JP6806362B2 - Dental handpiece - Google Patents

Description

The present invention relates to a dental handpiece.

Cutting treatment tools such as reamers and files are used to treat root canals in dental treatment. Both reamers and files are needle-shaped, with spiral blades usually formed on their surface. The blade of the file has a stronger degree of twist than the reamer, and the reamer is inserted into the root canal by continuously rotating (reaming) in the positive direction and by moving the file forward and backward (filing). Cut the root canal wall. Then, together with these original motion, the reciprocating motion to the reamer, is also performed to cause the rotary movement to the file.

Some of these therapeutic tools are directly gripped by hand, while others are used by inserting them into a handpiece. The handpieces used by inserting a reamer or file have forward / backward movements and rotational movements. There is something to be given.

For example, Patent Document 1 discloses a dental handpiece having a drive mechanism that moves a dental cutting tool forward and backward in the direction of its rotation axis, rotates forward only in the vicinity of the most advanced position, and does not rotate when retracting. .. This dental handpiece has a spiral blade formed on the dental cutting tool only near the most advanced position of the root canal, that is, near the position where the root canal should be cut. It rotates in the normal direction and discharges cutting chips to the outside at the same time as cutting.

Further, in Patent Document 2, the uniformity of the operation of the dental tool is enhanced by giving the dental tool a slow rotation near the most advanced position while causing the dental tool to move forward and backward at a relatively high frequency in the length direction. Dental tool displacement devices are disclosed.

Japanese Patent No. 4224745 Special Table 2012-531234

In the dental handpiece (dental tool displacement device) disclosed in Patent Documents 1 and 2, the force applied to the dental treatment tool is applied by rotating the dental treatment tool near the most advanced position while moving the dental treatment tool forward and backward. While minimizing, it prevents the dental tool from rotating and cutting the root canal wall more than necessary while pulling the dental tool from near the most advanced position, and also causes uneven wear of the dental tool. In addition, it is possible to avoid non-rotationally symmetric dental tools with non-uniform results in the tissue to be treated.

On the other hand, as a new type of dental treatment tool for root canal formation, a file called SAF (self-adjusting file) has been developed.
SAF is described in International Publication No. 2005/070320 and the like. This file is made of shape memory material, preferably a nickel-titanium alloy (Nitinol), and has an elastic and compressible grid-like and hollow interior structure with a file-like surface. Then, when the SAF is inserted into the root canal from its tip, it is compressed according to the change in the shape and diameter of the root canal and tries to expand to the original size, so that the file-like surface always becomes the root canal wall. It will be in a pressure-welded state. Therefore, especially when the root canal is not linear and has a non-uniform, non-circular cross section, the SAF moves forward and backward to polish on a file-like surface rather than cutting by rotary motion. In addition, it is possible to cut the root canal wall without changing the original shape of the root canal.
SAF can form a root canal with minimal invasion and expands without burdening the root canal wall, so microcracks are less likely to occur in the surrounding dentin, root canal fracture can be prevented, and instrument fracture is better than rotary cutting. Although it has various advantages such as less risk of folding, conventional dental handpieces can be used with conventional dental treatment tools, even if they are mainly for advancing and retreating movements for using files. Is not necessarily designed with consideration for the use of SAFs with different shapes and characteristics.
For example, the tip of SAF is thinner than that of a conventional dental treatment tool, but in the dental handpiece disclosed in Patent Documents 1 and 2, the dental treatment tool is rotated near the most advanced position. , The force to bite into the tooth is strong, and the load on SAF may increase.

The present invention has been made in view of such circumstances, and is used not only for conventional dental treatment tools (particularly files) but also for dentistry in which the load on the files is reduced, especially when SAF is used. Its purpose is to provide handpieces. Furthermore, it is an object of the present invention to provide a dental handpiece capable of forming a uniform and well-cut root canal wall.

In order to solve the above problems, a first aspect of the present invention, a drive mechanism for front advances and rear retirement dental treatment tool in the rotational axis direction for cutting the tooth, the drive mechanism, the dental it is characterized in that rotating the dental treatment tool only therapeutic tool in the vicinity of a position most to retreat back into the rotation axis direction.

