JP6966617B2 - Oral cleansing method - Google Patents

Description

The present invention relates to an oral cavity cleaning method and an oral cavity cleaning device.

Conventionally, an atmospheric pressure plasma generator has been used for surface cleaning of semiconductor substrates, glass substrates, various films and the like. As a method of generating atmospheric pressure plasma, a method of applying an AC voltage between opposing electrodes to generate glow discharge plasma between the electrodes is common. Plasma treatment by glow discharge is roughly divided into a direct method in which an irradiation target is installed in a discharge space between electrodes and a remote method in which an active species is blown out from the discharge space to irradiate the irradiation target. The remote method is adopted when there is concern about electrical damage to the irradiation target.

In the remote plasma apparatus, the electrode arrangement illustrated in FIG. 5 may be adopted. FIG. 5 is a schematic cross-sectional view of the plasma generating portion of the conventional plasma device 100. The plasma device 100 includes a gas tube 101 in which a plasma-generating gas is introduced from a lower end to an upper end, a pair of electrodes 102a and 102b arranged on the side surface of the upper end of the tube, and the electrodes and a tubular dielectric. It is provided with a nozzle 103 for accommodating the body. The gas pipe 101 is hollow and is an insulator. Atmospheric pressure plasma is generated by ionizing the gas discharged from the upper end portion of the gas pipe 101 between a pair of electrodes 102a and 102b (plasma generating portion) arranged opposite to each other above the upper end portion. The atmospheric pressure plasma is irradiated outward from the irradiation port of the nozzle 103.

Since the atmospheric pressure plasma irradiated from the conventional plasma device has a high temperature, there is a problem that it is not suitable for irradiation of a soft material containing water. For example, when a living body such as a cell, a living tissue, or an individual living body is irradiated, excessive heat stress is applied to the cell or tissue, and there is a risk of burns.

For the purpose of solving the above problem, Patent Document 1 discloses a normal pressure low temperature microplasma injection device. The device is provided with a large number of holes in the positive electrode of the plasma generating part, and a voltage of 2 to 3 kV is applied between the positive electrode and the negative electrode that also serves as a gas pipe, and the temperature is relatively low at about 41 ° C. It is said that it can inject atmospheric pressure plasma (normal pressure plasma).

Japanese Patent No. 5225476

However, the positive electrode of the plasma apparatus described in Patent Document 1 has a large number of fine holes having a diameter of 100 μm or less that generate plasma and transmit the plasma, so that the electrode structure is complicated. In manufacturing this electrode, a fine patterning technique applied in the field of MEMS is required, and there is a problem that the manufacturing cost of the electrode increases.

The present invention has been made in view of the above circumstances, and provides a plasma device that is easy to manufacture and a method of using the same. Further, the present invention provides a nitrogen gas plasma and a nitrogen gas plasma irradiation method applicable to medical applications.

<1>
A plasma generating gas is supplied at 5.0 L / min or less to a plasma generating portion having an electrode, a voltage is applied to the plasma generating gas at less than 20 kVpss to generate plasma, and the active species generated by the plasma is placed in the oral cavity. An oral cleansing method comprising an irradiation step of irradiating inside.
<2>
The oral cleaning method according to <1>, wherein the irradiation step is to irradiate the tooth surface with the active species.
<3>
The method for cleaning the oral cavity according to <1> or <2>, wherein the plasma-generating gas contains nitrogen.
<4>
The method for cleaning the oral cavity according to any one of <1> to <3>, wherein the irradiation step is performed twice or more with a predetermined period.
<5>
A plasma generator with electrodes and
A gas supply unit that supplies plasma generation gas to the plasma generation unit,
An irradiation amount control unit that reduces the amount of the plasma generation gas introduced into the plasma generation unit to 5.0 L / min or less.
It has a power supply control unit that controls the voltage applied to the electrodes to less than 20 kVpps.
An oral cleaning device that applies a voltage to the electrodes to generate plasma, generates active species by the generated plasma, and irradiates the oral cavity with the active species.
<6>
The oral cavity cleaning device according to <5>, which is used for cleaning the tooth surface.
<7>
The oral cleaning device according to <5> or <6>, wherein the gas supply unit supplies the nitrogen-containing gas for plasma generation.
<8>
The oral cleaning device according to any one of <5> to <7>, wherein the oral cavity is irradiated with the active species twice or more at a predetermined period.

