JP2009072425A - Syringe for dental anesthesia - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a syringe for dental anesthesia which minimizes the pains and burdens of a patient by optimally controlling the insertion speed and insertion distance, etc., of an injection needle. <P>SOLUTION: The syringe for dental anesthesia, in which the injection needle for injecting anesthetic solution to an injection portion is housed in a handpiece, is provided with: a drive motor 102 as a power source for moving the injection needle 120 forward and backward to the handpiece 1; an encoder 102A and a speed detection part 205 for detecting the insertion speed of the injection needle 120 to gingiva T1; a position sensor 115 for detecting the position of the injection needle 120; a load sensor 107, a load amplifier 207 and an insertion pressure detection part 222 for detecting a pressure applied to the injection needle 120; and a speed/distance control part 221 and a motor control part 206 for controlling the insertion speed and moving distance of the injection needle 120 by controlling the drive motor 102 so that an insertion speed detection value matches with an insertion speed setting value and the position detection value of the injection needle 120 corresponds to a moving distance setting value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a dental anesthesia syringe for injecting an anesthetic by inserting a needle into an injection site such as gums.

Conventionally, what was described in patent document 1 is known as this kind of dental anesthesia syringe.
The syringe according to Patent Document 1 is characterized in that the injection speed is increased at the beginning of anesthetic injection and the drive motor is driven so that the injection speed is constant after a predetermined period of time. The pain during injection is reduced by controlling the injection speed. In addition, consideration is given to further alleviating the patient's pain and fear by providing a structure that reduces the blurring of the needle tip of the injection needle and a circuit for playing a melody sound during injection.

Japanese Unexamined Patent Publication No. 2004-130005 (paragraphs [0055] to [0068], FIG. 3, FIG. 8, etc.)

Here, according to the inventor's earnest research, the pain felt by the patient is greatly influenced not only by the injection speed of the anesthetic, but also by the insertion speed, the insertion distance, and the insertion pressure of the injection needle into the injection site. ing.
That is, under the present circumstances, a practitioner such as a dentist is injecting an anesthetic by inserting the injection needle into the gingiva for a predetermined distance at an appropriate speed and pressure based on the sense and experience. Depending on the skill, there may be a case where a patient suffers a great deal of pain when the needle is inserted, and it has been desired to alleviate and reduce such pain as much as possible.

  SUMMARY OF THE INVENTION Accordingly, the problem to be solved by the present invention is to provide a dental anesthesia syringe that can optimally control the insertion speed, insertion distance, etc. of an injection needle and minimizes patient pain and burden.

In order to solve the above-mentioned problems, the invention according to claim 1 is a dental anesthesia syringe comprising a handpiece having an injection needle for injecting an anesthetic liquid into an injection site.
A drive motor as a power source for moving the injection needle forward and backward from the tip of the handpiece;
Speed detecting means for detecting the insertion speed of the injection needle into the injection site;
Position detecting means for detecting the position of the injection needle;
Pressure detecting means for detecting pressure applied to the injection needle;
The drive so that the insertion speed detection value obtained by the speed detection means matches the insertion speed setting value, and the position detection value obtained by the position detection means corresponds to the moving distance setting value of the injection needle. Control means for controlling the motor to control the insertion speed and movement distance of the injection needle;
It is equipped with.

The invention according to claim 2 is the dental anesthesia syringe according to claim 1,
The speed detecting means includes an encoder that detects a rotational speed of the drive motor.

The invention according to claim 3 is the dental anesthesia syringe according to claim 1 or 2,
The position detecting means includes a position sensor for detecting the position of the injection needle with respect to the handpiece by a variable resistance.

The invention according to claim 4 is the dental anesthesia syringe according to any one of claims 1 to 3,
The control means stops rotation of the drive motor when the pressure detected by the pressure detection means exceeds a set range.

According to the present invention, the insertion speed and the insertion distance when inserting the injection needle into the injection site can be controlled to the optimum values set in advance. For this reason, it is possible to inject an anesthetic at a puncture speed and a puncture distance that are always less painful for the patient, regardless of the sense, experience, and skill of the user.
In addition, even when the insertion pressure exceeds the set range, the patient's pain is significant, but the pain can be quickly removed by detecting this pressure abnormality and immediately stopping the insertion operation. .