The invention of claim 2, wherein the drive mechanism Rutoki advancing the dental treatment tool in the rotational axis direction, said dental treatment tool is characterized in that not rotate.

The invention of claim 3 has a rotating shaft arranged in a handpiece and a rotating cylinder arranged in a head case and rotated by the power of the rotating shaft, and the rotating cylinder is used for the dental treatment. A dental handpiece for inserting a tool to treat a tooth, the rotating shaft has a protruding portion eccentric with respect to the rotating shaft at the tip, and the rotating cylinder is in the axial direction of the rotating cylinder. The rotary cylinder has a large diameter portion at a position separated from the first cylindrical member in the axial direction of the rotary cylinder, and the protruding portion is the protrusion. The rotary cylinder is arranged so as to be in contact with both the first cylindrical member and the large diameter portion, and when the rotary shaft is rotated, the rotary cylinder reciprocates in the axial direction of the rotary cylinder, and further, the rotation The cylinder is characterized in that when the protruding portion and the first cylindrical member come into contact with each other, the rotation of the rotating shaft is transmitted to the rotating cylinder via the cylindrical member.

The invention of claim 4 is characterized in that the first cylindrical member is provided with uneven grooves at regular intervals on a surface in contact with the protruding portion.

According to the fifth aspect of the present invention, the rotary cylinder is gripped by a second cylindrical member at the lower part of the rotary cylinder, and between the second cylindrical member and a bearing that rotatably supports the rotary cylinder. It is characterized by having a spring member for advancing the rotary cylinder in the axial direction.

According to the present invention, in a dental handpiece, when a file containing SAF is inserted as a dental treatment tool and the root canal is moved forward and backward to cut the root canal wall, the file bites into the root canal wall. It is possible to reduce the congestion, reduce the damage to the file, make the file hard to break, and form a uniform and well-cut root canal wall.

It is an exploded view of the handpiece which concerns on one Embodiment of this invention. (A) is a front view of the handpiece, and (B) is a cross-sectional view of the handpiece as seen from AA of (A). It is an enlarged view of FIG. 2B which shows the composition of the main part of a handpiece. (A) is a side view of the handpiece, and (B) is a cross-sectional view of the handpiece as seen from BB of (A). It is a partially enlarged view of FIG. 4 (B) which shows the structure of the main part of the handpiece centering on the protrusion 12. (A), (B), and (C) schematically show a state in which the protruding portion 12 is sandwiched between the first cylindrical member 30 (groove 31) and the large diameter portion 21 and repeatedly contacts and separates. It is a figure.

Hereinafter, preferred embodiments of the dental handpiece of the present invention will be described with reference to the drawings. In the following description, it may be assumed that the configurations with the same reference numerals in different drawings are the same, and the description thereof may be omitted.

FIG. 1 is an exploded view of a dental handpiece according to an embodiment of the present invention. FIG. 2 (A) is a front view of a configuration example of the dental handpiece shown in FIG. 1, and FIG. 2 (B) is a cross-sectional view of the dental handpiece seen from AA of FIG. 2 (A). Yes, FIG. 3 is an enlarged view of FIG. 2B showing the configuration of a main part of the dental handpiece shown in FIG. FIG. 4 (A) is a side view of a configuration example of the dental handpiece shown in FIG. 1, and FIG. 4 (B) is a cross-sectional view of the dental handpiece seen from BB of FIG. 4 (A). Yes, FIG. 5 is a partially enlarged view of FIG. 4B showing the configuration of a main part of the dental handpiece shown in FIG. 1 centered on the protruding portion 12. 6 (A), (B), and (C) show that in the dental handpiece shown in FIG. 1, the protruding portion 12 is sandwiched between the first cylindrical member 30 (groove 31) and the large diameter portion 21. , Is a diagram schematically showing a state of repeating contact and separation.

