JP2012235857A - Dental root canal treating handpiece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dental root canal treating handpiece having a contact point structure capable of selectively responding according to kinds of cutting tools by easily constituting a signal circuit to for measuring a root canal length so as to match with an outer shape of a head part.SOLUTION: In the dental root canal treating handpiece 1 having a front end head part 2, a small diameter neck part 3 arranged continuously to the front end head part 2, and a gripping part 4 arranged continuously to the neck part and grripped by hand fingers, a tool holding part 29 detachably holding a cutting rotating tool 5 is arranged in the front end head part rotatably around an axis, the neck part has an electroconductive body 85 for transmitting root canal length measuring signals arranged inward such that a part of the same faces a concave part 3a recessedly arranged from a surface periphery of the neck part and a cover member 36 detachably fitted and fixed to the concave part 3a, and the cover member has a contact point part piece 37 electrically contact the electroconductive body 85 when being fitted in the concave part 3a and an electrode part piece 38 arranged continuously to the contact point part piece and electrically connected to the rotating tool 5.

Description

  The present invention relates to a dental root canal treatment handpiece, and more particularly to a dental root canal treatment handpiece used for tooth root canal enlargement treatment and root canal length measurement, and more particularly, an electric signal circuit for root canal length measurement. It is related with the improvement of the electrical contact part which comprises.

  A handpiece used for the treatment of cutting and enlarging the root canal of a tooth, and as a dental root canal treatment handpiece used for measuring a root canal length, for example, those disclosed in Patent Documents 1 to 3 Can be mentioned. In Patent Document 1, a mounting portion of a head for mounting on a handpiece body is composed of a conductive member, and by mounting on the handpiece body, a root canal length measurement circuit in the mounting portion and the handpiece body is provided. A handpiece head with a root canal length measuring function configured to be electrically connected to a conductive member (such as a drive transmission mechanism) is described. And in this example in this patent document 1, between a mounting part and the tool holding mechanism for mounting | wearing a cutting tool with a head is electrically connected via the brush mechanism provided in the mounting part, Constitutes one of the signal transmission circuits for measuring the root canal length leading to the cutting tool (examples shown in FIGS. 2 and 3 of the document). Further, in Patent Document 2, a terminal pin, a contact plug, and a contact jack connected to the lead wire in the handpiece body are provided in the head, and the contact on the lower surface of the head is connected to the contact jack via the contact plate. A handpiece with a root canal length measuring function to be attached is described. Here, the contact is brought into contact with the cutting tool by vertical rotation, horizontal rotation or sliding, thereby forming an electric circuit for measuring the root canal length. Further, in Patent Document 3, the handpiece body is made of a conductive member, and a conductor wire for transmitting a root canal length measurement signal is provided in the handpiece body and the tip of the conductor wire is bifurcated. A handpiece having a root canal length measuring function is described. Then, one of the forked conductors is brought into contact with the head shaft member (tool holding portion) via a contact means, the other is connected to a U-shaped elastic wire, and this U-shaped elastic wire is attached to the tool holding portion. Configured to contact the tool.

Japanese Patent No. 3213480 Japanese Patent No. 3213539 Japanese Patent No. 4638796

  By the way, in the handpiece head of the above-mentioned example in Patent Document 1, it is necessary that the mounting portion of the head, that is, the head housing is formed of a conductive member. Therefore, since the root canal length measurement circuit is affected by touching the tissue in the oral cavity during use, it is necessary to form an insulating film on the outer surface of the head housing. A cutting tool used for this kind of root canal enlargement treatment is called a file or a reamer, and is composed of a shank portion held by a tool holding mechanism and a cutting action portion integrated with the shank portion. In this case, in addition to the whole made of a conductive member, a shank portion made of a non-conductive member, or a surface whose surface has been subjected to insulation treatment (for example, alumite treatment) is often used. Therefore, in the latter case, even if the brush mechanism is in contact with the tool holding mechanism, the signal transmission circuit for measuring the root canal length reaching the cutting tool is not configured. In Patent Document 1, as shown in the example of FIG. 4, a countermeasure for such a case is taken by causing the cutting piece to directly contact the contact piece attached to the head housing. However, also in this case, since the head housing is made of a conductive member, it is necessary to form an insulating film on the outer surface thereof. And in this patent document 1, the brush mechanism shown in FIG.2 and FIG.3 and the contact piece shown in FIG. 4 are selectively used according to the kind (whether the whole consists of an electroconductive member) of a cutting tool. There is no technical idea that can be configured.

  Moreover, in the example shown in Patent Document 2, a contact is attached to the lower surface of the head, and this contact is brought into contact with a cutting tool protruding from the lower surface of the head, so that the contact is exposed to the outside of the head. Therefore, at the time of use, there is a concern that the contactor touches the tissue in the oral cavity and the root canal length measurement circuit is affected, or it is damaged by other members during handling or falls off. Also in this case, there is no technical idea that can be selected and used in combination with a mechanism for contacting the tool holding portion inside the head according to the type of the cutting tool as described above.

