Closing device for releasably closing the nozzle of a syringe barrel

Abstract

To provide a blocking tool for blocking a nozzle part of a syringe outer cylinder in a freely releasable manner, which can be favorably used when generating a paste by mixing a powder material containing a non-crosslinking resin as a main component and a liquid material containing a radical-polymerizable monomer as a main component and which can discharge the paste that has the proper mixing rate of the powder material and the liquid material from the discharge initial stage and that is obtained by sufficiently excellently mixing the powder material and the liquid material.SOLUTION: A blocking tool is molded from elastomer and includes a shaft part and a tip flange part which is arranged in the tip of the shaft part. The shaft part has the outer diameter smaller than the inner diameter of a nozzle part of a syringe outer cylinder, and the outer peripheral edge of the tip flange part is in the circular shape that has the outer diameter same as or larger than the inner diameter of the nozzle part of the syringe outer cylinder. The blocking tool is inserted from the tip of the nozzle part of the syringe outer cylinder and the tip flange part seals the base end of the nozzle part.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a sealing device for releasably sealing the nozzle portion of a syringe barrel, and more specifically to a sealing device for releasably sealing the nozzle portion of a syringe barrel, which has a cylindrical main portion and a nozzle portion extending from the tip of the main portion and having an inner surface that is cylindrical or tapered truncated cone-shaped, the inner diameter of the nozzle portion being smaller than the inner diameter of the main portion, and the tip of the main portion and the base end of the nozzle portion being connected by an annular connecting wall. [Background technology]

[0002] Patent Document 1 below discloses that when forming a denture from a reference denture, a powder material mainly composed of a non-crosslinked resin such as polyethyl methacrylate and a liquid material mainly composed of a radically polymerizable monomer such as a methacrylate monomer are mixed to produce a paste to be used as a powder-liquid mixed denture base relining material, and this paste is applied to the reference denture. Furthermore, Patent Documents 2 and 3 below describe in detail preferred examples of a powder material mainly composed of a non-crosslinked resin and a liquid material mainly composed of a radically polymerizable monomer.

[0003] The inventors have investigated the use of a syringe to mix powder and liquid materials to produce a paste for convenient use. Specifically, the nozzle of the syringe barrel is sealed with a sealing device, and the powder and liquid materials are poured into the syringe barrel. An appropriate mixing tool, such as a mixing spatula, is inserted into the syringe barrel to mix the powder and liquid materials to produce a paste. A plunger is then attached to the syringe barrel, and the sealing device is removed to unseal the nozzle of the syringe barrel. The plunger is then operated to dispense the paste from the tip of the nozzle and apply it to the desired portion of the reference denture. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2021-187780 A [Patent Document 2] Republished Patent Publication WO2018 / 016602 [Patent Document 3] JP 2020-45459 A Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors initially conducted experiments using a sealing device that releasably seals the nozzle portion of a syringe barrel, a sealing device that fits over the tip of the nozzle portion and therefore seals only the tip of the nozzle portion. However, when using such a sealing device, when powder and liquid materials are introduced into the syringe barrel and mixed, the powder and liquid materials do not enter the nozzle portion of the syringe barrel in the required ratio and are not mixed sufficiently. As a result, the mixture ratio of the powder and liquid materials is not appropriate at the initial stage of discharge from the tip of the nozzle portion, resulting in an insufficiently mixed paste that cannot be used. Furthermore, as described above, the powder and liquid materials do not enter the nozzle portion of the syringe barrel in the required ratio, resulting in an inappropriate mixture ratio of the powder and liquid materials in the main portion of the syringe barrel.

[0006] The present invention has been made in consideration of the above facts, and its main technical object, although not limited to this, is to provide a sealing device for releasably sealing the nozzle portion of a syringe outer barrel, which can be conveniently used when producing a paste by mixing a powder material whose main component is a non-crosslinked resin with a liquid material whose main component is a radical polymerizable monomer, and which enables the discharge of a paste in which the mixing ratio of the powder material and the liquid material is appropriate from the initial stage of discharge and in which the powder material and the liquid material are sufficiently well mixed. [Means for solving the problem]

[0007] As a result of intensive research and experiments, the inventors have found that in order to achieve the above-mentioned main technical object, when introducing and mixing powder and liquid materials into the syringe barrel, it is important to seal the base end of the nozzle to prevent the powder and liquid materials from entering the nozzle, instead of sealing the tip of the nozzle. Based on this finding, they have found that the above-mentioned main technical object can be achieved by a unique sealing device equipped with a shaft and a tip flange.

