JP3283181B2 - Root canal forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a root canal forming apparatus in the field of dental care, and more particularly to a root canal forming apparatus capable of automating a root canal forming procedure.

[0002]

2. Description of the Related Art The treatment of root canal formation in dental practice is as follows.
A cutting tool such as a file or a reamer is attached to the head of the handpiece and inserted into the root canal while driving this with a motor or an ultrasonic vibrator. It is performed manually, and the insertion amount is determined by the operator. As described above, root canal formation is an area where automation is delayed, and the procedure requires skill and sufficient attention, requires a long working time, and the operator's fatigue after root canal formation is extremely severe. Was.

In order to solve this problem, a root canal length measuring function is added to a root canal forming apparatus, and a root canal is formed while measuring a root canal length by using a cutting tool also as a measuring needle. There is known a tool in which cutting is automatically stopped when a tip of a tool reaches a set position such as an apex. However, even in these devices, the insertion of the cutting tool itself is a manual operation, and it is far from fully automated root canal formation.

[0004] For example, Japanese Patent Application Laid-Open No. 8-38510 discloses a root canal forming apparatus having such a root canal length measuring function, in which a measuring needle and an oral electrode arranged in a patient's oral cavity are connected. Apply the measurement voltage during the period, detect the tip position of the cutting tool from the change characteristic of the impedance obtained between both electrodes, and automatically stop or reverse the cutting tool when the cutting tool reaches the set position I have. Further, in other prior arts, there is a technique in which an output signal corresponding to the impedance is differentiated to detect a point at which the impedance change becomes maximum. It ’s difficult to keep the speed constant,
The output signal has not only a change in impedance but also a change in insertion speed superimposed thereon. Therefore, accurate measurement cannot be performed, and this problem needs to be solved for practical use.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of these points, and has been made to improve the safety and operability while enabling the operation of a root canal forming apparatus to be automated.

[0006]

In order to achieve the above object, a root canal forming apparatus according to the present invention uses a cutting drive attached to a tip of a holder and inserted into the root canal by a cutting drive unit. In a root canal forming apparatus that drives and performs root canal formation,
An automatic feed mechanism is provided for automatically moving the reference position of the cutting tool with respect to the holder in the axial direction of the cutting tool.

This apparatus can be provided with means for sequentially detecting the load in order to control the automatic feed mechanism and the cutting drive in accordance with the magnitude of the load applied to the cutting tool during operation. When the load when moving in the apical direction reaches a preset reference value, control is performed to stop movement by the automatic feed mechanism or reverse the direction of movement, or to stop the cutting tool. Control is performed. In addition, it is possible to control to automatically repeat the movement of the cutting tool in the apical direction and the movement in the crown direction. In this case, the amount of movement in the apical direction and the amount of movement in the crown direction can be reduced. It is configured so that each can be set independently. The moving direction of the cutting tool is appropriately displayed on a display as information for an operator or the like.

[0008] As a motor for feeding the cutting tool in the root canal forming apparatus, for example, a pulse motor can be used.

In the above apparatus, the cutting tool also serves as a measuring needle for measuring the root canal length, and the automatic feeding mechanism can be controlled according to the measured data of the root canal length. That is, as is well known, the position of the tip of the measuring needle and the measurement data obtained by the measurement have a substantially constant correspondence relationship. Therefore, for example, a value corresponding to a desired position such as the apex is set in advance, and the automatic feeding is performed. When the measurement data of the root canal length when the cutting tool is moved in the apical direction by the mechanism reaches the set value, the movement is stopped or the moving direction is reversed.

The position of the tip of the measuring needle can be detected from a change in the measurement data of the root canal length accompanying the movement. Therefore, the root canal length measurement operation is automatically performed each time the cutting tool moves a preset distance in the apical direction, and based on the result, the tip position of the measuring needle is detected to stop the above-described feed. And control such as inversion. In the present invention, since the cutting tool can be moved at an arbitrary constant speed, the cutting tool may be measured every time a predetermined time elapses instead of every time the set distance is moved.

For the measurement accompanying this movement, comparison data obtained by comparing the previous measurement data with the current measurement data can be used, and in addition to this comparison data, the current measurement data can also be used. In the latter case, the detection accuracy can be improved by the amount of data used.