  Furthermore, in the example shown in Patent Document 3, the leading end of the conductive wire disposed in the handpiece body is bifurcated to contact each of the tool holding part in the head and the cutting tool protruding outside the head. It is made to contact through. Therefore, it can respond to any of the different types of cutting tools as described above. However, since it is not possible to attach / detach the contact means that contacts at least the tool holding portion, a measure for avoiding the influence on the root canal length measurement circuit caused by wear caused by friction of the contact means with the tool holding portion is taken. It becomes difficult to take. Further, in the case of a cutting tool made entirely of a conductive member, the contact means that directly contacts the cutting tool has no use, while the portion (shank portion) held by the tool holding portion of the cutting tool is non-conductive. In such a case, the contact means that contacts the tool holding portion is not necessary.

  The present invention has been made in view of such circumstances, and a signal circuit for measuring a root canal length is simply configured so as to be matched with the outer shape of the head portion, and according to the type of cutting tool. An object of the present invention is to provide a dental root canal treatment handpiece having a contact structure capable of being selectively handled.

  A dental root canal treatment handpiece according to a first invention includes a tip head portion, a narrow neck portion connected to the tip head portion, a grip portion connected to the neck portion and gripped by fingers, In the dental root canal treatment handpiece comprising: a tool holder for detachably holding a cutting rotary tool is rotatably mounted on the distal end head portion, and the neck portion is formed from the outer periphery of the surface of the neck portion. A root canal length measurement signal transmission conductor incorporated so that a part thereof faces the recessed portion provided in the recess, and a cover member that is detachably fitted into the recess, the cover member including the recess A contact piece that is brought into electrical contact with the conductor when fitted into the conductor, and an electrode piece that is connected to the contact piece and brought into electrical connection with the rotary tool. It is characterized by.

  In the dental root canal treatment handpiece of the present invention, the tool holding portion is made of a conductive member, and the electrode piece is integrally connected to the contact piece and contacts the outer peripheral surface of the tool holding portion to hold the tool. The cover member is configured to be in an electrically conductive state with the rotary tool held by the tool holding part via the part, and the cover member is in the vicinity of the concave part in the neck part in a state where the cover member is fitted in the concave part. It is good also as what is made into the shape matched with the outer shape of this.

  In the dental root canal treatment handpiece of the present invention, the electrode piece is connected as a separate member to the contact piece, and is swingably attached to the cover member, and is attached to the tool holding portion. It is good also as what is comprised so that the cutting action part of the rotary tool hold | maintained may be in electrical continuity with the said rotary tool.

  A dental root canal treatment handpiece according to a second invention includes a tip head portion, a narrow neck portion connected to the tip head portion, a grip portion connected to the neck portion and gripped by fingers, In the dental root canal treatment handpiece comprising: a tool holder for detachably holding a cutting rotary tool is rotatably mounted on the distal end head portion, and the neck portion has an outer peripheral surface of the neck portion. A root canal length measurement signal transmission conductor built in so that a part thereof faces a more recessed recess, and a cover member that is detachably fitted into the recess, the cover member being A contact piece that is brought into electrical contact with the conductor when fitted into the recess, and an electrode piece that is connected to the contact piece and brought into electrical conduction with the rotary tool, The cover member is such that the electrode piece is the contact A first cover member that is integrally connected to a piece and is in contact with the tool holding portion; and the electrode piece is connected to the contact piece as a separate member and is swingable so that the rotary tool And a second cover member configured to come into contact with the cutting action portion, wherein the first and second cover members can be selectively fitted into the recess and attached.

  According to the first aspect of the present invention, root cutting of the tooth can be expanded by holding the cutting rotary tool in the tool holding portion that is rotatably mounted on the tip head portion and rotating the cutting rotary tool. it can. In addition, since the cutting rotary tool is detachably attached to the tool holding part, it is possible to appropriately replace and hold cutting rotary tools having different diameters and shapes and to carry out accurate root canal enlargement treatment according to the root canal enlargement process. it can. The root canal length measurement signal transmission conductor built in the neck part is partially exposed to the recessed part provided in the recessed part from the outer periphery of the surface of the neck part, so that the cover member is fitted into the recessed part. Then, the contact piece provided in the cover member is brought into electrical contact with the conductor. At this time, the electrode piece connected to the contact piece is electrically connected to the rotary tool. Therefore, a part of the circuit for transmitting the root canal length measurement signal can be simply configured by fitting the cover member into the recess, and can be used for root canal length measurement.