[0008] That is, according to the present invention, a blocking device that achieves the above-mentioned main technical object is: A sealing device for releasably sealing off the nozzle portion of a syringe barrel, the sealing device comprising: a cylindrical main portion; and a nozzle portion extending from a tip of the main portion and having an inner peripheral surface in the shape of a cylinder or a tapered truncated cone, the inner diameter of the nozzle portion being smaller than the inner diameter of the main portion, the tip of the main portion and the base end of the nozzle portion being connected by an annular connecting wall, The shaft is molded from an elastomer and includes a tip flange disposed at a tip of the shaft, The shaft portion has an outer diameter smaller than the inner diameter of the nozzle portion of the syringe barrel, and the outer peripheral edge of the tip flange portion is the same as or smaller than the inner diameter of the nozzle portion of the syringe barrel. too Large Outside a circular shape having a diameter The syringe barrel is inserted from the tip of the nozzle portion, and the tip flange portion closes the base end of the nozzle portion. A closure is provided which is characterized by the following. When the inner peripheral surface of the main portion of the syringe barrel is not cylindrical but polygonal or elliptical, the term "inner diameter of the main portion" means the inner diameter of an imaginary cylinder inscribed in the inner peripheral surface of the main portion.

[0009] Preferably, the outer diameter of the tip flange portion is larger than the inner diameter of the nozzle portion, the tip flange portion extends beyond the base end of the nozzle portion into the main portion, and the rear surface of the tip flange portion is in close contact with the inner surface of the annular connecting wall. The Shore A hardness of the elastomer is preferably 10 to 70. The elastomer is preferably silicone rubber. The front surface of the tip flange portion is desirably frustoconical. Preferably, the shaft portion includes a restricting flange portion disposed at the rear end thereof, the outer peripheral edge of which is circular and larger than the inner diameter of the tip of the nozzle portion, and the front surface of the restricting flange portion is a flat surface perpendicular to the shaft portion, and insertion into the nozzle portion is restricted by the front surface of the restricting flange portion abutting against the tip of the nozzle portion. Preferably, the shaft portion includes a protruding grip portion disposed at the rear end thereof. It is desirable that the rear surface of the protruding grip portion is a flat surface perpendicular to the shaft portion, the front surface of the protruding grip portion is frusto-conical, the rear surface of the restricting flange portion is frusto-conical, and the front surface of the protruding grip portion and the rear surface of the restricting flange portion form an annular recess. At least one additional flange portion is attached to the shaft portion at a distance rearward from the tip flange portion, and the outer peripheral edge of the additional flange portion is preferably circular and has an outer diameter that is smaller than the outer diameter of the tip flange portion and corresponds to the inner diameter of the nozzle portion of the syringe barrel. It is desirable that the front surface of the additional flange portion is frusto-conical. Preferably, the shaft portion has a built-in rigid core material. The Main part It is convenient to introduce and mix a powder material mainly composed of a non-crosslinked resin and a liquid material mainly composed of a radical polymerizable monomer into the container to produce a powder-liquid mixed type denture base relining material. [Effects of the Invention]

[0010] According to the sealing device of the present invention, the distal flange seals the base end of the nozzle of the syringe barrel, thereby preventing the powder and liquid materials introduced into the main part of the syringe barrel from entering the nozzle. Thus, when applied to mixing a powder mainly composed of a non-crosslinked resin with a liquid mainly composed of a radical polymerizable monomer to produce a paste, it is possible to discharge a paste in which the mixture ratio of the powder and liquid is appropriate from the initial stage of discharge and in which the powder and liquid are sufficiently mixed. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is an exploded front view, partially in cross section, of a typical example of a syringe to which a sealing device constructed in accordance with the present invention is applied; [Figure 2] 1 is a front view of a preferred embodiment of a closure constructed in accordance with the present invention; [Figure 3] FIG. 3 is a plan view of the closure shown in FIG. 2. [Figure 4] FIG. 3 is a bottom view of the closure shown in FIG. 2. [Figure 5] 5 is a partial cross-sectional view showing a state in which the sealing device shown in FIGS. 2 to 4 is inserted into the nozzle portion of the syringe barrel of the syringe shown in FIG. 1 to seal the base end of the nozzle portion. DETAILED DESCRIPTION OF THE INVENTION

[0012] A more detailed description will now be given with reference to the accompanying drawings showing a preferred embodiment of a sealing device constructed in accordance with the present invention, together with a typical example of a syringe to which the sealing device is applied.

