JP2017113361A - Dental root amputation instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dental root amputation instrument attached to a dental handpiece to be used and capable of smoothly removing amputated matters generated by amputating a root canal.SOLUTION: A dental root amputation instrument 10 includes: a working part 11 consisting of a spiral cutting blade and having such a shape as to get narrower toward a tip end; a shaft 12 continued to a rear end of the working part 11 and having a same diameter as that of a circumscribed circle of the rear end cross section of the working part; and a grip part 13 continued to the rear end of the shaft 12 and connected to the dental handpiece. The shaft 12 includes a spiral groove 12a continued to the cutting blade of the working part, formed thereon.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a dental root canal cutting tool used for enlarging and cleaning a root canal in dental treatment.

  Examples of dental root canal cutting tools used for root canal enlargement and cleaning in dental treatment include reamers and files (see Patent Document 1). The reamer mainly cuts the root canal by rotating, and the file cuts the root canal by rotating or pushing and pulling in the axial direction.

  Conventional dental root canal cutting tools are made of stainless steel, but in recent years, nickel titanium having high elasticity suitable for treatment of curved root canals may be used. Furthermore, not only a manual type but also an electric type used as a power connected to a dental handpiece (engine) is increasing. And, it is possible to perform treatment quickly by using an electric type.

  FIG. 4 is a perspective view of a dental root canal cutting tool. The dental root canal cutting tool 100 shown here is a file used by being connected to a dental handpiece. This dental root canal cutting tool 100 includes a working part 101 formed of a cutting blade having a spiral shape that narrows toward the tip, a shaft 102 connected to the rear end of the working part 101, and a rear part of the shaft 102. And a grip portion 103 connected to the end and attached to the dental handpiece.

  A general manufacturing method of such a dental root canal cutting tool is to first process a portion that becomes a working portion from a thin wire rod so as to have a constant taper ratio (for example, 2/100) by a centerless processing machine. Then, a groove to be a cutting edge of the working part is formed by a blade groove grinding machine. Here, if it is processed from a thick wire, it is technically possible to simultaneously form the taper of the part that becomes the working part and the groove that becomes the cutting edge, but the grinding amount is large and the grindstone is easily damaged. In many cases, a method of grinding a thin wire in two stages of taper formation and cutting edge formation is employed. In the case of a nickel titanium file, it is preferable to form a thin wire since it is easy to damage the grindstone.

  Here, if it is formed from a thick wire, there is an advantage that the length of the working portion can be increased. However, if it is formed from a thin wire, there is a disadvantage that the length of the working portion cannot be increased. That is, even if it connects with a dental handpiece and tries to cut the inside of the root canal quickly, it has a problem that it is difficult to smoothly discharge the cut material from the root canal because the length of the working part is short. .

Japanese Patent No. 4247346

  In view of such circumstances, the present invention is a dental root canal cutting tool which is used by being attached to a dental handpiece, and can smoothly discharge a cut material generated by cutting the inside of the root canal. The purpose is to provide.

  The dental root canal cutting tool according to the present invention includes a working part having a spiral cutting edge and being narrowed toward the tip, and a circumscribed circle of the rear end section of the working part connected to the rear end of the working part. A shaft having the same diameter and a grip portion connected to the dental handpiece connected to the rear end of the shaft, and a spiral groove continuous from the cutting edge of the working portion is formed on the shaft. It is a feature.

  Here, it is preferable that the spiral groove has a spiral pitch larger than the spiral shape of the cutting edge of the working unit or a groove width larger than the spiral shape of the cutting edge of the working unit. Further, the edge of the spiral groove may have a function as a cutting edge or may not have a function.

  In addition, the working portion is formed of a spiral cutting blade and is narrowed toward the tip, a shaft connected to the rear end of the working portion, and a grip connected to the dental handpiece connected to the rear end of the shaft. A tapered portion that is tapered toward the rear end of the working portion, and a straight portion that is continuous with the rear end of the tapered portion and has the same diameter as the thickest portion of the tapered portion. The dental root canal cutting tool may be characterized in that the diameter of the finest portion of the tapered portion is smaller than the diameter of the circumscribed circle of the rear end cross section of the working portion.

  According to the present invention, by providing the shaft with a spiral groove or a tapered portion, there is an effect that the cut material cut by the working portion can be smoothly discharged out of the root canal.

It is a dental root canal cutting tool which has a helical groove | channel on a shaft, Comprising: (a) A perspective view, (b) is an enlarged plan view of a shaft. It is a dental root canal cutting tool which has a taper part in a shaft, Comprising: (a) A perspective view, (b) is an enlarged plan view of a shaft. It is a figure which shows the rear end cross section of a working part, Comprising: (a) is a case where a working part cross section is a triangle, (b) is a case where the working part cross section is a shape which cut off a part of circle. It is a perspective view of a dental root canal cutting tool.

  The present invention is a dental root canal cutting tool in which a function of improving the dischargeability of a cut object is added to a shaft. Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a dental root canal cutting tool having a spiral groove on a shaft, where (a) is a perspective view and (b) is an enlarged plan view of the shaft.

  The dental root canal cutting tool 10 includes a working portion 11 having a spiral cutting edge and narrowing toward the tip, and a circumscribing section of the rear end of the working portion 11 connected to the rear end of the working portion 11. The shaft 12 has the same diameter as the circle, and the grip 13 connected to a dental handpiece (not shown) connected to the rear end of the shaft 12. That is, it is a dental root canal cutting tool 10 used by being connected to a dental handpiece, and corresponds to a file made of stainless steel or nickel titanium.

