Dental root canal treatment instruments

Abstract

To provide dental files that offer high flexibility, machinability, and / or fracture resistance. [Solution] The shape of the tip cross section is configured to include a cutting vertex 110 located on a virtual circle 101 having a center 103, an arc-shaped portion 111 located on the virtual circle and positioned to pass through the intersection of the cutting vertex and the center diameter line segment 102 and the virtual circle, a first vertex 131 located within a first region occupied by the line segment 102 connecting one end of the arc-shaped portion to the cutting vertex and the virtual circle, a second vertex 132 located within a second region occupied by the line segment connecting the other end of the arc-shaped portion to the cutting vertex and the virtual circle, a first linear portion 121 connecting one end of the arc-shaped portion to the first vertex, a second linear portion 122 connecting the other end of the arc-shaped portion to the second vertex, a third linear portion 123 connecting the cutting portion to the first vertex, and a fourth linear portion 124 connecting the cutting portion to the second vertex.

Description

Technical Field

[0005] , , , ,

[0001] The present invention relates to a dental file used for root canal enlargement and cleaning in dental treatment.

Background Art

[0002] As dental root canal cutting tools used for root canal enlargement and cleaning in dental treatment, there are reamers and files (for example, see Patent Document 1). A reamer mainly cuts the inside of the root canal by rotation, and a file cuts the inside of the root canal by rotating or pushing and pulling in the axial direction.

[0003] General dental files are classified into those that are held by hand at the gripping part and those that are connected to a dental handpiece at the gripping part. A dental file has a working part in a spiral shape that becomes thinner toward the tip, a shaft connected to the rear end of the working part, and a gripping part connected to the rear end of the shaft. The main performances required for such a dental file include flexibility to follow a root canal with a complex shape, cutting ability to appropriately cut the root canal, and fracture resistance that does not break during work. The higher these performances are, the easier and faster root canal formation can be performed, and the burden on the operator and the patient can be reduced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In view of the above circumstances, an object of the present invention is to improve the flexibility, cutting ability, and / or fracture resistance of a dental file.

Means for Solving the Problems

[0006] [1] The objective of the present invention is, A dental file having a working section in which a groove is formed around a longitudinal axis of rotation, The shape of the tip section perpendicular to the longitudinal direction at the tip end of the above-mentioned work section is: A cutting vertex located on a virtual circle having the above center, An arc-shaped portion located on the above-mentioned virtual circle, and positioned so as to pass through the intersection point of the diameter line segment passing through the cutting vertex and the center and the above-mentioned virtual circle, A first vertex located within the first region occupied by the line segment connecting one end of the arc-shaped portion and the cutting vertex, A second vertex located within the second region occupied by the line segment connecting the other end of the arc-shaped portion and the cutting vertex, and the virtual circle, A first linear portion connecting one end of the above-mentioned arc-shaped portion and the above-mentioned first vertex, A second linear portion connecting the other end of the arc-shaped portion and the second vertex, A third linear portion connecting the above-mentioned cutting portion and the above-mentioned first vertex, A fourth linear portion connecting the above-mentioned cut portion and the above-mentioned second vertex, It is configured to include, The first linear portion and the fourth linear portion maintain a parallel state to each other from the tip end to the base end, and the second linear portion and the third linear portion are Maintain parallelism between the tip end and the base end, A dental file characterized in that the length of the arc-shaped portion is formed to decrease from the tip end to the base end while maintaining the parallel state. The objective is to provide.

[0007] The dental file according to the present invention has high flexibility, machinability, and / or fracture resistance.

[0008] [2] In the dental file described in [1], the arc-shaped portion on the proximal end side of the working part may disappear, resulting in a third vertex.

[0009] [3] In the dental file described in [1] or [2], the angle formed by the first linear portion and the second linear portion, and the angle formed by the third linear portion and the fourth linear portion, may be variable from the tip end to the proximal end.

