US 3595439 A
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I United States Patent 1 1 3,595,439
 Inventors Glenn A. Newby  R fe n Cit d W154 N UNlTED STATES PATENTS [2| 1 A I No gggg 1,943,120 1/1934 Kabnick 128/218 M 2,705,956 4/1955 McLaughlm 128/218 M  3 344 914 10/1967 B1 00m etal 215/6X 1971 3 351 05s 11/1967 w bb 128/272 x 73] Assignee Minnesota Mining and Manufacturing e "I p y 3,494,359 2/1970 zackheim 128/272 X St Paul, Minn. 3,537,605 1 1/1970 Solowey 128/272 X Primary Examiner- Robert B. Reeves Assistant Examiner-Frederick R. Handren Attorney Kinney, Alexander, Sell, Steldt & Delahunt ABSTRACT: A combination mixing capsule and dispenser [54} MIXING CAPSULE AND capable of separately holding complementary materials, such 5 C u D i F as dental restorative materials until they are to be mixed and used and further serving as a dispensing device when used with  U.S.Cl 222/80, suitable implements. The capsule has at least two compart- 128/218 M, 128/272, 215/6, 222/136, 222/386 ments separated by an impermeable rupturable seal with each  lnLCl B65d1/04, compartment containing one of the ingredients which are 865d 8/00 thereafter to be mixed and further has means to insure an  Field of Search 222/80, adequate mixing chamber and means to permit complete expulsion of the mixed ingredients directly from the capsule.
COMBINATION MIXING CAPSULE AND DISPENSER BACKGROUND OF THE INVENTION The invention relates to a combination mixing capsule and dispenser having two compartments separated by a rupturable material with each compartment containing one of the ingredients to be thereafter mixed and dispensed. The capsule comprises means for controlling the size of the mixing chamber while permitting complete expulsion therefrom when dispensing the mixed ingredients.
At present, many dentists or their nurses mix dental restoratives, such as amalgam comprising silver powder and mercury, which are tobe used to fill cavities, by hand, using a mortar and pestle, or similar means to homogeneously disperse the ingredients into each other. Not only is this procedure laborious and cumbersome, but is less sanitary than is desirable. In an attempt to circumvent this problem, mixing capsules have been developed which allow the dental ingredients to be held separately within the capsule until use at which time the ingredients are combined, mixed, taken out of the capsule, and then packed into a cavity. See, for example, US. Pat. No. 3,344,914, issued to Bloom. This type of mixing capsule is still not ideal as the mixed ingredients have to be removed from the capsule manually before use which takes some time and may decrease sanitation. No mixing capsule, to applicants knowledge, allows dental ingredients to be separately stored and thereafter mixed in a capsule and which allows direct extrusion of the mixed dental materials directly from the mixing capsule into a restorative area in a tooth.
SUMMARY OF THE INVENTION According to the present invention, a dental mixing capsule is provided which enables the components of a dental restorative to be stored in compartments separated by a displacable membrane therein until the capsule is activated. The compartments may be prefilled to hold sufficient quantities of the ingredients which, upon mixing, will provide a mass sufficient to fill a tooth cavity thereby eliminating human error in the measurement of the proper ratio of ingredients to be mixed to provide a dental restorative having optimum properties. This is quite important, particularly with polymeric resin restoratives as a change in ratio of the ingredients can greatly affect the properties of thefinal product, much as in the mixture of concrete for example.
To activate the capsule, means is provided to displace the membrane, e.g., by rupture or angular displacement, to cause the ingredients to come together in a mixing chamber of predetermined sizei thereafter, upon agitation, mixing of the ingredients occurs. The capsule includes a unique dispensing mechanism whereby, after the ingredients are mixed together, the mixing capsule may immediately be placed in an extrusion device which dispenses the mixed together ingredients, which now form a dental restorative material, from the capsule directly into a cavity of a tooth, or the like. After packaging in the capsule, the ingredients are stored, mixed and dispensed into a restoration area without exposure to human handling. Thus, the restorative material may be asceptically packaged, and the mixing ratio of ingredients and the dispensing of the product all provided for at the point of manufacture, thereby assuring optimum cleanliness and reproduceability of product.