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, FIG. 1 shows the overall configuration of a dental anesthesia syringe according to this embodiment. In FIG. 1, 1 is a handpiece with a syringe needle, a drive motor, and the like built in, 2 is a device that controls the drive motor based on set values such as the needle insertion speed and insertion distance, and is supplied to the injection needle A control unit for controlling the anesthetic supply operation and performing various displays, alarm operations, etc., 3 is a tube for supplying the anesthetic to the injection needle, and 4 is a wiring between the handpiece 1 and the control unit 2 A cable 5 in which a cord is accommodated is a cartridge holder for holding a cartridge containing an anesthetic.

  Next, the internal structure of the handpiece 1 will be described based on the cross-sectional views of FIGS. 2 (a) and 2 (b) and the enlarged cross-sectional view of FIG. 2A is a side sectional view of the handpiece 1, FIG. 2B is a plan sectional view, and FIG. 3 is an enlarged sectional view of the main part of FIG.

In these drawings, a main body case 101 has a built-in drive motor 102, and a lead screw 103 is fixed to the drive shaft. A screw portion 103a is formed coaxially at the axial end portion of the lead screw 103, and a nut 104 is screwed around the screw portion 103a.
A pulse encoder for detecting the rotational speed of the drive motor 102 is provided inside the housing of the drive motor 102 as will be described later.

The nut 104 is formed in an approximately H shape when viewed from the side, and a concave load sensor holding portion 104 a is provided at the axial end 104 on the distal end side of the handpiece 1.
The nut 104 is for converting the rotational movement of the lead screw 103 into a linear movement by a so-called feed screw action, and is arranged in the groove 105a of the cylindrical body sleeve 105 as shown in FIG. The rotation of the nut 104 is prevented by screwing the non-rotating screw 106 to the load sensor holding portion 104a.

A load sensor 107 is disposed at the bottom of the load sensor holding unit 104a. 107 a is a lead wire of the load sensor 107. Here, the load sensor 107 is configured by a load cell having a strain gauge, as is well known.
A bottomed cylindrical slide shaft 108 is arranged on the same axis as the nut 104 and the load sensor 107, and the end surface of the bottom flange 108a has a pressure receiving force composed of a strain gauge of the load sensor 107 as shown in FIG. The portion 107b is pressed.
As shown in FIG. 2B, the bottom flange 108a is held in a non-rotatable manner by the non-rotating pin 109 with respect to the load sensor holding portion 104a.

A cylindrical ball guide 110 is mounted on the outer peripheral surface of the slide shaft 108, and the axial movement distance of the slide shaft 108 and the ball guide 110 is regulated by stop springs 111 and 112. Reference numeral 113 denotes a ball guide holder that surrounds the outer peripheral surface of the ball guide 110, and the retaining springs 111 and 112 are disposed on the inner peripheral surfaces of both axial ends thereof.
Reference numeral 114 denotes a cylindrical shaft sleeve that is attached to substantially the first half in the axial direction of the ball guide holder 113 so as to surround the slide shaft 108.

As shown in FIG. 2A, an operation switch 116 and an operation display lamp 117 are arranged on a part of the outer peripheral surface of the main body sleeve 105.
As shown in FIG. 2B, a position sensor 115 is integrally connected to the outer peripheral surface of the load sensor holding portion 104a. Although the position sensor 115 will be described later with reference to FIG. 7, the movable pin terminal 115a (see FIG. 7) is connected to the load sensor holding portion 104a and moves integrally therewith, and the load sensor holding portion 104a. A variable resistor that can detect a resistance value (voltage value) corresponding to the position of the movable pin terminal 115a is configured. That is, the position sensor 115 is for detecting the position along the axial direction of the load sensor holding portion 104a with respect to the main body case 101 of the handpiece 1, in other words, the position along the axial direction of the injection needle 120.

  An injection needle holder 118 is fixed to the distal end portion of the slide shaft 108, and the injection needle 120 is held on the central axis of the injection needle holder 118 via a tube holder 119. A tube 3 for supplying an anesthetic is attached to the rear end of the tube holder 119, and an injection needle 120 is attached to the front end of the tube holder 119. The anesthetic is transferred from the tube 3 to the tube holder. 119 is supplied to the central shaft hole of the injection needle 120 through the inside of 119.