Further, according to the present invention, the cutting drive unit can be controlled in accordance with the measured data of the root canal length. That is, a value corresponding to a desired position such as an apex is set in advance similarly to the case where the automatic feed mechanism is controlled by the above-described root canal length measurement data, and the cutting tool is moved in the apical direction. When the measured data of the root canal length at the time reaches the set value, the cutting is stopped by stopping the cutting tool, reducing the driving force, or reversing the rotation direction.

Further, the measured data of the root canal length can be appropriately displayed as information for an operator or the like as well as used for automatic control as described above.

As the measurement data of the root canal length, one type of measurement voltage was applied between a cutting tool which also serves as a measuring needle inserted into the root canal and an oral electrode arranged in a patient's mouth. The value obtained from the impedance response value in the case or the value obtained from the difference or ratio of each impedance response value when two types of measurement voltages are applied is used. In the present invention, these measurement data are used. It is configured to control one or both of the automatic feed mechanism and the cutting drive unit in accordance with any one or combination of the above.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to illustrated examples. 1 is a block diagram showing the overall circuit configuration, FIG. 2 is a diagram showing an example of a motor controller circuit, FIG. 3 is a diagram showing an example of a root canal length measurement circuit, and FIG. 4 is a structure of a head having an automatic feed mechanism. FIG. 5 is a flowchart showing an example of the control procedure.

In FIG. 1, 1 is a tooth, 1a, 1b and 1c are root canals, apical and crown portions of the tooth 1, 2 is a file serving as both a cutting tool and a needle for measuring root canal length, and 3 is a file. An oral electrode for root canal length measurement, 4 is a handpiece, and 5 is a head at the tip of the handpiece. The handpiece 4 is provided with an automatic feed mechanism 7 including a feed motor 7a, in addition to a cutting drive unit 6 including a cut motor 6a. 8
Is a control device main body, 9 is a foot pedal, and the control device main body 8 is, for example, a control unit 11 using a microcomputer, a motor controller 12, a root canal length measuring circuit 13, which will be described later. A setting unit 14 for performing setting operations for various kinds of control, a display 15,
A memory 16 and the like are provided.

The cutting motor 6a and the feed motor 7a are connected to a motor controller 12, one output terminal of the root canal length measuring circuit 13 is connected to the file 2 via a contact 13a, and the other output terminal is connected to the file 2. It is used by being connected to the oral electrode 3. In addition, the foot pedal 9 is connected to the control unit 11, and as described later, the cutting motor 6a and the feed motor 7a are driven by operating the foot pedal 9, and various operations such as measurement of the root canal length are set. The setting is performed in accordance with the setting contents of the unit 14.

A DC motor is used as the cutting motor 6a of the cutting drive unit 6, and a pulse motor is used as the feed motor 7a of the automatic feed mechanism 7, and the motor controller 12 has a control unit 11 A DC output circuit that outputs a predetermined drive voltage to the cutting motor 6a based on a command, and a pulse output circuit that outputs a predetermined drive voltage to the feed motor 7a are provided. Although the mechanism becomes complicated, a single motor may be used as the cutting motor and the feed motor in some cases.

The motor controller 12 includes a cutting motor 6
A function for detecting the load torque of a is provided, and a circuit as exemplified in FIG. 2 is employed as a DC output circuit for the cutting motor 6a, for example. That is, the power transistor T1 is connected in series to the cutting motor 6a, and the energizing state of the power transistor T1 is controlled by the driver circuit D1 to adjust the motor current, and the load torque during cutting flows to the resistor R1. It is detected from the magnitude of the motor current.

As a method of measuring the root canal length, a measurement voltage is applied between a measuring needle inserted into a root canal of a tooth and an oral electrode arranged in the oral cavity, and the root canal is determined from an obtained impedance response value. One that calculates the length is known. For example, Japanese Patent Publication No. 62-25381 discloses a simple correspondence method for calculating the tip position of a measuring needle from an impedance response value with respect to a resistance value or the like obtained using one type of measured voltage.