  Further, if the tool holding part is made of a conductive member, the electrode holding piece is integrally connected to the contact piece and is configured to contact the outer peripheral surface of the tool holding part. In the case where the entire rotary tool held by the electrode is made of a conductive member, the rotary tool and the electrode piece are brought into electrical conduction via the tool holding portion. Accordingly, the rotary tool can be used as one of the root canal length measurement electrodes, and the root canal length can be measured in parallel with the root canal enlargement treatment. In this case, the cover member has an overall shape that matches the outer shape of the neck portion in the vicinity of the concave portion in a state where the cover member is fitted in the concave portion. There is nothing and does not interfere with the visual field in root canal treatment.

  Furthermore, if the electrode piece is connected to the contact piece as a separate member and is swingably attached to the cover member, the cutting action portion of the rotary tool is removed from the conductive member. If the part held by the tool holder does not have electrical conductivity, the electrode piece and the rotary tool are in an electrically conductive state by swinging the electrode piece and making contact with the cutting action portion. It can be. Therefore, even if the part held by the tool holding part is a rotary tool that does not have conductivity, the rotary tool is used as one of the root canal length measurement electrodes and the root canal length is measured in parallel with the root canal enlargement treatment. It can also be configured to allow treatment.

  According to the second invention, since the first and second cover members can be selectively fitted and mounted in the recesses, the first is used when the entire rotary tool is made of a conductive member. When the cover member is used and the portion held by the tool holding portion of the rotary tool is non-conductive, the second cover member can be used. Therefore, in addition to the above-described effects, the user side can accurately establish a circuit for transmitting a root canal length measurement signal according to the type of the rotary tool.

It is sectional drawing which shows the whole structure of 1st embodiment of the dental root canal treatment handpiece which concerns on this invention. It is the schematic which shows an example of the root canal expansion and root canal length measurement system incorporating the dental root canal treatment handpiece. It is a schematic control block diagram of the root canal enlargement and root canal length measurement system. (A) and (b) are the enlarged views of the X section in Drawing 1, (a) shows the state before attaching a cover member, and (b) shows the state where the cover member was attached. It is a top view of the cover member which comprises the dental root canal treatment handpiece of the embodiment. (A) (b) It is a figure similar to FIG. 4 (a) (b) which shows the modification of the dental root canal treatment handpiece of the embodiment. (A) (b) is a figure similar to FIG. 4 (a) (b) of the dental root canal treatment handpiece of 2nd embodiment. It is a top view of the cover member which comprises the dental root canal treatment handpiece of the second embodiment. It is the same figure as Fig.7 (a) which shows the modification of the dental root canal treatment handpiece of 2nd embodiment.

  Hereinafter, embodiments of a dental root canal treatment handpiece of the present invention will be described with reference to the drawings. First, an example of a root canal enlargement and root canal length measurement system incorporating a dental root canal treatment handpiece according to the present invention will be described with reference to FIGS. In FIG. 2, a dental root canal treatment handpiece 1 includes a tip head portion 2, a narrow neck portion 3 connected to the tip head portion 2, and a grip connected to the neck portion 3 and gripped by fingers. Part 4. And the motor unit 6 for rotating the cutting rotary tool 5 with which the front-end | tip head part 2 is mounted | worn is detachably connected to the base part of the holding part 4. As shown in FIG. The dental instrument 10 is configured with the motor unit 6 connected to the handpiece 1. The motor unit 6 includes a hose 61 that includes a power supply lead 71 for the micromotor 7 built in the motor unit 6 and one signal lead 8 for a root canal length measurement signal circuit. The hose 61 is connected to the control box 9. As will be described later, the signal lead wire 8 is electrically connected to the cutting rotary tool 5 through the motor unit 6 and the handpiece 1, and the cutting rotary tool 5 is one of the root canal length measuring circuits 12 described later. Electrode.

  The control box 9 includes a control unit 11, a root canal length measurement circuit 12, a motor driver 13, an auto stop position setting unit 14, an operation unit 15, a display unit 16, and the like, and the instrument 10 is disposed on the side when not in use. A holder 17 for holding is attached. Further, the foot controller 18 is connected to the control box 9, and the other signal lead wire 19 for the root canal length measurement signal circuit connected to the root canal length measurement circuit 12 is led out from the control box 9. ing. An oral electrode (the other electrode) 19a that is applied to the patient's lips is connected to the distal end of the signal lead wire 19 in an electrically conductive state. The control unit 11 controls the entire root canal enlargement and root canal length measurement system, and the main part is composed of a microcomputer. When performing the root canal enlargement treatment of the tooth while rotating the cutting rotary tool 5, the auto stop position setting unit 14 sets a reference position in the root canal in advance while viewing the display unit 16, and the cutting rotary tool 5. When the tip of the cutting tool reaches this set position, the rotation of the cutting rotary tool 5 is automatically stopped or reversely rotated. The selection of whether to perform such control as automatic stop is performed by the operation unit 15. The rotation control of the cutting rotary tool 5 by the micromotor 7 is performed by a foot operation of the foot controller 18, and an operation switch (not shown) is provided in the grip portion 4 of the handpiece 1. Rotation control may be performed in combination. Further, for example, when the foot controller 18 is being stepped on, the rotation is stopped when the root canal length measuring circuit 12 detects that the cutting rotary tool 5 has been inserted into the root canal. You may make it do.