The injection needle holder 118 can move in the axial direction in conjunction with the slide shaft 108 inside the shaft sleeve 114, and a lip guard 121 is press-fitted into the outer peripheral surface of the tip portion of the shaft sleeve 114.
The lip guard 121 is slightly movable in the axial direction with respect to the distal end portion of the shaft sleeve 114, and is rotatable about the shaft. The lip guard 121 is positioned in the front-rear direction and the direction of the distal end edge 121a cut obliquely. Can be adjusted. Thereby, the optimal position and direction of the lip guard 121 can be obtained according to the variation in the length of the injection needle 120 and the contact surface of the gingiva.

Here, FIG. 4 is an external view of the lip guard 121. An alignment scale 121b composed of three lines (arcs) is engraved on the outer peripheral surface of the tip of the lip guard 121. The scale 121b is for positioning the origin position of the injection needle 120 by aligning the tip of the injection needle 120 protruding from the tip edge 121a with, for example, the center line of the three lines.
FIG. 5 is an explanatory view of the main part in the use state, and is used by applying the tip edge 121a of the lip guard 121 so as to contact the side surface of the gingiva T1.

The handpiece 1 is configured as described above. When the drive motor 102 is rotated, the lead screw 103 is rotated, and the rotational motion is converted into an axial linear motion by the nut 104. Since the nut 104, the load sensor 107 and the slide shaft 108 are integrally connected in the axial direction, the linear motion of the nut 104 is transmitted to the slide shaft 108.
In addition, since the slide shaft 108, the injection needle holder 118, the tube holder 119, and the injection needle 120 are also integrally connected, the injection needle 120 moves forward and backward in the axial direction in accordance with the movement of the slide shaft 108. .

If the polarity of the applied voltage is reversed, the drive motor 102 rotates in the reverse direction. If the injection needle 120 moves to the left in FIG. 2 when the drive motor 102 rotates in the forward direction, the drive motor 102 rotates in the reverse direction. Sometimes, the nut 104 moves in the direction opposite to that during forward rotation, so that the injection needle 120 moves to the right in FIG.
That is, when the anesthetic is injected by inserting the injection needle 120 into the gingiva T1, if the drive motor 102 is rotated forward, the injection needle 120 protrudes from the tip edge 121a of the lip guard 121 and is inserted into the gingival T1. Then, after injecting the anesthetic liquid in this state, the injection needle 120 can be retracted to the inside of the distal end edge 121a by reversing the drive motor 102.

  FIG. 6 shows the moving state of the injection needle 120. In this embodiment, when the position where the tip of the injection needle 120 is at the tip edge 121 a of the lip guard 121 is the origin position (the middle position in FIG. 6), the tip of the injection needle 120 is from the state inside the lip guard 121. The movement distance (so-called running distance) until the tip of the injection needle 120 reaches the origin position is set to, for example, about 0 to 2 mm, and the distance (so-called insertion distance) by which the tip of the injection needle 120 moves (projects) from the origin position. ) Can be set to a maximum of about 5 mm.

Next, FIG. 7 is a block diagram showing the overall configuration of the present embodiment.
In the figure, a unit main body 208 in the control unit 2 includes a one-chip microcomputer 201. A switching power supply 204 is connected to the microcomputer 201 via a fuse 202 and a power switch 203.

The microcomputer 201 processes the output signal of the motor control unit 206 for controlling the drive motor 102 in the handpiece 1 and the pulse encoder 102A provided in the drive motor 102 to obtain the rotational speed of the drive motor 102, that is, A speed detector 205 for detecting the moving speed of the injection needle 120 and a load amplifier 207 for amplifying the output signal of the load sensor 107 are connected. The position sensor 115 described above is also connected to the microcomputer 201.
Further, the microcomputer 201 is connected with an operation display lamp 117 on the handpiece 1 side, and includes an anesthetic supply unit 209 including a pump, a cartridge, and the like for supplying the anesthetic to the injection needle 120 via the tube 3. Is connected.

  In the figure, 6 is a foot switch, 210 is a switch between automatic operation and manual operation, 211 is a pilot lamp, and 212 is an operation display lamp. The changeover switch 210 is a switch for switching whether the insertion speed of the injection needle 120 is automatically controlled as will be described later or artificially as in the past.