For example, Japanese Patent Publication No. 62-2817 or Japanese Patent Application Laid-Open No. 4-64354 discloses that at least two kinds of measurement voltages having different frequencies are used and each impedance response value obtained for each measurement voltage is compared. A comparison method for calculating the position of the tip of the measurement needle from a value obtained from the difference or ratio is disclosed. FIG. 3 shows a basic configuration of a root canal length measuring circuit according to a comparison method. Signals of frequencies f1 and f2 output from oscillators OS1 and OS2 are added by an adder A and applied to a measuring needle F. Then, the impedance response voltages generated in the resistors R are respectively converted into shaping circuits L1
Then, after shaping by L2, comparison data is obtained by the comparison circuit C to obtain measurement data.

Each of the above methods has its own features. That is, for example, the simple response method using only the measurement voltage of 400 Hz cannot perform accurate measurement when the inside of the root canal is wet, and the comparison method using the measurement voltage of 400 Hz and 8000 Hz has an impedance response value near the apex, for example. Since both change rapidly, it is effective to use both methods in order to improve the measurement accuracy. Therefore, it is desirable to be able to select whether to use only the simple correspondence method, only the comparison method, or a combination thereof. An operation unit for this selection is provided in the setting unit 14 of the control device main body 8, and the operation is performed. The required method can be selected by the user.

Next, the structure of the head 5 will be described. FIG.
(A) is a plan view showing a part in section, (b) and (c) are side sectional views, (a) is a sectional view taken along line AA of (b), (b) is (a) 3 is a sectional view taken along line BB of FIG. (B) is file 2
Is moved in the crown direction, and (c) shows the file 2 moved in the apical direction.

The cutting drive unit 6 includes a cutting motor 6a located on the main body of the handpiece 4 and a motor 6a.
The rotating shaft 6b is driven by a, a driving gear 6c provided at the tip thereof, a rotating gear 6e supported by a bearing 6d and meshing with the driving gear 6c. The automatic feed mechanism 7 includes a feed motor 7a located in the main body of the handpiece 4 and a rotary shaft 7 driven by the motor 7a.
b, a pinion 7c provided at the tip thereof, a slide rack 7d supported vertically slidably and engaged with the pinion 7c, and the like.

Further, a pipe-shaped slide shaft 5a for holding the inserted file 2 is provided in the head 5, and is supported by a slide bearing 5b so as to be rotatable and vertically slidable. A connection groove 5c is formed in the outer periphery of the slide shaft 5a in the axial direction. The connection pin 6f of the rotating gear 6e is engaged with the connection groove 5c, and the upper end of the slide rack 7d is engaged with the upper end of the slide shaft 5a. are doing.

The head 5 has such a structure. When the cutting motor 6a is driven, its rotation is transmitted to the slide shaft 5a via the rotary shaft 6b, the drive gear 6c and the rotary gear 6e, and the slide shaft 5a rotates. I do. In addition, the feed motor 7
When a is driven, the rotation is performed by the rotation shaft 7 b and the pinion 7.
(c) The slide shaft 5a is transmitted to the slide shaft 5a via the slide rack 7d, and slides up and down.
Therefore, similarly to the conventional device, the file 2 inserted into the root canal 1a can be rotated to perform a root canal formation treatment on the root canal 1a. In this device, however, the file 2 is transferred to the root canal 1a. The insertion can be performed by the automatic feed mechanism 7.

That is, when the file 2 is inserted into the root canal 1a, first, as shown in FIG. 4B, the file 2 is moved most in the direction of the crown, and then the tip of the file 2 is moved to the root canal 1a. The head 5 is fixed so as to face the crown 1c at the upper end, and the relative position of the head 5 with respect to the tooth 1 is kept constant. This fixation can be easily realized, for example, by providing a fixation arm on a medical table or the like and holding the handpiece 4 with the arm. Thus head 5
When the feed motor 7a of the automatic feed mechanism 7 is driven after fixing the file 2, the slide shaft 5a moves downward, and the file 2
Is automatically inserted into the root canal 1a while rotating and the apex 1b
Will be sent in the direction of.