  The root canal length measurement circuit 12 uses the cutting rotary tool 5 attached to the head portion 2 of the handpiece 1 as one electrode as described above, the oral electrode 19a as the other electrode, and the oral electrode 19a as the patient's lip. The circuit is configured with the cutting and rotating tool 5 inserted into the root canal of the tooth. The root canal length measurement circuit 12 applies a voltage between the electrodes 5 and 19a and measures the impedance between the electrodes 5 and 19a, whereby the impedance when the tip of the cutting rotary tool 5 reaches the apex position. Is detected, that is, the root canal length is measured. This type of root canal length measuring apparatus is conventionally known. The illustrated control box 9 is used by being mounted on a tray table or a side table installed on the side of the dental examination table, but may be incorporated in the tray table or the side table. . Further, the handpiece 1 is a cordless type, and a battery pack, a micro motor, and a control system corresponding to the control box 9 are incorporated in the gripping portion 4 of the handpiece 1, and various operation portions are provided on the surface of the gripping portion 4. The lead wire 19 for the oral electrode 19a may be led out from the grip portion 4.

  Next, the configuration of the handpiece 1 will be described with reference to FIGS. 1, 4, and 5. The hand piece 1 is formed in a contra-angle shape in which the front half of the handpiece 1 is composed of a grip housing 4a made of a synthetic resin molding and a head housing 2a made of a synthetic resin molding via a neck portion 3. In the gripping part housing 4a, when the motor unit 6 is connected to the base part of the gripping part 4, the first drive transmission shaft 20 connected to the output shaft 72 of the micromotor 7 via the coupling part 20a is connected. The interior is rotatable. A second drive transmission shaft 22 is connected to the tip of the first drive transmission shaft 20 via a first reduction gear mechanism 21 so as to be rotatable. Further, a portion reaching the neck portion 3 has a second bent portion. A third drive transmission shaft 24 is connected to the reduction gear mechanism 23 so as to be rotatable. At the base of the grip portion 4, a plug 82 is provided which is connected to one of the signal lead wires 8 for the root canal length measurement signal circuit and is plugged into a socket 81 provided at the tip of the motor unit 6. ing. A lead wire 83 is routed from the plug 82 in the grip portion housing 4a, and is electrically connected to a strip-like conductor 85 extending over the neck portion 3 via a connector portion 84 comprising a socket and a pin. It is connected. A concave portion 3a is formed on the lower surface of the neck portion 3 toward the axial center side from the outer periphery of the neck portion 3 so that the leading end portion of the conductor 85 is exposed to the concave portion 3a.

  The third drive transmission shaft 24 is supported through a bearing 26 in a metal sleeve 25 that is integrally fitted in the gripping portion housing 4a, and a bevel gear 27 is fixed to the tip thereof. ing. The conductor 85 is insulated from the sleeve 25 through a space. A female screw portion 25a is formed in a portion of the sleeve 25 corresponding to the concave portion 3a. The head housing 2 a of the head portion 2 is internally provided with a tool holding mechanism portion 28 that holds the cutting rotary tool 5 so as to be rotatable about an axis perpendicular to the axis of the third drive transmission shaft 24. The tool holding mechanism portion 28 includes a hollow cylindrical rotor (tool holding portion) 29 made of a conductive member having a gear portion 29 a that meshes with the bevel gear 27, and a chuck member that is externally fitted to the rotor 29. 30 and a cylindrical rotor exterior member 31 that is integrally fitted to the chuck member 30. The rotor 29, the chuck member 30, and the rotor exterior member 31 are supported by the head housing 2 a through bearings 32 and 33 so as to be capable of axial rotation integrally.

  The cutting rotary tool 5 is called a file or reamer, and a shank portion 5a that is detachably fitted into the inner cylinder portion of the rotor 29, and a needle that is concentrically press-fitted into the shank portion 5a. And the whole is constituted by a conductive member. A locking recess 5c is formed at the upper end of the cutting rotary tool 5 to elastically lock a pair of chuck claws 30a, 30a formed on the chuck member 30. In the following, the terms “upper” or “lower” are used to represent the upper side of the drawing as “up” and the lower side as “down” in relation to the diagram shown in FIG. When the cutting rotary tool 5 is inserted into the inner cylinder portion of the rotor 29 with the shank portion 5a, the chuck claws 30a, 30a are elastically fitted and locked in the locking recesses 5c, thereby cutting and rotating. Extraction of the tool 5 from the rotor 29 is prevented. A D-cut portion (not shown) is formed at the upper end portion of the cutting rotary tool 5, while a receiving portion (not shown) having a shape matching the D-cut portion is formed on the rotor exterior member 31. . In a state where the cutting rotary tool 5 is inserted into the rotor 29 so as not to be extracted, the D-cut portion is received by the receiving portion, and the cutting rotary tool 5 is allowed to rotate integrally with the rotor 29. At this time, the cutting rotary tool 5 is tightly fitted to the rotor 29, and the cutting rotary tool 5 and the rotor 29 are brought into electrical conduction.

