Patent Publication Number: US-2015079539-A1

Title: Dental mixing device having an auto-aligning mixing tip

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This continuation application claims the benefit of U.S. patent application Ser. No. 13/736,412, filed Jan. 8, 2013, and entitled “Dental mixing device having an auto-aligning tip mixing tip,” which claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 61/585,130, filed Jan. 10, 2012, and entitled “Dispensing syringe having multiple barrels and mixing apparatus,” the disclosure of which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates generally to mixing dual and multi component dental materials in dentistry procedures, and specifically to an improved dental mixing device. 
     2. Description of Related Art 
     There are many dental procedures that require the mixing of two or more dental materials (also known as compositions, compounds, and substances) before the mixed dental material can be used in that particular dental procedure. In the past, a common practice was to measure the separate dental materials, drop them into a mixing dish, mix the dental materials together using an applicator brush, and then use the applicator brush to apply the mixed dental materials to the desired teeth surfaces. However, mixing using the applicator brush led to a host of problems including being tedious, time consuming, causing contamination from the patient&#39;s saliva, and having dental material evaporate or harden. For example, when bleaching teeth using peroxide, the peroxide will decompose immediately after mixing. 
     In view of such problems, auto-mixing dental mixing devices such as a dispensing syringe (also known as a double barrel syringe) were developed to address these problems. In general, dispensing syringes include two separate, elongated barrels (also known as chambers) that are arranged in a side-by-side configuration. The barrels are sealed, and the base paste is stored in one barrel, while the catalyst paste is stored in the other barrel. The barrels are connected to a dispensing tip. 
     In practice, the user, which is typically a dentist, pushes on the plunger of the syringe to force the base and catalyst pastes from their respective barrels and into the dispensing tip. The dispensing tip typically contains a static mixer. As the base and catalyst pastes are extruded through the static mixer, they are combined and mixed together to form the final, mixed dental cement. Then, the dentist can dispense the cement onto the desired target, for example, a temporary crown, and mount the crown over a crown-prepped tooth in the mouth of the patient. Dispensing syringes are used in dentistry for storing, mixing, and dispensing a wide variety of dental materials such as whiting gels, impression materials, dental filling materials temporary dental restoration materials, cements, and adhesives. 
     One example of a dispensing syringe is illustrated in Drake, U.S. Pat. No. 4,538,920. Drake discloses a dispensing device having a having a pair of chambers for storing dental resins separately and a pair of plungers that are forced into the chambers to discharge the resins. The device further includes a static-mixing element housed with an exit conduit and a discharge nozzle. The static-mixing element is held in a fixed position in order to maintain a predetermined alignment of a first blade in the static-mixing element relative to the two streams of resinous material. 
     Another example of a dispensing syringe is illustrated in Spehar et al., U.S. Pat. No. 4,753,536. Spehar discloses a double barrel syringe having two compartments for storing two separate dental polymeric materials, a discharge assembly, and a nozzle assembly for dispensing the material. The nozzle assembly comprises a common nozzle, a static-mixing element with an arm extending from one end. The static mixer is arbitrarily inserted into the bore of the nozzle. The discharge of the polymeric material from the compartments causes the static mixer to turn until the arm engages an end stop. The end stop prevents further rotation of the arm as material is fed into the nozzle, thereby allowing the mixer to intermix the two materials from the storage compartments. 
     Dentists often prefer working with these types of auto-mixing devices, such as dispensing syringes, because the base and catalyst pastes are stored in commercially-available cartridges and can be dispensed from the cartridges in a pre-determined volume ratio to form an optimally mixed composition. Thus, the dentist can save time using such auto-mixing devices and avoid mixing ratio errors. 
