DEVICE FOR INJECTING A FILLING MATERIAL IN THE FLUID PHASE INTO A CANAL SPACE

Abstract

A method is for fabricating a device for injecting a filler material in the fluid phase into a root canal space, the device including an adapter nozzle, an auto-mixer connected to the adapter nozzle, an intra-oral injection nozzle positioned at the upper end of the auto-mixer. The method includes using a shape memory material to make the injection nozzle so as to be bendable according to a desired orientation. The method also includes arranging on the exterior surface of the injection nozzle, circular ribs defining a groove, and moulding the upper end of the auto-mixer in this groove so that the injection nozzle is lodged in position in the upper end while retaining a degree of freedom in rotation around its axis of symmetry, or one or multiple circular ribs parallel to each other.

Description

DESCRIPTION

1. Field of the Invention

A principal object of the present invention is a device for injecting a filler material in the fluid phase into a canal space, and particularly in the viscous phase.

It relates to the technical field of odontology and restorative dentistry and more particularly that that of intra-oral injection nozzles enabling injection of a filler, sealing, or impression material into a canal space.

2. State of the Art

In conventional dentistry, it is common to have to devitalize a tooth. Referring to FIG. 1, after this operation, the root canals 1 should be filled or sealed with a paste in order to protect them from possible bacterial intrusions. This paste is then designed to harden after a chemical and/or thermal reaction.

It is also common to use prosthetic crowns to repair damaged teeth. Referring to FIG. 1, in order for the crown 2 (shown dotted) to hold, it is necessary that the prosthetic pillar 3 be sufficiently large. This is why, when there was a significant fracture of the tooth, it is necessary to artificially reconstruct this pillar, by using composite or metal materials. If the lack of material is substantial, it is possible to anchor in a root canal for more resistance: this is what is called a crown-root reconstruction. In this case, posts 4, fibers or non-fibers, which are sealed in canal spaces made in the previously obturated root canals, can be used. In general, the sealing of the posts is carried out via resins, or glues adapted to cure by chemical reaction. This post 4 is then embedded in a reconstitution material, in order to reconstruct the prosthetic pillar 3 on which the crown 2 will be set.

It is also possible to use root posts made-to-measure and in one piece (or inlay-core in English). They fill two roles principally: anchoring in the root canal and reconstitution in one piece of the prosthetic pillar 3. This solution is carried out in two steps: the taking first of an impression in the course of which silicone is injected into the canal space. Using this impression, the prosthetist will be able to make the inlay-core that will fit perfectly into the canal anatomy. The second step is the sealing of this prosthetic piece in the canal space.

The sealing or impression materials introduced into the canal space are hereinafter called “filler materials in the fluid phase.” They are generally obtained from the mixture of a base and a catalyst.

To date, devices, enabling injection of these materials in the fluid phase, are known. These devices known in the prior art are for example shown in FIGS. 2 and 3. They generally include:

• • an adapter nozzle 10′,
  • an auto-mixer 11′ connected to the aforementioned adapter nozzle,
  • an intra-oral injection nozzle positioned at the end of the aforementioned auto-mixer.

The adapter nozzle 10′ is configured to attach to the outlet of a cartridge generally having watertight compartments containing the constituent base and the catalyst of the filler material. Generally, the cartridge is in the form of a syringe or of a gun fitted with a means to eject the base and the catalyst to an outlet on which is connected the adapter nozzle 10′. The mixture of the base and of the catalyst initiates a chemical reaction that will enable curing of the final material once injected into the canal space. The mixture is achieved with the means of auto-mixer 11, which consists of a multiple helix configured to automatically mix, and very homogeneously, the base and catalyst. This type of device is well known to the person skilled in the art and are for example marketed by the company MIXPACK® under the name “MIXING NOZZLES” and “INTERA-ORAL NOZZLES”.

The document EP 0,815,802 (3M) describes a device of this type in which the injection nozzle is made of a shape memory material formed to be bendable according to a desired orientation by a simple finger pressure. A conical flared end enables maintenance of the injection nozzle in the auto-mixer while allowing it a degree of freedom in rotation around its longitudinal axis. This configuration appears to be particularly restrictive in the design of the device. Indeed, it is necessary to beforehand position the injection nozzle in the plastic tube forming the auto-mixer before installing the double helix. The latter enable fixing in position of injection nozzle at the end of the auto-mixer.

