Dental root canal treatment handpiece

Abstract

The present application provides a dental root canal treatment handpiece. The head (11) of the dental root canal treatment handpiece (100) is provided with: a contact (81) that contacts a base end side end surface (15a) of a dental treatment tool (15); a head cap (75) having an inner space in which the contact (81) is arranged; a first elastic member (83) that elastically applies a force to the contact (81) toward the dental treatment tool side; a ring-shaped member (79) that is arranged opposite the dental treatment tool side of the head cap (75); and a second elastic member (77) that is arranged between and in contact with both the head cap (75) and the ring-shaped member (79) and that elastically applies a force to the head cap (75). The ring-shaped member (79) is in conduction with a signal line (51), and the contact (81), the head cap (75), the second elastic member (77), and the ring-shaped member (79) each have electrical conductivity, and they form a conduction path (35) from the dental treatment tool (15) in this order.

Description

Technical Field

[0001] This invention relates to dental handpieces for root canal treatment. Background Technology

[0002] For example, Patent Documents 1 and 2 disclose dental handpieces for treating and measuring root canal length by cutting to enlarge the root canal of a tooth. The handpiece in Patent Document 1 uses a cutting tool such as a file as an electrode for measuring root canal length, allowing root canal treatment to be performed while measuring the root canal length. In this case, since the cutting tool is used as an electrode in the root canal length measuring circuit, a measurement signal needs to be transmitted from the handpiece side to the cutting tool. Therefore, a conductive path is provided that electrically connects the tool holding mechanism for holding the cutting tool and the root canal length measuring circuit.

[0003] Figure 15 The mobile phone shown in Patent Document 1 has a conductive path that connects a cutting tool 111 to a rotor 113 that holds the cutting tool 111, an electrode plate 117 having a clip-shaped electrode plate (brush) 115 that contacts the rotor 113, and a conductor 119 connected to the electrode plate 117. Furthermore, to ensure reliable contact between the cutting tool 111 and the rotor 113, a force is applied to the cutting tool 111 by a compression coil spring 121.

[0004] Furthermore, the mobile phone in Patent Document 2 also has the aforementioned conduction path. Figure 16 The mobile phone shown in Patent Document 2 has a conductive path that electrically connects a cutting tool 111 to a conductive spring 123 that contacts the base end face of the cutting tool 111 at one end, a pressing cover (headcap) 125 that contacts the other end of the conductive spring 123, a cover plate 127 that supports the pressing cover 125, and a head shell (holding part) 129 that fixes the cover plate 127.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2013-213

[0008] Patent Document 2: Description of Chinese Patent Application Publication No. 112618062

[0009] In the mobile phone described in Reference 1, the electrode piece 117 affects the circuit for measuring root canal length when it comes into contact with the tissues in the oral cavity. Therefore, a resin cover member 131 is attached to the outside to prevent contact with the tissues. However, the exposed cover member 131 reduces aesthetics. In addition, due to wear and tear from the use of the mobile phone, the electrode piece 117 and the like need to be replaced, which is a complicated and time-consuming operation.

[0010] In the mobile phone described in reference 2, the conduction spring 123 is in direct contact with the cutting tool 111. Therefore, the conduction spring 123 is prone to radial displacement due to the rotation and vibration of the cutting tool. Consequently, the contact state between the cutting tool and the conduction spring 123 becomes unstable, potentially affecting the circuit used for root canal length measurement. Furthermore, when wear occurs due to the wear of the conduction spring 123, the wear plate may become a cause of malfunction. Moreover, as the wear of the conduction spring 123 deepens, it needs to be replaced, but this replacement is time-consuming. Additionally, measuring current flows through the components that come into contact with the human body, such as the pressing cover 125, the cover plate 127, and the head shell 129. Therefore, the surfaces of these components need to be electrically insulated to prevent noise from being superimposed on the measuring signal. Summary of the Invention

[0011] Therefore, the object of the present invention is to provide a dental handpiece for root canal treatment that can maintain a good electrical connection for the conduction path of the circuit for measuring root canal length, and that allows for easy replacement of consumables without compromising the aesthetic appearance of the handpiece.

[0012] The present invention comprises the following components.

[0013] A dental endodontic handpiece includes: a head having a tool holding mechanism for holding a dental procedure tool in a rotatable manner; and a handle connected to the head, the handle having a built-in signal wire for transmitting a root canal length measurement signal. The dental endodontic handpiece forms a conductive path electrically connecting the dental procedure tool held in the tool holding mechanism to the signal wire.

[0014] The head has:

[0015] The contact point contacts the base-side end face of the dental treatment tool held in the tool holding mechanism;

[0016] The head cap has an inner space for the contacts to be configured to move axially toward the dental treatment tool;

[0017] A first elastic member is disposed in the inner space and elastically applies force to the contact towards the dental treatment tool side;

[0018] An annular member is disposed opposite the dental treatment tool side of the head cap; and

[0019] The second elastic member is disposed between the headgear and the annular member and in contact with both, and applies elastic force to the headgear.

