CARTRIDGE FOR STORING, DISCHARGING AND APPLYING A DENTAL COMPOUND

Abstract

The invention relates to a cartridge for storing, discharging and applying a dental compound, in particular a paste for preparing and drying the gingival sulcus (sulcus gingivae) during dental impression taking. The invention relates to a cartridge (1) for storing, discharging and applying a dental compound, comprising a container (2), which has a hollow chamber (4) for accommodating the dental compound, and a cannula (3). The hollow chamber (4) comprises an outlet opening (5) and an actuator opening (6) opposite the outlet opening (5), and the cannula (3) is fluid-connected to the outlet opening (5), is arranged on the container (2) and is straight in the starting state. The cartridge is characterised in that the cannula (3) is made of plastic and is plastically deformable under standard conditions with the application of manual force in such a manner that a permanent bend by an angle of at least up to 65 in comparison with the starting state can be achieved without buckling the cannula (3).

Claims

1. A cartridge (1) for storing, discharging and applying a dental compound, comprising a container (2), which has a hollow chamber (4) for accommodating the dental compound, and a cannula (3), wherein the hollow chamber (4) comprises an outlet opening (5) and an actuator opening (6) opposite the outlet opening (5), and the cannula (3) is arranged on the container (2) in such a way as to be fluid-connected to the outlet opening (5), and is straight in the initial state, characterized in that the cannula (3) is made of plastic and is plastically deformable in such a manner under standard conditions, with the application of manual force, that a permanent bend by an angle of at least up to 65 in comparison with the initial state can be achieved without buckling of the cannula (3).

2. The cartridge as claimed in claim 1, characterized in that the bend in the cannula (3) is reversed as the dental compound is dispensed from the hollow chamber (4) with a squeezing force of less than 130 N, preferably of less than 150 N, further preferably of less than 200 N by no more than 10, preferably by no more than 5, further preferably being reversed by no more than 1.

3. The cartridge as claimed in one of the preceding claims, characterized in that, at 23 C., the plastic of the cannula (3) has a bending modulus of from 2.2 to 2.9 GPa, preferably of from 2.3 to 2.6 GPa, preferably of about 2.4 GPa, in accordance with DIN EN ISO 178:2013.

4. The cartridge as claimed in one of the preceding claims, characterized in that the outlet opening (5) and the actuator opening (6) of the hollow chamber (4) lie on a common axis (7), wherein the cannula (3) preferably extends parallel to or along the axis (7) in the initial state.

5. The cartridge as claimed in one of the preceding claims, characterized in that the cannula (3) is formed integrally with the container (2), wherein the cannula (3) is preferably produced together with the container (2) by 1-component or multicomponent injection molding.

6. The cartridge as claimed in one of the preceding claims, characterized in that the cannula (3) and/or the container (2) is made from a thermoplastic, preferably a substantially amorphous thermoplastic copolymer, terpolymer and/or quadropolymer, further preferably a partially cross-linked, substantially amorphous thermoplastic copolymer, terpolymer or quadropolymer, further preferably from acrylonitrile butadiene styrene (ABS).

7. The cartridge as claimed in claim 6, characterized in that the thermoplastic contains pigments and/or fillers, wherein the proportion of pigments and/or fillers is preferably less than 50% by weight, further preferably less than 30% by weight.

8. The cartridge as claimed in one of the preceding claims, characterized in that the cartridge (1) is designed for use with a standard dispenser.

9. The cartridge as claimed in one of the preceding claims, characterized in that a piston (8) is provided in the hollow chamber (4), said piston being arranged in such a way in the initial state of the cartridge (1) that a dental compound can be accommodated in the hollow chamber (4) between the piston (8) and the outlet opening (5).

10. The cartridge as claimed in one of the preceding claims, characterized in that the outlet opening (10) of the cannula (3) has an inside diameter of from 0.4 mm to 2 mm, preferably 0.6 mm to 0.9 mm, wherein the outlet end of the cannula (3) is preferably rounded, preferably with a radius of from 0.5 mm to 1.5 mm.

11. The cartridge as claimed in one of the preceding claims, characterized in that the flexible region of the cannula (3) has a length of from 15 mm to 25 mm, preferably of about 20 mm.

12. The cartridge as claimed in one of the preceding claims, characterized in that the container (2) is substantially tubular, has an outside diameter of from 6 mm to 7 mm, preferably of from 6.2 mm to 6.6 mm, and has a wall thickness of at least 0.5 mm, preferably at least 0.9 mm and/or a wall thickness of less than 1.5 mm, preferably less than 1.0 mm.

13. The cartridge as claimed in one of the preceding claims, characterized in that the container (2) has an annular enlargement of the outside diameter (9) in the region of the outlet opening (5) and/or of the actuator opening (6).

