Patent Application
20080113314
The present invention generally relates to the delivery of materials such as dental materials. More particularly, the invention relates to heating such materials prior to or during their delivery or other intended use, such as delivery to the oral cavity. Specifically, the invention relates to the use of an exothermic chemical reaction heat pack to warm the materials ad/or the material delivery device or devices.
In the art of dispensing dental materials, it is common practice to provide the dental professional with 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”.
One example of a cartridge of interest to the present invention comprises the subject matter of prior U.S. Pat. No. 4,391,590 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. An example of a cartridge heretofore known in the art is sold by DENTSPLY International Inc. of York, Pa., under the registered trademark COMPULES.
While such cartridges have enjoyed widespread use, there is always a difficulty in dispensing highly filled and highly viscous dental materials. It is generally known that heating the dental material may help to temporarily reduce its viscosity and assist in the subsequent delivery of the material to the patient. Other dental materials that are not delivered with an ampoule, cartridge, syringe or gun may still benefit from being heated prior to use. For example, heating may not only assist in the delivery of the material by whatever means, but may also initiate, propagate or otherwise assist in polymerization or other reactions. In short, a wide variety of dental materials may benefit from heating for a wide variety of purposes.
An example of a dental material that benefits from heating is described in co-pending U.S. Pat. App. Ser. No. 60/630,495 which is hereby incorporated by reference for such disclosure. The material of that pending application unexpectedly reduces its viscosity at elevated temperatures. For example, the material is extrudable from an ampoule upon reaching 50 to 60 degrees C., it is packable at 35 to 37 degrees C., and it is substantially solid at room temperature.
A variety of other dental materials such as dental composites are currently marketed. These dental composites have a wide range of viscosity. Some of these composites have high viscosity, which makes it difficult for them to be extruded from the primary package, which is often a syringe or ampoule. One way to reduce the extrusion force is to apply heat to the material and package. Warming the material reduces its viscosity and decreases extrusion force.
In the case of the material of U.S. Pat. App. Ser. No. 60/630,495, it was found that warming the ampoule containing the material in a microwave oven or with a commercially available ampoule warmer did allow the material to flow as desired. A problem with both of those heating systems is that they require extra equipment that takes up a large amount of counter space and that such equipment is generally expensive to obtain and operate.
A need exists therefore for an efficient and simple device and procedure for heating dental materials.
According to the present invention, dental materials are heated using exothermic chemical reactions. The reactive components are preferably contained within a package termed a “hot pack”. These Hot Packs preferably utilize a dry chemical reaction that produces heat. Any hot pack chemistry that produces heat in the proper range is within the scope of the invention. One useful chemical system comprises iron powder, water, a salt, activated charcoal, and vermiculite. This system is activated by exposure to air, which begins the chemical reaction.
As stated above, it is often useful in the dental arts and in fact many different arts, to heat or warm materials prior to their use. Such materials may benefit from heating for a variety of reasons including for example, to assist in viscosity reduction to promote flow and delivery, to catalyze, initiate or otherwise induce or promote a chemical reaction, and the like. An example of an ampoule useful for containing a dental material is shown for background purposes as ampoule 10 in
As shown in
The shape and construction of heat pack 30 is not necessarily a limitation of the invention. For example, heat pack 30 may be pillow shaped such that the exothermic chemical components are contained therein. Heat pack 30 may also separately hold components that when mixed cause the appropriate reaction. Further, any material of construction for heat pack 30 is within the scope of the invention, such as a spun fiber fabric or other material. Any and all such constructions are within the scope of the invention.
One useful heat pack 30 has is envelope of sock shaped and is formed by a flat sheet being welded at its edges 40. In addition, one or more sides of heat pack 30 may be provided with an at least partially transparent window 41 so that the operator can view the contents of heat pack 30. Further, if desired, open end 31 may be sealed along its edges 50 after insertion of ampoule 10 by any means such as by use of a pressure sensitive adhesive or the like.
It is another aspect of the present invention to provide temperature indicia 60 so that an operator can determine when the proper temperature has been reached or even to determine that the heating has taken place for a sufficient period of time. Any such indicia is within the scope of the present invention. Exemplary indicia 60 is a label that is affixed to heat pack 30. When the appropriate temperature has been reached and/or when the appropriate temperature has been maintained for a predetermined period of time, indicia 60 is induced to provide a visual reference of the same. For example, indicia 60 my change color, a word may appear, it may peal from heat pack 30 or the like. Similarly, heat pack 30 itself may be fabricated from a material that changes color or the like, such that heat pack 30 or a portion thereof itself constitutes and carries out the function of indicia 60. Further still, ampoule 10 may have similar characteristics which would be useful with window 41.
It will be appreciated that envelope-shaped heat pack 30 is merely one example of a heat pack within the scope of the present invention. Other heat packs within the scope of the invention (not shown) could be flat or sheet-like, boxes, bags, bottles, rigid or non-rigid in structure or the like. In addition, a separate non-heating container (not shown) could be provided such that the ampoule 10 and a heat pack are placed therein to induce heating of the ampoule 10. All such constructions are within the scope of the invention and are exemplified by heat pack 30 in the drawings.
If heat pack 30 is of the type wherein the exothermic reaction is initiated upon exposure to air, then it would be necessary to place heat pack 30 into an air-barrier package 70 as shown in
In one experiment, a heat pack 30 was prepared containing iron powder, water, a salt, activated charcoal, and vermiculite. Once the exothermic reaction was initiated by exposure to air, the hot pack reached temperatures of from 23 to 63° C. within two hours and maintained its temperature and at least 60° C. for five hours. After 15 hours, the temperature was still above 45° C. Samples of dental materials were heated using this method and the extrusion force required to extrude the material was found to be acceptable for use in conventional dental procedures. The benefits of the inventive system includes low-cost, minimum space requirements, complete and easy disposability for aseptic concerns, no electricity requirements (therefore, no power cords or the like) and that it is environmentally friendly for disposal.
It should be apparent therefore that a heat pack as shown and described accomplishes the concepts of the present invention. The invention has been exemplified herein and on the drawings without attempting to show all embodiments within the scope thereof The scope of the invention shall be limited only be any attached claims.
This application claims the benefit of U.S. Provisional Application Ser. No. 60/658,682 filed on Mar. 4, 2005 (LDC-972-1).
| Number | Date | Country | |
|---|---|---|---|
| 60658682 | Mar 2005 | US |