In addition, the present invention has the following aspects.
[1] A tubular dielectric into which a gas for generating atmospheric pressure plasma is introduced, and an internal electrode having a coiled shape or an uneven surface that extends in the axial direction of the tubular dielectric in the inner space of the tubular dielectric. , A plasma device comprising an external electrode along the internal electrode on the outside of the tubular dielectric.
[2] The plasma apparatus according to [1], wherein the shape of the external electrode is a tubular shape surrounding the outer peripheral portion of the tubular dielectric.
[3] The plasma apparatus according to [1] or [2], wherein the atmospheric pressure plasma generation gas is nitrogen gas.
[4] The plasma apparatus according to any one of [1] to [3], wherein the irradiation port of the atmospheric pressure plasma has a size that can be inserted into the human oral cavity.
[5] The plasma apparatus according to any one of [1] to [4], wherein the generated atmospheric pressure plasma is used for treatment or activation of cells, biological tissues or individual organisms.
[6] The plasma apparatus according to any one of [1] to [5], further comprising an irradiation amount control device for controlling the irradiation amount of the generated atmospheric pressure plasma.
[7] The method of using the plasma apparatus according to any one of [1] to [6], wherein an alternating current of less than 20 kVpp and less than 20 kHz is applied between the external electrode and the internal electrode. , How to use a plasma device, characterized by generating atmospheric pressure plasma.
[8] By controlling the introduction amount of the atmospheric pressure plasma generation gas introduced into the tubular dielectric, the irradiation amount of the atmospheric pressure plasma irradiated from the irradiation port is controlled to less than 5.0 L / min. The method of using the plasma apparatus according to [7].
[9] Control at least one of the AC and the introduction amount of the atmospheric pressure plasma generation gas so that the temperature of the atmospheric pressure plasma becomes 40 ° C. or less at a distance of 1 mm or more and 10 mm or less from the irradiation port. The method of using the plasma apparatus according to [7] or [8].
[10] Nitrogen gas characterized by purifying or activating the irradiated portion or promoting healing of a wound or abnormality in the irradiated portion when irradiated to a cell, a living tissue or an individual organism. plasma.
[11] By irradiating cells, biological tissues or individual organisms with nitrogen gas plasma, the irradiated portion is cleaned or activated, or the wound or abnormality in the irradiated portion is promoted to heal. Nitrogen gas plasma irradiation method (however, except when the individual organism is a human).
[12] The method for irradiating a nitrogen gas plasma according to [11], wherein the nitrogen gas plasma is irradiated to the periodontal tissue or the tooth.
[13] The method for irradiating nitrogen gas plasma according to [11], wherein the nitrogen gas plasma is irradiated to the epithelial tissue.

The plasma apparatus of the present invention can be manufactured at a relatively low cost.
According to the plasma apparatus of the present invention, low-temperature atmospheric pressure plasma can be irradiated. This atmospheric pressure plasma can be applied to a living body or a soft material to clean the irradiated surface. Furthermore, the living body can be treated or activated by the plasma irradiation.
According to the method of using the plasma apparatus of the present invention, low-temperature atmospheric pressure plasma can be easily generated by applying a predetermined alternating current between the electrodes provided in the plasma generating unit.
According to the nitrogen gas plasma of the present invention and the irradiation method thereof, the irradiated portion can be cleaned or activated, or the healing of a wound or an abnormality in the irradiated portion can be promoted.

It is a schematic diagram of the plasma generation part in one Embodiment of the plasma apparatus of this invention. 1 is a cross-sectional view taken along the line xx of FIGS. 1 and 4. FIG. It is sectional drawing which cut at the yy line of FIG. It is a schematic diagram of the plasma generation part in another embodiment of the plasma apparatus of this invention. It is a schematic diagram which shows the structure of the plasma generation part in the conventional plasma apparatus.

《Plasma device》
FIG. 1 shows a main part of the plasma apparatus 1 of the first embodiment according to the present invention.
The plasma device 1 includes a plasma generation unit 2 in which an atmospheric pressure plasma generation gas G is ionized to generate an atmospheric pressure plasma P, and an irradiation port 6 for irradiating the atmospheric pressure plasma P to the outside.

The plasma generation unit 2 is a coil that is installed in the tubular dielectric 3 into which the atmospheric pressure plasma generation gas G is introduced and in the inner space of the tubular dielectric 3 and extends in the axial direction (arrow D1) of the tubular dielectric 3. It is provided with an internal electrode 4 having a shape, and an external electrode 5 installed on the outer peripheral portion of the tubular dielectric 3 and extending along the internal electrode 4. The constituent materials of the internal electrode 4 and the external electrode 5 are not particularly limited as long as they are conductive materials, and metals used for electrodes of known plasma devices can be applied. A power source E for applying a voltage is connected between the internal electrode 4 and the external electrode 5.

