Patent Application
20060286503
The present invention relates, generally, to dental dosing devices including cartridges for dispensing dental composite material with leveraged extruding syringe and more particularly to an improved cartridge and piston detailed to reciprocate in the cartridge.
Since the first introduction of a composite resin dental material filling syringe, such as the one disclosed in U.S. Pat. No. 3,581,399, there have been numerous improvements thereto. These improvements often related to the cartridge or tip containing the dental filling material used within a syringe, gun or extruding device.
Four examples of improved dental cartridges can be found in U.S. Pat. No. 4,391,590; U.S. Pat. No. 4,963,093; U.S. Pat. No. 5,100,320 and U.S. Pat. No. 5,122,057. These patents disclose a cartridge combined with a tip to be placed in a syringe for extruding the dental material contained within the cartridge or tip. They relate to an opaque cartridge having a first axis for the reservoir or body portion and a second linear axis for the nozzle discharge portion. The cartridges are intended to contain a light sensitive dental material that will cure or harden when exposed to a specific wavelength of light. Therefore, the cartridges are intended to be pre-loaded in a controlled environment for subsequent distribution to the dentist. The dentist then dispenses the dental material contained therein in a simple application. The said listed patents in the above are incorporated herein in their entirety.
U.S. Pat. No. 5,122,057 also discloses a cartridge or tip for dispensing dental material, comprising a body portion opaque to actinic light of the dental material contained therein and transparent to at least a portion of the visible light spectrum. This permits the dentist to see the material being placed within the body portion.
In an embodiment, the body portion is formed in the shape of a toroidal segment improving visibility and material flow. This embodiment is also combined with with a piston having an appendage to fit within the nozzle portion of the cartridge or tip. This permits complete extrusion of the costly dental material.
Many dental restorative compositions become more viscous upon storage in the cartridges which are usually constructed of polymeric materials such as nylon-6. This is probably cause by absorption of polar components from the composition into the cartridge itself. Accordingly, some of the desired physical handling and dispensing properties of the compositions are compromised. Further, upon storage, the force to extrude a composition from a nylon-6 cartridge can become so high that the cartridge bursts when the composition is extruded at a useful rate, particularly a relatively viscous dental composition is extruded.
The invention overcomes this problem by providing a cartridge specially adapted to be mounted in a handheld ejector type gun, compromising:
a hollow cartridge body having an inner wall defining an elongate inner chamber open at one end of the body and adapted at the open end to be detachably mounted to the gun or such similar mechanically advantaged device, and having at the opposite end of the body an orifice to allow discharge of a dental composition from the inner chamber; and a two part piston inserted into the open end of the body wherein the body has an enhanced burst strength.
The body portion and/or tip portion is opaque to actinic light of the dental material contained therein and transparent to at least a portion of the visible light spectrum. This permits the dentist to see the material being placed within the body portion and/or the tip portion.
The piston has a front portion with a surface that is of shape that complements the closed discharge end of the cartridge. The piston is constructed of two substantially equal parts which are in tandem with the front portion constructed of a polymer that is more resilient than the rear portion. The front portion is molded with a centrally located recess in the bottom thereof. The rear portion is molded with a centrally located linearly extending “Christmas tree” spike adapted and constructed to mate into the recess of the said bottom of the front portion.
Attentions is called to
The bottom portion 14 of the cartridge 12 terminates in a mouth 13 through which the cartridge 12 may be easily filled and into which the piston 15 may the be fitted, shown separated from the cartridge 12. A relatively large integral flange 17 circumscribes the bottom portion 14 and mouth 13 of the cartridge 12. The flange 17 is detailed to snap fit into a tool (not shown).
A primary feature of the present invention will now be discussed. The piston 15 has an unique construction. Attention is directed to
Another feature of the present invention resides in the unique structure of the upper part 15B of the piston 15. The upwardly facing portion is in the shape of a nose or a dome 25 substantially complementary to the downwardly facing dome 16 at the top of the cartridge 12. However, a lower portion 26 of the dome 25 has a smaller diameter than the remainder of the piston 15 so that there is an annular shoulder 27 that connects the said lower portion 26 with remainder of the piston 15B. As the piston 15 is moved under force in the direction of cartridge dome 16 and nozzle 20 the piston dome 25 is easily deformed against the underside of the dome of cartridge 12 to fill up the space while efficiently and completely extruding essentially all of the vestiges of the to be extruded material.
The part 15A of the piston has a flange 31 at the bottom most portion of a diameter so that it acts as a conventional piston ring as it is substantially of the same diameter as the inside diameter of the of the cartridge 12. On the other hand the part 15B is primarily of a diameter which is substantially the same as the inside diameter of the cartridge 12.
In
In the embodiment as shown the nozzle 20 is of a size and is configured to be sealed with a cap having a cup-like configuration. It is also contemplated that the nozzle be more elongated of ever diminishing diameter in the direction of its end so that goods be extruded therefrom may be carried more conveniently into a cavity of a tooth, for instance. In all instances in another embodiment the nozzle may be centrally located and extend axially from the cartridge.
Although the preferred embodiments have been illustrated and described, it will be obvious to those skilled in the art that various modifications may be made without departing from the spirit and scop of the invention.