[0020] The annular component is connected to the signal line.

[0021] The contacts, caps, second elastic members, and annular members, each having conductivity, form the conductive path from the dental treatment tool in such an order.

[0022] Invention Effects

[0023] According to the present invention, the electrical connection of the conduction path of the circuit for measuring root canal length can be maintained well, and consumables can be easily replaced in a manner that does not damage the aesthetic appearance of the mobile phone. Attached Figure Description

[0024] Figure 1 This is an overall view of the dental handpiece of the present invention.

[0025] Figure 2 It includes Figure 1 The diagram shown is a schematic block diagram of a dental medical device for mobile phones.

[0026] Figure 3 It is a simplified cross-sectional view showing the internal structure of a mobile phone.

[0027] Figure 4 This is an explanatory diagram showing the rotary drive mechanism of a dental treatment tool.

[0028] Figure 5 It is a partial assembly diagram showing the wires, retainer, and leaf spring.

[0029] Figure 6 This is a cross-sectional view of the main part of the head of the mobile phone.

[0030] Figure 7 yes Figure 6 The diagram shows a sectional perspective view of the head.

[0031] Figure 8 This is an enlarged sectional view of the upper part of the head.

[0032] Figure 9A It is an illustration showing the clamping action of the tool holding mechanism on the dental treatment tool in stages.

[0033] Figure 9B It is an illustration showing the clamping action of the tool holding mechanism on the dental treatment tool in stages.

[0034] Figure 9C It is an illustration showing the clamping action of the tool holding mechanism on the dental treatment tool in stages.

[0035] Figure 10 This is an explanatory diagram showing the assembly, including the cap and cap ring, being easily assembled and disassembled onto the head.

[0036] Figure 11 It is along Figure 10 The sectional view of the XI-XI line shown.

[0037] Figure 12 It is an exploded 3D view of the assembly.

[0038] Figure 13 It is a cross-sectional view showing the composition of the assembly of the modified example.

[0039] Figure 14 yes Figure 13 An exploded perspective view of the assembly shown.

[0040] Figure 15 It is a partial cross-sectional view showing the structure of a traditional mobile phone.

[0041] Figure 16 It is a partial cross-sectional view showing the structure of other previous mobile phones.

[0042] Explanation of reference numerals in the attached figures:

[0043] 11: Head; 13: Holding part; 14: Motor part; 15: Dental treatment tool; 15a: Abutment side face; 15b: Clamping groove; 15c: Step part; 21: Motor; 23: Drive part; 25: Oral electrode; 27: Root canal length measuring part; 29: Control part; 31: Setting part; 33: Display part; 35: Conduction path; 37: Rotating shaft; 39: Embedded member; 41: Bevel gear; 43: Tip rotating shaft; 45: Gear part; 47: Bevel gear; 49: Gear part; 51: Wire; 53: Retainer; 55: Leaf spring; 57: Holding part housing; 61: Tool holding mechanism; 63: Rotor part; 63a: Protrusion; 65: Chuck mechanism; 65a: Locking piece; 65b: Locking elastic member; 67A, 67B: Rolling bearings; 67a: End face; 69: Locking recess; 71: Head housing; 73: Cap ring; 73a: Inner circumferential surface; 73b: Small diameter stepped portion; 73c: External thread portion; 75, 75A: Head cap; 75a: Flange; 75b: Back side; 75c: Stepped portion; 75d: Opening hole; 75e: Inner circumferential surface; 75f: Annular locking portion; 76: Inner space; 77: Cap spring (second elastic member); 79: Annular structure Components; 79a: Circular part; 79b: Cylindrical part; 81: Contact; 81a: Thick-walled part; 83: Contact spring (first elastic member); 85: Cylindrical support part; 85a: Circular locking part; 85b: Fixing flange; 87: Outer ring; 87a: End face; 87b: Outer peripheral surface; 88: Inner ring; 89: Rotating body; 91, 91A: Assembly; 100: Dental root canal treatment handpiece. Detailed Implementation

[0044] Hereinafter, embodiments of the dental root canal treatment handpiece of the present invention will be described in detail with reference to the accompanying drawings.

[0045] Figure 1 This is an overall view of the dental handpiece 100 for root canal treatment according to the present invention. The dental handpiece 100 (hereinafter referred to as the handpiece) includes a head 11 and a gripping portion 13 and a motor portion 14 extending rearward from the head 11. The head 11 has a tool holding mechanism, detailed below, which allows for easy attachment and detachment of a dental treatment tool 15. The dental treatment tool 15, attached to the tool holding mechanism, is rotated by a drive source such as a motor built into the motor portion 14. In this configuration, a file (reamer) for root canal treatment is used as the dental treatment tool 15, but the type of dental treatment tool 15 is not limited to this.

