Abstract:
An applicator assembly includes an applicator having a tip and a cap initially extending over the tip and detachably connected to the applicator. The applicator includes a flexible portion that can be bent in an arc as the cap is detached from the applicator in order to enhance access to the application site when needed. In preferred embodiments, the tip is supplied with a quantity of composition such as a dental composition, and as a result is especially advantageous for single patient use.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a packaged applicator assembly that includes an applicator for applying a composition to a surface. The invention also relates to a method for preparing an applicator for use, and a method for applying a dental composition to tooth structure. 
     2. Description of the Related Art 
     Applicators for applying compositions to surfaces are in widespread use in a variety of medical, commercial and household applications. Typical examples of such applicators include brushes and swabs having an overall stick-like configuration. Applicators that are relatively inexpensive represent a significant convenience to the user, in that the applicator can be disposed of after a single use. 
     In some instances, disposable applicators are individually packaged in closed, sealed containers. Individually packaged applicators are an advantage in medical and dental operatories because sterility of the applicator can be assured until such time as the applicator is removed from the package in preparation for use. Examples of known packaged applicators include swabs that are contained between two sheets of a plastic or paper film, and swabs that are contained within a plastic tube or casing. 
     Another type of disposable applicator that is known in the art has been available from Microbrush Corporation of Grafton, Wisconsin under the name “Microbrush”. This applicator has an elongated handle that is connected to an outer tip. The tip is flocked with a number of small fibers that facilitate spreading of a composition over the application site. The handle includes a reduced-diameter flexible portion that can be bent past its yield point to a desired angular orientation to facilitate placement of the composition in certain instances, such as when it is necessary to apply the composition to an area where access is limited. 
     In some procedures, the composition to be applied by the applicator is provided in bulk containers. In those instances, the users may elect to dip the swab or brush tip of the applicator directly into the container in order to coat the tip with a small quantity of the composition. The tip is then removed from the container and moved across the desired surface in order to transfer the composition from the tip to the surface. 
     However, the practice of dipping the applicator tip directly into a bulk container is not satisfactory in many medical and dental applications due to the possibility of cross-contamination between patients. For example, if the applicator is used in a dental procedure to apply an adhesive to the surface of tooth structure, the practitioner may unknowingly transfer infectious disease from one patient to another if the applicator is returned to the bulk container after initial use in the oral cavity. The issue of cross-contamination can be avoided by using a new applicator in those instances where additional composition is needed, but such practice represents an additional expense and also requires a certain amount of time for retrieving, opening and preparing a new packaged applicator for use. 
     The problems of cross-contamination as mentioned above can be avoided by use of a dispensing well or pad. For example, in dental procedures a small quantity of composition is dispensed from the bulk container onto the well or pad, and the tip of the applicator is then used to transfer the composition from the well or pad to the patient&#39;s tooth structure. Such practice avoids the need for returning the applicator to the bulk container so that issues of cross-contamination between patients can be avoided. Once the procedure has been completed, the well or pad is disposed of or cleaned for reuse. 
     In recent years, there has been increased interest in packaged, disposable applicators having a tip that is pre-supplied with a quantity of a composition. These prepackaged applicators are a significant advantage in that the time that would otherwise be associated with handling of a bulk container and a dispensing well or pad can be avoided. Moreover, such packaged applicators are a particular advantage when used with compositions that are messy or that are considered hazardous. 
     One example of a packaged swab assembly is described in U.S. Pat. No. 4,952,204 and includes a swab having a cotton bud that is pre-supplied with a quantity of composition. The swab is contained within a plastic sleeve that includes a relatively small diameter cylindrical handle portion at one end, a substantially larger diameter receptacle portion at the opposite end and a transition portion of compound configuration between the small diameter portion and the larger diameter portion. This patent indicates that when the sleeve is squeezed at the intersection between its larger diameter receptacle portion and its transition portion, the material of the sleeve will snap, crack or tear such that the swab is exposed for use upon removal of the receptacle portion. 