Although widely used by practitioners, these devices known in the prior art, including those described in patent document EP 0,815,802, have certain drawbacks. Indeed, the intra-oral injection nozzle 12′ is generally in the form of a conical tube approximately 20 mm long. Its external diameter at the distal end is approximately 1.5 mm and the external diameter at the proximal end is approximately 3 mm. However, in practice, the canal spaces have a diameter of approximately 1.5 mm, a depth of 8 mm to 15 mm. The distal end of the intraoral nozzle 12′ therefore cannot reach the most apical part of the canal space, the filler material in the fluid phase cannot penetrate into the entire prepared root canal space. Moreover, the injection nozzle 12′ is generally made of plastic, so it is not possible to change its initial orientation. This is particularly restrictive, because with this configuration imposed, the practitioner may have great difficulties reaching the canal space according to the position of the tooth in which it is made.

The patent document EP 0,035,481 (SODERSTROM) discloses a device enabling production of a core for a tooth having a prepared root. A material for taking an impression is injected at the bottom of the canal space to fill successively from the bottom to the exterior while expelling the air there. The injection is effectuated using an injection needle provided with a cylindrical body and a piston. Except to generally modify it, this very specific injection needle cannot in any way replace the injection nozzle of an injection device with auto-mixer of the type described in the patent document EP 0,815,802.

Given this state of affairs, the principal objective of the invention is to improve the injection devices with auto-mixer of the type described in patent document EP 0,815,802, to inject with great stringency a filler material in the phase fluid into a canal space, in a manner to obtain a homogeneous filler virtually free of air bubbles.

Another objective of the invention is to provide an injection device enabling easy access to the most apical part of the canal space.

Yet another objective of the invention is to provide an injection device having simple design and whose use is particularly easy for the practitioner.

DISCLOSURE OF THE INVENTION

The solution provided by the invention is an injection device of the type described in the patent document EP 0,815,802, which is remarkable in that:

1. the injection nozzle is a tube whose distal end has an external diameter less than or equal to 1.5 mm over a length greater than or equal to 8 mm,

2. the injection nozzle is made of a shape memory material so as to be bendable according to a desired orientation

3. the injection nozzle is molded at the upper end of the aforementioned auto-mixer,

4. the injection nozzle comprises on its exterior surface:

• • circular ribs defining a groove, the upper end of the auto-mixer being molded in this groove so that the aforementioned injection nozzle is lodged in position in the aforementioned upper end while retaining a degree of freedom in rotation around its axis of symmetry, or
  • one or multiple circular ribs parallel to each other, the upper end of the auto-mixer being molded on this circular rib so that the aforementioned injection nozzle is lodged in position in the aforementioned upper end while retaining a degree of freedom in rotation around its axis of symmetry.

The first feature enable complete filling of the canal space, the distal end of the injection nozzle being able to easily reach the most apical portion of the aforementioned space. The second feature allows the practitioner to confirm the injection nozzle according to the position of the tooth to be treated and the orientation of the canal space to be filled. The practitioner can for example choose the place where the injection nozzle will be folded as well as its radius of curvature to best fit to the configuration of the canal space. The third feature enables simplification of the design of the injection device by obtaining a single piece obtained directly by molding. The fourth feature allows the practitioner to pivot only the injection nozzle, and not the entire device, so as to properly orient the aforementioned nozzle in the direction of the tooth to be treated. These features combine to achieve the cited objectives.

Optimally, the injection nozzle is a cylindrical tube whose distal end has an external diameter between 0.75 mm and 0.95 mm, preferably 0.8 mm. This range of diameters not only enables injection of a large number of viscous phase filler, sealing, or impression materials, but still easy insertion of the injection conduit in any type of canal space.

In a preferred implementation mode, the injection nozzle is made of metal, so the practitioner can easily adjust it to give it the desired shape.

Preferably, the injection nozzle has a length greater than or equal to 15 mm.

Another aspect of the invention is a system for injecting a filler material in the fluid phase into a canal space, comprising:

• • a cartridge containing in watertight compartments a base and a catalyst to be mixed to obtain the aforementioned filler material in the fluid phase, the aforementioned cartridge being provided with a means to eject the aforementioned base and the aforementioned catalyst to an outlet,
  • an auto-mixer positioned at the outlet of the cartridge and configured to mix the primary materials,
  • an intra-oral injection nozzle according to the preceding features and laid out at the upper end of the auto-mixer.

Yet another aspect of the invention relates to a ready to use dental kit comprising:

• • a cartridge containing in watertight compartments of primary fluid materials to be mixed, the aforementioned cartridge being provided with a means to eject the aforementioned primary materials to an outlet,
  • the injection device in accordance with the preceding features.