[0046] Figure 2 It includes Figure 1The diagram shows a schematic block diagram of a dental medical device 200 with a mobile phone 100. The dental medical device 200 includes a mobile phone 100 with a built-in motor 21, a drive unit 23, an oral electrode 25, a root canal length measuring unit 27, a control unit 29, a setting unit 31, and a display unit 33.

[0047] Motor 21 drives the dental treatment tool 15, which is mounted on handpiece 100, to rotate. Drive unit 23 adjusts the voltage applied to motor 21 based on instructions from control unit 29.

[0048] An oral electrode 25 is attached to the patient's lip and electrically connected to a root canal length measuring unit 27. The root canal length measuring unit 27 uses the dental treatment tool 15 as one electrode and the oral electrode 25 as the other, applying a measuring voltage between the electrodes to measure the impedance between the dental treatment tool 15 and the oral electrode 25. This allows the control unit 29 to be notified of the tip position of the dental treatment tool 15 within the root canal. The handpiece 100 has a conductive path 35 that forms a pathway from the root canal length measuring unit 27 to one electrode, namely the dental treatment tool 15.

[0049] The control unit 29 is responsible for storing the set values ​​of the program, driving conditions, etc., and controlling each part according to the program. The control unit 29 consists of a computer with a processor, memory, storage, interface, etc., which are used to control the dental medical device 200 as a whole.

[0050] The setting unit 31 is responsible for setting the driving conditions (rotation direction, speed, rotation torque, etc.) of the motor 21 and the control mode. Examples of control modes include: a control mode that reverses the motor 21 after the driving torque of the motor 21 reaches the set torque in order to prevent the file used as a dental treatment tool 15 from breaking; and a control mode that automatically stops (or reverses) the rotation of the motor 21 after the file reaches the root tip in order to avoid penetrating the root tip.

[0051] The display unit 33 displays various information such as the driving conditions of the motor 21, the rotational speed of the motor 21 during treatment, and the position of the tip of the file in the root canal.

[0052] Figure 3 This is a schematic cross-sectional view showing the internal structure of mobile phone 100. Figure 4 This is an explanatory diagram showing the rotary drive mechanism of the dental treatment tool 15. Figure 3 The gripping part 13 of the mobile phone 100 shown, although details omitted, is related to the motor 21 ( Figure 2The rotating shaft 37, which transmits the rotational force, is rotatably supported on the embedded member 39. The rotational force is transmitted from the bevel gear 41 provided on the rotating shaft 37 to the top rotating shaft 43 via a gear portion 45 provided at one end of the top rotating shaft 43. Furthermore, as... Figure 4 As shown, the rotational force transmitted to the top rotating shaft 43 is transmitted via a bevel gear 47 located at the other end of the top rotating shaft 43 to a gear portion 49 that is coaxially supported with the dental treatment tool 15. In this way, the dental treatment tool 15 is driven to rotate by the rotational force from the motor 21.

[0053] A conduction path 35 is formed inside the gripping part 13 along the aforementioned rotational force transmission path. For example... Figure 3 As shown, the guide path 35 is disposed inside the holding housing 57, including one end connected to the root canal length measuring part 27. Figure 2 The wire (signal line) 51 is embedded in a metal member 39 in an electrically conductive state. The other end of the wire 51 is fixed to a retainer 53 located near the head 11 and is electrically conductive with the retainer 53.

[0054] Figure 5 This is a partial assembly diagram showing the wire 51, retainer 53, and leaf spring 55. The retainer 53 is annular with a large diameter portion and a small diameter portion. The wire 51 is fixed to a notch 53a formed on a portion of the outer peripheral surface of the large diameter portion. A flat surface 53b is formed on a portion of the outer peripheral surface of the small diameter portion, and the conductive leaf spring 55 is fixed to this flat surface 53b. The leaf spring 55 contacts the component on the head 11 side (described later), causing the conduction path 35 to extend toward the dental treatment tool 15.

[0055] Next, the composition of head 11 will be explained.

[0056] Figure 6 This is a cross-sectional view of the main part of the head 11 of mobile phone 100. Figure 7 yes Figure 6 The diagram shows a sectional perspective view of the head 11. In the following description, the insertion direction of the dental treatment tool 15 when it is attached to the head 11 is also referred to as the "up-down direction" or "insertion direction", the front of the insertion direction is also referred to as "above" or "base side", and the rear of the insertion direction is also referred to as "below" or "top side".