[0010] [4] In the dental files described in [1] to [3], the angle formed by the first linear portion and the second linear portion and the angle formed by the third linear portion and the fourth linear portion may be smaller than the angle formed by the first linear portion and the third linear portion and the angle formed by the second linear portion and the fourth linear portion. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1A shows a right side view of the dental file according to this embodiment, Figure 1B shows a front view of the dental file according to this embodiment, and Figure 1C shows an enlarged view of the working section in Figure 1A. [Figure 2] Figure 2 shows a cross-sectional view along line II-II in Figure 1. [Figure 3] Figure 3 shows a cross-sectional view along line II-II, illustrating the first and second regions. [Figure 4] Figure 4 shows a cross-sectional view along line III-III in Figure 1. [Figure 5] Figure 5 shows a cross-sectional view of line IV-IV in Figure 1. [Figure 6] Figure 6 shows a cross-sectional view of line VV in Figure 1. [Modes for carrying out the invention]

[0012] definition For the sake of convenience, the specific terms used in this application are collected herein. Unless otherwise specified, all technical and scientific terms used in this application shall have the same meaning as commonly understood by those skilled in the technical field to which the present invention pertains. Unless otherwise clearly specified in the context, the singular forms "A", "AN", and "THE" include plural references.

[0013] The numerical ranges and parameters indicated in the present invention are approximate values. Although the numerical values shown in specific examples are described as accurately as possible, any numerical value inherently includes certain errors that inevitably result from the standard deviation found in each test measurement. Also, as used herein, the term "about" generally means within 10%, 5%, 1%, or 0.5% of a given value or range. Alternatively, the term "about" means within an acceptable standard error when considered by those skilled in the art.

[0014] Hereinafter, embodiments of the present invention will be described. The following embodiments are illustrative, and the scope of the present invention is not limited to those shown in the following embodiments. For the sake of avoiding repetition and complexity, explanations will be omitted as appropriate for similar content.

[0015] Dental file 100 FIG. 1A shows a right side view of the dental file 100 according to this embodiment, FIG. 1B shows a front view of the dental file 100 according to this embodiment, and FIG. 1C shows an enlarged view of the working portion 100A in FIG. 1A.

[0016] As shown in FIG. 1A, the dental file 100 has a working portion 100A for cutting the root canal, a shaft 100B connected to the rear end of the working portion 100A, and a gripping portion 100C connected to the rear end of the shaft 100B and attached to a dental handpiece. The working portion 100A includes a first region 100E located on the tip side and a second region 100F located on the rear end side. As the material of the dental file 100, for example, highly elastic nickel titanium suitable for treating complexly curved root canals is used.

[0017] The working portion 100A of the dental file 100 has a groove formed around a rotation axis in the longitudinal direction, and the outer enclosing surface has a tapered shape in which the cross-section becomes smaller towards the tip, and a similar cross-section is formed in a spiral shape. More specifically, the shape of the tip cross-section perpendicular to the longitudinal direction in the working portion 100A is formed as shown in Figures 2 and 4 to 6, for example, in the cross-sectional view along line II-II to line VV in Figure 1C.

[0018] In Figures 2 to 6, the dashed circles and lines are auxiliary circles and lines (hereinafter referred to as virtual circle 101 and diameter segment 102, respectively) used to explain this embodiment. Diameter segment 102 passes through the center 103 of virtual circle 101. The diameter of virtual circle 101 is set to decrease from the base end to the tip end of the working section 100A. In Figures 2 to 6, for convenience, the figures are drawn to a scale such that the diameter of virtual circle 101 is equal.

[0019] The primary rotational direction R of the dental file 100 is the direction in which, during normal use of the dental file 100, cutting debris from the working section 100A is carried toward the base. Specifically, for example, if the helix of the dental file 100 is a right-hand thread, the primary rotational direction R, viewed from the tip side, is counterclockwise. Note that the rotational direction of the dental file 100 is not limited to the R direction; it may also be used in modes that include reverse rotation or modes in which the rotation alternates.

[0020] Each cross-section shown in Figures 2 to 5 consists of a cutting vertex 110, an arc-shaped portion (land portion) 111, a first linear portion 121, a second linear portion 122, a third linear portion 123, a fourth linear portion 124, a first vertex 131, and a second vertex 132.

[0021] Cutting apex 110 The cutting apex 110 is located on the virtual circle 101. The cutting apex 110 cuts the contact area by rotating around the rotation axis of the dental file 100 and making contact with the root canal.

[0022] Arc-shaped portion 111 The arc-shaped portion 111 is located on the virtual circle 101 and is positioned to pass through the intersection point 104 of the virtual circle 101 and the diameter line segment 102 that passes through the cutting vertex 110 and the center 103. The arc-shaped portion 111 is located in the first region 100E of the working section 100A.