  Here, the shaft 12 is formed with a spiral groove 12 a continuous from the cutting edge of the working unit 11. In addition, the spiral groove 12a has a spiral pitch larger than that of the cutting blade spiral or a groove width larger than that of the cutting blade spiral, thereby further improving the discharge performance of the cut object. be able to. However, when designing a detailed shape such as the length of the spiral groove 12a, it is necessary to consider the balance between the dischargeability of the cut material and the breaking strength of the dental root canal treatment instrument 10. Moreover, the edge of the spiral groove 12a may have a function as a cutting edge, or may not have it.

  FIG. 2 shows a dental root canal cutting tool having a tapered portion on a shaft, where (a) is a perspective view and (b) is an enlarged plan view of the shaft. If the overall length of the shank 22 is made thin without providing the tapered portion 22a, the evacuation strength of the cut material can be improved, but the breaking strength of the dental root canal cutting tool 20 is weakened. The breaking strength is secured by setting 22a.

  This dental root canal cutting tool 20 is similar to the one shown in FIG. 1, and has a working portion 21 having a spiral cutting edge and narrowing toward the tip, and a rear end of the working portion 21. It has a continuous shaft 22 and a grip 23 connected to a dental handpiece (not shown) connected to the rear end of the shaft 22.

  Here, the shaft 22 includes a tapered portion 22a that narrows toward the rear end of the working portion 21, and a straight portion 22b that is continuous with the rear end of the tapered portion 22a and has the same diameter as the thickest portion of the tapered portion 22a. It consists of.

  And the diameter of the finest detail of the taper part 22a shall be smaller than the diameter of the circumscribed circle of the rear-end cross section of the working part 21. FIG. FIGS. 3A and 3B are diagrams showing a rear end cross section of the working unit, where FIG. 3A shows a case where the working unit cross section is a triangle, and FIG. 3B shows a case where the working unit cross section is a part of a circular shape. Of course, the shape of the rear end 21a of the working unit 21 is merely an example, and is not limited to these two types.

  Here, since the working part 21 has a tapered shape with a thin tip, the rear end 21 a of the working part 21 is the thickest part of the working part 21. The circumscribed circle 21c is a circle inscribed in the cross section of the rear end 21a of the working unit 21, and is indicated by a two-dot chain line in the drawing. That is, when the cross-sectional shape of the rear end 21a of the working unit 21 is a polygon such as a triangle as shown in FIG. 3A, the circumscribed circle 21c is a circle in which each vertex of the polygon passes on the circumference. . In addition, when the cross-sectional shape is a shape in which a part of a circle is cut out to form a cutting blade as shown in FIG. 3B, a circle in which the cut-out part is virtually filled is circumscribed. Think of it as 21c.

  In consideration of the dischargeability of the cut object, the most detailed diameter 22a1 of the tapered portion 22a is as shown by a broken line when the cross section of the rear end 21a of the working portion is polygonal as shown in FIG. It is considered that the diameter should be about the inscribed circle of the polygon or less. Similarly, when the cross section of the rear end 21a of the working portion 21 is a shape obtained by cutting a part of a circle as shown in FIG. 3B, the cut portion as shown by the broken line in FIG. It is good to make it the diameter which touches the position of the bottom of this, or the diameter below it. This is because, with such a shape, the cut material that has passed through the spiral cutting blade can smoothly enter the tapered portion 22a and be discharged.

  In summary, the most detailed diameter 22a1 of the tapered portion 22a is smaller than the circumscribed circle 21c of the rear end 21a of the working portion, and if possible, the diameter is about the inscribed circle of the rear end 21a of the working portion. Is good. However, when the finest diameter 22a1 is small, the breaking strength as a dental root canal cutting tool becomes weak, so a design that takes into account the balance between strength and dischargeability is required.

  As described above, according to the present invention, the spiral groove and the taper portion are provided in the shank to improve the dischargeability of the cut material. Therefore, the object to be attached to the dental handpiece is basically targeted. This is because, in the case of a type in which a handle is provided and moved by hand, the amount of discharge of the cut material is not so large, and even if a spiral groove or a tapered portion is provided, the effect of promoting discharge is small. However, even in the case of manual operation, since the cut object is discharged, there is no problem even if a spiral groove or a tapered portion similar to the present invention is provided.

10, 20 Dental root canal cutting tool 11, 21 Working portion 21a Working portion rear end 12, 22 Shaft 12a Spiral groove 22a Taper portion 22a1 Finest diameter 22b Straight portion 13, 23 Grasping portion

Claims (4)

A working part having a spiral cutting edge and narrowing toward the tip;
A shaft having the same diameter as the circumscribed circle of the rear end cross section of the working portion, which is connected to the rear end of the working portion;
A gripping part connected to a dental handpiece connected to the rear end of the shaft,
A dental root canal cutting tool, wherein a spiral groove continuous from the cutting edge of the working portion is formed on the shaft.   The dental root canal cutting tool according to claim 1, wherein the spiral groove has a spiral pitch larger than a spiral shape of the cutting edge.   The dental root canal cutting tool according to claim 1 or 2, wherein the spiral groove has a larger groove width than the spiral shape of the cutting edge. A working part having a spiral cutting edge and narrowing toward the tip;
A shaft connected to the rear end of the working unit;
A gripping part connected to a dental handpiece connected to the rear end of the shaft,
The shaft is composed of a tapered portion that is narrowed toward the rear end of the working portion, and a straight portion that is continuous with the rear end of the tapered portion and has the same diameter as the thickest portion of the tapered portion, A dental root canal cutting tool, wherein the diameter of the finest part of the tapered portion is smaller than the diameter of the circumscribed circle of the rear end cross section of the working portion.

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