[0057] The head 11 has a tool holding mechanism 61 for holding the dental treatment tool 15. The tool holding mechanism 61 includes: a hollow cylindrical rotor portion 63 for inserting the dental treatment tool 15; a chuck mechanism 65 disposed above the rotor portion 63; and rolling bearings 67A and 67B supporting the rotor portion 63 for free rotation. The rotor portion 63 is concentrically arranged with the gear portion 49 and rotates integrally with the gear portion 49. The chuck mechanism 65 includes: a locking piece 65a inserted into a locking recess 69 formed radially recessed on the side of the base end of the dental treatment tool 15; and a locking elastic member 65b, such as a C-shaped retaining ring, fitted to the outer periphery of the locking piece 65a. The locking elastic member 65b elastically applies force to the locking piece 65a radially inward. This locking elastic member 65b is not limited to a C-shaped retaining ring; it can also be other components such as a helical spring disposed radially outside the locking piece 65a to apply force to the locking piece 65a radially inward. The locking piece 65a is inserted into the locking recess 69, and the locking piece 65a is locked in the locking recess 69, which prevents the dental treatment tool 15 from falling off the rotor portion 63. The rotor portion 63 is supported by a pair of rolling bearings 67A, 67B arranged at intervals in the vertical direction of the dental treatment tool 15, and is rotatable relative to the head housing 71 covering the outer periphery of the head 11.

[0058] The head housing 71 has an opening at the top, through which a cap ring 73 is fitted. The cap ring 73 integrally holds the head cap 75, the cap spring (second elastic member) 77, and an annular member 79 that serves as a receiver for the cap spring 77. The annular member 79 is positioned opposite the dental treatment tool 15 side of the head cap 75. The head cap 75 has a contact 81 and an inner space 76 that accommodates the contact spring (first elastic member) 83 and the cylindrical support 85, arranged to cover the cylindrical end of the cylindrical support 85 opposite to the dental treatment tool 15. The cap spring 77 applies force to the cylindrical support 85 and the head cap 75 toward the side opposite to the dental treatment tool 15. The cap spring 77 and the contact spring 83 are preferably metal coil springs, but other elastic members may also be used. In particular, the contact spring 83, by adopting a wave spring structure in which the entire spring uniformly bears the load, can make the upper and lower surfaces of the contact 81 in the thickness direction displace with high parallelism, which can improve the contact stability between the contact 81 and the dental treatment tool 15, and is therefore preferred.

[0059] Figure 8 This is an enlarged sectional view of the upper part of head 11. Figure 8 In the diagram, only the components that form the described conductive path 35 are marked with a shaded line.

[0060] By pressing down the cap 75, as detailed below, the clamping action of the chuck mechanism 65 on the dental treatment tool 15 is released. The cap 75, viewed from above, is a circular release button, and its vertical cross-section is shaped like a hat with an upward protrusion. An annular flange 75a protruding radially outward is formed at the bottom of the cap 75. Furthermore, a small-diameter stepped portion 73b protruding radially inward is formed on the upper part of the inner circumferential surface 73a of the cap ring 73. Thus, the cap 75 can move vertically along the inner circumferential surface 73a of the cap ring 73, and is prevented from falling off the cap ring 73 by the flange 75a abutting against the small-diameter stepped portion 73b.

[0061] The contact 81 is disposed within the internal space 76 formed in the cap 75 in a manner movable axially toward the dental treatment tool 15. The lower side of the contact 81 abuts against the base end face 15a of the dental treatment tool 15 held in the tool holding mechanism 61. The contact 81 is circular when viewed from above, and has a thick-walled portion 81a protruding toward the dental treatment tool 15 at its center. The lower surface of the thick-walled portion 81a can be a flat surface or a convex curved surface protruding downward. The contact between the base end face 15a of the dental treatment tool 15 and the contact 81 is a contact between a convex curved surface and a flat surface or a contact between convex curved surfaces, thereby ensuring conductivity and reducing frictional resistance generated by the rotation of the dental treatment tool 15.

[0062] The cylindrical support portion 85 is a cylindrical member whose inner circumferential surface contacts the outer periphery of the contact 81. The cylindrical support portion 85 supports the contact 81 so that it can move axially toward the dental treatment tool 15. An annular locking portion 85a protruding radially inward is provided at the lower end of the cylindrical support portion 85 to prevent the contact 81 from leaving the cylindrical support portion 85. In addition, a contact spring 83 is disposed inside the cylindrical support portion 85, from the upper end of the cylindrical support portion 85 to the contact 81. One axial end of the contact spring 83 abuts against the back side of the inner space 76 side of the cap 75, and elastically applies force to the contact 81 toward the dental treatment tool 15.

[0063] A fixing flange 85b protruding radially outward is provided on the outer periphery of the cylindrical support portion 85. The fixing flange 85b is embedded in a stepped portion 75c formed at the bottom of the cap 75. The lower surface of the fixing flange 85b contacts a cap spring 77. The cap spring 77 is disposed between the cap 75, the cylindrical support portion 85, and the annular member 79. The annular member 79 has: a flat circular portion 79a having a predetermined radial width; and a cylindrical portion 79b extending downward from the outer periphery of the circular portion 79a in a manner orthogonal to the circular portion 79a. In the annular member 79, the cap spring 77 is pressed against the upper surface of the circular portion 79a, and the lower surface of the circular portion 79a abuts against the end face 87a of the outer ring 87 of the rolling bearing 67A. Furthermore, the cylindrical portion 79b covers the outer peripheral surface 87b of the outer ring 87.

