WO2024142554A1 - Intraoral cleaning tool - Google Patents

Abstract

The objective of the present invention is to provide an intraoral cleaning tool that can deliver ultrasonic cavitation energy to a target area without attenuation to clean the inside of the oral cavity more effectively. Provided is an intraoral cleaning tool including an ultrasonic emitter (6) and a reflector (8), wherein the ultrasonic emitter (6) includes an oscillator and a horn located at an output end of the oscillator, the reflector (8) is located apart from the horn, and when ultrasonic waves are emitted from the horn, some or all of the ultrasonic waves are reflected in any direction by a reflective surface (81) of the reflector (8).

Description

Oral cleaning tools

The present invention relates to an oral cavity cleaning tool.
This application claims priority based on Japanese Patent Application No. 2022-209866, filed on December 27, 2022, the contents of which are incorporated herein by reference.

Plaque control is important for preventing oral diseases such as periodontal disease and caries. Manual and electric toothbrushes that combine different bristle shapes, bristle planting patterns, and vibration mechanisms have been proposed to more effectively remove plaque. However, the bristles of the toothbrush may not be effective enough to remove plaque on adjacent surfaces, subgingival plaque, or minute stains that have adhered to uneven tooth surfaces, and there are limitations to physical cleaning.

To address these issues, there is ultrasonic cavitation technology, which uses the shock waves generated by bursting microscopic bubbles in liquid to clean objects without contact.Ultrasonic cavitation is a phenomenon in which ultrasonic waves are applied to water, causing a sudden change in pressure in the gas dissolved in the water, which then generates shock waves due to the collapse of the bubbles.
For example, Patent Document 1 proposes an oral cleaning tool that has a cleaning head containing a solid detergent, a handle, and a vibration part, and disperses the solid detergent in the oral cavity while generating ultrasonic cavitation in the vibration part.

International Publication No. 2018/056734

However, ultrasonic waves have the property of traveling in a straight line. Therefore, when an oral cleaning tool is simply held in the mouth, the ultrasonic energy generated by the oral cleaning tool acts in a direction different from the target tooth (for example, toward the throat), and the energy does not reach the target tooth sufficiently. In order to improve the cleaning effect of an oral cleaning tool using ultrasonic cavitation, it is necessary to deliver the ultrasonic cavitation energy to the target area without attenuation.
SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide an oral cavity cleaning tool that can clean the oral cavity more effectively.

The present invention has the following aspects.
<1> An ultrasonic transducer having an ultrasonic oscillator and a reflector,
The ultrasonic oscillator has a transducer and a horn located at an output end of the transducer,
The reflector is located at a distance from the horn,
An oral cavity cleaning tool in which, when ultrasonic waves are emitted from the horn, a part or all of the ultrasonic waves are reflected in any direction by the reflecting surface of the reflector.
<2> The reflector is located ahead of the horn in a direction of an axis from the transducer to the horn,
The oral cavity cleaning tool described in <1>, wherein a part or all of the reflector overlaps with the horn when viewed from the tip in the axial direction.
<3> The oral cavity cleaning tool according to <2>, wherein the distance between the horn and the reflector in the axial direction is within 20 mm.
<4> The oral cavity cleaning tool according to <2> or <3>, wherein the angle between the reflecting surface and the axis is 30 to 89°.
<5> The oral cavity cleaning tool according to any one of <2> to <4>, wherein the reflector overlaps with the horn by 50% or more of its area when viewed from the tip in the axial direction.
<6> A cover body that integrally covers the horn and the reflector,
The oral cavity cleaning tool according to any one of <2> to <5>, wherein the cover body opens in a direction inclined with respect to the axis.
<7> The oral cavity cleaning tool according to any one of <2> to <6>, wherein the surface of the reflector facing the horn is mirror-finished.
<8> The oral cavity cleaning tool according to any one of <1> to <8>, wherein the difference between the specific acoustic impedance of the material constituting the reflecting surface and the specific acoustic impedance of liquid present in the oral cavity is 30×10 ⁶ N·s/cm ³ or more.

The oral cavity cleaning tool of the present invention allows for more effective cleaning of the oral cavity.

1A is a front view of an oral cavity cleaning tool according to one embodiment of the present invention, and FIG. 1B is a side view of the oral cavity cleaning tool according to one embodiment of the present invention. This is a cross-sectional view taken along line II-II of FIG. FIG. 2 is a cross-sectional view of an ultrasonic oscillator according to one embodiment. FIG. 4 is a schematic diagram showing an example of the shape of a reflector. FIG. 4 is a schematic diagram showing an example of the shape of a reflector. FIG. 4 is a schematic diagram showing an example of the shape of a reflector. FIG. 4 is a schematic diagram showing an example of the shape of a reflector. FIG. 2 is a schematic diagram showing a reflector and an ultrasonic oscillator. 1A is a diagram showing a method for cleaning the lateral surface of a tooth, and FIG. 1B is a diagram showing a method for cleaning the occlusal surface of a tooth. FIG. 1 is a diagram illustrating a method for cleaning teeth.

