Further, as a device for measuring the diameter of the tapered working portion, a pair of linear contacts provided with linear contacts at the tip are opposed to each other and biased in a direction in which they are brought into close contact with each other by a biasing member. There is a technique in which an axial instrument is inserted between the linear contacts in an orthogonal direction to perform measurement (for example, see Patent Document 2). In this technique, the diameter can be accurately measured even though the outer shape is wavy due to the spirally formed blade.
[0007]
[Patent Document 1]
JP-B-61-53059
[Patent Document 2]
Japanese Patent Publication No. 05-53361
[0008]
[Problems to be solved by the invention]
When manufacturing a tapered dental root canal treatment instrument, the columnar body before being subjected to torsion processing is formed with a taper that takes into account the change in angle accompanying torsion processing and a thickness corresponding to the target size Have been. Then, after the torsion process is performed, the diameter at a plurality of positions separated by a predetermined distance from the tip is measured to determine whether the taper and the diameter of the tip portion conform to the standard.
[0009]
For example, the standard of the K file is described in ISO3630-1983 (E). In this standard, the taper of the working unit is set to 2/100. The tip diameter is set at 0.05 mm pitch between 0.10 mm to 0.60 mm and at 1.0 mm pitch between 0.60 mm to 1.40 mm, and ± 0.02 mm for each standard diameter. Is set. Further, the minimum length of the working unit is set to 16 mm.
[0010]
As described above, according to the ISO standard, the tolerance of the diameter of the tip portion of the working unit is ± 0.02 mm. However, since the size of 0.60 mm or less is set at the 0.05 mm pitch, when the root canal treatment instruments of adjacent sizes are at the upper and lower limits of the tolerance range with respect to each other, the dimensional difference despite the difference in size is obtained. Is only 0.01 mm, impairing its significance in treating root canals. For this reason, dentists demand that the dimensional accuracy of the product be improved and that the tolerance range be at most about ± 0.01 mm.
[0011]
Therefore, a tolerance range that satisfies the above requirements is set, and the accuracy of the columnar body is improved in accordance with the set tolerance. However, there is a problem that the cost increases and the number of defective products increases with the processing for improving the accuracy.
[0012]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for manufacturing a dental root canal treatment instrument which improves accuracy without significantly increasing cost.
[0013]
[Means for Solving the Problems]
A method for manufacturing a dental root canal treatment instrument according to the present invention for solving the above-mentioned problem is a method for manufacturing a dental root canal treatment instrument having a working portion formed in a tapered tapered shape, comprising a tapered tapered shape. After processing the working part, the diameter of the working part is measured by a measuring tool which is gripped in a tapered shape along the tapered surface of the working part, and the tip is processed by using the measured value to finish to a predetermined diameter. It is characterized by the following.
[0014]
In the method of manufacturing the dental root canal treatment instrument (hereinafter referred to as “root canal treatment instrument”), a cross section corresponding to a cross-sectional shape of a working portion of a target root canal treatment instrument and a taper that allows for a change in angle due to twisting are provided. After forming an intermediate member having a working part formed by twisting the columnar body with a column, a diameter of a plurality of positions set in advance from the tip of the working part is measured by a measuring tool. Thus, the taper between the measurement positions can be calculated, and the diameter of the tip portion can be calculated.
[0015]
When the calculated diameter of the tip portion is within a preset tolerance (a tolerance narrower than the tolerance range of the ISO standard (for example, a tolerance of ± 0.01 mm)), the measured intermediate material is regarded as a non-defective product. It is recognized and proceeds to a predetermined next process. When the calculated diameter of the tip portion deviates downward from the above-described tolerance, the tip portion is additionally processed to increase the diameter, thereby making it possible to obtain a non-defective product having a desired size.
[0016]
Therefore, by deviating from the target size tolerance, it is possible to produce a product by additionally processing a product that has been conventionally determined as a defective product, and to manufacture a dental treatment instrument with high accuracy. Can be done.
[0017]
That is, in the root canal treatment instrument, the taper of the working portion is the same, and when the size is different, the diameter of the distal end portion of the working portion changes. Therefore, if the condition that the taper of the working portion is within the tolerance range of the ISO standard is satisfied, the diameter of the tip portion is processed to the value of the ISO standard size and the value of the precision tolerance range, and the diameter is adjusted according to this diameter. It can be manufactured as a root canal treatment instrument of a size.