     However, the prior art falls short of truly simplifying the auto-mixing process. Prior to the use of a dispensing syringe, the mixing tip must be connected to the dual barrel container. This is because mixing tips are typically designed for a single use, since after one use the dental material hardens into cement within the tip such that the mixing tip cannot be reused. When the dentist wants to connect a new mixing tip to a dual barrel container, the dentist must pay close attention to align the outlets of the dual barrel container with the inlets of the mixing tip, along with paying attention to any other connection means (e.g., seal, threads, etc.). This alignment takes time, effort, and can be frustrating. Since this connection is typically performed while working with a dental patient, when time is of the essence, it is important that this connection be made quickly. Also, it is critical that the dentist&#39;s attention not be distracted from the dental procedure on hand. 
     Conventional devices exist to help fasten the mixing tip to the barrel, but do not simplify the attachment process. For example, U.S. Pat. No. 5,918,772 issued to Keller et al. discloses a bayonet fastening device for the attachment of an accessory to a multiple component cartridge or dispensing device. The bayonet attachment on the cartridge for attaching a mixer or accessory to a multiple component cartridge is formed as a ring-shaped bayonet socket with two internal recesses and two diametrically opposed cutouts forming one bayonet coupling part means, whereas the bayonet attachment of the mixer or accessory comprises two bayonet lugs corresponding to the cutouts. In a preferred embodiment the lugs and cutouts are of different widths for the coded alignment of the mixer or accessory to the cartridge in one predetermined position only. 
     U.S. Pat. Pub. No. 2011/0198,370 to Ho et al. discloses a device for mixing and discharging plural materials. The device for mixing and discharging plural materials has a body, a housing and a sealing plug. The body has multiple barrels and multiple tubes communicating with the barrels. The housing is rotatably attached to the body in a thread manner and has a mixing chamber and a discharging segment. The sealing plug is mounted in the mixing chamber to seal the tubes and has a sealing disk and multiple sealing sleeves. 
     Keller and Ho fall short because they do not simplify the alignment between the barrel and the tip. Instead, they tighten a connection that is already established. Kelly and Ho still require the user to carefully align the mixer&#39;s base/tip with the cartridge&#39;s outlets during installation. Additionally, Kelly and Ho lack a combination of hard and soft materials of a mixer and syringe tip that ensure a perfect seal and prevent cross contamination. 
     SUMMARY OF THE INVENTION 
     The present invention includes an improved dental mixing device with a barrel, a mixing tip, and a plunger. The plunger moves dental material through the barrel where it is mixed using a mixing tip. The mixing tip includes an auto-aligning fitting female element configured to align with an auto-aligning fitting male element of the barrel. This auto-alignment simplifies the attachment between the mixing tip and the barrel, saving the user the time and effort. The mixing tip also includes a seal component with a soft material (or component) to insert into the auto-aligning fitting element which is a hard material (or component) to achieve an ideal seal. The seal component and auto-alignment fitting element can be combined together into one component instead of two components. 
     An advantage of the present invention is that the assembly easier for the user by eliminating the need to align the mixing tip&#39;s inlet and the container barrel&#39;s outlet. The invention accomplishes this by having an auto-matching, auto-aligning, auto-locking structure such that no aiming or aligning is required. 
     Auto-matching refers to the screw thread-based mechanism between the barrel and the syringe in such a way that does not require the user to carefully and purposefully match the barrel and the syringe together during installation. The screw thread-based mechanism can be, for example, a luer-lock or a non-luer-lock, can be a single thread or multi-thread. Auto-aligning refers to the one or more raised ridges located in between the syringe outlets and one or more grooves on the syringe&#39;s internal sealing component that work in tandem to automatically align the ridges with the grooves during installation. The shapes of the raised edges and grooves could be different cosmetically from each other. Exemplary shapes include slotted, cross, hexagon, triangle, square, rectangle, circle, ellipse, star, trapezoid, etc. 
