TECHNICAL FIELD [0001] The present invention generally relates to the delivery of dental materials. More particularly, the invention relates to the delivery of dental materials from a cartridge or ampoule. Specifically the invention relates to such a device wherein the dispensing of the dental material from the cartridge is assisted with applied energy.

BACKGROUND OF THE INVENTION [0002] hi the art of dispensing cartridges it is common practice at present, for example, to provide the dental profession with such devices which are pre-loaded with cements, filling material, restoratives, adhesives, bonding agents, composites, and the like. Often such devices take the form of an ampoule or cartridge, which is inserted into a handheld delivery gun or the like having operating handles or levers and, by operation thereof, desired amounts of the material in the cartridges are discharged readily and precisely. It is often the case in dentistry that relatively small quantities of such materials are used in a given application. Therefore, such materials are often packed in one-time use cartridges in approximately single use amounts or "unit doses." [0003] One example of a cartridge of interest to the present invention comprises the subject matter of prior U.S. Pat. No. 4,391,590 to Dougherty, dated July 5, 1983, and assigned to the assignee of the present invention, and hereby incorporated by reference in its entirety for such disclosure. In the patented structure, the body of the cartridge is cylindrical and of uniform inner diameter and in which a discharge piston is mounted in position in the open filling end of the cartridge to form both a closure and an ejecting piston. Cartridges of this type are miniature and, by way of example, have an outer diameter of about one-quarter inch and an inner diameter of approximately one-eighth inch. The piston, accordingly, has a complementary outer diameter of about one-eighth inch and at present is composed of solid plastic material. [0004] An example of a cartridge heretofore known in the art is sold by DENTSPLY International Inc. of York, PA, under the registered trademark COMPULES. [0005] While such cartridges have enjoyed widespread use, there is always a difficulty in dispensing highly filled and highly viscous dental materials. A need exists therefore for a cartridge that has all of the ease of use characteristics of those heretofore known, but which can be used to more easily dispense highly viscous materials.

SUMMARY OF THE INVENTION [0006] According to one embodiment of the invention, a cartridge of the type having a reservoir body and a fluidly connected dispensing nozzle and a piston within the body, wherein the material to be dispensed is preloaded in the body between the dispensing nozzle and the piston, is improved by having an energy delivery device wrapped or otherwise positioned around at least a portion of the body. The energy delivery device can impart heat energy and/or sonic or ultrasonic vibration. The application of such energy causes the dental material to soften allowing it to be more easily moved by the piston toward and out of the dispensing nozzle. In another embodiment of the invention, the heating element is embedded within the body during its formation. The heating element may be for example, a wire, a tube, a mesh or the like. [0007] According to another embodiment of the invention, the body is formed from a plastic material having metallic particles embedded therein. In this embodiment, the energy delivery device induces a magnetic flux proximate to the body. The embedded particles are thereby heated and in turn impart thermal energy to the dental material to be dispensed. The application of such energy causes the dental material to soften allowing it to be more easily moved by the piston toward and out of the dispensing nozzle. [0008] A delivery device according to the invention comprises means to removably accept such a cartridge and to have exert a force upon the piston. The delivery device also has suitable connectors, electrical, air pressured or other to facilitate the operation of providing energy to the cartridge. In one embodiment of the inventrve delivery device, electrical contacts are provided to mate with electrical contacts associated with the cartridge to provide electricity thereto. In another embodime∏Lt the delivery device also imparts sonic or ultrasonic energy to the cartridge or alternatively or in addition thereto, a condenser element. BRIEF DESCRIPTION OF THE DRAWINGS [0009] Fig. 1 is a side plan view of a cartridge according to the present invention, and showing a wire embedded in a body, the body being shown transparent and partially broken away. [0010] Fig. 2 is an alternative embodiment of a cartridge according to the present invention. [0011] Fig. 3 is another alternative embodiment of a cartridge according to the present invention. [0012] Fig. 4 is a close-up, perspective view of one portion of a cartridge according to the present invention. [0013] Fig. 5 is a delivery device useful for example, in accepting and employing a cartridge as in Figs. 1-4.

PREFERRED EMBODIMENTS FOR CARRYING OUT THE INVENTION [0014] As shown in Fig. 1, according to one embodiment of the invention, a cartridge 10 of the type having a reservoir body 11 and a fluidly connected dispensing nozzle 12 and a piston 13 (Fig. 3) within the body 10 is preloaded with a dental material 14 to be dispensed (Fig. 3) in the body 11 between the dispensing nozzle 12 and the piston 13. An energy delivery device 20 is wrapped (Fig. 3) or otherwise positioned around, within and/or embedded within at least a portion of the body 11, and is provided with electrical contacts 21. Electrical contacts 21 can electrically contact an electrical supply in a delivery device (Fig. 5) or in a remote supply unit (not shown). The energy delivery device can impart heat energy and/or sonic or ultrasonic vibration. The application of such energy causes the dental material 14 to soften allowing it to be more easily moved by the piston 13 toward and out of the dispensing nozzle 12. In another embodiment of the invention, the heating element (20) is embedded within the body during its formation, which is preferably formed from a suitable plastic material. The heating element may be for example, a wire (Fig. 1), a tube (Fig. 2), a mesh (Fig. 2) or the like. [0015] According to another embodiment of the invention, the body 11 is formed from a plastic material having metallic particles 30 embedded therein. Metal particles 30 may be any metal responsive to a magnetic flux. In this embodiment, the energy delivery device 20 induces a magnetic flux 40 proximate to the body 11. The embedded particles 30 are thereby heated and in turn impart thermal energy to the dental material 14 to be dispensed. The application of such energy causes the dental material 14 to soften allowing it to be more easily moved by the piston 13 toward and out of the dispensing nozzle 14. [0016] Electrical contacts 21 are shown more clearly in Fig. 4, and may be in turn connected to any of the energy delivery elements 20. [0017] A delivery device 50 (Fig. 5) according to the invention comprises means 51 to removably accept such a cartridge 10 and to have exert a force upon the piston 13, such as by use of moveable rod 52. The delivery device also has suitable connectors (not shown) that provide electrical, air pressured or other energy to facilitate the operation of providing energy to the cartridge 10. In one embodiment, delivery device 50 has an internal battery 53 to provide the energy supply. Battery 53 is electrically connected to contacts 21 in any conventional manner. [0018] In one embodiment of the inventive delivery device a condenser element 60 is provided which is caused to vibrate by sonic or ultrasonic energy delivered by delivery device 50. Actuating button 61 may be provided to operate moveable rod 52 and/or energy delivery device or element 20. Similarly, button actuator 62 may be provided to impart energy to condenser element 60. Otherwise, condenser element 60 is a conventional dental condenser.