The handpiece 1 shown in FIG. 1 has a head case 10 and a support member 13. Bearings 14 and 15 are fitted to the axial ends of the support member 13, and the rotating shaft 11 penetrates the inside of the hollow support member 13 and is rotatably supported by the bearings 14 and 15. It is provided. The tip of one of the rotating shafts 11 on the head case 10 side is larger than the diameter of the rotating shaft 11, and is further provided with a protruding portion 12 made of a round bar eccentric in the axial direction of the rotating shaft 11. A coupling member 17 is fitted to the tip of the rotating shaft 11 on the side opposite to the head case 10 side, and power transmitted by a motor or the like (not shown) is transmitted to the rotating shaft 11. The support member 13 is inserted into the head case 10 on the side of the rotating shaft 11 having the protruding portion 12, and is fixed by the fixing member 16.

As shown in FIG. 3, the head case 10 is provided with a rotary cylinder 20 that detachably holds a dental treatment tool in an axial direction orthogonal to the rotary shaft 11. The rotary cylinder 20 is fixed to the first cylindrical member 30 on the side opposite to the side where the dental treatment tool is inserted in the axial direction, and is rotatable and axially reciprocates by the bearings 50 and 60. It is held possible. A large-diameter portion 21 is provided in the middle of the rotary cylinder 20, and a protruding portion 12 is sandwiched between the large-diameter portion 21 and the first cylindrical member 30. In the present embodiment, the surface of the first cylindrical member 30 in contact with the protruding portion 12 has a constant frictional force so that the rotational movement of the rotating shaft 11 is transmitted through the protruding portion 12, and has a constant interval. As shown in FIG. 1, a radial groove 31 may be provided. On the other hand, the surface where the large diameter portion 21 contacts the protruding portion 12 is configured to have a low frictional force so that the rotary cylinder 20 does not rotate at the time of contact. In addition, instead of the radial groove 31, an unevenness may be provided on the axial end surface of the first cylindrical member 30 as long as it has a shape that meshes with the protruding portion 12.

The rotary cylinder 20 is further fixed to the second cylindrical member 40 on the side where the dental treatment tool is mounted, and the rotary cylinder 20 is moved forward in the axial direction between the bearing 60 and the second cylindrical member 40. It may be configured to have a spring member 70 for making the spring member 70. The rotary cylinder 20 is kept in a state of being housed in the head case 10 by attaching the head portion 80.

In FIG. 5, the projecting portion 12 provided eccentrically at the tip of the rotating shaft 11 moves in the axial direction of the rotating cylinder 20 as the rotating shaft 11 rotates, and the first cylindrical member 30 and the large diameter portion 21 A configuration is shown in which the rotary cylinder 20 is moved forward and backward by contact with each other.

Further, when the rotating shaft 11 is rotated by the power of a motor or the like (not shown), the protruding portion 12 rotates about the rotating shaft 11. In FIGS. 6A, 6B, and 6C, the locus of rotation of the protrusion 12 is indicated by a chain line circle. Here, a case where the spring member 70 is provided between the bearing 60 and the second cylindrical member 40 will be described.