There is a known root canal forming apparatus that reciprocates a file finely in the axial direction. For example, the file only reciprocates at a constant stroke in association with the rotation. The reference position of the file with respect to the holder of No. does not change. Therefore, the present invention is completely different from the feed operation for moving a cutting tool such as a file in the axial direction.

According to the apparatus of the present invention, in addition to the above-described feed to the apical side, control such as insertion amount control and reverse feed control to the crown side as described below are automatically performed. By doing so, complete automation of file operations becomes possible.

First, when the root canal is formed, the file 2 may bite into the root canal or break, so the load torque is always detected from the magnitude of the motor current of the cutting motor 6a, and this load torque is detected. When reaches a preset reference value, the rotation direction of the feed motor 7a is reversed, and reverse feed to the crown 1c side is performed. This prevents the file 2 from being forcibly driven, and prevents troubles such as biting into the root canal. In this case, control is also performed such that the insertion in the direction of the apex 1b is not continuously performed, and the insertion amount is gradually increased while alternately repeating feed to the apex 1b and reverse feed to the crown 1c. The setting unit 14 of the control device main body 8 is provided with an operation unit capable of independently setting the feed amount in the apical direction and the crown direction independently.

As described above, when the load torque reaches the reference value, the cutting drive unit 6 may be controlled to stop cutting, thereby also preventing biting of the file 2 or the like. The cutting may be stopped, for example, by stopping, reducing, or reversing the rotation direction of the cutting motor 6a.

In the above example, the automatic feed mechanism 7 is controlled in accordance with the load. In the illustrated apparatus, the automatic feed mechanism 7 is also controlled by the root canal length measurement data by the root canal length measuring circuit 13. You. In other words, in the root canal length measuring device, the measurement data obtained when the tip of the measuring needle is located near the apex is known in advance, so that when the measurement data reaches a set value based on that, for example, the apex Is generally determined to have been reached. This device also follows this concept. When the measurement data when the file 2 is sent in the direction of the apex 1b reaches a preset value, the feed motor 7a is stopped or the rotation direction is reversed. The reverse feed to the crown 1c is performed. Therefore, a mistake such that the file 2 is inserted deeply through the apex 1b is prevented beforehand and automatically.

As described above, the root canal length can also be measured from the impedance change characteristics obtained between the measurement needle and the oral electrode. In this case, it is necessary to detect the impedance change state. Therefore, even in the apparatus of this example, the operation of measuring the root canal length is performed each time the file 2 moves a preset distance in the direction of the apex 1b, thereby detecting a change in impedance and detecting the tip of the file 2. You can know the position of. More specifically, the impedance change state can be detected by comparing the measurement data after the previous movement, that is, before the current movement and after the current movement, so that the file 2 can be obtained from the comparison data obtained as a result of the comparison.
Is determined to have reached the apex 1b, and the sending of the file 2 is stopped or reversed.

Unlike the manual insertion of a file which has been conventionally performed, in this apparatus, the movement when inserting the file 2 is performed by the feed motor 7a, so that the moving speed can be kept constant. For this reason, instead of the method of measuring each time a certain distance is moved as described above, the root canal length may be measured each time a predetermined time elapses, and the measured data before and after may be compared. In addition, since not only the comparison data obtained by comparing the measurement data before and after the movement but also the measurement data itself after the movement indicates the position of the leading end of the file 2, both the measurement data and the comparison data are used. More accurate detection is also possible.

The above description has been made on various controls for the automatic feed mechanism 7. In addition to these controls, the cutting drive unit 6 can be controlled based on the root canal length measurement data. The control for the cutting drive unit 6 is to stop cutting by the file 2 when the measurement data when the file 2 is sent in the direction of the apex 1b reaches a preset value. The cutting is stopped, for example, by stopping or reducing the speed of the cutting motor 6a, reversing the rotation direction, or the like. As a result, an error such that the cutting is continued even though the file 2 reaches the apex 1b is prevented beforehand and automatically.

The apparatus of this embodiment rotates the file 2. For example, in the case of a method of cutting by ultrasonic vibration, the apparatus is similarly stopped by stopping the vibration or reducing the output of the ultrasonic vibrator. Cutting can be stopped.