14. The cartridge as claimed in one of the preceding claims, characterized in that the hollow chamber (4) of the container (2) is filled substantially by a pasty dental compound, wherein the dental compound is preferably an astringent retraction paste.

15. The cartridge as claimed in claim 13, characterized in that the dental compound comprises a liquid and a proportion of fillers greater than 50% by weight.

16. The cartridge as claimed in claim 13 or 14, characterized in that the dental compound contains a strong acid (pK.sub.s2), in particular HCl.

Description

[0029] The invention will now be described by way of example by means of an advantageous embodiment with reference to the attached drawings. In the drawings:

[0030] FIG. 1: shows a first illustrative embodiment of a cartridge according to the invention;

[0031] FIG. 2: shows a sectional view of the cartridge shown in FIG. 1; and

[0032] FIG. 3: shows a schematic illustration of the manual bending of the cannula of the cartridge shown in FIGS. 1 and 2.

[0033] A first illustrative embodiment of a cartridge 1 according to the invention is illustrated in FIGS. 1 and 2. The cartridge 1 comprises a container 2 and a cannula 3, wherein the cannula 3 is connected permanently to the container 2. In the illustrative embodiment shown, the container 2 and the cannula 3 are formed integrally with one another and are produced in a single operation by 1-component injection molding. The plastic used for the production of the cannula 1 in the illustrative embodiment shown is acrylonitrile butadiene styrene (ABS) with a bending modulus of 2. GPa at 23 C.

[0034] The container 2 is of tubular configuration and comprises a hollow chamber 4 for accommodating a dental compound (not shown). The hollow chamber 4, in turn, comprises an outlet opening 5 and an actuator opening 6, which are arranged on a common longitudinal axis 7. Arranged in the hollow chamber 4 is a piston 8, which, in the illustrated initial state of the cartridge 1, is arranged close to the actuator opening 6, enabling the dental compound situated in the hollow chamber 4 to be accommodated between the piston 8 and the outlet opening 5.

[0035] The container 2 has an outside diameter of 6.5 mm with a mean wall thickness of 2 mm. The container 2 furthermore has annular enlargements of the outside diameter 9, in the region of the outlet opening 5 and of the actuator opening 6 respectively. Given this configuration of the container 2, it is immediately apparent that the cartridge 1 can be used in a standard dispenser (not shown).

[0036] The cannula 3 is formed on the container 2 in such a way that it is fluid-connected to the outlet opening 5 to ensure that dental compound emerging from the outlet opening 5 of the container 2 passes directly into the cannula 3. In the initial state illustrated in FIGS. 1 and 2, the cannula 3 extends along the axis 7 and has a total length of 25 mm, wherein the flexible region 3 thereof, which is described below, extends over 20 mm from the outlet opening 10 of the cannula 3. The outlet opening 10 of the cannula 3 has an inside diameter of 0.7 mm and is rounded with a radius of 0.1 mm.

[0037] Under standard conditions, the cannula 3 can be deformed plastically solely by the application of manual force, and it is therefore possible to achieve a permanent bend relative to the initial state shown in FIGS. 1 and 2 through an angle of at least up to 65 without buckling of the cannula 3. FIG. 3 shows by way of example how the cannula 3 of the cartridge 1 can be bent manually or solely by means of fingers 90. Here, the bend is permanent, i.e. is maintained even when the fingers 90 are removed. At the same time, bending up to 65 takes place completely without buckling, i.e. there are no significant changes in shape, due to buckling for example, over the entire length of the cannula 3. Only the area of the internal cross section of the cannula 3 resulting from the inside diameter in the initial state may be reduced by bendingdepending on the bending angleby up to a maximum of 5%.

[0038] The cartridge 1 is suitable for high-viscosity dental compounds with a dynamic viscosity of over 27,000 Pa s, at a shear stress of 9,000 N/m.sup.2, a shear rate of 0.3 1/s and a temperature of 23 C. In particular, the dental compound can be an aqueous astringent retraction paste containing clay minerals and corrosive astringents, the proportion of fillers in which is greater than 50% by weight and which contains HCl as a strong acid (pK.sub.s2). Since the cannula 3 in the cartridge 1 according to the invention does not need to comprise metal either, corrosion problems are avoided.

[0039] As already stated, the cartridge 1 illustrated in FIGS. 1 to 3 is designed for standard dispensers, which can apply a maximum squeezing force of 200 N. In terms of its shape but also by means of the material used (see above), the cannula 3 is here matched to the retraction paste described above in such a way that the bent cannula 3 (cf. FIG. 3) makes a return movement of at most 1 during discharge of the high-viscosity dental compound. In other words, therefore, the bend in the cannula 3 produced manually beforehand remains substantially dimensionally stable, even during the discharge of dental compound through the cannula 3.