[0064] The cap spring 77 applies an elastic force to the cap 75 upwards via the fixing flange 85b of the cylindrical support portion 85. The cap spring 77 is compressed when the user presses the cap 75 downwards, generating an elastic force that pushes the cap 75 back upwards in the opposite direction to the pressing direction.

[0065] The aforementioned contact 81, cylindrical support 85, cap spring 77, and annular member 79 are all conductive. These members can be made of, for example, a metallic material, or they can be members with a conductive layer formed on their surface. Furthermore, the aforementioned leaf spring 55 presses against the lower end of the cylindrical portion 79b of the annular member 79, and the annular member 79 and the leaf spring 55 are connected.

[0066] Figures 9A to 9C This is an explanatory diagram illustrating the phased clamping actions performed by the tool holding mechanism 61 on the dental treatment tool 15. (See diagram for example.) Figure 9A As shown, when the dental treatment tool 15 is not clamped, the contact 81 is elastically forced downward by the contact spring 83 inside the cylindrical support portion 85, and the outer periphery of the contact 81 is pressed against the annular locking portion 85a. Thus, the contact 81 is locked at the lowest position of its movable range within the cylindrical support portion 85. Furthermore, the locking piece 65a of the chuck mechanism 65 is radially inwardly forced by the locking elastic member 65b, resulting in a state where it protrudes radially inward from the inner periphery of the rotor portion 63.

[0067] When the dental treatment tool 15 is inserted from below the rotor 63 in this state, as Figure 9B As shown, the base-side end face 15a of the dental treatment tool 15 abuts against the locking piece 65a of the chuck mechanism 65. When the dental treatment tool 15 is pushed further upward, the base-side end face 15a and the locking piece 65a slide against each other, and the locking piece 65a moves radially outward.

[0068] Then, as Figure 9C As shown, when the dental treatment tool 15 is pushed further upward, the locking piece 65a moves radially inward and engages in the locking groove 15b of the dental treatment tool 15. Furthermore, the base end face 15a of the dental treatment tool 15 contacts the thick-walled portion 81a of the contact 81, thereby pushing the contact 81 upward. The insertion of the dental treatment tool 15 into the rotor portion 63 continues until the radially inward recessed step portion 15c of the dental treatment tool 15 abuts against the radially inward protrusion 63a of the rotor portion 63.

[0069] like Figure 8As shown, when the dental treatment tool 15 is held in the tool holding mechanism 61 of the head 11 according to the above process, a conduction path 35 is formed from the dental treatment tool 15 to the wire 51. That is, the base end face 15a of the dental treatment tool 15 is in communication with the thick wall portion 81a of the contact 81 (arrow D1), and the outer periphery of the contact 81 is in communication with the inner periphery of the cylindrical support portion 85 (arrow D2). The fixing flange 85b (or the annular locking portion 85a) of the cylindrical support portion 85 is in communication with the cap spring 77 (arrow D3), and the cap spring 77 is in communication with the annular portion 79a of the annular member 79 (arrow D4). Furthermore, the lower end of the cylindrical portion 79b of the annular member 79 is in communication with the leaf spring 55 (arrow D5). The leaf spring 55 is in communication with the retainer 53 (arrow D6) and with the wire 51 (arrow D7). This creates a conductive path 35 from the dental treatment tool 15 to the wire 51.

[0070] The aforementioned conduction path 35 is disposed inside the cap 75, cap ring 73, and head shell 71 and is not exposed on the outer surface of the head 11. In addition, the leaf spring 55, retainer 53, and wire 51 that form the conduction path 35 are also disposed inside the grip housing 57 and are not exposed on the outer surface of the grip 13.

[0071] Other components in contact with the aforementioned conduction path 35, such as the head cap 75, cap ring 73, head housing 71, and grip housing 57, are made of electrically insulating resin materials or have insulating coatings on their surfaces, thereby preventing noise superposition and other interference from the conduction path 35. It should be noted that the annular member 79 abuts against the outer ring 87 of the rolling bearing 67A, but the annular member 79 is kept electrically insulated relative to the inner ring 88. That is, lubricant is applied between the rotating surfaces of the outer ring 87 and the inner ring 88 and the rotating body (ball) 89, and the outer ring 87 and inner ring 88 are insulated from each other by the lubricant.

[0072] Thus, the internal conductive path 35 of the handpiece 100 is configured to be electrically insulated from the external environment of the handpiece 100. As a result, when using the handpiece 100, the internal conductive path 35 is not directly connected to the user and patient, and it does not affect the circuitry used for root canal length determination.