A cylinder (not shown) for supplying the atmospheric pressure plasma generation gas G is connected to the first end portion (rear end portion) of the tubular dielectric 3 via a pipe. The constituent material of the tubular dielectric 3 is not particularly limited, and a dielectric material used in a known plasma device can be applied, and examples thereof include glass, ceramics, and synthetic resin. The lower the dielectric constant of the tubular dielectric 3, the more preferable. The cross-sectional shape of the tubular dielectric 3 is not particularly limited, and examples thereof include a circle, an ellipse, a quadrangle, and a hexagon.

The cowling 7 houses the external electrode 5, the tubular dielectric 3, and the internal electrode 4 in the internal space. With this configuration, it is prevented from inadvertently contacting the external electrode 5 or the internal electrode 4 from the outside and receiving an electric shock. The cowling 7 is preferably made of an insulating material.

The shape of the tip of the cowling 7 is tapered, and the irradiation port 6 for deriving the atmospheric pressure plasma P is opened at the top thereof. The irradiation port 6 is located above the tip of the tubular dielectric 3 on an extension of the axis of the tubular dielectric 3.

FIG. 2 shows a cross-sectional view taken along the line xx of FIG. A cylindrical cowling 7, a cylindrical external electrode 5, a tubular dielectric 3, and a coiled internal electrode 4 are arranged concentrically from the outside to the center in this order. The external electrode 5 is arranged in close contact with the outer peripheral surface of the tubular dielectric 3. The internal electrodes 4 are arranged at a predetermined distance from the inner peripheral surface of the tubular dielectric 3.

FIG. 3 shows a cross-sectional view cut along the yy line of FIG. However, the cowling 7 is omitted and not shown.
As shown in FIG. 3, the longitudinal directions of the tubular dielectric 3, the external electrode 5, and the internal electrode 4 are along the same direction (direction of arrow D1). In this cross section, the outer peripheral surface of the coil of the internal electrode 4 faces the inner peripheral surface of the external electrode 5 with the tube wall 3a of the tubular dielectric 3 interposed therebetween, and there are a plurality of adjacent locations 4p. Each location 4p is separated from each other and is dispersedly arranged.
With the above arrangement, the internal electrode 4 to which the voltage is applied is prevented from being overheated locally, and a low temperature atmospheric pressure plasma P is easily generated.

The distance between each portion 4p of the coil of the internal electrode 4 and the external electrode 5 may be the same or different. It is preferable that two or more of the plurality of adjacent locations 4p are close to the inner peripheral surface of the external electrode 5 at a distance at which atmospheric pressure plasma can be generated. Examples of the distance at which a low-temperature atmospheric pressure plasma can be easily generated include 0.01 to 2.0 mm.

The shape of the internal electrode 4 provided in the plasma device 1 is not limited to the coil shape, and may be a shape having irregularities on the surface of the electrode facing the external electrode 5. For example, a shape in which a plurality of warts (projections), grooves, holes, and through holes are formed on the outer peripheral surface of the rod-shaped or cylindrical internal electrode 4 can be mentioned. The cross-sectional shape of the internal electrode 4 is not particularly limited, and examples thereof include a circle, an ellipse, a quadrangle, and a hexagon.
Further, any other shape may be used as long as it has a shape facing the inner surface of the outer electrode 5 at a plurality of points on the outer peripheral surface of the inner electrode 4 in a cross section orthogonal to the length direction.

FIG. 4 shows a schematic diagram of the plasma generating unit 2 of the plasma apparatus 10 of the second embodiment according to the present invention. The same members as those of the plasma apparatus 1 of the first embodiment are designated by the same reference numerals. On the outer peripheral surface of the internal electrode 4'of the plasma device 10, a plurality of wart-shaped protrusions 4q are arranged so as to be separated from each other and dispersed. The wart-shaped protrusions 4q are arranged as described above in the region of the outer peripheral surface of the internal electrode 4'in FIG. 4 that overlaps with the external electrode 5 (the region hidden in the figure). The schematic cross section cut along the xx line of the outer peripheral surface view 4 is shown in FIG.

