Packaged orthodontic assembly with retaining member

Orthodontic assemblies and related methods are provided where an adhesive coated orthodontic appliance is received in a container that includes a substrate and a lid having a retaining member. When the lid is closed, the retaining member is complemental to the shape of the appliance and engages with the appliance. By conforming to the shape of the appliance, the retaining member constrains the appliance from shifting in lateral and vertical directions within the container. When the lid is opened, the associated retaining member disengages from the appliance, thereby facilitating user access to the appliance.

1. FIELD OF THE INVENTION

Provided are packaged assemblies for orthodontic appliances. More particularly, packaged assemblies are provided for orthodontic appliances that are coated with an adhesive for facilitating bonding of the appliances to a tooth structure.

2. DESCRIPTION OF THE RELATED ART

Orthodontics is a specialized area of dentistry concerned with the diagnosis and treatment of dental malocclusions to improve bite function, hygiene, and facial aesthetics. Orthodontic therapy commonly uses tiny appliances called brackets and molar tubes which are bonded to a patient's teeth. Brackets and molar tubes contain slots and passageways, respectively, to accommodate a resilient “U”-shaped wire called an orthodontic archwire. During treatment, the archwire is secured within the slots and passageways of the brackets and molar tubes. While the archwire is initially distorted, it gradually returns to its original shape over the course of treatment, thereby applying therapeutic forces to urge the malpositioned teeth to proper locations.

Brackets, molar tubes, and other bondable appliances are generally affixed to teeth using a suitable orthodontic adhesive. Traditionally, adhesives were painstakingly applied, one at a time, to each appliance by an orthodontic assistant at the orthodontic office. Since this can be a tedious process, manufacturers have provided appliances that are coated in advance, or “pre-coated,” at the factory to save time for the orthodontist. Coated appliance configurations are described in detail in issued U.S. Pat. No. 4,978,007 (Jacobs, et al.), U.S. Pat. No. 5,015,180 (Randklev), and U.S. Pat. No. 5,328,363 (Chester et al.).

Pre-coated brackets and molar tubes provide a significant advantage to the practitioner. First, these appliances provide for a high degree of precision in the amount of adhesive that is dispensed on the base of each appliance compared with hand-coating appliances. Second, these appliances are easy to use and save time, since a practitioner can conveniently remove a bracket from its respective container and place it directly on the patient's tooth without need for intervening steps. Typically, the adhesive is a light curable adhesive which allows the appliance, once placed on the tooth surface, to be carefully positioned in a proper orientation before a curing lamp is activated to cure the adhesive and securely fix the appliance in place.

Various approaches have been taken in packaging adhesive-coated orthodontic appliances. In one approach, the appliance and adhesive are placed in a sealed “blister” or similar disposable container. The adhesive is secured against a wall of the container having a suitable release surface such that the appliance and adhesive lift off together when the appliance is plucked from the container. This approach is described in, for example, issued U.S. Pat. No. 6,183,249 (Brennan, et al.). Another approach involves using mechanical structures to suspend the appliance in the container such that the adhesive does not contact any surfaces of the container. Examples of this approach are described in issued U.S. Pat. No. 5,827,058 (Kelly, et al.) and U.S. Pat. No. 6,089,861 (Kelly, et al.).

3. SUMMARY OF THE INVENTION

In packaging an adhesive coated orthodontic appliance, it can be challenging to provide ease of use in dispensing the appliance from the package while also ensuring that the appliance is properly secured during transportation and handling. These considerations often militate against one another. For example, placing support structure against all four sides of an appliance would securely hold the appliance, but such structure may be a nuisance when trying to extract the appliance from the container. On the other hand, a package with minimal support structure would allow easy access to the appliance, but also increases the risk that the appliance would be dislodged when the package is dropped or otherwise mishandled. Moreover, configurations having little or no support structure generally rely on the unhardened adhesive to secure the appliance in the container, thereby adding an engineering constraint to the adhesive formulation that would not otherwise be present.

As a solution, orthodontic assemblies and related methods are provided where an adhesive coated orthodontic appliance is received in a container that includes a substrate and a dual-purpose lid. The lid protectively seals the coated appliance in the container, and also has retaining structure that is at least partially complemental to the shape of the appliance and engages with the appliance when the lid is closed. By conforming to the shape of the appliance, the retaining structure constrains the appliance from shifting in lateral and vertical directions within the container. When the lid is opened, the associated retaining structure disengages from the appliance, allowing convenient user access.