(oral cleaning tool)
The oral cavity cleaning tool of the present invention has an ultrasonic oscillator and a reflector. An example of the oral cavity cleaning tool of the present invention will be described below.

The oral cleaning tool 1 in FIG. 1 has a long handle portion 2 and a head portion 4 located at the tip of the handle portion 2. The handle portion 2 has a grip portion 22 and a neck portion 24 extending from the tip of the grip portion 22. The head portion 4 is located at the tip of the neck portion 24.

The head part 4 has a cover body 41. The cover body 41 has a cover main body part 41a and a cover mouth part 41b protruding from the cover main body part 41a in the front direction. The cover mouth part 41b is a square tube surrounded by four walls. The cover mouth part 41b has an opening part 42 at its tip. In this embodiment, the cover mouth part 41b has an enlarged diameter part 43 near the opening part 42 that widens toward the opening part 42. The cover mouth part 41b is not limited to a square tube shape, and may be a cylindrical shape or a polygonal tube shape other than a square. In addition, the cover mouth part 41b may not have the enlarged diameter part 43, and may widen from the base end (the boundary with the cover main body part 41a) toward the opening part 42. Alternatively, the cover mouth part 41b may be open in the direction from the handle part 2 toward the head part 4 when viewed from the front. In other words, the cover opening portion 41 b may have a wall portion only in a direction perpendicular to the direction from the handle portion 2 toward the head portion 4 .
The cover body 41 has an elastic body 44 on the periphery of the opening 42. That is, the cover opening portion 41b has the elastic body 44 at its tip.

The handle portion 2 is, for example, a cylindrical or rectangular tubular molded product. Examples of the material for the handle portion 2 include resin, metal, etc. Examples of the resin include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, polyacetal, and acrylonitrile-butadiene-styrene polymer (ABS).
The grip portion 22 may be provided with an elastomer coating. Examples of the elastomer include olefin-based elastomers, styrene-based elastomers, polyester-based elastomers, and polyurethane-based thermoplastic elastomers.

The cover body 41a is a housing having a rectangular parallelepiped appearance. The material of the cover body 41a may be the same as or different from the material of the handle portion 2.
The material constituting the inner surface of the cover mouth 41b is preferably the same as the material constituting the reflecting surface 81 described later. When the inner surface of the cover mouth 41b is made of such a material, the ultrasonic waves generated from the ultrasonic oscillator 6 can be propagated from the opening 42 into the oral cavity without being attenuated. For example, ultrasonic waves reflected after colliding with the surface to be cleaned are reflected by the inner surface of the enlarged diameter portion 43 of the cover mouth 41b toward the surface to be cleaned. This allows the oral cavity to be cleaned more efficiently.

Examples of materials for the elastic body 44 include silicone resin, olefin-based elastomer, styrene-based elastomer, polyester-based elastomer, and polyurethane-based thermoplastic elastomer.

The length L1 of the intra-oral cleaning tool 1 (the length from the rear end of the handle portion 2 to the tip of the head portion 4) is, for example, 50 to 200 mm.
The length L4 of the head portion 4 (the length from the boundary with the neck portion 24 to the tip) is, for example, 10 to 30 mm.
The width W4 of the head portion 4 in a front view is, for example, 5 to 25 mm.
The thickness T4 of the head portion 4 in a side view is, for example, 10 to 20 mm.

When viewed from the front, the length L42 of the opening 42 (the length from the rear end of the intraoral cleaning tool 1 to the front end) is, for example, 5 to 25 mm.
The width W42 of the opening 42 in a front view is, for example, 5 to 20 mm.
The size of the opening 42 is preferably such that the opening 42 covers only the teeth when cleaning the oral cavity. The size of the opening 42 will be described with reference to FIG. 10. FIG. 10 is a partial cross-sectional view of the cover body 41 of the head unit 4, showing the state in which the opening 42 is applied to the side of the teeth. In FIG. 10, the elastic body 44 is in contact with the boundary 102a between the upper jaw tooth 100a and the gum 110a, and the boundary 102b between the lower jaw tooth 100b and the gum 110b, when the teeth are in occlusion. By setting the size of the opening 42 so that the elastic body 44 is in contact with both the boundaries 102a and 102b, the ultrasonic waves transmitted from the opening 42 can be propagated more efficiently toward the teeth, and the teeth can be cleaned more efficiently. That is, by making the size of the opening 42 smaller than the distance between the boundaries 102a and 102b, the teeth can be cleaned more efficiently.