[0073] Figure 10 This is an explanatory diagram showing the assembly 91, including the cap 75 and the cap ring 73, being easily assembled and disassembled onto the head 11. Figure 11 It is along Figure 10 The sectional view of the XI-XI line shown. Figure 12 This is an exploded perspective view of assembly 91.

[0074] like Figure 10As shown, assembly 91 can be detached from head 11. Assembly 91 can be separated from head 11 while remaining as a single unit, and the detached assembly 91 is easy to operate. Figure 11 , Figure 12 As shown, the assembly 91 integrally includes a cap 75, a cap spring 77, an annular member 79, and a cap ring 73. The inner space 76 of the cap 75 accommodates a contact 81, a contact spring 83, and a cylindrical support 85.

[0075] In this configuration, an external thread 73c is formed on the outer periphery of the lower end of the cap ring 73, and an internal thread 71a is formed on the inner periphery of the upper opening of the grip housing 57. The assembly 91 is fixed to the head 11 (see reference) by the engagement of the external thread 73c and the internal thread 71a. Figure 8 The annular member 79 contacts the leaf spring 55 at the lower end of the cylindrical portion 79b, so the annular member 79 can reliably communicate with the leaf spring 55 regardless of the rotation stop position of the assembly 91 when it is threaded onto the head 11. Furthermore, the method of fixing the assembly 91 relative to the head 11 is not limited to the aforementioned threaded fastening; a well-known locking mechanism can also be used.

[0076] The assembly 91, as shown Figure 11 The contact 81 and contact spring 83 are inserted in sequence from the upper opening opposite to the annular locking portion 85a of the cylindrical support portion 85. Then, the upper opening of the inserted cylindrical support portion 85 is covered by a cap 75, whereby the contact 81 and contact spring 83 are accommodated in the inner space 76 of the cap 75. Furthermore, the cap 75 and cap spring 77 are inserted from the lower opening of the cap ring 73. The annular member 79 is further inserted from the annular portion 79a, whereby the cap 75 is forcefully pushed upwards via the cylindrical support portion 85 by the elastic force of the cap spring 77. Thus, the cap 75 is supported on the cap ring 73 in a manner that allows it to be pressed in relative to the cap ring 73.

[0077] The dental treatment tool 15, which rotates and contacts components such as the contact 81, contact spring 83, and cap spring 77, are consumables that wear out and deteriorate due to use of the handpiece 100 and need to be replaced at specified intervals. Previously, this replacement process involved disassembling the handpiece 100 to replace smaller consumables, a cumbersome procedure. However, in this handpiece 100 configuration, replacement is accomplished simply by removing the assembly 91, which integrates all the consumables, from the head 11 and inserting a new assembly 91 into the head 11. Furthermore, because replacement is performed on an assembly-by-assembly basis, the user does not need to manually insert small consumables such as the contact 81 into designated positions, making handpiece maintenance easier.

[0078] Figure 13This is a cross-sectional view showing the configuration of the modified assembly 91A. Figure 14 yes Figure 13 An exploded perspective view of the assembly 91A is shown. In this modified example, the assembly 91A has an opening 75d formed at the top of the cap 75A, and a cover 93 is attached to the opening 75d in a detachable manner. Furthermore, the contact 81 is supported so that it can move vertically along the inner circumferential surface 75e of the cap 75A. Moreover, the contact 81 is prevented from falling off by an annular locking portion 75f protruding radially inward from the lower end of the inner circumferential surface 75e.

[0079] The cover 93 is fixed to the cap 75A by screwing an internal thread formed on the inner circumferential surface of the opening 75d with an external thread formed on the outer circumferential surface 93a of the cover 93. Furthermore, a groove 93b is formed on the top surface of the cover 93, allowing the cover 93 to be removed from the cap 75A by inserting a tool such as a screwdriver into the groove 93b and rotating it. The cover 93 can be fixed by threads as described above, but it can also be fixed by other methods such as a snap-fit ​​mechanism.

[0080] According to the assembly 91A of this configuration, the contact 81 and contact spring 83 can be easily replaced by removing the cover 93 from the cap 75A, thereby further improving maintainability. Furthermore, the aforementioned cylindrical support portion 85 (see reference) can be omitted. Figure 11 ).

[0081] The conduction path 35 in the assembly 91A is a path in which the base side face of a dental treatment tool (not shown) contacts the contact 81, the outer periphery of the contact 81 contacts the cap 75A, and further contacts the annular portion 79a of the annular member 79 via the cap spring 77. In this case, it is preferable to provide an insulating layer on the outer surface of the cap 75 that is touched by the user.

[0082] This invention is not limited to the embodiments described above, and can be appropriately modified or improved. Furthermore, the material, shape, size, value, form, quantity, and arrangement of the constituent elements in the above embodiments are arbitrary and not limited, as long as they achieve the purpose of this invention.