[0018]
In particular, in the ISO standard, the working section is defined only as having a length of 16 mm or more, and does not specify the maximum length. For this reason, by making the length of the working portion larger than the above value, even if the diameter of the tip portion of the intermediate material deviates from the target size standard, the tip portion is ground. By increasing the diameter of the tip portion by performing additional processing according to the above, it is possible to obtain a product of a desired size within a desired tolerance range. Therefore, the yield can be improved by reducing defective products, and the cost can be reduced.
[0019]
When measuring the diameter of the working part, twisted work is performed by using a measuring tool provided with a measuring element along a line (tapered surface) connecting the peaks corresponding to the blades constituting the tapered working part. Since the portion can be gripped along the tapered surface, accurate measurement of the diameter can be performed even with a root canal treatment instrument having a corrugated outer shape.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment of the method for manufacturing the root canal treatment instrument will be described with reference to the drawings. FIG. 1 is a diagram illustrating the configuration of a file as an example of a root canal treatment instrument. FIG. 2 is a diagram illustrating a cross-sectional shape of the working unit. FIG. 3 is a diagram illustrating a process of manufacturing a file. FIG. 4 is a view for explaining a measurement position when measuring the diameter of the working portion subjected to the twisting. FIG. 5 is a view for explaining the structure of a tracing stylus for measuring the diameter of the working unit.
[0021]
The method of manufacturing a root canal treatment instrument according to the present invention is to process a tapered working portion having a diameter corresponding to a cross-sectional shape and a size of a target root canal treatment device, and then to a tapered surface of the working portion. The diameter of a plurality of preset positions of the working section is measured by a measuring tool which is held in a tapered shape along the tip, and the tip portion is ground to a predetermined size by grinding the tip portion using the measured value. A root canal treatment instrument is manufactured by finishing the diameter within the tolerance range.
[0022]
That is, if the measured diameter of the working portion is out of the target tolerance range of the size of the root canal treatment device, the product is defective. However, in the present invention, the diameter of the distal end portion is increased by reworking the distal end portion, thereby obtaining a product having a target size and a tolerance range. Therefore, the yield can be improved by reducing the number of defective products, and the cost can be reduced.
[0023]
First, the configuration of a file as an example of a root canal treatment instrument will be briefly described with reference to FIGS. The file A shown in the figure is formed by cutting and shaping the root canal wall by operating the doctor with a delicate touch between the fingertips and responding to the fact that the diameter of the root canal increases with this shaping. While exchanging the large file A, the affected part is further operated to form a root canal having a desired diameter and shape.
[0024]
For this reason, a plurality of sizes of the file A are set in the range of No. 06 (the diameter of the tip portion is 0.06 mm) to No. 140 (the diameter of the tip portion is 1.40 mm). For example, if the diameter is 0.10 mm or less, the size is set at 0.02 mm intervals, from 0.10 mm to 0.60 mm, the size is set at 0.05 mm intervals, and from 0.60 mm to 1.40 mm, the size is set at 0.10 mm intervals. The size is set in.
[0025]
In the file A of each size, the diameter of the leading end portion is allowed to have a precision tolerance within a preset range. The precision tolerance is smaller than ± 0.02 mm, which is the tolerance of the ISO standard, and is a value that can satisfy the requirement for accuracy from a doctor, and is set as a tolerance in a range of approximately ± 0.01 mm.
[0026]
However, the manufacturing method according to the present invention does not limit whether or not the tolerance range with respect to the diameter of the target root canal treatment instrument is the above-mentioned value, and a tolerance of ISO standard or a more accurate tolerance is set. It can be applied to a root canal treatment device.
[0027]
The file A includes a shaft portion 1 and a working portion 2 connected to the shaft portion 1. The point 4 of the working portion 2 has a predetermined angle irrespective of the size or the sectional shape of the working portion 2. (For example, 60 degrees to 90 degrees).
[0028]
The shaft portion 1 is integrated with a synthetic resin handle 3 by insert molding. The shaft portion 1 is formed such that the cross section changes from a circular shape to a cross-sectional shape of the working portion 2 as it approaches the working portion 2 from the handle 3 side, thereby eliminating a sudden change in the cross-sectional shape and the cross-sectional area. It is possible to prevent concentration of stress.
[0029]
Since the file A is to be manually operated by a doctor to treat the root canal, the shaft portion 1 is integrated with the handle 3, but the root canal treatment instrument is not limited to this configuration. For example, in a device such as a reamer that performs a rotation operation to treat a root canal, the device is grasped by a chuck of a rotating tool called a handpiece and operated by a doctor, so that the handpiece is preferably used instead of the handle 3 shown in the figure. It is configured to be capable of chucking. Therefore, it is not limited whether the shaft portion 1 is integrated with the handle 3 or integrated with a member having a chucking function (not shown).