     Although a wide variety of applicators and application methods are known in the art as demonstrated by the foregoing, there exists a need for an improved applicator that is especially adapted for use in regions where access is limited. Such an applicator would be particularly useful in certain dental applications where a composition must be applied to remote posterior regions of the patient&#39;s oral cavity. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a packaged applicator assembly that represents a significant improvement over previously known applicators and applicator assemblies. The assembly of the invention includes an applicator and a cap, and the applicator includes a flexible portion. As the cap is detached from the applicator, the flexible portion is bent in an arc in order to facilitate use of the applicator, particularly in areas where access is limited. 
     In one preferred embodiment of the invention, a tip of the applicator bears a quantity of a composition such as a dental adhesive that is initially covered by the cap. As the cap is removed, the flexible portion of the applicator can be bent to any one of a number of angles in order to facilitate spreading the adhesive on the patient&#39;s tooth structure of interest. As such, there is no need to attempt to bend the applicator by hand once the cap has been removed, and potential contact of the adhesive with the practitioner&#39;s fingers or with other structure can be avoided. 
     In more detail, the present invention in one aspect is directed toward an applicator assembly that comprises an applicator including a handle and an elongated shaft connected to the handle. The shaft includes a tip remote from the handle and a flexible portion located between the tip and the handle. The assembly further includes a cap extending over the tip and at least part of the flexible portion. The cap is detachably connected to the applicator. The flexible portion of the applicator can be bent as the cap is detached from the applicator. 
     In another aspect, the present invention is directed toward a method of preparing an applicator for use. The method includes the acts of covering a tip of the applicator with a cap, and connecting the cap to the applicator. The method also includes the act of detaching the cap from the applicator, wherein the act of detaching the cap from the applicator includes the act of bending a shaft of the applicator. 
     The present invention is also directed toward a method of applying a dental composition to tooth structure. The method includes the act of providing an applicator having a handle, a tip and a shaft, wherein the shaft is located between the handle and the tip. The method also includes the acts of covering the tip with a cap and placing a dental composition on the tip. The method additionally includes the act of removing the cap from the tip, wherein the act of removing the cap from the tip includes the act of bending the shaft. The method also includes the act of contacting the tip with tooth structure in order to transfer at least a portion of the composition to the tooth structure. 
     Preferably, the applicator and the cap are disposed of after a single use. As such, the invention is particularly useful for dental compositions where issues of cross-contamination might otherwise present a problem. The invention is also beneficial when used to dispense and apply a composition that cannot be feasibly dispensed from a bulk container over a period of time, such as a composition that rapidly cures upon exposure to the atmosphere or to ambient light. Optionally, the cap includes a reservoir of the composition that enables the user to rewet the tip by reinserting the tip in the cap, an especially useful advantage in instances where an additional application is needed. 
     These and other aspects of the invention are described in more detail below and are illustrated in the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an applicator assembly that is constructed in accordance with one embodiment of the invention; 
     FIG. 2 is a side cross-sectional view of the applicator assembly illustrated in FIG. 1; 
     FIG. 3 is a side cross-sectional view of the applicator assembly depicted in FIGS. 1 and 2 after a cap of the assembly has been detached from an applicator to expose a tip of the applicator;and 
     FIG. 4 is a side cross-sectional view of an applicator assembly that is constructed in accordance with another embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An applicator assembly according to one embodiment of the invention is broadly designated by the numeral  20  in FIGS. 1-3. The assembly  20  includes an applicator  22  as well as a cap  24  that is detachably connected to the applicator  22 . Initially, and as shown in FIG. 1, the assembly  20  has an overall cylindrical configuration along the majority of its length and has a straight, longitudinal central reference axis. 
     The applicator  22  of the assembly  20  has an outer handle  26  and an elongated shaft  28  that is connected to the handle  26 . In the particular embodiment shown, the shaft  28  extends through almost the entire length of the handle  26 . The shaft  28  includes an outer tip  30  that is located in a position remote from the handle  26 . Optionally, and as illustrated in FIGS. 2 and 3, the tip  30  has a generally spherical configuration, although other shapes are also possible. 
     Preferably, but not necessarily, the tip  30  includes a material that facilitates spreading of a composition across the surface to which the composition is to be applied. The material may be of any suitable structure that is compatible with the composition and functions to distribute the composition over the receiving surface. Suitable materials include small bristles or fibers that serve as a brush and that are applied to all or only part of the tip  30 . 