In FIG. 6A, the protruding portion 12 and the first cylindrical member 30 come into contact with each other through the groove 31, the protruding portion 12 pushes up the first cylindrical member 30, and the first cylindrical member 30 is fixed. The rotary cylinder 20 is retracted in the axial direction, and the first cylindrical member 30 is given a rotational motion in one direction to rotate the rotary cylinder 20. At this time, since the rotary cylinder 20 retracts most, the bearing 60 and the second cylindrical member 40 are closest to each other, and the spring member 70 is in the most compressed state. Therefore, the repulsive force of the spring member 70 exerts a force to advance the rotary cylinder 20 and the first cylindrical member 30 fixed to the rotary cylinder 20 in the axial direction. Therefore, the contact pressure between the first cylindrical member 30 and the protruding portion 12 increases, and the rotational movement of the rotating shaft 11 is more reliably transmitted to the first cylindrical member 30 via the protruding portion 12 and the groove 31. Will be.
FIG. 6B shows that after the protruding portion 12 comes into contact with the first cylindrical member 30, it is in a state where it does not come into contact with either the first cylindrical member 30 or the large diameter portion 21. In this state, the protruding portion 12 does not give the rotary cylinder 20 any rotational or axial forward / backward movement. At this time, with respect to the state of FIG. 6A, the rotary cylinder 20 advances in the axial direction, and the separation distance between the bearing 60 and the second cylindrical member 40 increases, so that the spring member 70 is relatively relaxed. To do.
FIG. 6C shows that, through the state of FIG. 6B, the protruding portion 12 comes into contact with the large diameter portion 21 to further advance the large diameter portion 21 and the rotary cylinder 20 in the axial direction. .. At this time, the force with which the spring member 70 pushes the rotary cylinder 20 through the second cylindrical member 40 is further reduced. Since the protruding portion 12 rotates very quickly, the protruding portion 12 comes into contact with the large diameter portion 21 earlier than the movement in which the rotary cylinder 20 tries to move forward due to the pressing force of the spring member 70, and the large diameter portion 21 is pressed. Push in the forward direction. As a result, the rotary cylinder 20 advances in the axial direction. As described above, since the friction between the protruding portion 12 and the large diameter portion 21 is formed to be small, the large diameter portion 21 does not rotate due to the protruding portion 12.
After that, when the protruding portion 12 continues to rotate about the rotating shaft 11, the intermediate state shown in FIG. 6 (B) (however, the protruding portion 12 comes to the position on the right side of the rotating shaft 11 on the paper surface. ), The groove 31 in contact with the protruding portion 12 moves to the adjacent groove one after another, and the rotary cylinder 20 fixed to the first cylindrical member 30 is moved to the state of FIG. 6A again. The result is rotation only near the last retracted position.

As described above, in the dental handpiece, when a file containing SAF is inserted as a dental treatment tool and the root canal is moved forward and backward to cut the root canal wall, the file for the root canal wall is obtained. It is possible to weaken the bite of the root canal, reduce the damage to the file, make the file hard to break, and form a uniform and well-cut root canal wall.

1 ... Handpiece, 10 ... Head case, 11 ... Rotating shaft, 12 ... Protruding part, 13 ... Support member, 14 ... Bearing, 15 ... Bearing, 16 ... Fixing member, 17 ... Coupling member, 20 ... Rotating cylinder, 21 ... Large diameter portion, 30 ... first cylindrical member, 31 ... groove, 40 ... second cylindrical member, 50 ... bearing, 60 ... bearing, 70 ... spring member, 80 ... head portion.

Claims (5)

The dental treatment tool for cutting tooth includes a drive mechanism for front advances and rear retreat in its axial direction,
The drive mechanism, a dental handpiece, characterized in that rotating the dental treatment tool only said dental treatment tool in the vicinity of a position most to retreat back into the rotation axis direction. The drive mechanism so that advancing said dental treatment tool in the rotational axis direction Rutoki A dental handpiece according to claim 1, wherein the dental treatment tool is characterized in that it does not rotate. It has a rotating shaft arranged in a handpiece and a rotating cylinder arranged in a head case and rotated by the power of the rotating shaft, and the dental treatment tool is inserted into the rotating cylinder to insert a tooth tooth. It is a dental handpiece that treats
The rotating shaft has a protruding portion at its tip that is eccentric with respect to the rotating shaft.
The rotary cylinder is gripped by a first cylindrical member at the axially upper portion of the rotary cylinder.
The rotary cylinder has a large diameter portion at a position separated from the first cylindrical member in the axial direction of the rotary cylinder.
The protruding portion is arranged so as to be in contact with both the first cylindrical member and the large diameter portion.
When the rotating shaft is rotated, the rotating cylinder reciprocates in the axial direction of the rotating cylinder, and further
1. The rotary cylinder is characterized in that when the protruding portion and the first cylindrical member come into contact with each other, the rotation of the rotary shaft is transmitted to the rotary cylinder via the cylindrical member. Alternatively, the dental handpiece according to claim 2. The dental handpiece according to claim 3, wherein the first cylindrical member is provided with uneven grooves on the surface in contact with the protruding portion at regular intervals. The rotary cylinder is gripped by a second cylindrical member at the lower part of the rotary cylinder.
3. A claim 3 or 4 , wherein a spring member for advancing the rotary cylinder in the axial direction is provided between the second cylindrical member and a bearing that rotatably supports the rotary cylinder. dental handpiece according to.

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