[0013] Referring to Fig. 1 showing a typical example of a syringe, the syringe generally designated by the numeral 2 is composed of a syringe barrel 4 and a plunger 6. The syringe barrel 4 and the plunger 6 can be made of an appropriate synthetic resin such as polyethylene or polypropylene. The syringe barrel 4 and the plunger 6, particularly the syringe barrel 4, are preferably transparent or translucent.

[0014] The syringe barrel 4 includes a main portion 8 and a nozzle portion 10 extending from the tip (lower end in FIG. 1 ) of the main portion 8. The main portion 8 in the illustrated syringe barrel 4 is cylindrical, having a cylindrical inner circumferential surface and a cylindrical outer circumferential surface. The inner and outer circumferential surfaces of the main portion 8 are not limited to cylindrical shapes but may be polygonal, such as a hexagonal cylinder, or elliptical. Furthermore, the inner and outer circumferential surfaces may not be identical in shape; for example, the inner circumferential surface may be cylindrical and the outer circumferential surface may be polygonal. A protruding flange 11, which may be approximately elliptical, is attached to the base end (upper end in FIG. 1 ) of the main portion 8. The nozzle portion 10 in the illustrated syringe barrel 4 is cylindrical, having a cylindrical inner circumferential surface and a cylindrical outer circumferential surface. If desired, the inner and / or outer circumferential surfaces of the nozzle portion 10 may be tapered truncated cone-shaped (i.e., inverted truncated cone-shaped). The nozzle portion 10 extends from the tip of the main portion 8 concentrically with the main portion 8, and the tip of the main portion 8 and the base end (upper end in FIG. 1 ) of the nozzle portion 10 are connected by an annular connecting wall 12. The nozzle portion 10 does not necessarily have to be concentric with the main portion 8, and can also extend from the tip of the main portion 8 eccentrically with respect to the main portion 8.

[0015] The illustrated plunger 6 has a pushing portion 14 located at the tip end (lower end in FIG. 1), an operating portion 16 located at the base end (upper end in FIG. 1), and a connecting portion 18 that connects the pushing portion 14 and operating portion 16. The pushing portion 14 is in the shape of a thin disk having an outer peripheral surface that corresponds to the inner peripheral surface of the main portion 8 of the syringe barrel 4, and therefore has a cylindrical outer peripheral surface in the illustrated plunger 6. The outer diameter of the pushing portion 14 is substantially the same as or slightly smaller than the inner diameter of the main portion 8 of the syringe barrel 4. In the illustrated plunger 6, the operating portion 16 is also in the shape of a thin disk, and its outer diameter is slightly larger than that of the main portion 8 of the syringe barrel 4. The connecting portion 18 is formed from four elongated thin plate pieces 20 (only three elongated thin plate pieces 20 are shown in FIG. 1 ) arranged at 90-degree angular intervals, with the inner edges of these four elongated thin plate pieces 20 connected to each other, the lower edges connected to the upper surface of the pushing portion 14, and the upper edges connected to the lower surface of the operating portion 16. The outer edges of the four elongated thin plate pieces 20 are located radially inward from the outer circumferential edge of the pushing portion 14.

[0016] The syringe 2 described above is a typical example of a syringe to which a sealing device constructed according to the present invention is applied, and since it is a form well known to those skilled in the art, detailed description thereof will be omitted in this specification.

[0017] Next, referring to Figures 2 to 4, a preferred embodiment of a sealing device constructed in accordance with the present invention will be described. The sealing device shown, generally designated by the numeral 22, includes a substantially straight shaft portion 24. The shaft portion 24, which may be an elongated round rod, has an outer diameter smaller than the inner diameter of the nozzle portion 10 of the syringe barrel 4. A radially extending tip flange portion 26 is disposed at the tip end (the upper end in Figure 2) of the shaft portion 24. The outer peripheral edge of the tip flange portion 26 is circular and has an outer diameter larger than the inner diameter of the nozzle portion 10 of the syringe barrel 4 (as will be further described below, the outer diameter of the tip flange portion 26 may be the same as the inner diameter of the nozzle portion 10 of the syringe barrel 4). The front surface (the upper surface in Figure 2) of the tip flange portion 26 is preferably frustoconical, with the diameter gradually decreasing forward. The rear surface (the lower surface in FIG. 2) of the tip flange portion 26 may be a flat surface extending perpendicular to the shaft portion 24 .