     Optionally, fibers can be applied to the tip  30  by a flocking process. The flocking can be carried out by any technique known in the art. Preferably, the flocked fibers define small interstitial spaces that can advantageously fill with the composition, and retain and suspend a small amount of the composition for efficient application to the surface of interest. The fibers preferably also allow relatively uniform application of the composition over the surface regardless of whether the surface is irregular, rough or smooth, and apply the composition in the same way as a brush would. If used in a dental procedure, the outwardly extending fibers permit the composition to be applied easily to side and overhanging surfaces of a tooth cavity as well as to the bottom of the tooth cavity. 
     Alternatively, other types of material may be applied to the tip  30  for facilitating spreading of the composition across a surface. Examples of such other materials include an open cell foam material such as polyurethane foam or synthetic sponge. Additional examples of suitable materials include woven and non-woven fabrics, gauzes and the like. Microstructured surfaces could also be employed, including microstructured surfaces that are integrally formed as part of the tip  30 . 
     The shaft  28  of the applicator  22  also includes a flexible portion  32  that is located between the tip  30  and the handle  26 . The flexible portion  32  is deformable by finger pressure past its yield point to any one of a number of angular orientations, and once bent will substantially self-remain in a bent orientation without returning to its initially straight orientation. Although some amount of return to its initially straight position is possible, particularly if the flexible portion is made of a resilient material, it is preferred that the flexible portion  32  remain in approximately the same angular orientation to which it is bent after the bending pressure is released. 
     One method of making the flexible portion  32  involves the provision of one or more grooves that serve to facilitate bending of the shaft  28 . In the example shown in the drawings, the flexible portion  32  includes a single groove that circumscribes the shaft  28 . The groove lies in a reference plane that is oriented perpendicular to the longitudinal axis of the assembly  20 . However, other constructions are also possible, including the use of a series of grooves, a section of reduced cross-sectional area of another shape or an articulated joint to facilitate bending. 
     The shaft  28  also includes a gripping portion  33  located rearwardly of the flexible portion  32 . The gripping portion  33  is made of a series of grooves  34  that are uniformly spaced apart from each other. The gripping portion  33  is optional and is not gripped in use of the applicator  22  since it is located within the hollow handle  26 . 
     In the embodiment shown in the drawings, the shaft  28  also includes a tapered portion  36  that is located between the flexible portion  32  and the tip  30 . The tapered portion  36  has a generally conical configuration, and advantageously provides clearance in areas adjacent the tip  30  when used in certain applications. For example, if the tip  30  is used to apply a dental composition to overhanging tooth surfaces, the tapered portion  36  facilitates application of the composition in areas beneath that overhanging surface. 
     The cap  24  has an inner cavity that surrounds the tip  30 , the flexible portion  32  and the tapered portion  36  when the cap  24  is connected to the applicator  22 . Preferably, the cap  24  provides a reservoir for composition to be dispensed and applied by the tip  30 . Optionally, the reservoir includes a porous material that facilitates retention of the composition in the cap  24  so that the composition does not drip from the cap  24  when the cap  24  is inverted after it is detached from the applicator  22 . 
     Preferably, the reservoir is a compressible porous material such as a synthetic sponge  38  as shown in FIG.  2 . An example of a suitable material for the sponge  38  is polyurethane. However, other materials, including woven and non-woven fabrics and gauzes, are also possible. 
     Preferably, the sponge  38  has suitable dimensions and is located in the cap  24  such that the tip  30  slightly compresses the sponge  38  when the cap  24  is connected to the applicator  22 . Such construction ensures that the tip  30  will remain wetted with the composition carried by the sponge  38 . Moreover, if additional composition is needed once the composition on the tip  30  has been exhausted, the tip  30  can be re-inserted into the cap  24  in order to contact the sponge  38  again and transfer additional composition to the tip  30 . 
     The cap  24  is connected to the applicator  22  by any suitable detachable connection known in the art. An example for a suitable detachable connection is a line of weakness  40  that circumscribes the assembly  20  in a region overlying the flexible portion  32 . Preferably, the line of weakness  40  is a frangible area of reduced cross-sectional thickness that initially integrally interconnects the cap  24  to the handle  26 . However, other detachable connections are also possible, including the use of an adhesive, a friction fit or a pressure sensitive tape that initially retains the cap  24  in secure connection to the applicator  22 . 