BRIEF DESCRIPTION OF THE DRAWINGS

The cited FIG. 1 is a schematic sectional view of a molar showing the root canal anatomy and the installation of different prosthetic components,

The cited FIGS. 2 and 3 schematically show an injection device known from the prior art,

FIG. 4 schematically shows an injection device according to the invention,

FIGS. 5A and 5B are schematic vertical sectional views of the injection device according to the invention,

FIG. 6A schematically shows an injection device according to the invention mounted on a cartridge incorporated into a syringe.

FIG. 6B schematically shows an injection device according to the invention mounted on a cartridge to be mounted on a pistol.

Other advantages and features of the invention will become more apparent upon reading the description of a preferred implementation mode which is going to follow, with reference to the accompanying drawings, made by way of indicative and non limiting examples.

IMPLEMENTATION MODES OF THE INVENTION

Referring to FIGS. 4 to 6B, the injection device of the invention comprises:

• • an adapter nozzle 10 configured to attach to the outlet of a cartridge directly containing the filler material in the fluid phase or a base and a catalyst to be mixed to obtain the aforementioned material,
  • an auto-mixer 11 connected to the aforementioned adapter nozzle,
  • an intra-oral injection nozzle 12 positioned at the upper end of the aforementioned auto-mixer.

In practice, the adapter nozzle 10 is a cylindrical nozzle made of rigid plastic, having a diameter between 10 mm and 25 mm, screwed, clipped or directly moldable on the outlet of the cartridge 13. Referring to FIGS. 6A and 6B, the cartridge 13 generally comprises two compartments 13a, 13b containing respectively a base and a catalyst, which when mixed will enable attainment of the fill material in the fluid phase. The cartridge 13 is provided with a means 13c, typically the plunger of a syringe (FIG. 6A) or a pistol, enabling ejection, on demand of the practitioner, of the base and catalyst to an outlet on which is positioned the adapter nozzle 10. These cartridges 13 are those conventionally used by the practitioner. In practice, they are cartridges 13 incorporated into a syringe (better known under the name SMART KIT®) (FIG. 6A) or those, more bulky designed to be mounted on a gun (FIG. 6B). When the device of the invention is designed to be mounted on the cartridges incorporated into syringes, the adapter nozzle 10 will have a diameter of approximately 10 mm and when it will be mounted on the cartridges for pistols, the aforementioned adapter module will have a diameter of approximately 15 mm. It is to be noted that one could foresee using a cartridge containing filler material directly into the fluid phase already prepared. In this case, only a single compartment is necessary.

The adapter nozzle 10 optimally integrates two tubes 10a, 10b which, when the aforementioned nozzle is positioned on the cartridge 13, penetrate into each of the compartments 13a, 13b. The two tubes 10a, 10b, are joined together at the base of the auto-mixer 11.

The auto-mixer 11 is attached at the upper end of the adapter nozzle 10. It appears in the form of a plastic tube having a length between approximately 20 mm and 50 mm and a diameter between approximately 4 mm and 6 mm, in the interior of which is laid out a double helix 11a configured to mix homogeneously the base and the catalyst. For example, when the device object the invention will be mounted on the cartridges incorporated into syringes, the auto-mixer 11 will have a length of approximately 20 mm and a diameter of approximately 4 mm (FIG. 6A), and when it will be mounted on the cartridges for pistols (FIG. 6B), the aforementioned auto-mixer will have a length of approximately 50 mm and a diameter of approximately 6 mm. The adapter nozzle 10 and the auto-mixer 11 are known to the person of skilled in the art and are for example marketed by the company MIXPACK® under the name MIXING NOZZLES.

In the case where the cartridge 13 contains the filler material directly prepared, the auto-mixer 11 is no longer necessary and/or may only serve to work the aforementioned material before its injection to initiate the chemical reaction. Similarly, if the auto-mixer 11 is molded directly at the outlet of the cartridge 13, the adapter nozzle 10 is no longer useful.

The intra-oral injection nozzle 12 is positioned at the upper end of the auto-mixer 11 where the base and the catalyst arrive intimately mixed. Referring to FIGS. 4, 5a and 5b, the injection nozzle 12 is in the form of a tube whose distal end has an external diameter less than or equal to 1.5 mm, over a length greater than or equal to 8 mm. In practice, the injection nozzle 12 is a cylindrical tube having a constant external diameter less than or equal to 1.5 mm, optimally between 0.75 mm and 0.95 mm, preferentially of 0.8 mm, and a length greater or equal to 15 mm, preferably equal to 18 mm. However, a length of 30 mm or even more can be provided for, the goal being to have an injection nozzle 12 sufficiently long so that its distal end can reach the bottom of the canal space, regardless of the position of the tooth to be treated. In an implementation variation, one can envisage using a substantially conical tube approximately 15 mm long, and whose external diameter at the distal end is approximately 0.8 mm and the external diameter at the proximal end is approximately 1.5 mm. The internal diameter of the injection nozzle 12 is approximately 0.8 mm.