[0018] At least one additional flange portion 28 and 30, and in the illustrated embodiment, two additional flange portions 28 and 30, are also disposed on the shaft portion 24 at a distance rearward (downward in FIG. 2) from the tip flange portion 26. The outer peripheral edges of the additional flange portions 28 and 30 have an outer diameter that is smaller than the outer diameter of the tip flange portion 26 and corresponds to the inner diameter of the nozzle portion 10 of the syringe barrel 4 (i.e., the same as, or slightly larger or smaller than, the inner diameter of the nozzle portion 10). The front surfaces (upper surfaces in FIG. 2) of the additional flange portions 28 and 30 preferably have a truncated conical shape with a diameter that gradually decreases toward the front, and the rear surfaces (lower surfaces in FIG. 2) of the additional flange portions 28 and 30 may be flat end surfaces extending perpendicular to the shaft portion 24.

[0019] The shaft portion 24 further has a protruding grip portion 32 at its rear end (lower end in FIG. 2 ), and a restricting flange portion 34 located forward (upper in FIG. 2 ) of the protruding grip portion 32. The protruding grip portion 32 has a base portion with a cylindrical outer peripheral surface, and its front surface is preferably a truncated cone shape whose outer diameter gradually decreases toward the front, and its rear surface is preferably a flat end surface extending perpendicular to the shaft portion 24. The restricting flange portion 34 has a cylindrical base portion, and the outer peripheral edge of this base has an outer diameter larger than the inner diameter of the tip of the nozzle portion 10. The front surface (upper surface in FIG. 2 ) of the restricting flange portion 34 is preferably a flat surface extending perpendicular to the shaft portion 24, and its rear surface (lower surface in FIG. 2 ) is preferably an inverted truncated cone shape whose outer diameter gradually decreases toward the rear. The front surface of the protruding grip portion 32, which is shaped like a truncated cone, and the rear surface of the restricting flange portion 34, which is shaped like an inverted truncated cone, form an annular recess.

[0020] It is important that the shaft 24, tip flange 26, additional flanges 28 and 30, protruding gripping portion 32, and restricting flange 34 of the closure 22 described above are formed from a suitable elastomer, preferably a thermosetting elastomer such as vulcanized rubber, urethane rubber, silicone rubber, or fluororubber, or a thermoplastic elastomer such as polystyrene resin, olefin / alkene resin, polyvinyl chloride resin, polyurethane resin, polyester resin, or polyamide resin, with silicone rubber being particularly preferred. The Shore A hardness of the elastomer is preferably 10 to 70.

[0021] The shank 24 of the closure 22 preferably has a rigid core 36 extending longitudinally within the shank 24 to increase the strength of the shank 24. The rigid core 36 may be an elongated round bar made of a rigid material such as stainless steel. The closure 22 incorporating the rigid core 36 within the shank 24 can be conveniently formed by injection molding an elastomer into the desired shape using the rigid core 36 as a core.

[0022] Next, as an example of using the sealing device 22 as described above together with the syringe 2, a method of mixing a powder material and a liquid material to produce and discharge a mixed powder-liquid denture base relining material will be described.