As shown in FIG. 4, the longitudinal directions of the tubular dielectric 3, the external electrode 5 and the internal electrode 4'are along the same arrow D1 direction. The wart-shaped protrusions 4q on the outer peripheral surface of the internal electrode 4 ′ face the inner peripheral surface of the external electrode 5 with the tube wall 3a of the tubular dielectric 3 interposed therebetween. There are a plurality of wart-shaped protrusions 4q as locations close to the inner peripheral surface of the external electrode 5.
With the above arrangement, the internal electrode 4'to which the voltage is applied is prevented from being overheated locally, and a low temperature atmospheric pressure plasma P is easily generated.

The shape of the external electrode 5 is not particularly limited as long as it can be arranged along the internal electrode 4 (hereinafter, unless otherwise specified, it is not distinguished from the internal electrode 4'), and is, for example, a cylinder, a rod, or a plate. The shape such as a shape can be mentioned. Of these, a cylindrical shape is preferable, and a cylindrical shape having an inner diameter that can be installed in close contact with the outer peripheral surface of the tubular dielectric 3 is more preferable. Due to such a cylindrical shape, the external electrode 5 can be arranged so that the inner peripheral surface of the external electrode 5 surely faces the outer peripheral surface of the internal electrode 4.

When the external electrode 5 has a rod shape or a plate shape, the number of the external electrodes 5 to be installed is not particularly limited, and may be one or two or more. When two or more are installed, it is preferable that they are arranged on the outer periphery of the tubular dielectric 3 at equal intervals because the ionized parts of the atmospheric pressure plasma generation gas G are dispersed.

The shape of the cowling 7 is not particularly limited, and it is preferable that the external electrode 5 and the internal electrode 4 have a shape that can be accommodated in the internal space. It is preferable that the tubular dielectric 3 is also housed in the internal space, but the tip of the tubular dielectric 3 may protrude to the outside of the cowling 7. The cowling 7 preferably has an irradiation port 6 that irradiates the atmospheric pressure plasma P emitted from the tip end portion of the tubular dielectric 3 toward an external irradiation target.

The cowling 7 preferably functions as a nozzle that irradiates the atmospheric pressure plasma generated by the plasma generating unit 2 to the outside of the apparatus. When the nozzle portion of the irradiation port 6 and the cowling 7 constituting the irradiation port 6 is large enough to be inserted into the human oral cavity, the atmospheric pressure plasma P can be easily applied for dental treatment or aesthetic purposes.

The plasma device 1 preferably includes a power supply control unit (not shown) that controls the voltage and frequency of the power supply E that applies a voltage between the external electrode 5 and the internal electrode 4. Examples of the power supply control unit include known power supply control devices.

The plasma device 1 preferably includes an irradiation amount control unit (not shown) that controls the irradiation amount of the atmospheric pressure plasma P. Examples of the irradiation amount control unit include a device that controls the introduction amount of the plasma generation gas G introduced into the tubular dielectric 3. Specifically, for example, a known mass flow controller that controls the flow rate of the gas introduced into the tubular dielectric 3 from the cylinder (not shown) of the plasma generation gas G via the pipe can be mentioned.

As described above, since the plasma generation unit 2 of the plasma device 1 has a simple structure, it can be manufactured at a relatively low cost.

<< How to use the plasma device >>
The usage method of the plasma apparatus 1 of FIG. 1 is illustrated. The plasma generation gas G supplied from the cylinder is introduced from the lower end portion (first end portion) of the tubular dielectric 3 to the inner space thereof. The plasma generation gas G introduced into the inner space is ionized at a plurality of locations 4p where the internal electrode 4 and the external electrode 5 installed at the tip (second end) of the tubular dielectric 3 face each other, and is large. It becomes the pressure plasma P. At this time, a voltage is applied between the internal electrode 4 and the external electrode 5.

Atmospheric pressure plasma P generated at a plurality of locations 4p where the outer peripheral surface of the internal electrode 4 and the inner peripheral surface of the external electrode 5 face each other is emitted from the tip of the tubular dielectric 3 and is emitted from the irradiation port in the internal space of the cowling 7. You will be guided to 6. The irradiation port 6 is directed at the irradiation target, and the atmospheric pressure plasma P is irradiated. Since the internal space of the tip portion of the cowling 7 has a tapered shape and the irradiation port 6 is provided at the top thereof, the tip portion of the cowling 7 functions as a nozzle.

In the inner space of the tubular dielectric 3, the outer peripheral surface of the inner electrode 4 and the inner peripheral surface of the outer electrode 5 are arranged so as to face each other with the tube wall 3a of the tubular dielectric 3 interposed therebetween. Due to this arrangement, a plurality of locations 4p where electric field concentration occurs for ionization of the atmospheric pressure plasma generation gas G are dispersed. As a result, the internal electrode 4 to which the voltage is applied is prevented from being overheated locally, and a low-temperature atmospheric pressure plasma P is easily generated.
Not only when the internal electrode 4 is coiled, but also the above-mentioned internal electrode having a plurality of irregularities formed on the surface, a low-temperature atmospheric pressure plasma can be easily generated.