Advantageously, these assemblies and methods enable the appliance to be held securely during shipping and handling. This protects the appliance and also preserves the integrity of the adhesive pad interposed between the substrate and base of the appliance. Moreover, because the retaining structure is conveniently withdrawn from the appliance immediately prior to use, there is an abundance of space along the periphery of the appliance to provide easy access using tweezers or other hand instruments. Finally, by bracing the appliance within the container, these assemblies alleviate the burden on the adhesive to support the appliance during transit, leading to greater freedom in engineering the composition of the adhesive.

In one aspect, a packaged orthodontic assembly is provided. The packaged orthodontic assembly comprises an orthodontic appliance having a base for attachment to a tooth surface; an adhesive extending across at least a portion of the base; a substrate having a release surface in contact with the adhesive; a lid coupled to the substrate and comprising a retaining member that contacts the appliance at a non-zero angle relative to the release surface to hinder relative sliding movement between the appliance and the release surface.

In another aspect, a method of packaging an orthodontic appliance is provided, comprising coating a base of the appliance with an orthodontic adhesive; placing the appliance on a substrate, wherein the adhesive contacts the substrate; and placing a lid over both the appliance and the substrate, wherein the lid comprises a retaining member that at least partially surrounds the appliance to hinder relative sliding movement between the appliance and the substrate.

5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A packaged orthodontic assembly according to one embodiment is illustrated inFIG. 1and designated by the numeral100. The assembly100includes a substrate102having a recess104. The recess104, in turn, has vertical surfaces106and a horizontal surface108. The horizontal surface108further includes a release surface107. As defined herein, a release surface107is a surface that is initially in contact with an adhesive and from which the adhesive may be subsequently removed. Preferably, the release surface107is a non-stick surface, such as provided by a low surface energy polymer coating, porous foam, or release liner such as a polyester film or fluorinated copolymer film. Further examples and aspects of release surfaces are described in issued U.S. Pat. No. 6,183,249 (Brennan, et al.).

Received in the recess104is an orthodontic appliance110. As shown, the appliance110is an orthodontic bracket having a body50, archwire slot52, tiewings54, and a bonding base112for attachment to a tooth surface of a patient. The appliance110need not be a bracket and may instead be any of a number of bondable orthodontic appliances, including buccal tubes, buttons, cleats and sheaths. Moreover, the appliance110may be suitable for attachment either to the labial or lingual surface of the patient's teeth. The appliance110is coated with an orthodontic adhesive114that extends over at least a portion of the base112.

The orthodontic adhesive114may include any of a variety of bonding compositions known in the art. Preferably, the orthodontic adhesive114is a light curable adhesive that is hardenable by exposure to actinic radiation. Suitable adhesives include, for example, TRANSBOND XT brand Light Cure Adhesive and TRANSBOND PLUS brand Color Change Adhesive, both available from 3M Unitek. As another option, the adhesive114can be a compressible adhesive, as described in U.S. Patent Publication Nos. 2008/0096150 (Cinader) and 2009/0233252 (Cinader). Further aspects of adhesive pre-coated appliances are described in U.S. Pat. No. 5,575,645 (Jacobs, et al.) and U.S. Pat. No. 6,960,079 (Brennan et al.).

As shown inFIG. 1, the adhesive114contacts the release surface107of the substrate102. In some embodiments, the release surface107allows the adhesive114to separate cleanly from the substrate102when the appliance110is lifted or peeled away from the substrate102without leaving any portion of the adhesive114on the substrate102and without unduly deforming the initial pillow-like shape of the adhesive114. In other embodiments, a portion of the adhesive114is intentionally absorbed into, or otherwise retained on, the release surface107when the appliance110is lifted or peeled away from the substrate102. This can be especially advantageous for compressible adhesives, where it may be desirable for the adhesive114to be maintained in a resin-saturated state.

A peelable lid120, having a top surface121and a bottom surface122, is coupled to the substrate102and extends over the appliance110and the recess104. In the example shown, the lid120laminated to the substrate102by a releasable adhesive. However, a hinge or other type of coupling may also be used. When the lid120is in a closed configuration, as shown inFIG. 1, the appliance110is located between the substrate102and the lid120. In some embodiments, the lid120contacts the substrate102along one or more locations that partially or fully surround the appliance110, as viewed from directions perpendicular to the top and bottom surfaces121,122of the lid120. In some embodiments, the lid120hermetically seals the appliance110within the recess104of the substrate102.