[0023] When producing the above-mentioned lining material, the plunger 6 is separated from the syringe barrel 4. Then, as shown in Fig. 5, the sealing tool 22 is inserted into the nozzle portion 10 of the syringe barrel 4. More specifically, the protruding gripping portion 32 of the sealing tool 22 is grasped with the fingers, and the front end (upper end in Fig. 5) of the sealing tool 22 is positioned at the tip (lower end in Fig. 5) of the nozzle portion 22, and the sealing tool 22 is advanced until the front surface of the restricting flange portion 34 of the sealing tool 22 abuts against the tip surface of the nozzle portion 10. The presence of the annular recess facilitates the grasping of the protruding gripping portion 32, and the protruding gripping portion 32 can be grasped sufficiently and reliably with the fingers even if the outer diameter of the protruding gripping portion 32 is small, on the order of 5 to 8 mm. Furthermore, when the closing device 22 is inserted into the nozzle 10 and advanced, the rigid core 36 built into the shaft 24 prevents the shaft 24 from bending. Furthermore, because the front surfaces of the distal flange 26 and the additional flanges 28 and 30 are frustoconical, the distal flange 26 and the additional flanges 28 and 30 elastically bend rearward (downward in FIG. 5 ) with sufficient ease, allowing the closing device 22 to be advanced through the nozzle 10 with sufficient ease. When the closing device 22 is advanced to the position shown in FIG. 5 , i.e., to the position where the front surface of the restricting flange 34 abuts the distal face of the nozzle 10, the distal flange 26 of the closing device 22 passes beyond the proximal end (upper end in FIG. 5 ) of the nozzle 10 and enters the main section 8 of the syringe barrel 4, and the rear face of the distal flange 26 is brought into tight contact with the inner surface of the connecting wall 12, thereby sealing the proximal end (upper end in FIG. 5 ) of the nozzle 10. If desired, when the sealing device 22 is inserted into the nozzle portion 10 to a position where the front surface of the regulating flange portion 34 abuts the tip surface of the nozzle portion 10, the tip flange portion 26 is located at the base end of the nozzle portion 10, and the front surface of the tip flange portion 34 is substantially flush with the inner surface of the annular connecting wall 12, thereby sealing the base end of the nozzle portion 10 (in this case, the outer diameter of the tip flange portion 26 of the sealing device 22 can be the same as or slightly larger than the inner diameter of the nozzle portion 10). Additional flanges 28 and 30 of closure 22 are positioned closely adjacent to the inner periphery of nozzle 10 to provide additional sealing against nozzle 10 and also to prevent tilting of closure 22 relative to nozzle 10.

[0024] Since the sealing device 22 constructed according to the present invention is made of an elastomer, preferably an elastomer having a Shore A hardness of 10 to 70, the sealing device 22 can be inserted into the nozzle portion 10 of the syringe outer barrel 4 with an appropriate force (neither excessive nor insufficient) even if the nozzle member 10 of the syringe outer barrel 4 has a tapered truncated cone shape.When the sealing device 22 is inserted to the required position in the nozzle member 10, the tip flange portion 26 of the sealing device 22 is tightly fitted to the inner surface of the connecting wall 12 of the syringe outer barrel 4 or the inner surface of the base end of the nozzle portion 10 as required, thereby reliably sealing the base end of the nozzle portion 10.Furthermore, when removing the sealing device 22 from the nozzle portion 10 as described below, the sealing device 22 can be moved backward (downward in Figure 5) with an appropriate force (neither excessive nor insufficient).

[0025] Next, the required amounts of powder and liquid materials (not shown) are sequentially introduced into the main portion 8 of the syringe barrel 4 through an opening located at the proximal end of the main portion 8, either in this order or in reverse order. The powder material used to produce the lining material is a powder material primarily composed of a non-crosslinked resin such as polyethyl methacrylate, and the liquid material is a liquid material primarily composed of a radically polymerizable monomer such as a methacrylate monomer. Details of such powder and liquid materials are described in detail in Patent Documents 2 and 3, and are omitted herein. The proximal end of the nozzle portion 10 of the syringe barrel 4 is sealed with a sealing device 22, reliably preventing the powder and liquid materials introduced into the main portion 8 from entering the nozzle portion 10. Next, an appropriate mixing tool (not shown), such as a mixing spatula, is inserted into the main portion 8 of the syringe barrel 4 to mix the introduced powder and liquid materials. Thus, a paste or lining material is created within the body 8 of the syringe barrel 4.

[0026] Thereafter, the tip of the plunger 6 is inserted into the syringe barrel 4, and the plunger 6 is combined with the syringe barrel 4. At the same time, the protruding gripping portion 32 of the closure 22 is grasped to force the closure 22 backward (downward in FIG. 5) and detach it from the nozzle portion 10, thereby unblocking the nozzle portion 10. Then, the index finger and middle finger are placed on the protruding flange 11 of the syringe barrel 4, and the thumb is engaged with the operating portion 16 of the plunger 6. A pressing force is applied to the plunger 6, and the plunger 6 is gradually advanced into the main portion 8 of the syringe barrel 4. This causes the pushing portion 14 of the plunger 6 to press the paste in the main portion 8 and discharge it through the nozzle portion 10 onto the desired location, for example, onto the base surface (back surface) of the reference denture. [Explanation of symbols]