The combination mixing capsule and dispenser of the present invention comprises essentially a first elongated body having means at one end for displacing a seal, a second elongated body having a cavity formed therein opening into one end thereof and having dispensing means at the other end thereof, removable means closing said dispensing means, said cavity providing first and second interconnecting compartments. said first compartment being larger than said second compartment with the wall of said cavity providing a shoulder at the juncture of said compartments, at least onecup open at one end and having a seal closing the other end, the thickness of the sidewall of said cup approximating the width of said shoulder, said cup being disposed in said first compartmen' and having said sealed end thereof resting on said shoulde. said first body member being tightly slidably received in said cup and extending only partially thereinto to provide a sealed chamber, said first body having means for limiting the amount of penetration of said first body through'said seal and into said second compartment to form a'sealed mixing chamber in said second compartment between said first body and said dispensing means to permit the mixing therein of ingredients carried in said cup and said second compartment, said first body further including means for the connection therewith of an extrusion plunger for forcing said first body toward the other end of said second body through said mixing chambers through said dispensing means upon removal of said closing means from said dispensing means.
The following detailed description taken with the drawings will further illustrate the present invention but it is not intended that the invention should be limited thereby. In the drawings:
FIG. I is a telescopic view of the mixing capsule of the present invention,
FIG. 2 is a partial cross section of a capsule before compression,
FIGS. 3 to 5 show the capsule at various stages of compression,
FIG. 6 is a pressure-inducing device used to disrupt the intercompartmental seal and cause the ingredients to mix,
FIG. 7 is a cross section of FIG. 6,
FIG. 8 is a perspective view of a device for extruding the mixed dental ingredients from the combination capsule and dispenser into a dental cavity,
FIGS. 9 and 10 are side and cross-sectional views of the device in FIG. 8, and
FIG. 11 is a front view of the device of FIG. 8.
In the drawings, the capsule 10 of FIG. 1 comprises a first elongated body member 14 which is closed on both ends, one end having a cap 12 thereon with an aperture therethrough (not shown); a sleeve 18 which is adapted to have one open end fit snugly over the first body member 14 only up to a small ridge I6 thereon and is sealed at the other end with a rupturable material 20; and a second elongated body member 22 is open on one end and has a dispensing tube 26 on the other end and may or may not have a circumferentially flanged portion 24 near the dispensing end, and similarly, may have a retaining ring. The tube is sealed until use by a nail or plug 28. The second body member 22 is adapted to receive and tightly hold the sealed sleeve member I8 and rupturable material 2' which together form a cup, and the first body member M. Tnt second body member 22 has an inner wall of unequal diameter which forms a shoulder or ledge 34 therein to arrest further advancement of the sealed sleeve 18. The second body member may additionally have a retaining ring (not shown) on the open end 21 of said second body member 22 to aid in holding the sleeve member 18 against the shoulder 34.
Prior to assembly of the capsule, the required amount of one of the dental resin ingredients may be measured into tltt cup formed by the sleeve 18 and seal 24), hereinafter referred to as the sleeve cup, and another ingredient into a compare merit formed in the second body member 22. The ingredients are thus separated by the seal 20. The premeasurement of the ingredients prevents error in measurement by a dentist or his assistant when the ingredients are to be used and further enhances sterility of the ingredients. Premeasurement also reduces the amount of time the dentist must use in preparing the dental materials for use.
As shown in FIG. 2, the capsule is assembled so that a first compartment 29 is formed between the rupturable seal 20 and one end of the first body member or plunger I4 which has a cap 12 on the other end. This compartment ordinarily carries the liquid component 31 of the final composition since 'a liquid will not become wedged between the capsule wall and the plunger wall increasing friction therebetween as would a powdered material and also allows hydrostatic pressure created by advancing the plunger (first body member 14) inward and against the liquid ingredient to assist in rupturing the seal. There are, however, certain powdered or powderlike materials, such as microcapsules, that could satisfactorily be carried in this compartment. A typical liquid ingredient which would be placed in the first compartment 29 would be mercury 31 in a mercury-silver amalgam commonly used at present by many dentists. The second compartment 30 will generally carry the powder (e.g., silver) portion 32 of the mixture, separated from the first ingredient by the rupturable seal 20. Again, suitable liquids could be carried in the second compartment 30 and the capsule would also be useful to hold two liquids or two powders depending on the system desired. A plug or nail 28 is inserted into the dispensing tube 26 of the capsule to prevent any of the ingredients, both before and after mixing, from leaking out and extends to the capsule body to eliminate entrapment of a portion of one component of the restorative in the crevice formed by the aperture leading into the dispensing tube 26.
The wall of the second body member 2.2 is designed so that the inner wall on the dispensing end of that body member has a diameter less than the inner wall at the nondispensing end forming a shoulder 34 on the inside of the wall. When the plunger 14 with the ingredient-carrying sleeve cup 18 is received by the second body member 22 during assembly, the shoulder 34 arrests any further advancement of the sleeve cup into the second body member 22. Thus, when the.,capsule is to be activated, the sleeve cup 18 will remain stationary with respect to the capsule while pressure may be asserted on the plunger, pushing the plunger toward the horizontally extending film 20 causing it to rupture. The capsule illustrated in FIG. 2 is the form the capsule remains in until it is to be activated. The capsule is impermeable and unreactive to the ingredients held therein and may thus separately store these materials over a relatively long period of time.