  As is well known, the microcomputer 201 has a CPU, a memory, an input / output interface and the like mounted on one chip, and controls the speed of the drive motor 102 based on output signals from the load sensor 107, the position sensor 115, and the like. And a program for controlling the driving of the anesthetic supply unit 209, a display program for displaying the injection pressure and injection volume of the anesthetic, the insertion pressure of the injection needle 120, the injection pressure of the anesthetic and the injection needle 120 It is configured to operate in accordance with an alarm program for issuing an alarm when the insertion pressure exceeds a set range, and further a program for controlling the operation of the entire system.

In the microcomputer 201, the moving distance of the injection needle 120 (the sum of the running distance and the piercing distance in FIG. 6 described above), the piercing speed, the anesthetic injection speed, the injection amount, and the like can be set. Further, the approaching distance, the insertion distance, and the insertion speed can be selected from a plurality of preset values or can be set to arbitrary values.
The injection speed of the anesthetic can be set, for example, in three stages of low speed, medium speed, and high speed. However, the method for controlling the injection speed is not the gist of the present invention, and thus the description thereof is omitted.

  On the other hand, although the same number is attached to each component in the handpiece 1, the pulse encoder 102A adjusts the rotational speed in order to detect the rotational speed of the drive motor 102, that is, the moving speed of the injection needle 120. It is configured to generate a proportional number of pulse signals. Terminals a and b of the pulse encoder 102A are pulse output terminals, and c and d are power supply terminals.

The position sensor 115 detects the position of the load sensor holding portion 104a that moves in the axial direction as described above, the terminals e and f are voltage application terminals, and the terminal g is a position detection signal output terminal.
Specifically, when the movable pin terminal 115a fixed to the outer peripheral surface of the load sensor holding portion 104a moves integrally with the load sensor holding portion 104a, the resistance value between the terminals e and g and between the terminals g and f. To change the voltage at the terminal g. By detecting this voltage, the position of the load sensor holding portion 104a with respect to the main body case 101 of the handpiece 1, that is, the injection needle 120 is detected.

  The load sensor 107 forms a bridge having a strain gauge as one side of the pressure receiving portion 107b, terminals h and i are voltage application terminals, and j and k are load detection signal output terminals. According to the load sensor 107, a voltage proportional to the load applied to the pressure receiving portion 107b is output from the output terminals j and k.

FIG. 8 is a functional block diagram showing the main part of the control unit 2 (unit main body 208), and mainly shows the part of the function of the microcomputer 201 relevant to the present invention.
8, the speed / distance control unit 221 includes an output signal from the speed detection unit 205, a position detection value of the injection needle 120 by the position sensor 115, an insertion speed setting value, and a movement distance of the injection needle 120 (an approach distance and an insertion distance). The sum of the input distance and the set value, and an abnormal stop signal from the insertion pressure detection unit 222 described later are input. The speed / distance controller 221 is an injection in which the speed detection value output from the speed detector 205 matches the insertion speed setting value, and the position detection value of the injection needle 120 is determined according to the movement distance setting value. A control command for the motor control unit 206 is generated and output so as to match the position setting value of the needle 120. Further, an abnormal stop command for stopping the drive motor 102 in response to the abnormal stop signal is generated and output.
The motor control unit 206 controls driving (forward / reverse) and stopping of the driving motor 102 based on these input signals.

  The insertion pressure detection unit 222 receives the output signal of the load amplifier 207, and is configured to detect the insertion pressure of the injection needle 120 with respect to the gingiva T1 based on this output signal. The detected insertion pressure is displayed on a digital display or the like via the display / alarm output unit 223. If the insertion pressure detection value exceeds the set value, the abnormal stop signal described above is generated and output to the speed / distance control unit 221, and the operation of FIG. 7 is performed via the display / alarm output unit 223. The display lamps 117 and 212 are configured to blink or generate an intermittent alarm sound.

  In this embodiment, the anesthetic injection speed and speed change mode (pattern) can be set in a plurality of stages, and an injection pressure display, an injection pressure abnormality display, an alarm, etc. are possible. A description of the control means and the like for realizing it will be omitted.