[0027] 2: Syringe 4: Syringe outer barrel 6: Pusher 8: Main part of syringe barrel 10: Nozzle part of syringe outer barrel 12: Connecting wall of syringe outer barrel 22: Blocking device 24: Shaft of the sealing device 26: Tip flange of sealing device 28: Additional flange part of the sealing device 30: Additional flange part of the sealing device 32: Protruding grip of the sealing device 34: Regulating flange part of sealing device 36: Rigid core of the closure

Claims

1. A sealing device for releasably sealing off the nozzle portion of a syringe barrel, the sealing device comprising: a cylindrical main portion; and a nozzle portion extending from a tip of the main portion and having an inner peripheral surface in the shape of a cylinder or a tapered truncated cone, the inner diameter of the nozzle portion being smaller than the inner diameter of the main portion, the tip of the main portion and the base end of the nozzle portion being connected by an annular connecting wall, The shaft is molded from an elastomer and includes a tip flange disposed at a tip of the shaft, the shaft portion has an outer diameter smaller than the inner diameter of the nozzle portion of the syringe barrel, and the outer peripheral edge of the tip flange portion is circular and has an outer diameter equal to or larger than the inner diameter of the nozzle portion of the syringe barrel; The syringe barrel is inserted from the tip of the nozzle portion, and the tip flange portion closes the base end of the nozzle portion. A sealing device characterized by:

2. 2. The closure of claim 1, wherein the outer diameter of the tip flange portion is larger than the inner diameter of the nozzle portion, the tip flange portion extends beyond the base end of the nozzle portion into the main portion, and the rear surface of the tip flange portion is in tight contact with the inner surface of the annular connecting wall.

3. 3. The closure of claim 1 or 2, wherein the elastomer has a Shore A hardness of 10 to 70.

4. 4. The closure of claim 3, wherein the elastomer is silicone rubber.

5. 5. A closure as claimed in any one of claims 1 to 4, wherein the front face of the tip flange is frustoconical.

6. A sealing device as described in any one of claims 1 to 5, which includes a regulating flange portion arranged at the rear end of the shaft portion, the outer peripheral edge of which is circular and larger than the inner diameter of the tip of the nozzle portion, the front surface of the regulating flange portion being a flat surface perpendicular to the shaft portion, and insertion into the nozzle portion being restricted by the front surface of the regulating flange portion abutting against the tip of the nozzle portion.

7. 7. A closure as claimed in any preceding claim, including a protruding gripping portion disposed at the rear end of the shank.

8. A protruding grip portion is provided at the rear end of the shaft portion, a restricting flange portion is disposed at the rear end of the shaft portion and positioned forward of the protruding grip portion, the outer peripheral edge of the restricting flange portion is circular and larger than the inner diameter of the tip of the nozzle portion, the front surface of the restricting flange portion is a flat surface perpendicular to the shaft portion, and the front surface of the restricting flange portion abuts against the tip of the nozzle portion to restrict insertion into the nozzle portion, a rear surface of the protruding grip portion is a flat surface perpendicular to the shaft portion, and a front surface of the protruding grip portion is frustum-shaped; The rear surface of the restriction flange portion is in the shape of an inverted truncated cone, an annular recess is formed by the front surface of the protruding grip portion and the rear surface of the restricting flange portion; A closure according to any one of claims 1 to 5.

9. A sealing device as described in any one of claims 1 to 8, wherein at least one additional flange portion is attached to the shaft portion at a distance rearward from the tip flange portion, and the outer peripheral edge of the additional flange portion is circular and has an outer diameter that is smaller than the outer diameter of the tip flange portion and corresponds to the inner diameter of the nozzle portion of the syringe outer barrel.

10. 10. The closure of claim 9, wherein the front surface of the additional flange portion is frustoconical.

11. 11. A closure as claimed in any preceding claim, wherein the shank has a rigid core therein.

12. A sealing device described in any one of claims 1 to 11, in which a powder material mainly composed of a non-crosslinked resin and a liquid material mainly composed of a radical polymerizable monomer are poured into and mixed with each other in the main portion of the syringe outer barrel to produce a powder-liquid mixed denture base relining material.

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