     Another advantage of the present invention is that hard and soft materials are used together in the female fitting element and the seal of the mixing tip to better seal the device. The hard/soft feature in the device is a novel feature of the present invention. Conventional sealing typically relies on a hard plastic sealing, which theoretically, cannot be a perfect seal. The fact that a soft material is able to shrink and expand depending on the applied force makes it the ideal material for a perfect seal, but using just soft material alone will not work because it still needs the support from the hard material, making the hard/soft combination a unique advantage of the present invention. The soft material could, for example, be over-molded onto the hard material making the female fitting element and the sealing component into one component. In another embodiment, the hard and soft materials are separate components. 
     The foregoing, and other features and advantages of the invention, will be apparent from the following, more particular description of the preferred embodiments of the invention, the accompanying drawings, and the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a perspective view of a dental mixing device according to one embodiment of the invention. 
         FIG. 2  illustrates an exploded view of the components of the device according to one embodiment of the invention. 
         FIG. 3  illustrates an auto-aligning fitting male element of a barrel of the device according to one embodiment of the invention. 
         FIG. 4  illustrates an auto-aligning fitting female element of a mixing tip of the device according to one embodiment of the invention. 
         FIG. 5  illustrates a sectional view illustrating the attachment of the male and auto-aligning fitting female elements of the device according to one embodiment of the invention. 
         FIG. 6  illustrates a flow chart showing a process for connecting the device according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Before the present composition, methods, and methodologies are described, it is to be understood that this invention is not limited to particular compositions, methods, and experimental conditions described, as such compositions, methods, and conditions may vary. It is also to be understood that the terminology used herein is for purposes of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only in the appended claims. 
     As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the invention, as it will be understood that modifications and variations are encompassed within the spirit and scope of the instant disclosure. 
     Further features and advantages of the invention, as well as the structure and operation of various embodiments of the invention, are described in detail below with reference to the accompanying  FIGS. 1-6 , wherein like reference numerals refer to like elements. Although the illustrations illustrate a dual barrel dental mixing device, one with skill in the art could add an additional barrel (referred to herein as a multi-barrel mixing device) or use the dental mixing device outside of the dental industry. 
     The present invention includes an improved barrel mixing device. The device includes a mixing tip, a barrel, and a plunger. The plunger moves the material through the barrel. The barrel can be dual or multi (e.g., more than two) barrel containers. The mixing tip includes a novel connection structure for simplifying the process of connecting a mixing tip with a dual barrel container. The mixing tip has an auto-aligning fitting female element having a split slot configured to connect with a protruding dam of an auto-aligning fitting male element of the dual barrel container. This auto-aligning fitting female element also includes a locating block configured to fit into a locating slot of the dual barrel to ensure the mixing tip is aligned correctly with the barrel. The novel seal component provides a soft material to insert the hard material of the auto-aligning fitting female element to achieve an ideal seal. 
     The device has several distinctive features. For example, the device has a unique auto-aligning/auto-matching design that no longer requires the user to carefully align the mixer&#39;s syringe with the cartridge&#39;s outlets during installation. Additionally, the device includes internal sealing and female fitting components that include both hard and soft materials which guarantees a perfect seal every time. Also, the device&#39;s syringe tip end has a ridged wall that separates the outlets of the multi-barrels, and works in tandem with the sealing component&#39;s groove, which is covered by soft material, to effectively prevent chemicals inside the multi-barrel syringe from cross-contamination during storage and dispensing. 
       FIG. 1  illustrates a perspective view of a dental mixing device  100  according to one embodiment of the invention. The device  100  (e.g., dual barrel syringe) includes a mixing tip  115 , a barrel  110 , and a plunger  105 . The device  100  can be used in the dental field for storing, mixing, and dispensing of dental materials including whitening gels, impression materials, filling materials, temporary dental restoration materials, etc. The plunger  105  pushes the dental material through the barrel  110  and into the mixing tip  115 . 