Subsequently, the usage method of the syringe concerning this embodiment is demonstrated one by one.
After the power is turned on, the anesthetic injection speed, injection volume, etc. are set, and then the moving distance (running distance and insertion distance) of the injection needle 120 and the insertion speed are controlled by the speed / distance control unit on the control unit 2 side. Set to 221.

Thereafter, the tube 3 is set in the tube holder 119 of the handpiece 1, the lip guard 121 is removed, and the injection needle 120 is set.
Further, the lip guard 121 is rotated or moved back and forth to adjust its position. At that time, the tip of the injection needle 120 is aligned with the origin position using the alignment scale 121b described above.
Then, the cartridge holder 5 loaded with the anesthetic drug cartridge is attached to the control unit 2.

Next, the air vent switch (not shown) provided in the control unit 2 is turned on to operate the anesthetic supply unit 209, and the anesthetic is sent into the tube 3 so that the air in the tube 3 and the injection needle 120 is turned off. Unplug. At this time, the central axis hole of the injection needle 120 has a small diameter, and the anesthetic that reaches the tip of the needle has a surface tension, so that the anesthetic does not spill out.
Further, when the air venting is finished, the drive motor 2 is reversed by the motor control unit 206, and the distal end of the injection needle 120 is moved backward from the origin position by the running distance and stands by.
Thereby, the preparatory work for performing the injection treatment is completed.

When actually performing injection treatment, the orientation of the lip guard 121 is adjusted and applied to the gingiva T1 which is the injection site.
In this state, the operation switch 116 of the handpiece 1 is turned on, and the anesthetic is supplied from the anesthetic supply unit 209 to the injection needle 120 via the tube 3. Since the motor controller 206 sends a forward rotation command to the drive motor 102 simultaneously with the start of the supply of the anesthetic, the drive motor 102 rotates forward and the injection needle 120 moves straight through the lead screw 103, nut 104, slide shaft 108, and the like. Start moving.

  At this time, by controlling the speed of the drive motor 102 so that the speed detection value by the speed detection unit 205 matches the insertion speed setting value, the injection needle 120 moves according to the insertion speed setting value. Therefore, by setting the insertion speed setting value to an appropriate value, the injection needle 120 can be inserted at a speed that is less painful for the patient.

The injection needle 120 is inserted into the gingiva T1 by moving the running distance as described above and then moving the insertion distance continuously.
Here, FIG. 9 is a diagram showing the output signal of the load sensor 107 according to the movement distance of the injection needle 120 together with the anesthetic supply period, and after the point in time when the injection needle 120 starts moving the run distance, the anesthetic agent Is supplied to the injection needle 120. For this reason, the anesthetic is supplied even during the run-up period in which the injection needle 120 is not inserted into the gingiva T1, but as described above, the central axis hole of the injection needle 120 has a small diameter, so that the surface tension acts, Because the run-up distance itself is very short, there is no risk of the anesthetic spilling out.

The injection needle 120 injects an anesthetic into the gingiva T1 while moving the insertion distance. During this time, as shown in FIG. 9, the reaction force (load) from the gingiva T1 is applied to the load sensor 107 as the injection needle 120, Since the reaction force is applied via the slide shaft 108 or the like, the reaction pressure is detected by the insertion pressure detection unit 222 as the insertion pressure.
When the detected insertion pressure exceeds the set range (for example, when the moving distance setting value of the injection needle 120 or the inserted portion is inappropriate and the tip of the injection needle 120 hits the root of the tooth) ), The rotation of the drive motor 102 is stopped via the speed / distance control unit 221 by the abnormal stop signal from the insertion pressure detection unit 222, and at the same time, the display / alarm output unit 223 operates to display an abnormality and alarm. Do.

During this time, the position of the injection needle 120 is detected by the position sensor 115, and when the position (movement distance) reaches a value corresponding to the movement distance set value, the speed / distance control unit 221 rotates the drive motor 102. The movement of the injection needle 120 is stopped. In addition, the operation of the display / alarm output unit 223 notifies the user that the injection needle 120 has stopped by voice or the like.
Note that the anesthetic is continuously injected even after the injection needle 120 is stopped.
And if the whole quantity of the anesthetic in a cartridge is inject | poured, this will be detected by a suitable means and the operation | movement of the anesthetic supply part 209 will be stopped. At the same time, by the operation of the display / alarm output unit 223, the user is notified by voice or the like that the entire amount of the anesthetic has been injected.