On the other hand, in the conventional plasma apparatus 100 of FIG. 5, the electrodes 102a and 102b are locally close to each other at one point at the tip of the gas tube 101, and electric field concentration occurs locally, so that the electrodes are placed when plasma is generated. There is a problem that the temperature of the generated atmospheric pressure plasma becomes high due to overheating.

In the plasma device 1, the content of active species contained in the atmospheric pressure plasma P and the temperature of the atmospheric pressure plasma P are controlled by controlling the voltage and frequency applied between the electrodes 4 and 5 by a power supply control unit (not shown). Can be easily controlled.
As an example, by applying an alternating current controlled in a range of less than 20 kVpp and less than 20 kHz between the external electrode 5 and the internal electrode 4, for example, atmospheric pressure plasma P of 40 ° C. or lower can be generated.

The AC voltage applied between the electrodes 4 and 5 is preferably 5.0 kVpp or more and less than 20 kVpp, more preferably 6.0 kVpp or more and less than 15 kVpp, and further preferably 7.0 kVpp or more and less than 10 kVpp. Here, the unit "Vpp (Volt peak to peak)" representing the AC voltage is the potential difference between the maximum value and the minimum value of the AC voltage waveform.
By setting the applied AC voltage to less than the upper limit of each of the above ranges, the temperature of the generated atmospheric pressure plasma P can be kept low. By setting the value to the lower limit of each of the above ranges or more, the atmospheric pressure plasma P can be easily generated.

The frequency of the alternating current applied between the electrodes 4 and 5 is preferably 0.5 kHz or more and less than 20 kHz, more preferably 1 kHz or more and less than 15 kHz, further preferably 2 kHz or more and less than 10 kHz, particularly preferably 3 kHz or more and less than 9 kHz, and 4 kHz or more and less than 8 kHz. Is the most preferable.
By setting the AC frequency to less than the upper limit of each of the above ranges, the temperature of the generated atmospheric pressure plasma P can be kept low. By setting the value to the lower limit of each of the above ranges or more, the atmospheric pressure plasma P can be easily generated.

It is preferable to control the irradiation amount of the atmospheric pressure plasma P irradiated from the irradiation port 6 to less than 5.0 L per minute by controlling the amount of the plasma generation gas G introduced into the tubular dielectric 3.
In the plasma apparatus 1, the introduced amount of the plasma generation gas G and the irradiation amount of the atmospheric pressure plasma P correspond to each other in a ratio of approximately 1: 1. By controlling the introduction amount to less than 5.0 L / min, the irradiation amount can be controlled to less than 5.0 L / min.

The introduction amount and the irradiation amount are preferably 0.1 L or more and less than 5.0 L per minute, more preferably 0.3 L or more and less than 3.5 L per minute, and further preferably 0.6 L or more and less than 2.0 L per minute. preferable.
When it is at least the lower limit of each of the above ranges, the efficiency with which the atmospheric pressure plasma P acts on the irradiated surface is sufficiently enhanced.
If it is less than the upper limit of each of the above ranges, it is possible to prevent the temperature of the irradiated surface of the atmospheric pressure plasma P from rising excessively. Further, when the irradiated surface is wet, rapid drying of the irradiated surface can be prevented. Further, when the irradiated surface is the affected area, it is possible to prevent the patient from being injured.

The voltage and frequency of the AC power supply and the frequency so that the temperature of the atmospheric pressure plasma P irradiated from the irradiation port 6 is 40 ° C. or less at a position (irradiation distance) separated from the irradiation port 6 by a distance of 1 mm or more and 10 mm or less. It is preferable to control at least one of the introduced amounts of the atmospheric pressure plasma generation gas G.
For example, the temperature of the atmospheric pressure plasma P at the above-mentioned position can be controlled to 40 ° C. or lower by setting it in a suitable range of the above-mentioned voltage and frequency, or by setting it in the above-mentioned suitable range of the introduction amount. ..
The temperature of the atmospheric pressure plasma P at the above position is measured by installing the tip of a rod-shaped thermocouple at the above position from the irradiation port 6 in a state where the atmospheric pressure plasma P is irradiated into the air from the irradiation port 6. ..