     The barrel  110  (e.g., dual barrels, multi-barrel container, etc.) stores dental materials prior to mixing. The barrel  110  includes at least two dental materials separated by different parallel chambers, and the chambers having inlets at one end and outlets at the other end. The inlets are for filling the materials and the outlets are for dispensing the material into the mixing tip. The outlet of the barrel  110  connects with a connector on the mixing tip  115 . The barrel  110  may have a male/female threaded coupling which matches with the mixing tip&#39;s female/male threaded coupling, such as a luer lock. 
     The mixing tip  115  is configured to receive a plurality of materials and mix them prior to the dental procedure. The mixing tip  115  has a mixing element and a connector which connects with the barrel&#39;s outlet. The connector of the mixing tip  115  includes a body, seal component(s) and separation element(s). The mixing tip  115  also has a threaded coupling which matches with the barrel  110 . The mixing tip  115  also has a pattern on the outside to increase the grip friction force. The mixing tip  115  auto-matches, auto-aligns and auto-locks with the barrel  110  using the connector without the need to aim and align the components&#39; outlets when connecting the mixing tip. A cutout region as part of the connector may include a flexible sealing element made of a soft plastic material with the result that dimensional and material elasticity is provided. The cutouts may be located at least partially in a hard plastic material of the connector. The cutout element may include welding surfaces that are in different planes and have a non-planar three-dimensional configuration. 
       FIG. 2  illustrates an exploded view of the components of the device  100  according to one embodiment of the invention. The plunger  105  can be a conventional plunger which is known by those with skill in the art. The plunger  105  can have a pressing means  220  for squeezing the dental material out of the barrel  110 . 
     The barrel  110  (e.g., barrel containers) has an auto-aligning fitting male element  225  configured to align, apply pressure in parallel with the device  100 , and lock together with the mixing tip  115 . 
     The mixing tip  115  has an auto-aligning fitting female element  230 , a seal component  235 , and a syringe  240 . The auto-aligning fitting female element  230  is used together with the auto-aligning fitting male element  225  to auto-align the mixing tip  115  and the barrel  110  to align to, attach with, and lock to the auto-aligning female element  230 . 
     The auto-matching, auto-aligning, male and female fitting elements  225 ,  230  include an auto-positioning and auto-locking ridge, a matching auto-positioning and auto-locking slot, and can also feature a locating slot (also known as a locating dowel). 
     The seal component or components  235  are used with the female fitting element  230  for sealing the dental materials before they are dispensed into an inlet of the mixing tip  115 . The female fitting element includes a hard material (e.g., plastic) and the seal component  235  includes a soft material to best attach to the syringe  240 . The hard material of the female fitting element  230  is for inserting the mixing tip  115  onto the barrel  110 . The soft material of the sealing component  235  is to achieve an ideal seal to prevent the dental material from leaking or cross-contaminating with each other prior to mixing. The attachment between the hard and soft material can be by over molding, adhesive, ultrasonic welding or other combination methods. The dental materials are separated by an auto-locking ridge and soft material components. 
     Further, at least one part of the connector (e.g., female fitting  230 ) may be made of a hard plastic material or may have a contact surface defined by the hard plastic material. The contact surface may provide connection with the barrel&#39;s outlet. The hard plastic material may be Polyoxymethylene (POM), Acrylonitrile butadiene styrene (ABS), or polypropylene (PE). The soft plastic material may be a thermoplastic Elastomer or Silicone. 
       FIG. 3  illustrates the auto-aligning fitting male element  225  of the barrel  110  of the device  100  according to one embodiment of the invention. The auto-aligning fitting male element  225  includes a protruding dam  345  having a top  350 , two outlets  355 ,  360 , a locating slot  365 , and a flange  370 . 
     The protruding dam  345  having the top  350  provides the male portion of the auto-aligning fitting male element  225  and is configured to align with and insert into the auto-aligning fitting female element  220 . The top  350  of the protruding dam  345  is used for keeping pressure on the auto-aligning fitting female element  230  to ensure the auto-aligning fitting female element  230  maintains in close contact with the seal component  235  of the mixing tip  115 . 