[0030]
The working unit 2 has a rod-like shape having a spiral structure in which a parallelogram cross-sectional shape is twisted at a predetermined torsion angle. When the peaks of the spiral are connected in the axial direction, the line connecting the peaks has a preset taper of 2/100.
[0031]
In this embodiment, the sectional shape of the working unit 2 is a parallelogram. However, the present invention is not necessarily limited to this cross-sectional shape, and is formed to have a cross-sectional shape such as a triangle, a rectangle, or the like that can optimally exhibit the function of a target root canal treatment instrument (for example, a K file, an H file, or a reamer). You.
[0032]
For example, when the cross section of the working unit 2 is a parallelogram as in this embodiment, the working unit 2 is twisted to form an acute angle 2a and an obtuse angle 2b on a diagonal line, respectively. The acute angle 2a comes into contact with the circle with which the working part 2 is inscribed, and exerts the function as a cutting edge, and the obtuse angle 2b does not come into contact with the circle and does not have the function as a cutting edge.
[0033]
In the file A having the working unit 2 as described above, the doctor grasps the handle 3 of the file A of a predetermined size and pushes and pulls the tip 4 of the working unit 2 so as to face the tooth to be treated. It is possible to cut the surface of the apical wall of the tooth and discharge the cut debris. When the cutting depth reaches a predetermined value, the doctor replaces the file A with a larger file and pushes and pulls again to enlarge the root canal diameter of the tooth to be treated and repeat this operation as appropriate. Thus, a dental treatment can be performed by forming a root canal of a tooth to be treated and further performing a predetermined treatment.
[0034]
Next, a method for manufacturing the root canal treatment instrument according to the present invention will be specifically described with reference to FIG.
[0035]
A wire having a thickness corresponding to the thickness of the shaft portion 1 of the file A of the target size is shaped into a straight line, and cut into a predetermined length as shown in FIG. The material 10 is constituted. The material of the material 10, that is, the material constituting the file A is not particularly limited, and steel, martensitic stainless steel, austenitic stainless steel, nickel-titanium (Ni-Ti) alloy, or the like is selected and used. Is possible.
[0036]
In particular, when steel or martensitic stainless steel is employed, it is possible to obtain an optimum hardness by quenching after forming a predetermined working portion. Also, when austenitic stainless steel is used, a wire thicker than the diameter of the shaft part of the target size is cold drawn at a predetermined area reduction rate to extend the austenite structure into a fiber shape, which is the most suitable. It is possible to obtain hardness.
[0037]
Next, a portion corresponding to the working unit 2 of the raw material 10 is processed (see FIG. 2B). This processing is performed such that the cross-sectional shape of the portion corresponding to the working unit 2 is formed into a parallelogram having a size corresponding to a preset size, and the taper of the working unit 2 becomes 2/100 when the processing is performed by twisting. Grind to a tapered shape.
[0038]
Next, as shown in FIG. 1C, a portion corresponding to the working unit 2 in the raw material 10 is subjected to a twisting process. At this time, the length of the twisted portion corresponding to the working unit 2 is set to be about 16.5 mm to 17.0 mm, which is larger than 16 mm according to the ISO standard, or longer. As described above, the length of the working unit 2 may be 16 mm or more, and a somewhat longer portion does not result in a defective product.
[0039]
Further, as shown in FIG. 3D, the tip end of the twisted working portion 2 is ground by a grindstone 21 to form a point 4, whereby the working portion 2 of the raw material 10 is processed. It becomes the intermediate material 11.
[0040]
Grinding, twisting, and grinding of the point 4 on the material 10 described above are performed by implementing the method disclosed in Patent Document 1 described in the related art. However, in the present invention, the length of the portion corresponding to the working unit 2 is increased by lengthening the torsion portion.
[0041]
After the working of the working part 2 is completed as described above, the working part 2 of the intermediate material 11 is inspected by measuring the diameters of the working part 2 at a plurality of positions.
[0042]
The size set in the file A is the diameter S of the base 5 of the point 4 shown in FIG. However, since it is extremely difficult to measure the diameter S of the base 5, the taper of the working unit 2 and the diameter S of the base 5 are calculated by measuring a plurality of positions separated by a predetermined distance from the point 4. I have. That is, it is possible to calculate the taper by measuring the diameter of at least two points in the working unit 2 and measuring the distance between the two points, and calculate the diameter S of the base 5 from the calculated taper. It is possible.