The lid120may include both rigid and flexible components. In some embodiments, the lid120is releasably coupled to the substrate102and flexibly peeled away from the substrate102. In other embodiments, the lid120is pivotally coupled to the substrate102and is opened using a hinge-type mechanism located at one side of the recess104.

Assuming that the adhesive114is a light curable adhesive, both the substrate102and the lid120preferably block passage of light, particularly light having wavelengths that induce hardening of the adhesive114. Optionally, either the lid120or the substrate102transmits light over a limited portion of the visible light spectrum such that the practitioner can visually ascertain whether or not the appliance110is situated in the recess104when the lid120is closed. Alternatively, the substrate102or the lid120may be constructed from a polymer composite that completely blocks passage of actinic radiation, as disclosed in U.S. Patent Publication No. 2003/0196914 (Tzou, et al.). In some embodiments, the substrate102and lid120also block passage of water vapor, oxygen, and other gases.

To facilitate opening of the lid, a portion of the lid120extends beyond a lateral edge of the substrate and acts as a handle that can be grasped between the thumb and forefinger of a user while peeling the lid120away from the substrate102.

As shown inFIG. 1, the bottom surface122of the lid120(adjacent to the recess104) and the release surface107of the substrate102are generally parallel with each other when the lid120is in its closed orientation. By contrast, the appliance110has certain surfaces123that contact the retaining member124. The surfaces123are non-parallel with both the bottom surface122of the lid120and the release surface107of the substrate102. In the embodiment shown inFIG. 1, the surfaces123are located on curved labial surfaces of the bracket tiewings.

A retaining member124extends outwardly from the bottom surface122of the lid120and contacts one or more surfaces123of the appliance110at a non-zero angle relative to the release surface107of the substrate102. Preferably, and as shown, the retaining member124is at least somewhat flexible and has a surface contour that generally conforms to at least a portion of the labial-facing surfaces of the appliance110. Advantageously, the retaining member constrains movement of the appliance110in both lateral and vertical directions.

First, by contacting the surfaces123of the appliance110, the retaining member124effectively hinders relative sliding movement between the appliance110and the lid120. Further, because the lid120and the substrate102are coupled to each other, the retaining member124also hinders relative sliding movement between the appliance110and the substrate102. Preferably, the retaining member124partially surrounds the appliance110to prevent both rotation of the appliance110in the plane of the release surface107and lateral translation of the appliance110across the release surface107. As used herein, “partially surrounding” the appliance indicates that interference can result from translating or rotating the appliance within the plane of the release surface.

Preferably, the retaining member124makes contact with the appliance110over a surface area of at least 2 square millimeters, more preferably over a surface area of at least 2.8 square millimeters, and most preferably over a surface area of at least 3.5 square millimeters.

Second, the retaining member124and substrate102engage opposite facing sides of the appliance110thereby maintaining the appliance110in a fixed vertical position within the recess104. In some embodiments, the retaining member124applies a gentle, continuous force that urges the appliance110toward the release surface107of the substrate102to help prevent the appliance110from wobbling when the packaged assembly100is handled and transported. Preferably, any force applied is sufficiently small so that the adhesive114located between the appliance110and the substrate102is not unduly compressed or otherwise distorted.

Preferably, the retaining member124exerts a compressive force on the appliance110having a component perpendicular to the release surface107ranging from 0 to 0.15 newtons (N), more preferably ranging from 0.02 to 0.12 N, and most preferably from 0.04 to 0.09 N. If present, it is preferable that these forces are small enough that the adhesive114does not extrude in lateral directions beyond the bonding base112. In other embodiments, the retaining member124exerts essentially zero compressive force on the appliance110in directions perpendicular to the release surface107as to avoid any significant distortion of the adhesive114.

Optionally, the retaining member124exerts gentle compressive forces on the appliance110in directions that are not perpendicular to the release surface107to further restrain lateral movement of the appliance110. For example, the retaining member124may exert compressive forces on the appliance110having components parallel to the release surface107. Preferably, any force components parallel to the release surface107are sufficiently small so that the retaining member124does not “grip” the appliance110and cause the appliance110and adhesive114to lift off prematurely from the release surface107when opening the lid120.