[0023] The length of the arc-shaped portion 111 is formed to decrease from the tip end to the base end. As a result, the tip end of the dental file 100 has high conformability and flexibility, while the base end of the dental file 100 has high rigidity.

[0024] The first vertex 131 and the second vertex 132 Refer to Figure 3. The first vertex 131 is located within the first region 151, which is occupied by the first line segment 141 connecting one end 111A of the arc-shaped portion 111 and the cutting vertex 110, and the virtual circle 101. The second vertex 132 is located within the second region 152, which is occupied by the second line segment 142 connecting the other end 111B of the arc-shaped portion 111 and the cutting vertex 110, and the virtual circle 101.

[0025] In Figure 3, the first line segment 141 and the second line segment 142, shown as dashed lines, are auxiliary lines for illustrating this embodiment. Furthermore, the shaded areas shown in Figure 3 are for the purpose of illustrating the first region 151 and the second region 152.

[0026] The first vertex 131 can be located within the first region 151, and may lie on the first line segment 141 or on the virtual circle 101. The second vertex 132 can be located within the second region 152, and may lie on the second line segment 142 or on the virtual circle 101. In one embodiment, the first vertex 131 does not lie on the first line segment 141. In one embodiment, the first vertex 131 does not lie on the virtual circle 101. In one embodiment, the second vertex 132 does not lie on the second line segment 142. In one embodiment, the second vertex 132 does not lie on the virtual circle 101.

[0027] The first linear portion 121, the second linear portion 122, the third linear portion 123, and the fourth linear portion 124 Refer to Figure 2 again. The first linear portion 121 connects one end 111A of the arc-shaped portion 111 to the first vertex 131, the second linear portion 122 connects the other end 111B of the arc-shaped portion 111 to the second vertex 132, the third linear portion 123 connects the cutting vertex 110 to the first vertex 131, and the fourth linear portion 124 connects the cutting vertex 110 to the second vertex 132.

[0028] The first linear portion 121 and the fourth linear portion 124 maintain parallelism with each other from the tip end to the base end when viewed from the front, and the second linear portion 122 and the third linear portion 123 maintain parallelism with each other from the tip end to the base end when viewed from the front.

[0029] The first linear portion 121, the second linear portion 122, the third linear portion 123, and the fourth linear portion 124 do not necessarily have to be perfectly straight lines; for example, they may be slightly curved.

[0030] The angle formed by the first linear portion 121 and the second linear portion 122 and / or the angle formed by the third linear portion 123 and the fourth linear portion 124 is variable in a front view from the tip end to the base end. In one embodiment, the angle formed by the first linear portion 121 and the second linear portion 122 and / or the angle formed by the third linear portion 123 and the fourth linear portion 124 increases in a front view from the tip end to the base end. In another embodiment, the angle formed by the first linear portion 121 and the second linear portion 122 and / or the angle formed by the third linear portion 123 and the fourth linear portion 124 varies from 75° to 90° in a front view from the tip end to the base end. Each angle may increase continuously from the tip end to the base end, increase in steps, or be a combination thereof. The angle formed by the third linear portion 123 and the diameter segment 102 may be the same as the angle formed by the fourth linear portion 124 and the diameter segment 102. The angle formed by the third linear portion 123 and the diameter segment 102 may be smaller or larger than the angle formed by the fourth linear portion 124 and the diameter segment 102. In one embodiment, the angle formed by the first linear portion 121 and the second linear portion 122 and the angle formed by the third linear portion 123 and the fourth linear portion are smaller than the angle formed by the first linear portion 121 and the third linear portion 123 and the angle formed by the second linear portion 122 and the fourth linear portion 124.

[0031] In Figure 2, the angle formed by the third linear portion 123 and the fourth linear portion 124 is 75°, the angle formed by the third linear portion 123 and the diameter segment 102 is 35°, and the angle formed by the fourth linear portion 124 and the diameter segment 102 is 40°. In Figure 4, the angle formed by the third linear portion 123 and the fourth linear portion 124 is 77°, the angle formed by the third linear portion 123 and the diameter segment 102 is 35°, and the angle formed by the fourth linear portion 124 and the diameter segment 102 is 42°. In Figure 5, the angle formed by the third linear portion 123 and the fourth linear portion 124 is 80°, the angle formed by the third linear portion 123 and the diameter segment 102 is 35°, and the angle formed by the fourth linear portion 124 and the diameter segment 102 is 45°.