[0043]
Although the position of the measurement point in the working unit 2 is not particularly limited, in this embodiment, the diameter D3 at the position 6 3 mm from the point 4 and the diameter D13 at the position 7 13 mm are measured. Therefore, it is possible to calculate the taper of the working unit 2 from the difference between the measured value D13 at the position 7 and the measured value D3 at the position 6. The diameter S of the base 5 can be calculated from the measured value D3 at the position 6 and the calculated taper.
[0044]
When measuring the working portion 2 of the torsionally processed intermediate material 11, the working portion 2 has a wavy shape in which the acute angles 2a and the obtuse angles 2b are alternately arranged. Is difficult to do. For this reason, it is possible to use a measuring device as described in Patent Document 2, but in the present invention, a measuring device B configured as shown in FIG. 5 is used.
[0045]
The measuring tool B fits the measuring element 31 provided with the stator 31a and the moving element 31b facing each other, the display section 32 for displaying the moving amount of the moving element 31b, and the working section 2 formed on the intermediate member 11. It has a guide member 33 having a groove 33a formed therein, and a stopper 34 provided at an end of the groove 33a for positioning the pointed end 4 of the intermediate member 11 fitted in the groove 33a by abutting. .
[0046]
Opposing surfaces 31c and 31d of the stator 31a and the moving element 31b that constitute the measuring element 31 have a dimension in a direction along the groove 33a larger than a pitch of a twist formed in the working section 2 and a taper of the working section 2. It is formed as an inclined surface having the same inclination angle as that of.
[0047]
The mechanism for measuring the moving amount of the movable element 31b is not limited, but may be a mechanism capable of performing accurate measurement in a unit that can satisfy the size and tolerance set in the root canal treatment instrument. is necessary. Therefore, it is necessary to satisfy about 0.005 mm to 0.01 mm as a unit of measurement.
[0048]
The display unit 32 is not particularly limited, and may be a so-called dial gauge that displays the amount of movement of the movable element 31b by rotating the display hand, or a digital display unit that electronically displays the amount of movement of the movable element 31b. It may be.
[0049]
The groove 33a formed in the guide member 33 is formed to have a dimension smaller than the width dimension of the surfaces 31c and 31d of the stator 31a and the moving element 31b constituting the tracing stylus 31. The stopper 34 is set to have a dimension (3 mm corresponding to the position 6 and 13 mm corresponding to the position 7) from the center of the movable member 31b to the position where the working unit 2 is to be measured.
[0050]
That is, in this embodiment, the measuring tool B for measuring the diameter D3 at the position 6 set at a distance of 3 mm from the point 4 and the diameter D13 at the position 7 set at a distance of 13 mm from the point 4 are measured. And a measuring tool B are prepared, and when measuring the intermediate material 11, the measurement is performed on one intermediate material in order using two measuring tools B.
[0051]
Therefore, the center of the tracing stylus 31 corresponds to the preset position 6 or position 7 by fitting the working portion 2 of the intermediate member 11 into the groove 33a and bringing the tip 4 into contact with the stopper 34. Then, by lowering the movable element 31b, the stator 31a and the movable element 31b come into contact with one of the tops of the corrugations in the working unit 2. Therefore, the working unit 2 can be gripped along the tapered surface and in a tapered shape by the stator 31a and the moving unit 31b, and accurate measurement can be performed regardless of the cross-sectional shape of the working unit 2. Becomes possible.
[0052]
As a result of calculating the diameter S of the base 5 by measuring the intermediate material 11 as described above, if the intermediate material is within the tolerance range in the target size, the intermediate material is recognized as a non-defective product and proceeds to the next step (not shown). Then, a patterning operation is performed through washing, drying, and appearance inspection, and after these steps, a product is obtained.
[0053]
If the calculated diameter S of the base 5 deviates from the tolerance range, the length to be ground of the tip portion in order for the diameter S of the base 5 to be within the tolerance range is determined from the diameter S, the size, and the tolerance range. After that, as shown in FIG. 3F, the tip portion is ground by the grindstone 21 by the calculated grinding length.
[0054]
After the re-grinding of the intermediate member 11 with respect to the working portion 2 is completed, the thicknesses of the positions 6 and 7 separated from the point 4 by a predetermined distance are measured, and the diameter S of the base 5 is calculated, as shown in FIG. . Then, after confirming that the diameter S of the base 5 is within the tolerance range of the target size, the intermediate material 11 proceeds to the next step (not shown), and becomes a product through a plurality of steps.