  The upper end of the head housing 2a is opened, and an unlocking button 34 that also serves as a lid is attached to the opening. An action cylinder portion 34a projects downward on the lower surface of the lock release button 34. The lock release button 34 is always urged upward by a spring member 35 and is prevented from being pulled upward. It is assembled in a state. Then, when the lock release button 34 is pushed against the urging force of the spring member 35, the lower end portion of the action cylinder portion 34a protruding from the lower surface of the release button 34 spreads the chuck claws 30a, 30a. Acts as follows. As a result, the locking of the chuck claws 30a, 30a with respect to the locking recess 5c is released, and the cutting rotary tool 5 can be removed from the rotor 29. A lower end portion of the head housing 2a is cut out in a circular shape so that a peripheral portion of the lower end portion of the rotor 29 is exposed, and the notch portion 2b is continuous with the concave portion 3a formed on the lower surface of the neck portion 3. Is formed.

  A cover member 36 is fitted and attached to the continuous recess 3a and the notch 2b. The cover member 36 is made of a non-conductive metal member or a synthetic resin member, and has a shape that can be fitted into the recess 3a and the cutout portion 2b in a state of being in close contact with the inner peripheral portion thereof. The cover member 36 is integrally formed so that a first portion 36A that fits into the recess 3a and a second portion 36B that fits into the notch 2b are connected in a stepped shape. A contact piece 37 made of a plate-like conductive member is fixed to the upper surface of the first portion 36A in a surface contact state, and arc-shaped portions 38a and 38a that are integrally connected to the contact piece 37 and face each other. Are formed so as to extend over the upper surface of the second portion 36B. The electrode pieces 38, 38 are formed so that their plate surfaces are perpendicular to the upper surface of the second portion 36B, and the virtual circles formed by the inner circumferences of the arc-shaped portions 38a, 38a of the two electrode pieces 38, 38 are formed. The diameter d is set to be slightly smaller than the outer diameter D at the lower end of the rotor 29 (see FIG. 5).

  A groove-like recess 36Aa that opens downward is formed on the lower surface of the first portion 36A of the cover member 36, and a circular hole 36Ab is formed at a substantially central portion thereof. Further, a circular hole 36Ba concentric with a virtual circle formed by the inner circumference of the arc-shaped portions 38a, 38a is formed at a substantially central portion of the second portion 36B. The circular hole 36 </ b> Ab opened in the first portion 36 </ b> A is a hole through which the stopper 39 is inserted, and a concentric through hole 37 a is formed at a corresponding position of the contact piece 37. A through hole 85a is also formed in a portion of the conductor 85 corresponding to the female screw portion 25a formed in the sleeve 25. The stopper 39 has a male threaded portion 39a, passes through the circular hole 36Ab, the through hole 37a and the through hole 85a, and causes a tool such as a screwdriver to act on the head 39b, thereby causing the female threaded portion 25a to have a male threaded portion. The screw part 39a can be screwed together. As a result, the cover member 36 fitted into the recess 3 a and the notch 2 a is attached and fixed to the sleeve 25. In this fixed state, as shown in FIG. 4 (b), the head of the stopper 39 is accommodated with almost no protrusion from the groove-like recess 36Aa, and the first portion 36A is also roughly accommodated in the recess 3a. It is in a state of alignment so as to form a part of the outer shape of the nearby neck portion 3. Further, the contact piece 37 is elastically brought into contact with the leading end of the conductor 85 so as to push up the leading end of the conductor 85, and both are brought into an electrically conductive state. In order to ensure this elastic contact state, a portion (tip portion) facing the concave portion 3a of the conductor 85 is a free end, and a refracting or curved shape that hangs down slightly in the concave portion 3a. It is desirable to do.

The diameter of the circular hole 36 </ b> Ba formed in the second portion 36 </ b> B of the cover member 36 is slightly larger than the outer diameter of the shank portion 5 a of the cutting rotary tool 5. As described above, the first portion 36A is fitted into the recess 3a so that the second portion 36B can be accommodated in the notch 2b at the same time. At this time, the pair of sandwiched electrode portions 38 and 38 are spread and the arc-shaped portions 38 a and 38 a are elastically contacted with the outer peripheral portion of the rotor 29 so as to sandwich the outer peripheral portion of the lower end portion of the rotor 29. Thereby, the electrical continuity between the electrode pieces 38 and 38 and the rotor 29 is achieved. In particular, due to the magnitude relationship between the diameter d of the virtual circle and the outer diameter D at the lower end of the rotor 29 as described above, the electrical conduction state due to the elastic contact between the two is stably maintained.
In addition, although the pair of sandwich-like electrode pieces 38, 38 have been illustrated as the electrode piece, one tongue piece-like piece may be elastically contacted with the rotor 29.