In some embodiments, the retaining member124has a customized, pre-determined shape when relaxed that at least partially conforms to the labial surface of the appliance110. By using a retaining member124having an outer surface that mechanically registers with at least a portion of the appliance110, both the relative location and orientation of the appliance110can be precisely controlled. Alternatively, or in combination, the retaining member124can flexibly and resiliently deflect such that the retaining member124assumes the contours of the underlying labial surfaces of the appliance110.

Optionally, the retaining member124is compressible. Various compressible materials can be used to construct the retaining member124, including porous, polymeric open-celled and closed-cell foams, woven and non-woven materials. Preferred foam materials include ethylene propylene diene monomer and crosslinked polyethylene. In exemplary embodiments, the retaining member124has a compression deflection at 25 percent at a pressure of at most 14 kilopascals (2 pounds per square inch).

As another option, the retaining member124can include a friction enhancing coating which further hinders sliding movement between the retaining member124and the appliance110.

FIG. 2again illustrates the assembly100, except with the lid120in a fully opened position. In this opened configuration, the retaining member124is removed from the vicinity of both the appliance110and the recess104. During a bonding operation, a user applies a pair of tweezers, pliers, or other hand instrument to rapidly and conveniently extract the appliance110from the recess104and place the appliance110onto the patient's tooth. Advantageously, the appliance110is free of obstructions on all lateral sides, thereby facilitating the removal process.

While the contacting surfaces123are located on the tiewings54of the appliance110, this need not be limiting. For example, other surfaces of the appliance110also non-parallel to the bottom surface122and release surface107include surfaces on the mesial and distal sides of the bracket body, between the bracket tiewings, and within the archwire slot. Any number of these surfaces may also contact the retaining member124.

FIG. 3ashows an alternative orthodontic assembly200, in which an appliance210is held in place by the combination of the substrate202and a retaining member224which is deformable but not volumetrically compressible (i.e. it does not decrease in volume). Retaining member224is an enclosed air-filled bladder that again conforms to the shape of the appliance when the lid220is closed. Like the retaining member124, the retaining member224prevents undue movement of the appliance210relative to the substrate202. In this case, the retaining member224contacts, and partially surrounds, a substantial portion of the labial face of the appliance210.

FIG. 3bshows a similar assembly800with a lid820that includes a retaining member824having a tubular cross-section. Because of its tubular shape, the retaining member824is capable of being deflected to conform to the labial surface of an underlying appliance810when the lid is closed. Retaining members that are hollow in general are also contemplated. Other aspects of the assemblies200,800are analogous to those described in assembly100.

Still another embodiment is shown inFIGS. 4 and 5. These figures show two separate views of an assembly300, in which a retaining member324having four discrete prongs326secures an appliance310within a substrate302. The four prongs326extend from a lid320toward the release surface of the substrate302and rest against each of the occlusal, gingival, mesial, and distal sides of the appliance310. Because the prongs326collectively surround the appliance310on at least two opposing sides, the appliance is again prevented from unduly shifting relative to the substrate302when the lid320is closed. If desired, the prongs326could be angled, bent, or curved to apply gentle compressive forces against the appliance310in the plane of the release surface thereby enhancing control over the lateral position and orientation of the appliance.

The substrate of the orthodontic assembly need not be recessed.FIG. 6shows an alternative assembly400having a substrate402that is rigid and generally planar in shape. In this configuration, a lid420having a pliable layer430and a rigid shell432extends over the substrate402. The rigid shell432has a recess that receives an appliance410when the lid420is closed. The retaining member424is coupled to the underside of the rigid shell432and restricts undesirable movement of the appliance410. The pliable layer430easily peels away from the substrate402, allowing the rigid shell432to swing open and present the appliance410.

The planar substrate further enhances the accessibility of the appliance410when the lid is opened. As another advantage, the overall size of the assembly can be made smaller, since it is no longer necessary to provide lateral space in the recess for hand instruments to access the appliance. Other options and advantages of using a recessed lid420are disclosed in U.S. Pat. No. 7,726,470 (Cinader et al.).

In other embodiments, the retaining member has one or more features that mechanically register with slots, grooves or other recesses located on the orthodontic appliance. For example,FIGS. 7 and 8ashow an orthodontic assembly500having a substrate502and a lid520with a retaining member524. The retaining member524has a blade-like protrusion525that is received into the archwire slot of an appliance510when the lid is closed.