As described above, the measurement data of the root canal length can be used for various controls. However, these measurement data and the like are not only used for automatic control but also displayed on the display unit 15. Used to provide information to the surgeon. For this reason, the setting unit 14 of the control device body 8 is provided with an operation unit for designating or selecting these display contents.

As described above, the setting section 14 has an operation section for independently setting the feed amount in the apical direction and the crown direction, and a section for selecting a method for measuring the root canal length. Although an operation unit is provided, the rotation speed of the cutting motor 6a,
Reference value of cutting load when reversing the feed of file 2,
An operation unit for setting the set value of root canal length measurement data when reversing the feed of file 2 or stopping cutting, an operation unit for selecting whether or not to perform these various controls are required It is provided according to.

Although the above description has individually described the contents of each claim, these various controls are employed alone or in an appropriate combination in an actual root canal forming apparatus. Although the flowchart of FIG. 5 illustrates a control procedure of the root canal forming apparatus that combines typical controls, this is merely an example, and it goes without saying that other procedures than those illustrated can be adopted.

First, a power switch (not shown) is turned on to turn on the power, and the setting section 14 sets various conditions at the time of treatment, such as a rotation speed, a feed amount, a reference value of a cutting load, and a set value of a root canal length. After that, the tip of the file 2 is the crown 1c of the root canal 1a.
With the handpiece 4 slightly inserted into it,
Step on the foot pedal 9 (step S1). In the next step 2, when it is confirmed that the file 2 is inserted into the root canal 1a from the impedance response value measured by the operation of the root canal length measuring circuit 13, the process proceeds to step S3, where the cutting motor 6a Then, the feed motor 7a starts rotating, and the file 2 is inserted into the root canal 1a at a constant speed while performing cutting by rotation.

When cutting is started, the load torque of the cutting motor 6a is detected in step S4. If the torque is within the reference value, the process proceeds to step S5. If the torque exceeds the reference value, the process proceeds to step S11. . In step S11, the rotation direction of the feed motor 7a is reversed, and the torque detected while returning the file 2 in the direction of the crown 1c is compared with a second reference value. The second reference value is selected to be, for example, の of the reference value in step S4. If the torque falls within the second reference value, the feed direction is reversed, and the feed is switched to the apex 1b again. And return to step S4. As a result, biting of the file 2 and breakage due to it are prevented.

In this flowchart, the feeding to the apex 1b and the feeding to the crown 1c are switched according to the detected load torque. 0.5 mm, 0. 0 on the crown 1c side.
Set as 3mm, advance by 0.5mm and 0.3mm
It is also possible to control such that the returning operation is automatically repeated. Instead of reversing the feed direction in this way, it is possible to adopt a control in which the feed is temporarily stopped until the load torque falls below the reference value.

In step S5, it is determined whether or not a predetermined time set in advance has elapsed. When the time has elapsed, the flow advances to step S6 to perform an operation of measuring the root canal length.
Here, for example, the impedance response values obtained for two types of measurement voltages having different frequencies are compared, and a process of a comparison method using a value obtained from the difference or the ratio is performed, and the calculated measurement data is displayed. Is displayed on the container 15.
The operations from steps S4 to S6 are repeated until it is determined in the next step S7 that the measured data has reached the set value.

Although this determination can be made based on the result of one measurement, it can also be determined from the state of change of the measured data before and after two times as described above. Can be determined using the comparison data obtained by comparing the above, or if necessary, the determination can be made using the comparison data and the current measurement data.

If it is determined in step S7 that the measured data has reached the set value, the flow proceeds to step S8, in which the feed motor 7a is rotated in the reverse direction to return the file 2 to the direction of the crown 1c and to perform a cutting operation. Is also stopped, and, for example, the final measured data of the root canal length is displayed on the display 15. The cutting is stopped when the cutting motor 6a is stopped, the rotation speed is reduced, or the rotation is reversed. Then, in step S9, the foot pedal 9
Is turned off, all the motors stop, and a series of cutting operations ends.

In addition to the measurement data of the root canal length, the moving direction, rotation speed, cutting torque, and the like of the file 2 are necessary information for the operator, and thus the display 15 is displayed on the display unit 15 in step S6 or step S8. In addition to displaying the measured data, these data may be constantly displayed during a series of cutting operations.