     The protruding dam  345  is located between the outlets  355 ,  360  and keeps the two dental materials separate before the materials are dispensed into the mixing tip  115 , preventing cross-contamination. The outlets  355 ,  360  are for the dental materials to pass through when the plunger  105  is pressed. 
     The locating slot  365  (e.g., locating dowel) ensures the barrel  110  can only be attached to the mixing tip  115  in one way. Further, the locating slot  365  locks the mixing tip  115  in place on barrel  110 . The flange  370  is used to lock up the barrel  110  to the mixing tip  115  by screwing the flange  370  around the mixing tip&#39;s screw thread shown in  FIG. 4 . 
       FIG. 4  illustrates the auto-aligning fitting female element  230  of the mixing tip  115  of the device  100  according to one embodiment of the invention. Corresponding with the auto-aligning fitting male element  225 , the auto-aligning fitting female element  230  of the mixing tip  115  has a split slot  445 , two inlets  455 ,  460 , a locating block  465 , and a screw thread  470 . The mixing tip  115  also has a handle  475 . 
     The split slot  445  is configured to receive and mate with the top  350  of the protruding dam  345  when the flange  370  is screwed onto the screw thread  470 . The inlets  455 ,  460  are configured to mate with the outlets  355 ,  360  and receive the dental materials passed through the outlets  355 ,  360 . The locating block  465  is configured to fit into the locating slot  365  to ensure there is only one way for the mixing tip  115  to be positioned on the barrel  110 . The screw thread  470  is configured to match and receive the flange  370 . The handle  475  allows the dentist to guide and control the syringe  240  and allows for secure gripping when screwing and tightening the flange  370 . 
       FIG. 5  illustrates a sectional view illustrating the attachment of the male and female auto-aligning fitting elements  225 ,  230  of the device  100  according to one embodiment of the invention.  FIG. 5  illustrates the alignment between the barrel  110  and the mixing tip  115 . The barrel  110  has the protruding dam  345 , outlets  355 ,  360 , and the flange  370 . The mixing tip  115  has the split slot  445 , inlets  355 ,  360 , screw thread  470 , seal component  235 , and syringe  240 . 
       FIG. 6  illustrates a flow chart showing a process for connecting the device  100  according to an embodiment of the invention. The process starts at step  600 . At step  610 , the user connects the mixing tip  115  into the barrel  110 . When tightening the mixing tip  115  onto the barrel  110 , the auto-aligning fitting male element  225  will first contact the split slot  445 , which auto-aligns the screw thread  470  and the flange  370 . 
     At step  620 , the user screws the flange  370  around the mixing tip  115 . This tightens the connection between the mixing tip  115  and the barrel  110  and allows the protruding dam  345  to press the auto-aligning fitting female element  230  against the seal component  235 . When screwing and tightening the mixing tip  115  onto the barrel  110 , the inlets  455 ,  460  on the mixing tip  115  and the outlets  355 ,  360  on the barrel  110  will align and be sealed by the seal component  235 . The protruding dam  345  applies tight pressure on the auto-aligning fitting female element  230 . The user presses the plunger  105  against the barrel  110  at step  630 . This squeezes the dental material through the mixing tip  115 . The process ends at step  640 . 
     It is to be recognized that depending on the embodiment, certain acts or events of any of the methods described herein can be performed in a different sequence, may be added, merged, or left out altogether (for example, not all described acts or events are necessary for the practice of the method). Moreover, in certain embodiments, acts or events may be performed concurrently, for example, through multi-threaded processing, interrupt processing, or multiple processors, rather than sequentially. 
     It should be understood that the invention is not limited to the embodiments set forth herein for purposes of exemplification, but is to be defined only by a fair reading of the appended claims, including the full range of equivalency to which each element thereof is entitled. Although the invention has been described with reference to the above examples, it will be understood that modifications and variations are encompassed within the spirit and scope of the invention. Accordingly, the invention is limited only by the following claims.