As shown in Fig. 2, the intra-oral cleaning tool 1 has an ultrasonic oscillator 6 at a position close to the head portion 4 within the neck portion 24. As shown in Fig. 3, the ultrasonic oscillator 6 has a vibrator 63 and a horn 66.
The intraoral cleaning tool 1 has a reflector 8 inside the cover body 41 of the head part 4. The ultrasonic oscillator 6 and the reflector 8 are spaced apart in the direction of the axis O1, and the tip (output end) 61 of the ultrasonic transmitter 6 faces a reflecting surface 81 (surface facing the ultrasonic oscillator 6) of the reflector 8. In other words, the reflector 8 is located ahead of the horn 66 in the direction of the axis O1 from the transducer 63 toward the horn 66.
In this embodiment, the axis O1 coincides with the traveling direction of the ultrasonic waves emitted from the tip 61 of the ultrasonic oscillator 6.

Because the reflector 8 and the horn 66 are in the above-described positional relationship, the reflector 8 overlaps part or all of the horn 66 when viewed from the tip of the axis O1 (i.e., when viewed from the X direction in FIG. 1).
The degree of overlap of the reflector 8 with the horn 66, as viewed from the X direction, is preferably 50% or more of the area of the horn 66, more preferably 70% or more, and even more preferably 100%. If the degree of overlap is equal to or more than the lower limit, more ultrasonic waves are reflected, and the oral cavity can be cleaned more effectively. In addition, it is preferable that the reflector 8 overlaps with the area including the center of the end face of the horn 66, as viewed from the X direction.

The oral cavity cleaning tool 1 has an oscillator (not shown) inside or outside the handle portion 2. The oscillator is connected to an ultrasonic oscillator 6, a power source (not shown), and a switch (not shown). The power source may be an external power source or an internal power source (such as a battery). The switch may be provided, for example, in the handle portion 2 or in the oscillator.

In the present invention, the vibrator 63 may be either an electrostrictive type or a magnetostrictive type. The vibrator 63 will be described using an electrostrictive type vibrator as an example.

The vibrator 63 has a metal block 62 and a piezoelectric element 64. The piezoelectric element 64 is located on one end surface of the metal block 62. In this embodiment, the metal block 62 and the piezoelectric element 64 are both cylindrical. However, the shapes of the metal block 62 and the piezoelectric element 64 are not limited to cylindrical, and may be polygonal tubular.
A horn 66 is located on the end face of the piezoelectric element 64 (the face opposite to the metal block 62). That is, the ultrasonic oscillator 6 has the metal block 62, the piezoelectric element 64, and the horn 66 arranged in this order. The metal block 62, the piezoelectric element 64, and the horn 66 are connected together by a bolt 68 inserted therein. In the ultrasonic oscillator 6, the tip of the horn 66 on the head portion 4 side forms the tip 61 of the ultrasonic oscillator 6.

In the present embodiment, the ultrasonic oscillator 6 has a piezoelectric element 64 sandwiched between a metal block 62 and a horn 66, but the ultrasonic oscillator 6 is not limited to this. For example, the piezoelectric element 64 may be sandwiched between two metal blocks 62 to form a vibrator 63, with the horn 66 located on one end face of the vibrator 63.

The size of the ultrasonic oscillator 6 is appropriately determined taking into consideration the size of the handle portion 2, etc.
The horn 66 may be in the form of a column having the same thickness from the rear end to the front end 61, or may be in a shape that becomes thinner partly or entirely from the rear end to the front end 61.
The cross-sectional shape of the horn 66 (a cross section perpendicular to the axis O1) may be, for example, a perfect circle, an ellipse, a flattened shape, or a polygonal shape.

The material of the piezoelectric element 64 is, for example, a piezoelectric material such as lead zirconate titanate (PZT).
The material of the metal block 62 is, for example, an alloy containing aluminum as a main component (aluminum alloy), ceramics, etc. An example of the aluminum alloy is duralumin.
The material of the horn 66 is a metal having high ultrasonic wave propagation efficiency and high strength, such as titanium alloy 64 (Ti-6Al-4V) or stainless steel (SUS304).
The material of the bolt 68 is similar to the material of the horn 66. The material of the bolt 68 and the material of the horn 66 may be the same or different.