Although FIG. 1 shows a control device body 8 provided separately from the handpiece 4, a control unit 11, a motor controller 12, a root canal length measuring circuit 13 and the like are provided. All of these circuits and functions may be housed in the handpiece 4, or a part of them may be housed in a separate control device body as needed.

[0048]

As is apparent from the above description, the root canal forming apparatus of the present invention drives the cutting tool attached to the distal end of the holder and inserted into the root canal by driving the cutting tool with the cutting drive. The root canal forming apparatus for forming a tube is provided with an automatic feed mechanism for automatically moving the reference position of the cutting tool with respect to the holder in the axial direction of the cutting tool.

[0049] For this reason, the insertion of the cutting tool into the root canal is automated, so that the operation of root canal formation can be completely automated and the burden on the operator can be greatly reduced. This eliminates the need for caution, reduces work time, and reduces fatigue. In addition, since the insertion into the root canal is automated and the insertion speed can be kept constant,
In a root canal forming device that can perform cutting while measuring the root canal length by adding a root canal length measurement function, fluctuations in insertion speed due to manual work are no longer superimposed on the measurement data, It becomes easy to accurately detect the tip position of the cutting tool that also serves as the cutting tool.

Further, in the apparatus in which the automatic feed mechanism and the cutting drive unit are controlled in accordance with the magnitude of the load applied to the cutting tool, it is possible to prevent the cutting tool from biting into the root canal and thereby to prevent breakage. it can.

In the apparatus in which the automatic feed mechanism and the cutting drive unit are controlled in accordance with the measured data of the root canal length,
It is possible to prevent mistakes such as cutting being performed more than necessary after passing through the apex.

In measuring the root canal length, comparison data obtained by comparing the previous and current measurement data obtained by successively measuring the cutting tool in the apical direction, and this comparison data In addition to the above, the position of the tip of the measuring needle is detected using the measurement data of this time, and since a lot of data is used, highly accurate detection is possible, and the control of the automatic feed mechanism and the cutting drive unit is performed. It can be performed more appropriately.

The measurement data obtained from the impedance response value when one type of measurement voltage is applied between the cutting tool also serving as the measurement needle and the oral electrode, and the measurement data obtained when two types of measurement voltage are applied. Even in the case of detecting the position of the tip of the measuring needle in accordance with the combination with the measurement data obtained from the difference or ratio of the impedance response values, highly accurate detection is possible because a large amount of data is used,
It is possible to more appropriately control the automatic feed mechanism and the cutting drive unit.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration of a root canal forming apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a motor controller circuit in the device.

FIG. 3 is a diagram showing an example of a root canal length measurement circuit in the same device.

FIGS. 4A and 4B are diagrams showing an example of the structure of a head in the same device, wherein FIG. 4A is a plan view showing a part of the head in cross section, and FIGS.

FIG. 5 is a flowchart illustrating an example of a control procedure of the apparatus.

[Explanation of symbols]

 Reference Signs List 1 tooth 1a root canal 1b apex 1c crown 2 file (cutting tool / measuring needle) 4 handpiece (holding tool) 5 head 6 cutting drive 6a cutting motor 7 automatic feed mechanism 7a feed motor 8 controller Main body 11 Control unit 12 Motor controller 13 Root canal length measurement circuit 14 Setting unit 15 Display

Continuation of the front page (56) References JP-A-8-640 (JP, A) JP-A-8-38510 (JP, A) JP-A-7-163597 (JP, A) JP-A-58-149109 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) A61C 5/02 A61C 1/00

Claims (20)