Next, the handpiece 1 is removed from the injection site by gently removing the injection needle 120 from the gingiva T1. Here, the drive motor 102 may be reversed to extract the injection needle 120 from the gingiva T1.
Thereafter, forward / reverse rotation of the drive motor 102 is controlled to return the injection needle 120 to the origin position in FIG. This return operation to the origin position is executed by turning on an origin return switch (not shown) and controlling the motor control unit 206.

As described above, according to the present embodiment, if the insertion speed and insertion distance of the injection needle 120 are set in advance to optimum values with less pain for the patient, it depends on the sense, experience, and skill of the user. The anesthetic can be injected while always controlling the insertion speed and the insertion distance of the injection needle 120 to the optimum values.
In this embodiment, the control unit 2 and the cartridge holder 5 are separately formed in order to reduce the weight of the handpiece 1 and improve the operability. However, the control unit 2 and the cartridge holder 5 are reduced in weight and size. If possible, a hand piece including both or one of them may be formed.

It is an external view which shows the whole structure of embodiment of this invention. It is sectional drawing which shows the internal structure of the handpiece in FIG. It is an enlarged view of the principal part of Fig.2 (a). It is an external view of a lip guard. It is explanatory drawing of the principal part in use condition. It is a figure which shows the movement state of an injection needle. It is a block diagram which shows the whole structure of embodiment. It is a functional block diagram which shows the principal part of the control unit in FIG. It is explanatory drawing of the load sensor output signal according to the movement distance of an injection needle.

Explanation of symbols

1: Handpiece 2: Control unit 3: Tube 4: Cable 5: Cartridge holder 6: Foot switch 101: Body case 102: Drive motor 102A: Pulse encoder 103: Lead screw 103a: Screw part 104: Nut 104a: Load sensor holding part 105: Body sleeve 105a: Groove 106: Non-rotating screw 107: Load sensor 107a: Lead wire 107b: Pressure receiving portion 108: Slide shaft 108a: Bottom flange 109: Non-rotating pin 110: Ball guide 111, 112: Stop spring 113: Ball Guide holder 114: Shaft sleeve 115: Position sensor 115a: Movable pin terminal 116: Operation switch 117: Operation indicator lamp 118: Injection needle holder 119: Tube holder 120: Injection needle 1 1: Lip guard 121a: Tip edge 121b: Positioning scale 201: 1 chip microcomputer 202: Fuse 203: Power switch 204: Switching power supply 205: Speed detection unit 206: Motor control unit 207: Load amplifier 208: Unit main body 209: Anesthetic supply unit 210: changeover switch 211: pilot lamp 212: operation display lamp 221: speed / distance control unit 222: insertion pressure detection unit 223: display / alarm output unit T1: gingiva

Claims (4)

In a syringe for dental anesthesia provided with a handpiece, an injection needle for injecting anesthetic liquid into an injection site,
A drive motor as a power source for moving the injection needle forward and backward from the tip of the handpiece;
Speed detecting means for detecting the insertion speed of the injection needle into the injection site;
Position detecting means for detecting the position of the injection needle;
Pressure detecting means for detecting pressure applied to the injection needle;
The drive so that the insertion speed detection value obtained by the speed detection means matches the insertion speed setting value, and the position detection value obtained by the position detection means corresponds to the moving distance setting value of the injection needle. Control means for controlling the motor to control the insertion speed and movement distance of the injection needle;
A syringe for dental anesthesia, comprising: The syringe for dental anesthesia according to claim 1,
The speed detection means includes
A syringe for dental anesthesia comprising an encoder for detecting a rotation speed of the drive motor. The dental anesthesia syringe according to claim 1 or 2,
The said position detection means was equipped with the position sensor which detects the position of the injection needle with respect to the said handpiece by variable resistance, The syringe for dental anesthesia characterized by the above-mentioned. In the syringe for dental anesthesia according to any one of claims 1 to 3,
The said control means stops the rotation of the said drive motor, when the pressure detected by the said pressure detection means exceeds the setting range, The syringe for dental anesthesia characterized by the above-mentioned.

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