[0055]
Here, as a result of measuring the positions 6 and 7 of the intermediate member 11 in the working unit 2, the method of calculating the diameter S of the base 5 and the length of re-grinding the tip of the working unit 2 from the calculated value of the base 5 are described. A method of calculating the value will be described.
[0056]
For example, when the size of the target file A is No. 10, the diameter S of the base 5 of the working unit 2 is 0.10 mm and the taper is 2/100. Therefore, by measuring the diameter D3 at the position 6 set at 3 mm from the point 4 and the diameter D13 at the position 7 at 13 mm from the point 4, the taper is calculated by substituting (D13−D3) / 10. Is possible.
[0057]
The diameter D3 at the position 6 located 3 mm from the point 4 is D3 = 0.10 + (2/100 × 3), which is 0.16 mm. The diameter S of the base 5 is S = D3- (2/100 × 3). Therefore, it is possible to calculate the diameter S of the base 5 from the measured value of the diameter D3 at the position 6.
[0058]
For example, if the measured value D3 at the position 6 is 0.14 mm, the diameter of the diameter S of the base 5 is 0.08 mm. In this case, according to the ISO standard, it falls within the range of -0.02 mm and can be determined as a good product, but it deviates from the range of -0.01 mm required by the doctor.
[0059]
If the diameter S is increased by +0.02 mm from the current value by driving the position of the base 5 in the thick direction of the working unit 2, a highly accurate file A in which the diameter S of the base 5 matches the standard value is obtained. It can be manufactured. Therefore, by calculating the length necessary to increase the diameter S of the base 5 by +0.02 mm and setting the re-grinding length based on the calculation result, it is possible to obtain a highly accurate non-defective product. .
[0060]
When calculating the re-grinding length, the taper of the file A (calculated by the measured values D3 and D13 at the positions 6 and 7, but in the following description, the taper is assumed to be 2/100) and the size Therefore, it is assumed that the normal value S3 and the measured value D3 at the position 6 are adopted as the calculation reference values.
[0061]
Therefore, by adding the reciprocal of the taper to the difference between the normal value S3 and the measured value D3 at the position 6 separated from the point 4 by 3 mm, the re-grinding length L required to match the base 5 to the standard value is obtained. Can be calculated. That is,
L = (S3-D3) × 100/2 Equation 1
It is possible to calculate the re-grinding length. For example, when the size is No. 10, the standard value is 0.10 mm, and the normal value S3 is 0.16 mm. If the measured value D3 is 0.14 mm, the re-grinding length L is
L = (0.16-0.14) × 100/2
= 1.00 (mm).
[0062]
As described above, in this example, the diameter S of the base 5 is increased by grinding the tip 4 further by 1 mm and driving the base 5, whereby the working unit 2 of the file A of No. 10 having high dimensional accuracy is formed. It is possible to manufacture an intermediate material 11 having the same.
[0063]
However, when the working part 2 of the intermediate material 11 is re-ground by 1 mm in length, it is necessary that the length of the working part 2 after the re-grinding is 16 mm or more in accordance with the ISO standard. For this reason, it is possible to cope with this by setting a dimension larger than 16 mm in advance when the material 10 is twisted.
[0064]
The intermediate material 11 processed as described above proceeds to the next step and a step subsequent to the next step, and a predetermined cleaning operation, a heat treatment operation, and, if necessary, a polishing operation such as a chemical polishing operation or an electrolytic polishing operation. After performing the appearance inspection, the shaft portion 1 is cut so as to have a predetermined length, and is further subjected to insert molding to integrally form a handle, thereby producing a regular file A shown in FIG.
[0065]
Next, another example of re-grinding the tip portion with reference to a measurement value obtained by measuring a predetermined position of the working unit 2 will be described. In the present embodiment, the lower limit for setting the intermediate material 11 as a non-defective product for each target size is set in advance, and the working unit 2 which can withstand re-grinding assuming that the measured value of the intermediate material 11 is the lower limit is set. Is to set the length. When the working part 2 is torsion-processed, the working part 2 is machined in accordance with the set length, and if the measured result is within the lower limit set in advance, the working part 2 is removed. It is re-ground to make a good product.
[0066]
That is, the manufacturing method according to the above-described first embodiment calculates the re-grinding length by using the measured value D3 obtained by measuring the predetermined position (position 6) of the working part 2 in the intermediate material 11, and calculates the re-grinding length. In contrast to re-grinding the tip of the working unit 2 based on the result, this embodiment sets the lower limit of the measured value that can be used as a non-defective product in advance, and sets the lower limit required at this lower limit. The work length 2 is lengthened in advance by calculating the grinding length, and re-grinding is performed based on actual measured values.