[0032] The third vertex 133 Figure 6 shows a cross-sectional view of the working section 100A located in the second region 100F. In the second region 100F, one end 111A and the other end 111B of the arc-shaped portion 111 converge at the same position, and a third vertex 133 is formed in place of the arc-shaped portion 111. In other words, the arc-shaped portion 111 disappears and becomes the third vertex 133. The third vertex 133 is connected to the first vertex 131 via the first linear portion 121, and also to the second vertex 132 via the second linear portion 122, forming a rectangular shape. As a result, cutting at the proximal end of the dental file 100 is performed by four vertices, thus providing high cutting capability. Note that although the cross-section of the working section 100A located in the second region 100F in Figure 6 is rectangular, it may be any other quadrilateral (e.g., square, parallelogram, or rhombus), as long as there is one side that is parallel to all sides.

[0033] Manufacturing method The cross-sectional shape of the dental file 100 in this embodiment can be easily manufactured, for example, by grinding it using a routine for a predetermined amount of material removal in a program that operates a grinding machine.

[0034] In this embodiment, the dental file 100 has a structure in which the first linear portion 121 and the fourth linear portion 124 are parallel to each other, and the second linear portion 122 and the third linear portion 123 are also parallel to each other. Therefore, the width between the first linear portion 121 and the fourth linear portion 124, and the width between the second linear portion 122 and the third linear portion 123 can be automatically measured by projection from the longitudinal direction perpendicular to the tip end, from the proximal end. This is possible because the two pairs of sides are parallel; if the pairs of sides are not parallel, the longest side will be projected, making measurement impossible. Furthermore, by rotating the dental file 100 and measuring the angle between measuring one width and measuring the next, the angle formed by each linear portion can also be automatically measured. The dental file 100 of this embodiment, which can automatically measure the above width and angle, can eliminate complicated manual work compared to conventional products, and is expected to improve productivity. [Explanation of Symbols]

[0035] 100...Dental file, 100A...Working section, 100B...Shaft, 100C...Gripping section, 100E...First area, 100F...Second area, 101...Virtual circle, 102...Diameter line segment, 103...Center, 104...Intersection, 110...Cutting vertex, 111...Arc-shaped section, 111A...One end, 1 11B...the other end, 121...first linear section, 122...second linear section, 123...third linear section, 124...fourth linear section, 131...first vertex, 132...second vertex, 133...third vertex, 141...first line segment, 142...second line segment, 151...first region, 152...second region

Claims

1. A dental file having a working section in which a groove is formed around a longitudinal axis of rotation, The shape of the tip cross-section perpendicular to the longitudinal direction at the tip end of the aforementioned work section is: A cutting vertex located on a virtual circle having the aforementioned center, An arc-shaped portion located on the virtual circle and positioned so as to pass through the intersection point of the diameter line segment passing through the cutting vertex and the center and the virtual circle, A line segment connecting one end of the arc-shaped portion and the cutting vertex, and a first vertex located within the first region occupied by the virtual circle, A second vertex located within the second region occupied by the line segment connecting the other end of the arc-shaped portion and the cutting vertex, A first linear portion connecting one end of the arc-shaped portion and the first vertex, A second linear portion connecting the other end of the arc-shaped portion and the second vertex, A third linear portion connecting the cutting portion and the first vertex, A fourth linear portion connecting the cutting portion and the second vertex, It is configured to include, The first linear portion and the fourth linear portion maintain a parallel state to each other from the tip end side to the base end side, and the second linear portion and the third linear portion, The tip end and the base end maintain a parallel state to each other, A dental file characterized in that the length of the arc-shaped portion is formed to decrease from the tip end to the base end while maintaining the parallel state.

2. The dental file according to claim 1, wherein the arc-shaped portion at the base end of the working part disappears and becomes a third vertex.

3. The dental file according to claim 1, wherein the angle formed by the first linear portion and the second linear portion and the angle formed by the third linear portion and the fourth linear portion are variable from the tip end side to the base end side.

4. The dental file according to claim 1, wherein the angle formed by the first linear portion and the second linear portion and the angle formed by the third linear portion and the fourth linear portion are smaller than the angle formed by the first linear portion and the third linear portion and the angle formed by the second linear portion and the fourth linear portion.

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