     In use, the assembly  20  is grasped by the user, preferably with one hand on the handle  26  and the other hand on the cap  24 . Next, the applicator  22  and the cap  24  are moved relative to each other in an arc such that the longitudinal axis of the applicator  22  moves from a position collinear with the longitudinal axis of the cap  24  to an orientation at a non-zero angle relative to the longitudinal axis of the cap  24 . During this bending movement, the line of weakness  40  fractures along all or at least a portion of its circumscribing length. Such bending motion of the cap  24  relative to the applicator  22  will also cause the flexible portion  32  to bend. 
     The cap  24  is then moved away from the handle  26  in a direction along the length of the applicator  22  to uncover the tip  30 . The flexible portion  32 , having moved past its yield point during the bending motion as the cap is removed, remains in its deformed, bent orientation as illustrated in FIG. 3 after the cap  24  is separated from the applicator  22 . If the user is not satisfied with the resultant angular orientation, the cap  24  can be temporarily replaced onto the applicator  24  so that the user&#39;s fingers need not contact the tip  30  or the composition during additional bending movements. 
     FIGS. 1 and 2 illustrate the assembly  20  as it initially appears while FIG. 3 depicts the assembly after the cap  24  has been detached from the handle  26  and the shaft  28  has been bent in the region of the flexible portion  32 . As can be appreciated, the applicator assembly  20  is an advantage in that bending of the applicator  22  can be carried out simultaneously with removal of the cap  24 . Such construction represents a time savings for the user, in that a separate step of bending the applicator  22  after removal of the cap  30  is not normally required. 
     Additionally, bending of the applicator  22  simultaneously with detachment of the cap  24  enables the applicator  22  to be bent to any desired angular orientation without fear of contamination of the tip  30 , the tapered portion  36 , the flexible portion  32  or the composition on the tip  30 . Such construction avoids the need to grasp the uncovered tip  30  with one hand for bending the flexible portion  32 , or the need to press the tip  30  against some other surface for bending the flexible portion  32 . The tip  30  and the composition remain safely covered by the cap  24  until the desired angular orientation is attained. 
     Optionally, the applicator  22  may be flexible in areas other than the flexible portion  32 , such as in areas of the tapered portion  36 . However, if the cap  24  is detached from the applicator  22  by relative bending movement, the cap  24  will tend to retain the forward section of the applicator  22  that is located within the cap  24  during bending in a straight orientation so long as the cap  24  fits closely over the forward section of the applicator. As a result, the applicator  22  only bends to any substantial degree in these instances in areas near the line of weakness  40 . Advantageously, the handle  26  and the cap  30  provide leverage for facilitating bending of the applicator. 
     A preferred method of making the assembly  20  is carried out using a length of cylindrical tubing and placing a sponge (such as sponge  38 ) near one end of the tubing. That end of the tubing is then placed between a pair of movable, heated jaws (or a heated platen and anvil assembly) that heat-seals the outer end region of the tubing. The jaws are then moved toward each other and press against opposite sides of the tubing. During this pressing and heat-sealing, an adjacent end section of the sponge is compressed between inner walls of the tubing adjacent the heat seal to retain the sponge in place. Next, a slender, hollow probe is inserted into the tubing through its open end and a quantity of composition is dispensed onto the sponge. 
     Subsequently, an applicator stick such as the “Microbrush” brand applicator described above is placed within the tubing such that the tip contacts the sponge and slightly compresses the sponge. In that position, the open, outer end of the tubing remote from the tip extends just slightly beyond the applicator stick surrounded within. A pair of heated jaws are then pressed against opposite sides of the remaining open end region of the tubing in order to heat seal the opening and also to mechanically capture by friction fit the adjacent end of the applicator stick. 
     The tubing described in the method above may be made of any material that provides sufficient strength and stiffness to the resultant assembly during shipping, storage, handling and use including the acts of removing the cap as described above. The selected material should also be compatible with the composition contained in the sponge and provide satisfactory shelf life performance. An example of a suitable material for the tubing is polyethylene. 