The type of the atmospheric pressure plasma generation gas G to be introduced into the tubular dielectric 3 is not particularly limited, and for example, in addition to known plasma generation gases such as oxygen, helium, and argon, conventionally used as far as the present inventors know. It is possible to use nitrogen gas that has never been used.
As described above, the plasma generation unit 2 of the plasma device 1 can efficiently ionize nitrogen gas at a plurality of locations 4p of the internal electrode 4 to easily generate a low-temperature nitrogen gas plasma.
The atmospheric pressure plasma generation gas G to be introduced into the tubular dielectric 3 may be one kind of gas or a gas in which two or more kinds are mixed.

When the nitrogen gas plasma is generated, the volume of the nitrogen gas contained in the atmospheric pressure plasma generation gas G introduced into the tubular dielectric 3 is preferably more than 50%, more preferably 70% or more. It is more preferably 90 to 100%. The type of the remaining gas component is not particularly limited, and for example, air can be mixed with nitrogen to generate a nitrogen gas plasma.

<< Use of atmospheric pressure plasma >>
The atmospheric pressure plasma P generated by the plasma device 1 is preferably used for the purpose of irradiating a living body such as a cell, a living tissue, or an individual living body. By irradiating a living body with atmospheric pressure plasma P, the living body can be treated or activated. For example, by irradiating the affected area with trauma such as cuts, abrasions, burns, or other abnormalities with atmospheric pressure plasma P, the effect of promoting the healing of the trauma and the abnormalities can be obtained.

When irradiating an affected area with trauma or abnormality with atmospheric pressure plasma P, it may be required to reduce the irradiation amount for the purpose of preventing pain to the patient. In this case, the irradiation amount of the atmospheric pressure plasma P irradiated from the irradiation port 6 is reduced by reducing the introduction amount of the plasma generation gas G introduced from the rear end portion of the tubular dielectric 3 of the plasma device 1. Can be done.

It may be required to further promote the healing by increasing the concentration of the active species contained in the atmospheric pressure plasma P. In this case, when irradiating the atmospheric pressure plasma P, the irradiation port 6 is brought closer to the irradiated portion at a distance of 0.01 mm or more and 10 mm or less to irradiate the atmospheric pressure plasma P containing a higher concentration of active species. can do.
Since the temperature of the atmospheric pressure plasma P irradiated from the plasma device 1 can be set to 40 ° C. or lower, the temperature of the irradiated portion may become excessively high even when the irradiation port 6 is brought close to the irradiated portion. No. Therefore, even when the irradiated portion is the affected portion, it is possible to irradiate the affected portion without causing burns.

The nitrogen gas plasma generated by the plasma device 1 has an effect of promoting healing of trauma and abnormalities. As shown in Examples described later, by irradiating a cell, a biological tissue or an individual organism with nitrogen gas plasma, the irradiated portion is cleaned or activated, or the wound or abnormality in the irradiated portion is healed. can do.
Examples of the biological tissue include organs such as internal organs, epithelial tissue covering the inner surface of the body surface and body cavity, periodontal tissue such as gingiva, alveolar bone, periodontal ligament and cementum, teeth and bone.

When irradiating nitrogen gas plasma for the purpose of promoting healing of trauma or abnormality, the irradiation frequency, number of irradiations and irradiation period are not particularly limited, and for example, nitrogen gas is irradiated at an irradiation amount of 0.5 L or more and 5.0 L per minute. When irradiating the affected area with plasma, irradiation conditions such as 1 to 5 times a day, 10 seconds to 10 minutes each time, 1 to 30 days, etc. are preferable from the viewpoint of promoting healing.

(Temperature measurement)
Using the plasma device 1, an alternating current of 8.2 kVpp and 7 kHz was applied between the external electrode 5 and the internal electrode 4 to generate an atmospheric nitrogen gas plasma. Nitrogen gas plasma was irradiated at 1 L per minute toward the tip of a rod-shaped thermocouple installed at a distance of 2 mm or 10 mm from the irradiation port 6, and the temperature was measured.
As a result, it was about 36 ° C. at a distance of 2 mm from the irradiation port 6 and about 32 ° C. at a distance of 10 mm from the irradiation port 6.

(Promotion of wound healing 1)
Prepare rabbits with equivalent wounds on two places on the back, and nitrogen gas plasma at atmospheric pressure (8.2 kVpp, 7 kHz, 1 L / min, 40 ° C.) from a distance of about 5 mm only for one wound. Was irradiated for 90 seconds. As a result, a scab was formed on the surface of the wound 1 day after irradiation, the area of the wound was reduced 3 days after irradiation, and healing was progressing. On the other hand, the other wound, which was not irradiated with nitrogen gas plasma for comparison, did not change after 1 day, and scabs began to form after 3 days.