  In the state where the cover member 36 is fitted and fitted into the recess 3a and the notch 2b as described above, the cutting rotary tool 5 is inserted through the through hole 36Ba of the second portion 36B and inserted into the inner cylinder portion of the rotor 29. The tool holding mechanism 28 is held by the chuck member 30 or the like. In this holding state, the rotor 29 and the cutting rotary tool 5 can be rotated integrally with each other, and the cutting operation part 5b is moved by rotating the cutting rotary tool 5 by transmitting the rotational power of the micromotor 7. Thus, the root canal enlargement treatment of the tooth can be performed. At this time, the clip-like electrode pieces 38 are in sliding contact with the outer peripheral portion of the rotor 29 as brush contacts. Further, the cutting rotary tool 5 is integrated with the rotor 29 in a close-fitting state, and the rotor 29 is used for measuring the root canal length via the electrode piece 38, 38, the contact piece 37, the conductor 85, the lead wire 83, and the like. One signal lead 8 for the signal circuit is brought into electrical conduction. Accordingly, the root canal shown in FIG. 2 is inserted in a state where the cutting rotary tool 5 is inserted into the tooth root canal as one electrode for measuring the root canal length and the oral electrode 19a is hooked on the patient's lip as the other electrode. By driving the length measuring circuit 12, the root canal length can be measured.

  6A and 6B show a modification of the above embodiment, but this modification is also applied to the examples of FIGS. 7 to 9 described later. In this example, since only the shape of the stopper 39 is different and the other configurations are the same as those in the above example, the same reference numerals are given to common parts, and only different parts will be described. The stopper 39 in the above example is configured such that after the cover member 36 is fitted in the recess 3a and the notch 2b, a tool such as a screwdriver is applied to the head 39b and screwed into the female screw portion 25a. Is fixed to the neck portion 3. The stop 39 of this example has a pair of claw pieces 39c, 39c that can be elastically locked to the edge of the circular hole 36Ab of the first portion 36A, instead of the head 39b for operating the tool. Before the cover member 36 is mounted, the male screw portion 39a is preliminarily engaged with the female screw portion 25a. That is, in this screwed state, the claw pieces 39c, 39c of the stopper 39 are inserted into the circular hole 36Ab of the cover member 36 so as to bend in the centripetal direction, and the claw pieces are inserted into the lower opening edge of the circular hole 36Ab. The cover member 36 is mounted and fixed by elastically locking the pieces 39c and 39c. In order to smoothly insert the claw pieces 39c and 39c into the circular hole 36Aa, the circular hole 36Ab is formed in a tapered shape whose inner diameter gradually increases upward. Such mounting and fixing is performed from the state shown in FIG. 6A to the state shown in FIG. 6B when the circular hole 36Ab is directed to the claw pieces 39c and 39c and the cover member 36 is pushed up. It is convenient because it is done with a one-touch patch type. The cover member 6 can be easily removed by bending the claw pieces 39c, 39c in the centripetal direction using a dedicated tool. In order to facilitate the removal, even if the nail pieces 39c and 39c are slightly protruded from the outer shape of the neck portion 3, the effect of the present invention can be obtained as long as the visual field of the operator is not obstructed. Absent.

  FIGS. 7A, 7B and 8 show a second embodiment of the present invention. This embodiment is applied when the shank portion 5a of the cutting rotary tool 5 does not have conductivity due to the surface being anodized. In the cutting rotary tool 5 as in this example, the conductor 85 and the cutting rotary tool 5 cannot be brought into an electrically conductive state via the rotor 29 and the shank portion 5a. Therefore, another electrode part piece 40 in electrical continuity with the contact piece 37 is provided on the cover member 36, and this electrode part piece 40 is brought into contact with the cutting action part 5 b of the cutting rotary tool 5. That is, the cover member 36 further includes a third portion 36C that extends from the first portion 36A to the opposite side (the grip portion 4 side) from the second portion 36B. The third portion 36 </ b> C includes a recess 36 </ b> Ca that is in contact with the lower surface of the grip portion 4 in the vicinity of the connection portion with the neck portion 3 and that forms a cavity portion with the lower surface. Further, the contact piece 37 is further extended with a tongue piece 37b facing the recess 36Ca, and the tongue piece 37b is formed to have a spring property that can be elastically deformed up and down. . Notches 36Cb are formed in both side walls of the recess 36Ca.