[0067]
Therefore, in the first embodiment, if the length of the working unit 2 is ignored, it is possible to manufacture a file having a size larger than the target size by re-grinding the tip of the working unit 2. However, in the second embodiment, a limit for excluding as a defective product is also set. From the measured values obtained by measuring the actual intermediate material 11, whether the product can be made a good product by re-grinding or must be eliminated as a defective product. Can be determined.
[0068]
For this reason, in this embodiment, a value (lower limit value D3d) that can be a non-defective product by re-grinding is set for the normal value S3 at the position 6 that is 3 mm away from the point 4 of the working unit 2, and The length of the working unit 2 is set by setting the length L at which the value D3d can be re-ground to the normal value S3. In other words, in this method, the length of the working unit 2 is set in advance to 16 mm or more, which is the ISO standard, and the lower limit value D3d is set based on the difference between the set length and 16 mm.
[0069]
That is,
(Length of working part 2) -16 = Re-grinding length L
L (mm) = (S3-D3d) × 100/2
D3d = S3-L × 2/100
It becomes.
[0070]
For example, when the length of the working unit 2 is set to 17 mm, the re-grinding length L in the working unit 2 is 1 mm. Therefore, if the size is number 10,

It becomes.
[0071]
Therefore, when the measured value D3 is obtained by measuring the position 6 of the intermediate member 11 in the working section 2 and the measured value D3 is equal to or less than the above value, it is possible to obtain a good product even by re-grinding. No, it can be eliminated at the measurement stage.
[0072]
In this embodiment, the length of the working portion 2 does not necessarily have to have a constant value, and the re-grinding length L may be calculated by measuring each intermediate material 11. In this case, by grasping the length of the working unit 2 for each of the intermediate materials 11, it is possible to accurately calculate the re-grindable length L for each of the intermediate materials 11 and produce a highly accurate file A. Is possible.
[0073]
As described above, the intermediate material 11 that can be a non-defective product by re-grinding is subjected to re-grinding with the grindstone 21 and the predetermined position is measured again. It is manufactured as a highly accurate file A. In the above-described embodiment, the root canal treatment instrument in which the working portion is formed by torsion processing has been described.However, the present invention is not limited to the root canal treatment instrument, and has a tapered tapered shape. As long as it can be made a good product by re-grinding, it is possible to apply a tool having a different purpose.
[0074]
【The invention's effect】
As described in detail above, in the method for manufacturing a root canal treatment instrument according to the present invention, the diameter of a predetermined position of the working part is measured by a measuring element that grips and measures the working part in a tapered shape, and a measurement result at this time By re-grinding the tip portion of the working unit using the method, it is possible to increase the thickness of the working unit by moving the reference portion of the working unit in the thick direction of the working unit.
[0075]
For this reason, when the reference portion of the processed working portion is smaller than the diameter of the target size, a non-defective product can be obtained by reworking, and defective products can be reduced and the yield can be improved. Therefore, although it takes time and effort to re-grind the working section, the number of defective products is reduced, and the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a file as an example of a root canal treatment instrument.
FIG. 2 is a diagram illustrating a cross-sectional shape of a working unit.
FIG. 3 is a diagram illustrating a process of manufacturing a file.
FIG. 4 is a diagram for explaining a measurement position when measuring the diameter of a working portion to which a twisting process has been performed.
FIG. 5 is a diagram illustrating a structure of a tracing stylus for measuring a diameter of a working unit.
[Explanation of symbols]
A file
B measuring tool
S Base diameter
S3 Regular diameter
D3 Measured value at 3mm from the tip
D3d Lower limit for re-grinding to a good product
D13 Measured value at 13mm from the tip
1 Shaft
2 Working section
2a acute angle
2b obtuse angle
3 Handle
4 point
5 Base
10 materials
11 Intermediate materials
21 Whetstone
31 Measuring element
31a Stator
31b mover
31c, 31d surface
32 Display
33 Guide member
33a groove
34 stopper

Claims (1)

A method for manufacturing a dental root canal treatment instrument having a tapered working part, comprising: processing a tapered working part, and measuring the tapered shape along the tapered surface of the working part. A method for manufacturing a dental root canal treatment instrument, comprising: measuring a diameter of a working portion using a tool;

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