When the cell tissue 7 days after the wound irradiated with the above nitrogen gas plasma was observed, it was confirmed that the thick epidermis was regenerated, fibroblasts were proliferated, and blood vessels were newly formed.
On the other hand, when the cell tissue of the comparative wound not irradiated with nitrogen gas plasma was observed after 7 days, the thin epidermis was regenerated, but the growth of fibroblasts and the renewal of blood vessels were not observed.

(Promotion of wound healing 2)
Another rabbit with equivalent wounds was prepared in two places on the back, and only one wound was irradiated with nitrogen gas plasma at atmospheric pressure similar to the above once a day for 7 consecutive days. .. Observation of the cell tissue 7 days after the wound confirmed that the epidermis was regenerated thicker than when it was irradiated only once, there was a vigorous proliferation of fibroblasts, and there was a large number of new blood vessels. rice field.
On the other hand, when the cell tissue of the comparative wound not irradiated with nitrogen gas plasma was observed after 7 days, the thin epidermis was regenerated, but the growth of fibroblasts was small and no new blood vessel was observed. ..

(Promotion of wound healing 3)
Normal rats (SD rats) with equivalent wounds on the back were prepared.
The first wound is irradiated with atmospheric pressure nitrogen gas plasma (8.2 kVpp, 7.4 kHz, 1 L / min, 35 ° C.) from a distance of about 1 mm only once immediately after the wound is inflicted for 90 seconds. bottom.
The second wound was irradiated once immediately after the wound was inflicted and once a day for 5 days thereafter, and a total of 5 times of nitrogen gas plasma was irradiated under the same conditions as above.
The third wound was not irradiated with nitrogen gas plasma.
Comparing the conditions 5 days after the wound was inflicted, the healing progressed in the order of the second wound (daily irradiation), the first wound (only one irradiation), and the third wound (no irradiation). board.
From the above results, it is considered that irradiation with nitrogen gas plasma promoted wound healing.

(Promotion of wound healing 4)
The same test as the above-mentioned normal rat (SD rat) was performed using a diabetic rat (SDT Fatty). As a result, it was confirmed that the healing progressed in the order of the second wound (daily irradiation), the first wound (only one irradiation), and the third wound (no irradiation) in the same manner as described above.

From the above results, it is clear that irradiation with atmospheric nitrogen gas plasma promotes wound healing.

(Removal of biofilm)
For extracted human molars, tartar and dirt are removed using an ultrasonic scaler, the tooth surface is mechanically polished using a tooth surface polishing agent, and the polishing agent etc. is removed using an ultrasonic cleaning machine. By sterilizing with ethylene oxide gas, an experimental tooth material was obtained.
By adhering periodontal disease bacteria (P. Gingivalis) to the surface of the tooth material and culturing it, a biofilm (plaque) was formed over a wide area on the surface of the tooth material.
The biofilm stuck to the surface of the tooth material was irradiated with atmospheric pressure nitrogen gas plasma (8.2 kVpp, 7.4 kHz, 1 L / min, 35 ° C.) from a distance of about 1 mm for 90 seconds.
After lightly rinsing the irradiated tooth material in water and observing the tooth surface, the biofilm at the irradiated site was washed off. On the other hand, the biofilm in the portion not irradiated with the nitrogen gas plasma remained attached.

When a comparative experiment was conducted in which a simple nitrogen gas was sprayed on the tooth material to which the biofilm was attached instead of the nitrogen gas plasma, the biofilm could not be removed.

(Treatment for periodontal disease 1)
Periodontal disease bacteria were infected around the first molars of healthy hamsters, and PCR examination at a later date confirmed that the periodontal disease bacteria had grown. The inflamed gingiva of this hamster was irradiated with atmospheric pressure nitrogen gas plasma (8.2 kVpp, 7.4 kHz, 1 L / min, 35 ° C.) for 90 seconds from a distance of about 1 mm.
When the gingiva of the irradiated part was observed one day later, the inflammation was clearly improved. On the other hand, the inflammation of the gingiva at the site not irradiated with nitrogen gas plasma was not improved.

