CARTRIDGE, A PISTON AND A SYRINGE COMPRISING THE CARTRIDGE AND THE PISTON
A cartridge and a piston for storing and dispensing a two-component dental material. The cartridge and the piston have a cross-section which substantially correspond to a D-shape in which the perimeter of the D-shape is defined by a plurality of circle segments only. At least two of the circle segments are based on different radii. The invention helps maximizing the time period over which a dental material can be stored in the compartment.
1 . A cartridge for storing and dispensing a two-component dental material, comprising:
two compartments each extending within the cartridge at a cross-section which substantially corresponds to a D-shape, wherein the perimeter of the D-shape is defined by a plurality of circle segments only, and wherein at least two of the circle segments are based on different definite radii.
2 . The cartridge of claim 1 , wherein the circle segments join each other at their ends such that all circle segments together form a closed line defining the perimeter of the compartment cross-section.
3 . The cartridge of claim 2 , wherein the circle segments join such that respective tangents on the two circle segments through the joint coincide.
4 . The cartridge of claim 2 , wherein the perimeter of the compartment cross-section is defined by only a first, second, third and fourth circle segment, and wherein the first and second circle segment being based on different radii and join at one of their ends with the third circle segment and join on the other of their ends with the fourth circle segment.
5 . The cartridge of claim 4 , wherein the third and the fourth circle segment are based on the same radius that is smaller than the radius of each of the first and second circle segment.
6 . The cartridge of claim 1 , further comprising at a front portion an outlet for each of the compartments for extruding one of the two components from the cartridge and a rear portion opposite of the front portion, wherein the rear portion is configured to receive a piston within the compartment.
7 . A piston for dispensing a component of a dental material, having a cross-section which substantially corresponds to a D-shape, wherein the perimeter of the D-shape is defined by a plurality of circle segments only, wherein at least two of the circle segments are based on different radii.
8 . The piston of claim 7 , wherein the circle segments join each other at their ends such that all circle segments together form a closed line defining the perimeter of the compartment cross-section.
9 . The piston of claim 8 , wherein the circle segments are concatenated such that at the joint of two circle segments respective tangents through that joint on each circle segment coincide.
10 . The piston of claim 8 , wherein the perimeter of the piston cross-section is defined by only a first, second, third and fourth circle segment, the first and second circle segment being based on different radii and join at one of their ends with the third circle segment and join on the other of their ends with the fourth circle segment.
11 . The piston of claim 10 , wherein the third and the fourth circle segment are based on the same radius that is smaller than the radius of each of the first and second circle segment.
12 . The piston of any of claim 7 , comprising a flexible sealing lip which forms the perimeter of the piston's cross-section.
13 . A syringe comprising a cartridge of claim 1 and two pistons for dispensing components of a dental material, wherein each piston has a cross-section, which substantially corresponds to a D-shape, wherein the perimeter of the D-shape is defined by a plurality of circle segments only, and wherein at least two of the circle segments are based on different radii.
14 . The syringe of claim 13 , further comprising a dispensing nozzle and a static mixer arranged in the dispensing nozzle and being configured to mix the two components as they are dispensed through the dispensing nozzle.
15 . The syringe of claim 14 , further comprising a plunger for pushing the pistons into the respective compartments for extruding the components towards the dispensing nozzle.