[0083] As stated above, the following matters are disclosed in this specification.

[0084] (1) A dental handpiece for root canal treatment, comprising: a head having a tool holding mechanism for holding a dental treatment tool in a rotatable manner; and a grip portion connected to the head, the grip portion having a built-in signal wire for transmitting a root canal length measurement signal, wherein the dental handpiece has a conductive path electrically connecting the dental treatment tool held in the tool holding mechanism to the signal wire, wherein...

[0085] The head has:

[0086] The contact point contacts the base-side end face of the dental treatment tool held in the tool holding mechanism;

[0087] The head cap has an inner space for the contacts to be configured to move axially toward the dental treatment tool;

[0088] A first elastic member is disposed in the inner space and elastically applies force to the contact towards the dental treatment tool side;

[0089] An annular member is disposed opposite the dental treatment tool side of the head cap; and

[0090] The second elastic member is disposed between the headgear and the annular member and in contact with both, and applies elastic force to the headgear.

[0091] The annular component is connected to the signal line.

[0092] The contacts, caps, second elastic members, and annular members, each having conductivity, form the conductive path from the dental treatment tool in such an order.

[0093] According to this dental root canal treatment handpiece, by having the dental treatment tool abut against the contact point forceped by the first elastic member, poor contact caused by vibrations generated during the rotation of the dental treatment tool can be prevented, thereby stably extracting the root canal length measurement signal.

[0094] (2) The dental handpiece for root canal treatment as described in (1), wherein,

[0095] The cap has a cylindrical support portion disposed within the inner space. This cylindrical support portion contacts the contact within the cylinder and supports the contact for axial movement toward the dental treatment tool. The cylindrical support portion forms the conduction path.

[0096] The first elastic member applies an elastic force to the contact point towards the dental treatment tool within the cylindrical support portion.

[0097] The second elastic member is configured to contact the cylindrical support portion in place of the head cap.

[0098] According to this dental handpiece for root canal treatment, the communication path is constructed by connecting the contact, cylindrical support, second elastic member, and annular member located on the inner side of the head to the signal line, thus the communication path is not exposed on the outside of the handpiece. Therefore, the user and patient will not cause electrical signal interference to the communication path.

[0099] (3) The dental handpiece for root canal treatment as described in (1) or (2), wherein,

[0100] The tool holding mechanism has:

[0101] A locking tab is movable between an engaged position and an unengaged position, wherein the engaged position is when the locking tab is inserted into a notch formed in a portion of the periphery of the dental instrument, and the unengaged position is when the locking tab is withdrawn from the notch; and

[0102] A locking elastic member applies force to the locking piece from the disengaged position toward the engaged position.

[0103] The engagement position is the position where the base side face of the dental treatment tool pushes the contact back along the axial direction, causing the contact to retract.

[0104] According to this dental handpiece for root canal treatment, when the dental instrument and locking clip are clamped together, the dental instrument and the contact point make contact while being stressed by the first elastic member. This ensures reliable contact between the dental instrument and the contact point.

[0105] (4) A dental handpiece for root canal treatment according to any one of (1) to (3), wherein,

[0106] The contact surface of the probe that contacts the base-side end face of the dental treatment tool is a flat surface or a convex curved surface protruding toward the base-side end face.

[0107] According to this dental handpiece for root canal treatment, friction between the base side face and the contact point of the dental treatment tool can be reduced.

[0108] (5) A dental handpiece for root canal treatment according to any one of (1) to (4), wherein,

[0109] The first elastic member and the second elastic member are helical springs.

[0110] According to this dental handpiece for root canal treatment, the elastic force can be stably obtained under a large range of elastic displacement through the extension and contraction of the coil spring, and a certain elastic force can be maintained even when wear occurs.

[0111] (6) A dental handpiece for root canal treatment according to any one of (1) to (5), wherein,

[0112] The first elastic component is a wave spring.

[0113] According to this dental handpiece for root canal treatment, it will improve the parallelism of the contact tip, thereby improving the contact stability between the contact tip and the dental treatment tool.

[0114] (7) The dental handpiece for root canal treatment according to any one of (1) to (6) comprises:

[0115] A retainer, provided on the holding portion, holds the signal line; and

[0116] A leaf spring protrudes from the retainer toward the head.

[0117] The leaf spring comes into contact with the annular member and is elastically stressed.

[0118] According to this dental handpiece for root canal treatment, the leaf springs are elastically stressed by the annular members, so that their mutual contact is reliable and can stably maintain good conductivity.

[0119] (8) A dental handpiece for root canal treatment according to any one of (1) to (7), wherein,

[0120] The outermost surfaces of the head and the gripping part are formed of an electrically insulating resin material or an electrically insulating layer.

[0121] According to this dental handpiece for root canal treatment, even if the user or patient touches the head or the handle, the conductive path will not be affected because the outermost surface of the head and the handle is electrically insulated.