The reflector 8 faces the tip 61 of the horn 66 and the opening 42 .
4, the reflecting surface 81 of the reflector 8 is flat, so that the ultrasonic wave S emitted from the tip 61 is reflected in a given direction (toward the opening 42 in this embodiment).

The shape of the reflecting surface 81 is not limited to a flat surface.
5, the reflecting surface 81b may be a concave surface that is concave with respect to the ultrasonic oscillator 6. When the reflecting surface 81b is a concave surface, the ultrasonic waves S oscillated from the tip 61 are reflected and collected at the focal point P1.
6, the reflector 81b may be a convex surface formed by combining two or more flat surfaces and projecting toward the ultrasonic oscillator 6. When the reflector 81b is a convex surface formed by combining flat surfaces, the ultrasonic waves S can be propagated in various directions within the oral cavity.
Furthermore, the reflecting surface 81c may have a zigzag bent shape in side view, as in the reflector 8c of Fig. 7. When the reflecting surface 81c has a zigzag bent shape, the ultrasonic waves S can be propagated in various directions within the oral cavity.
If the reflecting surface is made concave as described above, the effective range will be narrowed, but the ultrasonic waves S will be concentrated and the cleaning effect will be enhanced. If the reflecting surface is made convex as described above, the ultrasonic waves S will be diffused and the effective range will be widened, but the cleaning effect will be reduced.

8, the distance L8 between the tip 61 of the ultrasonic oscillator 6 and the reflector 8 is preferably 20 mm or less, more preferably 15 mm or less. When the distance L8 is equal to or less than the upper limit, the attenuation of the ultrasonic waves S is suppressed, and the cleaning effect is further improved. The lower limit of the distance L8 is not particularly limited, but is substantially equal to or more than 3 mm.
The separation distance L8 is the maximum distance between the tip 61 and the reflecting surface 81 in the direction of the axis O1.

The inclination angle θ1 between the axis O1 and the reflecting surface 81 is preferably 30 to 89°, and more preferably 15 to 30°.
When the reflecting surface 81 is a convex or concave surface, the inclination angle θ1 is the angle between the axis O1 and a straight line connecting both ends of the reflecting surface in a side view.

Preferable materials for forming the reflecting surface 81 include metals such as aluminum and stainless steel.
When cleaning the oral cavity with the oral cleaning tool 1, liquid (oral fluid) is present at least between the tip 61, the reflecting surface 81, and the surface to be cleaned (teeth). The difference between the specific acoustic impedance of the material constituting the reflecting surface 81 and the specific acoustic impedance of the oral fluid is preferably 30×10 ⁶ N·s/cm ³ or more, more preferably 35 N·s/cm ³ or more, and even more preferably 40 N·s/cm ³ or more. For example, when the oral fluid is water (specific acoustic impedance=1.5 N·s/cm ³ ), stainless steel (specific acoustic impedance=15.7 N·s/cm ³ ) can be selected as the material constituting the reflecting surface 81.
When the oral fluid is an aqueous solution, the difference may be calculated using the value of the specific acoustic impedance of water.

The reflecting surface 81 is preferably mirror-finished, which can prevent the ultrasonic waves S from diffusing and further enhance the cleaning effect.
The surface roughness Ra of the reflecting surface 81 is preferably less than 200 μm, and more preferably less than 100 μm. The surface roughness Ra is a value measured in accordance with JIS B601:1994.

(How to clean the oral cavity)
An example of a method for cleaning the oral cavity using the oral cavity cleaning tool 1 will be described.
FIG. 9 is a diagram showing a schematic diagram of a method for cleaning the oral cavity.
First, oral liquid is soaked in the oral cavity. Examples of oral liquid include water such as tap water and distilled water, and aqueous solutions containing disinfectants and surfactants. The oral liquid may be soaked in the oral cavity before starting to clean the oral cavity, or a source of oral liquid may be inserted into the oral cavity together with the oral cavity cleaning tool 1. Examples of the source of oral liquid include a tube connected to a reservoir of oral liquid via a pump.

The head part 4 of the oral cavity cleaning tool 1 is inserted into the oral cavity, and the opening 42 is directed toward the surface to be cleaned (tooth). When cleaning the side surface of the tooth 100, the opening 42 is directed toward the side surface of the tooth 100 (FIG. 9(a)). When cleaning the occlusal surface of the tooth 100, the opening 42 is directed toward the occlusal surface of the tooth 100 (FIG. 9(b)). At this time, the periphery of the opening 42 is brought into contact with the surface to be cleaned, and oral fluid 90 is placed inside the cover body 41 of the head part 4 (FIG. 10).
The amount of oral fluid 90 in the cover body 41 is preferably an amount that fills the inside of the cover body 41. The smaller the air layer in the cover body 41, the more the amount of attenuation of ultrasonic waves can be reduced.