     Optionally, the tubing can have a laminate construction made of one or more layers of different material in instances where one type of material may provide superior packaging characteristics in one aspect and another material may provide superior packaging characteristics in another aspect. For example, a two layer laminate tubing might be selected having a first layer that is made of a material that provides superior barrier properties such as resistance to fluid and vapor transmission. In this example, the second layer may be made of a material that provides superior strength and stiffness properties, to ensure that the resultant assembly  20  is strong and somewhat flexible and yet can be reliably opened when desired with a crisp snapping effect by fracturing along the line of weakness  40 . 
     The initially straight configuration of the applicator assembly  20  is an advantage during manufacturing, shipping and storage in that a large number of the assemblies  20  can be packaged in a compact, tight array with little wasted space. Moreover, the initially straight configuration of the assembly  20 , in combination with the flexible portion  32 , allows the user to bend the applicator  22  to a selected, preferred orientation that may be best suited for the task at hand. Such construction is beneficial in contrast to applicators that are pre-bent by the manufacturer, since the angle selected by the manufacturer may not be optimal or even satisfactory in every situation. 
     Optionally, the assembly  20  can be opened without bending the applicator in instances where the user desires to keep the applicator  22  in a straight configuration for use. To open the assembly  20  without bending the applicator  22 , the cap  24  can be twisted in an arc about its longitudinal axis while holding the handle  26  stationary. 
     Preferably, the tip  30  bears an amount of the composition when removed from the cap  24  that is sufficient to complete the chosen task. If desired, however, an additional amount of composition can be transferred to the tip  30  when needed by placing the tip  30  back into the cap  24  and into contact with the sponge  38 . Preferably, the material of the tip  30  has an affinity for the composition to facilitate transfer of the composition from the sponge  38  to the tip  30 . 
     Another embodiment of the invention is illustrated in FIG. 4, wherein an applicator assembly  20   a  comprises an applicator  22   a  and a cap  24   a.  Except as described below, the assembly  20   a  is identical to the assembly  20  and as such a detailed description of the various similar features, elements and aspects shall not be repeated. 
     The applicator  22   a  includes a hollow shaft  28   a  and has an inner chamber  42   a  that extends along its length. The chamber  42   a  includes a small passageway  44   a  that extends through a tapered portion  36   a  as well as through a tip  30   a.  Optionally, the assembly  20   a  may have a somewhat larger outer diameter in comparison to a preferred diameter of the assembly  20  in order to provide sufficient space for the chamber  42   a.  A handle  26   a  extends over a portion of the shaft  28   a.  Optionally, the initially open, rear end region of the shaft  28   a  is heat-sealed shut within a surrounding heat sealed region of the handle  26   a  in order to close the chamber  42   a  once the composition has been added. 
     A quantity of composition is initially received in the chamber  42   a.  Preferably, the tip  30   a  also bears some quantity of the same composition when the applicator  22   a  is within the cap  24   a  so that the applicator  22   a  is ready for immediate use as soon as the cap  24   a  is removed. In this embodiment, a sponge within the cap  24   a  (such as the sponge  38  described above) is optional. 
     In use, the cap  24   a  is detached from the applicator  22   a  in the manner described above in connection with the assembly  20 . However, once the composition carried by the tip  30   a  has been somewhat depleted, the user can replenish the supply of composition on the tip  30   a  by squeezing the walls of the handle  26   a  together. Compression of the walls of the handle  26   a  reduces the amount of space in the chamber  42   a  and as a consequence causes a portion of the composition in the chamber  42   a  to be urged through the passageway  44   a  and onto the tip  30   a.    
     The applicator assemblies described above are suitable for use with a wide variety of compositions for various procedures. The composition could be a liquid, semi-liquid, gel, paste or powder. A particularly preferred composition is a one-part dental adhesive that cures upon exposure to light. An example of a suitable dental adhesive is “Single Bond” brand adhesive from 3M Company. Other suitable compositions include dental etchants, sealants and primers. As used herein, the word “dental” includes all fields of dentistry including orthodontic and endodontic treatment. 
     A number of options and alternatives are possible to the applicator assemblies described above. For example, the handles described above could be provided with a flange or collar in order to assure that the composition does not drip onto the user&#39;s fingers when the tip is held in an upwardly position during use. A number of other options will also be apparent to those skilled in the art. Accordingly, the invention should not be deemed limited to the specific examples that are described in detail above, but instead only by a fair scope of the claims that follow along with their equivalents.