FIG. 8bshows an alternative assembly600in which a retaining member624is received in the vertical slot of an appliance610.FIG. 8cshows yet another assembly700in which a generally cross-shaped retaining member724is received in both the vertical slot and the archwire slot of the appliance710. The remainder of each of the assemblies ofFIGS. 8band8cis the same as shown inFIG. 7. Each of the retaining members524,624,724engages its respective appliance501,610,710to prevent undesirable tipping, rotation, or sliding movement when the lid is closed, yet disengages from its respective appliance510,610,710to facilitate user access when the lid is opened. Optionally and as shown, the protrusions may be shortened or tapered to facilitate disengagement of the respective retaining members524,624,724from the respective appliances510,610,710when opening the lid.

In an exemplary method of packaging an orthodontic assembly100, the base of the appliance110inFIGS. 1-2is initially coated with an orthodontic adhesive114. The appliance110is then placed onto the substrate102such that the adhesive114releasably contacts the substrate102. To seal the appliance110from light, moisture, and/or contaminants, the lid120is placed over both the appliance110and the substrate102. When the lid120is in its closed position, the retaining member124at least partially surrounds the appliance to hinder relative sliding movement between the appliance and the substrate.

In an alternative method of packaging the assembly100, the lid is inverted such that the bottom surface122is facing upwards. Then, the adhesive coated appliance110is placed upside down on the retaining member124of the lid120. Finally, the lid120is held stationary while the substrate102is secured over the appliance110and lid120. By closing the lid120in this manner, the adhesive114is pressed against the substrate102, allowing the appliance110to be retained on the substrate102when the lid120is subsequently opened. Advantageously, this method allows a manufacturer to visually confirm that the retaining member124and the appliance110are precisely engaged with each other prior to sealing the lid120.

It is understood that the above methods can also apply by analogy to assemblies200,300,400,500, and800.

These assemblies and methods are advantageous to the orthodontic practitioner for several reasons.

First, the retaining member of the lid operates to securely retain the orthodontic appliance and pre-coated adhesive in a protective container during shipment and handling. In particular, the retaining member prevents the appliance from undue sliding motion relative to the lid during shipment and handling of the packaged orthodontic assembly. The retaining structure provided by the lid not only protects the appliance from impact but also helps preserve the shape and integrity of the unhardened adhesive pad, which is typically very delicate. The retaining member also conveniently disengages from the appliance when the lid is pulled back, allowing easy access by an orthodontic practitioner or assistant. The adhesive coated appliance may be conveniently plucked from the substrate using a pair of tweezers, or any other hand instrument suitable for this purpose.

Second, this configuration provides an answer to a persistent technical challenge associated with bulky appliances, such as buccal tubes, which apply uneven weight across the underlying adhesive pad. When these appliances are freshly coated with an adhesive and placed on a substrate, gravity often causes these appliances to “tip,” resulting in an adhesive pad that is unduly thick on one side and unduly thin on the other. By mechanically registering with features on the appliance, the retaining member alleviates this undue tipping and preserves the uniformity of the adhesive pad on the base of the appliance.

Third, by securing the appliance on opposing sides, the retention mechanism provided by the retaining member alleviates the burden placed on the adhesive to retain the appliance on the substrate. As a result, the assembly can accommodate adhesives displaying a particularly wide range of tack and viscosity in the unhardened state. This is especially beneficial considering that filled orthodontic adhesives generally have viscosities that are shear-dependent and are susceptible to shift or distort within the container immediately after coating. These assemblies are also advantageous when exposed to elevated or reduced temperatures. While temperature fluctuations can affect the tack and/or viscosity of the coated adhesive, these effects are mitigated because the appliance is secured by the retaining structure.

Fourth, the use of retaining structure on the lid of a container also enables the use of non-porous release surfaces for retaining the pre-coated adhesive on the substrate. Previously, porous release surfaces were often preferred because of their effectiveness in preventing lateral “skating” of the adhesive along its surface. However, porous release surfaces also have the tendency to wick resin from the adhesive over time, leading to changes in adhesive texture. With the inclusion of a retaining member, it is possible to use non-porous, low-surface energy release surfaces that do not wick resin away from the pre-coated adhesive over time. Reduced wicking, in turn, provides for improved adhesive consistency during the shelf life of the pre-coated appliance.

All of the patents and patent applications mentioned above are hereby expressly incorporated by reference. The embodiments described above are illustrative of the present invention and other constructions are also possible. Accordingly, the present invention should not be deemed limited to the embodiments described in detail above and shown in the accompanying drawings, but instead only by a fair scope of the claims that follow along with their equivalents.