When the capsule is to be activated, it is placed in a pressure-inducing device of a type similar to that shown in H0. 6 which comprises essentially a base 45 with an indentation 48 therein adapted to receive the capsule 10. The indentation has a small opening 47 extending downward which is adapted to receive the dispensing tube 26 of the capsule so it will not be damaged during activation and further has a ledge 46 to hold the bottom portion of the capsule. Upon activation of the capsule, a lever 44 is pressed down on the cap 12 and plunger 14 of the capsule and, as shown in FIG. 3, advances the plunger 14 downward, rupturing the seal 20, and allowing the liquid 31 and powdered 32 components to come together in the newly formed compartment 42 between the plunger and the end of the capsule. The plunger is pushed downward until the cap 12 is stopped by the end 21 of the second body member 22 and is flush therewith preventing further advancement of the plunger. The stopping of the plunger at this point insures that there will be enough volume in the compartment 42, holding the mixture 33 for proper mixing. The sleeve 18, which remains held by the capsule shoulder 34, holds the plunger in the proper position for mixing while the seal 20 remains wedged between the plunger and the capsule wall (not shown). The ingredients are then mixed by placing the entire capsule in any suitable mixing apparatus. in the dental field, vibratory mixers adapted to hold capsules of similar exterior dimensions are available.
After the ingredients have been properly mixed, the plug 28 is removed from the dispensing tube 26 and the capsule is placed in a pressure-inducing hand extruder as illustrated in FIGS. 8 through 11. The extruder is designed so that the mixing capsule may be placed in a space 43 in the head 41 thereof in a manner so that the dispensing tube 26 of the capsule may be inserted into a niche 50 and rest therein at the end of the extruder. The small niche 50 at the end of the extruder is at angle between 0 and 60 from the axis, preferably about 4050. This angle is to give the dispensing tube some angle relative to the axis of the capsule which aids in the ease of dispensing of the dental mixture directly into a cavity or other small opening by decreasing the amount of manipulation and orientation of the extruder by the user, which would be necessary if the dispensing tube protruded straight out from the extruder. Thus, when the capsule is placed into the extruder head, the dispensing tube 26 of the capsule protrudes at the same angle the niche is to the axis.
The cap 12 on the capsule has an aperture 36 therethrough exposing a portion of the plunger 14. in the drawings, the plunger is shown with a hollow center 38 which is present only to conserve on the materials used and reduce costs. The plunger may be solid or may have a larger or smaller hollow center. When the scissors grip 51 of the extruder is manually squeezed together asserting nominal pressure, a post or rod 40 is forced toward the extruder head 41 and the capsule 10. As illustrated in F168. 4 and 5, the post 40 passes through the aperture 36 in the capsule cap 12 contacting the top of the plunger upon which the cap 12 rests. Thus, the plunger may be contacted by the post of the extruder without removal of the cap. Further, pressure then forces the plunger into the area 42 containing the mixed ingredients 33 to be dispensed, forcing them out through the dispensing tube 26 directly into a dental cavity or the like.
As a result, the dentist has a convenient means to directly apply a dental resin to a tooth without having to measure the ingredients used, mix the ingredients by hand, or if in a different type of mixing capsule, remove them from such capsule before application. By using the above-described three-step procedure, the dentist need only take a capsule having the ingredients already measured and activate the capsule, mix the ingredients together, and extrude them directly from the capsule into a restorative area.
The novel capsule of this invention may be used to extrude a variety of materials other than dental restorative materials into small remote areas. For example, an adhesive resin and a catalyst therefore, may be stored separately in the capsule, later mixed and extruded into an area where an adhesive is desired. It is considered to be within the scope of this invention to use the mixing capsule to separately store any two complementary materials until their use is desired at which time the materials may be mixed together and extruded from the capsule.