(57) [Claims] 1. A root canal forming apparatus for forming a root canal by driving a cutting tool attached to a tip portion of a holder and inserted into a root canal by a cutting driving unit, the reference position of the cutting tool with respect to the holder. A root canal forming apparatus comprising an automatic feed mechanism for automatically moving the cutting tool in the axial direction of the cutting tool. 2. The apparatus according to claim 1, further comprising means for sequentially detecting a load applied to the cutting tool, wherein the automatic feed mechanism and / or the cutting drive unit is controlled in accordance with the magnitude of the detected load. The root canal forming device as described in the above. 3. When the load during moving the cutting tool in the apical direction reaches a preset reference value, the moving by the automatic feed mechanism is stopped or the moving direction is reversed. The root canal forming device according to claim 2. 4. The root canal according to claim 1, wherein the automatic feed mechanism is controlled to automatically repeat the movement of the cutting tool in the direction of the apex and the direction of the crown. Forming equipment. 5. The root canal forming apparatus according to claim 4, wherein the amount of movement in the apical direction and the amount of movement in the crown direction can be set independently of each other. 6. The root canal forming apparatus according to claim 1, wherein the root canal forming apparatus is configured to display a moving direction of the cutting tool. 7. The root canal forming apparatus according to claim 1, wherein a pulse motor is used as a feed motor of the automatic feed mechanism. 8. The cutting tool according to claim 1, wherein the cutting tool also serves as a measuring needle for measuring the root canal length, and the automatic feed mechanism is controlled according to the measured data of the root canal length. A root canal forming apparatus according to any one of the above. 9. When the root canal length measurement data when the cutting tool is moved in the apical direction by the automatic feed mechanism reaches a preset value, the movement is stopped or the movement direction is reversed. The root canal forming apparatus according to claim 8, wherein the root canal forming apparatus is configured to perform the operation. 10. The root canal forming apparatus according to claim 8, wherein a root canal length measuring operation is automatically performed each time the cutting tool moves a predetermined distance in the apical direction. . 11. The measured data of the root canal length after the previous movement is compared with the measured data of the root canal length after the current movement, and the automatic feed mechanism is controlled using the comparison data obtained by the comparison. The root canal forming device according to claim 10, wherein the device is configured as follows. 12. Comparison data obtained by comparing the measured data of the root canal length after the previous movement with the measured data of the root canal length after the current movement, and the measurement of the root canal length after the current movement 11. The root canal forming device according to claim 10, wherein the root canal forming device is configured to control the automatic feeding mechanism using both of the data. 13. The method according to claim 8, wherein the moving speed of the cutting tool by the automatic feed mechanism is constant, and the operation of measuring the root canal length is automatically performed every predetermined time. Root canal forming equipment. 14. The root canal forming apparatus according to claim 13, wherein the moving speed of the cutting tool by the automatic feed mechanism can be arbitrarily set. 15. A configuration in which the previous measured data of the root canal length during the movement is compared with the measured data of the current root canal length, and the automatic feed mechanism is controlled using the comparison data obtained by the comparison. The root canal forming apparatus according to claim 13 or 14, wherein the root canal forming apparatus is used. 16. Using both the comparison data obtained by comparing the previous measurement data of the root canal length and the current measurement data of the root canal length while moving, and the measurement data of the current root canal length. 14. The apparatus according to claim 13, wherein the automatic feed mechanism is controlled.
Or the root canal forming device according to 14. 17. The cutting tool according to claim 1, wherein the cutting tool also serves as a measuring needle for measuring the root canal length, and the cutting drive unit is controlled according to the measured data of the root canal length. The root canal forming device according to any one of the above. 18. When the measured data of the root canal length when the cutting tool is moved in the apical direction by the automatic feed mechanism reaches a preset value, the driving of the cutting tool by the cutting drive unit is performed. 18. The root canal forming device according to claim 17, wherein the root canal forming device is configured to stop, reduce a driving force, or reverse a rotation direction. 19. The root canal forming apparatus according to claim 8, configured to display the measurement data of the root canal length. 20. A method according to claim 19, further comprising: a cutting tool serving as a measuring needle inserted into the root canal and an oral electrode arranged in the oral cavity of the patient.
The value obtained from the impedance response value when one type of measurement voltage is applied and the value obtained from the difference or ratio of each impedance response value when two types of measurement voltages are applied are measured data of root canal length. And an automatic feed mechanism or / depending on any or a combination of these measurement data.
9. The apparatus according to claim 8, wherein the driving unit is configured to control a cutting drive unit.
20. The root canal forming device according to any one of claims to 19.