The switch of the oral cavity cleaning tool 1 is turned on when the space between the tip 61, the reflecting surface 81, and the surface to be cleaned is filled with oral fluid. When the switch is turned on and power is supplied to the oscillator, the oscillator supplies high-frequency power to the vibrator 63. When the piezoelectric element 64 of the vibrator 63 receives high-frequency power, it expands and contracts in the direction of the axis O1, converting the high-frequency power into ultrasonic vibration. The converted ultrasonic vibration is transmitted through the horn 66 and oscillated from the tip 61 toward the reflector 8 as ultrasonic waves. The oscillated ultrasonic waves are reflected by the reflecting surface 81 of the reflector 8, changing their direction of travel, and propagate through the oral fluid from the opening 42 toward the surface to be cleaned. At this time, the ultrasonic waves cause a pressure change in the dissolved gas in the oral fluid, generating shock waves due to collapse (cavitation). These shock waves peel off and crush plaque and other substances attached to the teeth, cleaning the oral cavity.

The operating frequency when cleaning the oral cavity is preferably 20 kHz to 20 MHz, and more preferably 30 to 500 kHz. When the operating frequency is within the above range, cavitation occurs more efficiently, and the oral cavity can be cleaned more efficiently. The operating frequency is 40 to 100 kHz.

(Mechanism of action)
Since ultrasonic waves travel in a straight line, they propagate in the longitudinal direction of the ultrasonic oscillator (the direction in which the metal block and the piezoelectric element are stacked). Therefore, if an ultrasonic oscillator is simply provided on a long handle, ultrasonic waves are generated and propagated in the longitudinal direction of the handle, making it difficult to propagate ultrasonic waves to all sides of the teeth in the oral cavity.
As described above, the oral cavity cleaning tool of this embodiment has a reflector, and by changing the direction of ultrasonic propagation using the reflector, ultrasonic waves can be propagated toward all surfaces of the teeth, such as the occlusal surfaces and sides, thereby cleaning the teeth.

Other Embodiments
In the above embodiment, the head part has a cover body, but the present invention is not limited to this, and the head part does not have to have a cover body. However, it is preferable to have a cover body so that the path along which the ultrasonic waves propagate (the tip of the horn, the reflector, and the surface to be cleaned) can be filled with oral fluid.

The oral cavity cleaning tool of the present invention may be one in which the shape and angle of the reflector can be changed at will by the user. In addition, the oral cavity cleaning tool of the present invention may automatically change the shape and angle of the reflector depending on the duration of use, etc.

In the above embodiment, a long handle portion is provided, but the present invention is not limited to this, and a long handle portion is not required.

REFERENCE SIGNS LIST 1 Oral cavity cleaning tool 2 Handle portion 4 Head portion 6 Ultrasonic oscillator 8, 8a, 8b, 8c Reflector 41 Cover body 42 Opening 63 Transducer 66 Horn 81, 81a, 81b, 81c Reflecting surface O1 Axis

Claims (8)

The ultrasonic transducer has an ultrasonic oscillator and a reflector.
The ultrasonic oscillator has a transducer and a horn located at an output end of the transducer,
The reflector is located at a distance from the horn,
An oral cavity cleaning tool in which, when ultrasonic waves are emitted from the horn, a part or all of the ultrasonic waves are reflected in any direction by the reflecting surface of the reflector. the reflector is located ahead of the horn in a direction of an axis from the transducer to the horn,
The oral cavity cleaning tool according to claim 1 , wherein a part or all of the reflector overlaps with the horn when viewed from the tip in the axial direction. The oral cleaning tool according to claim 2, wherein the distance between the horn and the reflector in the axial direction is within 20 mm. The oral cavity cleaning tool according to claim 2, wherein the angle between the reflecting surface and the axis is 30 to 89 degrees. The oral cleaning tool of claim 2, wherein the reflector overlaps with 50% or more of the area of the horn when viewed from the tip in the axial direction. a cover body that integrally covers the horn and the reflector,
The oral cavity cleaning tool according to claim 2 , wherein the cover body opens in a direction inclined with respect to the axis. The oral cavity cleaning tool according to claim 2, wherein the surface of the reflector facing the horn is mirror-finished. 3. The oral cavity cleaning tool according to claim 1, wherein the difference between the specific acoustic impedance of the material constituting the reflecting surface and the specific acoustic impedance of liquid present in the oral cavity is 30 x ¹⁰⁶ Ns/ ^cm3 or more.

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