  The electrode piece 40 is produced by bending a conductive wire member. The electrode piece 40 includes a shaft portion 40a, a pair of sandwiching bar portions 40b and 40b bent at an acute angle from both ends of the shaft portion 40a and coupled to each other, and the sandwiching bar portions 40b and 40b. It consists of a pair of guide bar portions 40c, 40c coupled so as to be separated from the tip. The shaft portion 40a is fitted from above into the notches 36Cb and 36Cb so as to cross the third portion 36C (perpendicular to the axis of the grip portion 4). Then, the electrode piece 40 supports the shaft portion 40a so as to be hooked on the third portion 36C, and the clamping bar portions 40b and 40b and the guide bar portions 40c and 40c are provided on the cover member 36. It is assembled to the cover member so as to be located on the lower side and toward the front side of the second portion 36B. In the cover member 36 assembled with the electrode piece 40 in this manner, the first portion 36A is engaged with the concave portion 3a of the neck portion 3 by screwing the stopper 39 into the female screw portion 25a in the same manner as described above. The portion 36B is attached to the handpiece 1 so as to fit in the cutout portion 2b of the head portion 2, respectively.

  In this mounted state, as shown in FIG. 7B, the shaft portion 40 a of the electrode piece 40 elastically moves between the tongue piece portion 37 b of the contact piece 37 and the lower surface of the housing 4 a of the grip portion 4. It is sandwiched. As a result, the shaft portion 40a and the tongue piece portion 37b come into contact with each other, and both are brought into an electrically conductive state. In particular, since the tongue piece portion 37b has a spring property, the tongue piece portion 37b retains an upward biasing elastic force and elastically contacts the shaft portion 40a, and this electrically conductive state is stably maintained. Moreover, since the contact part with respect to the tongue piece part 37b of the axial part 40a is cut and made into the flat surface, both will be in surface contact and it will be set as a more favorable electrical continuity state. When the cover member 36 is mounted on the handpiece 1 as described above, the electrode pieces 38 and 38 elastically sandwich the lower end of the rotor 29 as described above. However, since the shank portion 5 a of the rotary tool 5 does not have conductivity, the electrode pieces 38 and 38 and the rotary tool 5 are not electrically connected via the rotor 29. Rather, the mounting state of the cover member 36 is further stabilized by elastic sandwiching of the electrode pieces 38 and 38 with respect to the rotor 29. In addition, depending on the user, the shank portion 5a may be used without knowing whether or not it has conductivity. Therefore, having the electrode portion pieces 38 and 38 also has an advantage in selective use described later. is there.

  With the cover member 36 attached to the handpiece 1 as described above, the cutting rotary tool 5 is held on the tool holding mechanism 28. In this case, since the electrode piece 40 exists near the lower surface of the head portion 2 and obstructs the mounting of the rotary tool 5, the electrode piece 40 is retracted to the position of the two-dot chain line in FIG. deep. The electrode piece 40 is supported so as to be swingable about the axis of the shaft portion 40a, and can be easily displaced to a two-dot chain line position by a finger operation. In this state, in the same manner as described above, the cutting rotary tool 5 is passed through the through hole 36Ba of the second portion 36B, inserted into the inner cylinder portion of the rotor 29, and the tool holding mechanism portion via the chuck member 30 and the like. 28. Thereafter, the electrode piece 40 is swung upward about the axis of the shaft portion 40a. At this time, if the guide bar portions 40c and 40c are pushed up so that the cutting action portion 5b of the cutting rotary tool 5 is sandwiched between the front guide bar portions 40c and 40c, the space between the holding bar portions 40b and 40b is expanded. The action part 5b passes between the two. After passing, the clamping bar portions 40b and 40b are abutted so as to be sandwiched by the cutting action portion 5b by the restoring elasticity, and return to the solid line position in FIG. 7B. In FIG. 8, the cutting action portion 5b is indicated by a two-dot chain line, and the sandwiching bar portions 40b and 40b hold the cutting action portion 5b in a state slightly expanded from the solid line and the broken line. Therefore, in this state, since the restoring elasticity of the sandwiching bar portions 40b and 40b is constantly acting, the sandwiching bar portions 40b and 40b and the cutting acting portion 5b are always in contact with each other and are maintained in an electrically conductive state. At this solid line position, since the cut surface of the shaft portion 40a is in contact with the tongue piece portion 37b, the state of the solid line position is stably maintained due to the combined spring action of the tongue piece portion 37b. Also, when the electrode piece 40 is displaced to the two-dot chain line position, it can be easily returned to the solid line position by the spring action of the tongue piece 37b.