The size and proportions of the capsule and its parts are dependent upon the physical and chemical properties of the ingredients used. It is important that the compartment formed after rupture of the seal is of sufficient volume to allow proper mixing of the dental ingredients. Obviously, where the viscosity, or other characteristics, result in a different volume of required ingredient, an appropriate mixing volume is required. The diameter and length of the capsule must thus be adapted to form a mixing compartment which will allow the energy from the mixing device to be transferred to the ingredients in the capsule during mixing. lf the mixing chamber is too long in relation to the diameter of the chamber and the volume of the ingredients, the ingredients will tend to stay in the middle of the capsule and good mixing is not probable. Similarly, if the diameter of the mixing chamber is too large in relation to the length of the chamber and the volume of the ingredients, the tumbling action necessary for proper mixing ofthe ingredients is usually lost. The dimensions required would be ascertainable by one skilled in the art upon calculation of the volume of the ingredients he intends to place in the capsule. For example, inmost instances, one-half gram of total dental resin comprising diethyleneglycolphthalate-bismethacrylate resin and fired ground lithium-aluminum-silicate powder with 0.75 percent dry benzoyl-peroxide filler are used to fill a dental cavity. in that case, it has been found that a mixing volume having a diameter of about 0.33 inch and a length of 0.28 to 0.40 inch is preferred, resulting in a total capsule length of about one and one-quarter inches after activation and exclusive of the dispensing means.
The rupturable material or sea] can be of any material that will form an impermeable barrier to the separated ingredients and will be chemically inactive with respect to them. It is also preferable that the material is capable of heat bonding to the sleeve member when the sleeve and ruptu'rable material are two distinct pieces. Examples of such material are polyesters, polyethlene, and laminates incorporating such materials wherein the polyester or polyethylene will be that portion of the material in contact with the sleeve while the other components of the laminate, such as a metal foil or coating, add strength and durability to the film. The seal may also be glued onto the sleeve and in such a case any rupturable metal foil and laminates thereof are suitable. The seal and sleeve do not have to be separate and the cup could be molded as one part, the horizontally extending portion being rupturable.
The capsule itself may be made from any suitable material which is impermeable to and unreactive with the ingredients contained therein. Typically, polyethylene, polypropylene, and polystyrene have been found satisfactory for most applications. Polyethylene is especially preferred as it iseconomical to use and has very good chemical resistance.
What we claim is:
l. A combination mixing capsule and dispenser for holding two or more ingredients separately from each other and serving to dispense a combination of said ingredients upon use comprising a first elongated body having means at one end for displacing a seal, a second elongated body having a cavity formed therein opening into one end thereof and having dispensing means at the other end thereof, removable means closing said dispensing means, said cavity providing first and second interconnecting compartments, said first compartment being larger than said second compartment with the wall of said cavity providing a shoulder at the juncture of said compartments, at least one cup open at one end and having a seal closing the other end, the thickness of the sidewall of said cup approximating the width of said shoulder, said cup being disposed in said first compartment and having said sealed end thereof resting on said shoulder, said first body member being tightly slidably received in said cup and extending only partially thereinto to provide a sealed chamber, said first body having means for limiting the amount of penetration of said first body through said seal and into said second compartment to form a sealed mixing chamber in said second compartment between said first body and said dispensing means to permit the mixing therein of ingredients carried in said cup and said second compartment, said first body further including means for the connection therewith of an extrusion plunger for forcing said first body toward the other end of said second body through said mixing chamber for dispensing the contents of said mixing chambers through said dispensing means upon removal of said closing means from said dispensing means,
2. A combination mixing capsule and dispenser as recited in claim 1 wherein said dispensing means is an elongated tube extending from an opening in said second body.
3. A combination mixing capsule and dispenser as recited in claim 1 wherein said seal is metal foil.
4. A combination mixing capsule and dispenser for separately storing and thereafter mixing a dental restorative resin and a catalyst therefor to allow initiation of hardening of said resin in the capsule later to be extruded into a dental restorative area comprising a first elongated body having a closed end for displacing a seal, a second elongated body having a cavity formed therein open therein opening into one end thereof and having a dispensing tube at the other end thereof, a plug closing said dispensing tube, said cavity providing first and second interconnecting compartments, said first compartment being larger than said second compartment with the wall of said cavity providing a shoulder at the juncture of said compartments, a cup open at one end and having a metal foil seal closing the other end, the thickness of the sidewall of said cup approximating the width of said shoulder, said cup being disposed in said first compartment and having said sealed end thereof resting on said shoulder, said first body member being tightly slidably received in said cup and extending only partially thereinto to provide a sealed chamber, said first body havin a ca thereon limiting the amount of penetration of said irst b0 y through said seal and into said second compartment to form a sealed mixing chamber in said second compartment between said first body and said dispensing tube to permit the mixing therein of the dental ingredients carried in said cup and said second compartment, said cap on said first body having an aperture therethrough for the connection therewith of an extrusion plunger for forcing said first body toward the other end of said second body through said mixing chamber for dispensing the contents of said mixing chamber through said dispensing tube upon removal of said plug from