According to the invention, the injection nozzle 12 is made of a shape memory material so as to be bendable according to a desired orientation. Preferably, a nozzle 12 made of metal is used, but other equivalent materials such as thermo formable plastics can be considered. The advantage of an injection nozzle 12 made of metal, is that it can easily and quickly be shaped by hand (or using pliers) by the practitioner in order to give it a desired geometry, adapted to the position of the tooth to be treated and to the configuration of the canal space to be filled. In the case of thermo-formable plastics, the practitioner will have to first heat the injection nozzle 12 in order to give it the desired shape.

The dotted lines in FIG. 4 show schematically various possible configurations of the injection nozzle 12. For example, for the treatment of an incisor or a canine, the practitioner will prefer to use a substantially straight injection nozzle 12 while the treatment of a molar will require bending the aforementioned nozzle to a point more or less close the distal end.

Referring to FIGS. 5A and 5B, the proximal end of the injection nozzle 12 is molded directly to the upper end of the auto-mixer 11.

Referring to FIG. 5A, the injection nozzle 12 comprises, on its exterior surface, circular ribs 1200 defining a groove. The upper end of the auto-mixer 11 is then molded into this groove thus formed. In this configuration, the injection nozzle 12 is lodged in the upper end of the auto-mixer 11 while retaining a degree of freedom in rotation around its axis of symmetry A.

In an implementation variation shown in FIG. 5B, the injection nozzle will comprise, on its outer surface, a circular rib 1201, the upper end of the auto-mixer 11 being then molded on this circular rib. In this configuration, the injection nozzle 12 is here still lodged in the upper end of the auto-mixer 11 while retaining a degree of freedom in rotation around its axis of symmetry A. A similar result would be obtained by arranging, on the outer surface of the injection nozzle 12, multiple circular ribs parallel to each other.

The injection device object of the invention can be an accessory independent of the cartridges or instead be directly incorporated into them during their manufacture. In the case where the injection device is a simple accessory, auto-mixer 11 must be provided with the adapter nozzle 10. The injection device is then optimally part of a dental kit ready for use, commonly referred to as Kit, further comprising a cartridge of the type described previously.

Claims

1-11. (canceled)

12. A method for fabricating a device for injecting a filler material in the fluid phase into a root canal space, the device comprising an adapter nozzle, an auto-mixer connected to the adapter nozzle, an intra-oral injection nozzle positioned at the upper end of the auto-mixer, the method comprising the steps of: using a shape memory material to make the injection nozzle so as to be bendable according to a desired orientation,arranging on the exterior surface of the injection nozzle: circular ribs defining a groove, and mold the upper end of the auto-mixer in this groove so that the injection nozzle is lodged in position in the upper end while retaining a degree of freedom in rotation around its axis of symmetry, orone or multiple circular ribs parallel to each other, and mold the upper end of the auto-mixer on this circular rib so that the injection nozzle is lodged in position in the upper end while retaining a degree of freedom in rotation around its axis of symmetry.

13. A method according to claim 12 wherein using includes making the injection nozzle have a constant external diameter less than or equal to 1.5 mm and greater than or equal to 0.75 mm, over a length greater than or equal to 8 mm.

14. A method of making a device for injecting a filler material in the fluid phase into a root canal space, the method comprising: making an injection nozzle by using a shape memory material, so that the injection nozzle is bendable to a desired orientation; andmolding an auto-mixer on the injection nozzle, so that the injection nozzle is lodged in position in the auto-mixer while retaining a degree of freedom in rotation around an axis of symmetry.

15. A method according to claim 14 wherein making the injection nozzle includes making the injection nozzle to include a groove on a external surface; andmolding includes molding an upper end of the auto-mixer the groove.

16. A method according to claim 14 wherein making the injection nozzle includes making the injection nozzle to include a circular rib; andmolding includes molding an upper end of the auto-mixer on the circular rib.

17. A method according to claim 16 wherein making the injection nozzle further includes making a plurality of circular ribs parallel to each other.

18. A method according to claim 14 further including directly molding the auto-mixer on an outlet of a cartridge, the cartridge including two compartments configured to contain respectively a base and a catalyst.

19. A method according to claim 18 wherein the cartridge 14 is configured to enable ejection, on demand of a practitioner, of the base and catalyst to the outlet.

20. A method according to claim 14 wherein making includes making the injection nozzle have a constant external diameter less than or equal to 1.5 mm and greater than or equal to 0.75 mm, over a length greater than or equal to 8 mm.