The cutting rotary tool 5 is held by the head unit 2 via the tool holding mechanism unit 28 and then used for tooth cutting enlargement treatment or root canal length measurement as described above. In the case of root canal length measurement, the cutting action portion 5b of the cutting rotary tool 5 is used as one electrode of the root canal length measuring circuit, and the electrode piece 40, the tongue piece 37b, the contact piece 37, the conductor 85, and the lead wire. One signal lead 8 for the root canal length measurement signal circuit is brought into electrical continuity through 83 and the like. Accordingly, the root canal length shown in FIG. 2 is shown in a state where the cutting rotary tool 5 is inserted into the tooth root canal as one electrode for measuring the root canal length and the oral electrode 19a is hooked on the patient's lip as the other electrode. The root canal length can be measured by driving the measurement circuit 12. As described above, if the cover member 36 of the first embodiment and the cover member 36 of the present embodiment are prepared with the former as the first cover member and the latter as the second cover member, the cutting to be used. These can be appropriately selected and used according to the type of the rotary tool 5, which is very convenient for the user.
Since other configurations in this embodiment are the same as those in the first embodiment, the same reference numerals are given to common portions, and descriptions thereof are omitted.

FIG. 9 shows a modification of the second embodiment shown in FIGS. In this embodiment, the electrode piece 38 as in the first embodiment is not necessarily required, and therefore the electrode piece 38 is removed in this example. As described above, even if the electrode piece 38 is removed, the basic effects in the second embodiment are exhibited.
Since other configurations are the same as those described above, the same reference numerals are assigned to the common portions, and the description thereof is omitted.

  In the above-described embodiment, the driving source of the cutting rotary tool 5 is a micromotor. However, the driving source is not limited to this, and a low-power air motor suitable for enlarging a root canal or other driving means may be used. Although illustration and explanation are omitted, in this type of handpiece (instrument), an air supply passage for cooling each mechanism portion, a light source and a light guide for irradiating the treatment tooth, A water injection pipe for injecting water into the teeth is also provided as necessary. Furthermore, although the example which provided the said recessed part 3a in the lower surface (the side from which the cutting rotary tool 5 protrudes) of the neck part 3 was shown, you may provide in the side surface of the neck part 3. FIG.

DESCRIPTION OF SYMBOLS 1 Dental root canal treatment handpiece 2 Head part 3 Neck part 3a Concave part 4 Grasping part 5 Cutting rotary tool 5b Cutting action part 29 Rotor (tool holding part)
36 Cover member (first and second cover members)
37 Contact piece 38 Electrode piece 40 Electrode piece 85 Conductor

Claims (4)

In a dental root canal treatment handpiece comprising a distal head part, a narrow neck part connected to the distal head part, and a grip part connected to the neck part and gripped by a finger,
The tip head part is internally provided with a tool holding part for detachably holding a cutting rotary tool so that the shaft can rotate,
The neck portion includes a built-in conductor for transmitting a root canal length measurement signal so that a part of the neck portion faces a recess formed from the outer periphery of the neck portion, and a cover member that is detachably fitted into the recess. And
When the cover member is fitted in the recess, the contact piece is brought into electrical contact with the conductor, and the electrode portion connected to the contact piece and brought into electrical conduction with the rotary tool. A dental root canal treatment handpiece comprising a piece. The dental root canal treatment handpiece according to claim 1,
The tool holding portion is made of a conductive member, and the electrode piece is integrally connected to the contact piece, is in contact with the outer peripheral surface of the tool holding portion, and is held by the tool holding portion via the tool holding portion. The cover member is configured to be in an electrically conductive state with the rotary tool, and the cover member has a shape that matches the outer shape of the neck portion in the vicinity of the recess when fitted into the recess. Dental root canal treatment handpiece characterized by. The dental root canal treatment handpiece according to claim 1,
The electrode piece is connected to the contact piece as a separate member, is swingably attached to the cover member, and rotates in contact with a cutting action portion of a rotary tool held by the tool holding portion. A dental root canal treatment handpiece configured to be in electrical communication with a tool. In a dental root canal treatment handpiece comprising a distal head part, a narrow neck part connected to the distal head part, and a grip part connected to the neck part and gripped by fingers,
The tip head part is internally provided with a tool holding part for detachably holding a cutting rotary tool so that the shaft can rotate,
The neck portion includes a built-in conductor for transmitting a root canal length measurement signal so that a part of the neck portion faces a recess formed from the outer periphery of the neck portion, and a cover member that is detachably fitted into the recess. And
When the cover member is fitted in the recess, the contact piece is brought into electrical contact with the conductor, and the electrode portion connected to the contact piece and brought into electrical conduction with the rotary tool. With a piece,
The cover member includes a first cover member configured such that the electrode piece is integrally connected to the contact piece and is in contact with the tool holding portion; and the electrode piece is connected to the contact piece as a separate member. And a second cover member configured to come into contact with the cutting action portion of the rotary tool.
A dental root canal treatment handpiece, wherein the first and second cover members can be selectively fitted and mounted in the recess.

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