[0122] (9) A dental handpiece for root canal treatment according to any one of (1) to (8), wherein,

[0123] The head includes an assembly having:

[0124] The cap holds the contact and the first elastic member in place;

[0125] The second elastic member;

[0126] The annular member; and

[0127] The cap ring secures the cap, the second elastic member, and the ring-shaped member together.

[0128] The assembly is secured in a manner that allows it to be easily attached to and detached from the head body other than the assembly itself.

[0129] According to this dental root canal treatment handpiece, the consumables that need to be replaced are constructed as an integral assembly, so the consumables can be easily replaced by swapping the assembly. Furthermore, there is no need to configure a cover to expose the outer surface of the handpiece, thus preserving the handpiece's aesthetic appearance.

[0130] (10) The dental handpiece for root canal treatment as described in (9), wherein,

[0131] The assembly is secured to the head body by the cap ring thread.

[0132] According to this dental root canal treatment handpiece, the cap ring is fastened to the head body by easily detachable screws, thereby allowing the assembly to be easily fixed or removed from the head body.

[0133] (11) The dental handpiece for root canal treatment as described in (9), wherein,

[0134] The cap has an opening at the top, through which a cover is attached in a detachable manner.

[0135] According to this dental handpiece for root canal treatment, the contacts and contact springs can be easily replaced by removing the cap, thereby further improving maintainability.

Claims

1. A dental handpiece for root canal treatment, comprising: a head having a tool holding mechanism for holding a dental treatment tool in a rotatable manner; and a grip portion connected to the head, the grip portion having a built-in signal wire for transmitting a root canal length measurement signal, wherein the dental handpiece for root canal treatment forms a conductive path electrically connecting the dental treatment tool held in the tool holding mechanism to the signal wire, wherein, The head has: The contact point contacts the base-side end face of the dental treatment tool held in the tool holding mechanism; The head cap has an inner space for the contacts to be configured to move axially toward the dental treatment tool; A first elastic member is disposed in the inner space and elastically applies force to the contact towards the dental treatment tool side; A ring-shaped member is disposed opposite the dental treatment tool side of the head cap; as well as The second elastic member is disposed between the headgear and the annular member and in contact with both, and applies elastic force to the headgear. The annular component is connected to the signal line. The contacts, caps, second elastic members, and annular members, each having conductivity, form the conductive path from the dental treatment tool in such an order.

2. The dental handpiece for root canal treatment according to claim 1, wherein, The cap has a cylindrical support portion disposed within the inner space. This cylindrical support portion contacts the contact within the cylinder and supports the contact for axial movement toward the dental treatment tool. The cylindrical support portion forms the conduction path. The first elastic member applies an elastic force to the contact point towards the dental treatment tool within the cylindrical support portion. The second elastic member is configured to contact the cylindrical support portion in place of the head cap.

3. The dental handpiece for root canal treatment according to claim 1, wherein, The tool holding mechanism has: A locking tab is movable between an engaged position and an unengaged position, wherein the engaged position is when the locking tab is inserted into a notch formed on a portion of the periphery of the dental instrument, and the unengaged position is when the locking tab is withdrawn from the notch; and A locking elastic member applies force to the locking piece from the disengaged position toward the engaged position. The engagement position is the position where the base side face of the dental treatment tool pushes the contact back along the axial direction, causing the contact to retract.

4. The dental handpiece for root canal treatment according to claim 1, wherein, The contact surface of the probe that contacts the base-side end face of the dental treatment tool is a flat surface or a convex curved surface protruding toward the base-side end face.

5. The dental handpiece for root canal treatment according to claim 1, wherein, The first elastic member and the second elastic member are helical springs.

6. The dental handpiece for root canal treatment according to claim 1, wherein, The first elastic component is a wave spring.

7. The dental handpiece for root canal treatment according to claim 1, comprising: A retainer, provided on the holding portion, holds the signal line; and A leaf spring protrudes from the retainer toward the head. The leaf spring comes into contact with the annular member and is elastically stressed.

8. The dental handpiece for root canal treatment according to claim 1, wherein, The outermost surfaces of the head and the gripping part are formed of an electrically insulating resin material or an electrically insulating layer.

9. The dental handpiece for root canal treatment according to any one of claims 1 to 8, wherein, The head includes an assembly having: The cap holds the contact and the first elastic member in place; The second elastic member; The annular component; as well as The cap ring secures the cap, the second elastic member, and the ring-shaped member together. The assembly is secured in a manner that allows it to be easily attached to and detached from the head body other than the assembly itself.

10. The dental handpiece for root canal treatment according to claim 9, wherein, The assembly is secured to the head body by the cap ring thread.

11. The dental handpiece for root canal treatment according to claim 9, wherein, The cap has an opening at the top, through which a cover is attached in a detachable manner.

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