(Treatment for periodontal disease 2)
The gingiva of a hamster having the same periodontitis as described above was irradiated with atmospheric pressure nitrogen gas plasma (8.2 kVpp, 7.4 kHz, 1 L / min, 35 ° C.) from a distance of about 1 mm for 90 seconds. After that, it was irradiated once a day for 7 days, and a total of 7 times of nitrogen gas plasma was irradiated under the same conditions as above.
Seven days after the first irradiation, the gingiva of the irradiated area was observed, and the inflammation had subsided and healed. On the other hand, the inflammation of the gingiva in the place where the nitrogen gas plasma was not irradiated was hardly improved.

(Treatment for periodontal disease 3)
By wrapping a thread around the upper left molar of four healthy beagle dogs (weighing about 10 kg), feeding them with soft food, and breeding them for 21 days in a state where dirt easily adheres to the periphery of the molar, the periphery of the molar. In addition, palpation caused gingival inflammation to the extent that it did not bleed.

For two of the above four beagle dogs suffering from periodontitis, nitrogen gas plasma (8.2 kVpp, 7.4 kHz, per minute) at atmospheric pressure from a distance of about 1 mm to the inflamed gingiva. 1 L, 35 ° C.) was irradiated for 90 seconds. This plasma irradiation was performed once every other day for a total of 7 times over 2 weeks.
Two weeks after the first irradiation, the gingiva at the irradiated area was observed, and the inflammation had subsided and healed.

For the other one of the above four beagle dogs suffering from periodontitis, 90 mere nitrogen gas (1 L / min, 20-25 ° C) was applied to the inflamed gingiva from a distance of about 5 mm. Sprayed for a second. This spraying was performed once every other day for a total of 7 times over 2 weeks.
Two weeks after the first spraying, the gingiva at the sprayed site was observed, and the inflammation of the gingiva was not improved.

No treatment was given to the remaining one of the above four beagle dogs suffering from periodontitis. When the gingiva was observed two weeks later, the inflammation of the gingiva was not improved.

(Activation of periodontal ligament cells)
Using a 12-well plate, human periodontal ligament cells were seeded in calcification medium (including a reagent that turns red when the cells were calcified) and cultured by a known method.
The cultured cells in the three wells were irradiated with atmospheric pressure nitrogen gas plasma (8.2 kVpp, 7.4 kHz, 1 L / min, 35 ° C.) from above about 1 mm away for 90 seconds. When the well was observed the next day, red cells indicating calcification were strongly observed in a wide area in the well.
The cultured cells in the other three wells were sprayed with simple nitrogen gas (1 L / min, 20-25 ° C.) for 90 seconds from above at a distance of about 1 mm. When the well was observed the next day, red cells indicating calcification were thinly observed in some parts of the well.
No treatment was performed on the cultured cells in the other three wells. When the well was observed the next day, almost no red cells indicating calcification were observed in the well.
From the above results, it is considered that the irradiation of the nitrogen gas plasma activates human periodontal ligament cells and promotes their calcification, whereby the alveolar bone and the tooth are joined to improve periodontal disease.

The present invention is available in the medical field.

1 ... Plasma device, 2 ... Plasma generator, 3 ... Tubular dielectric, 3a ... Tube wall, 4 ... Internal electrode, 5 ... External electrode, 6 ... Irradiation port, 7 ... Cowling, P ... Atmospheric pressure plasma, G ... Large Gas for atmospheric pressure plasma generation, E ... power supply, 100 ... conventional plasma device, 101 ... gas tube, 102a ... electrode, 102b ... electrode, 103 ... nozzle

Claims (3)

A tubular dielectric, wherein is installed in the hollow portion of the tubular dielectric extends in the axial direction of the tubular dielectric and internal electrode you apart from the inner peripheral surface of the tubular dielectric, the outer peripheral portion of the tubular dielectric placed against the plasma generating portion and an external electrode extending along the inner electrode, the nitrogen gas is supplied at less than min 5.0L plasma generation gas containing 90 to 100 vol% in said empty portion, A step of applying a voltage to the plasma generation gas at a frequency of less than 20 kVpp and a frequency of less than 20 kHz to ionize the nitrogen gas at a plurality of locations where the internal electrode and the external electrode face each other to generate plasma.
An irradiation step of irradiating the oral cavity with plasma containing an active species generated by the plasma at a distance of 0.01 mm or more and 10 mm or less from the irradiation port to the irradiated portion.
Oral cleansing method (excluding medical practice for humans). The oral cleaning method according to claim 1, wherein the irradiation step irradiates the tooth surface with plasma containing the active species (however, medical practice for humans is excluded). The oral cleansing method according to claim 1 or 2, wherein the irradiation step is performed twice or more with a predetermined period of time to irradiate the plasma containing the active species (however, medical practice for humans is excluded).

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