(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2009/0246724 A1
`(43) Pub. Date:
`Oct. 1, 2009
`Chen et al.
`
`US 20090246724A1
`
`(54) RESTORATIVE DENTAL APPLIANCES
`
`Publication Classification
`
`(76) Inventors:
`
`Yan Chen, Cupertino, CA (US);
`Chunhua Li, Cupertino, CA (US)
`
`Correspondence Address:
`ALIGN TECHNOLOGY CAO WAGNER
`BLECHER LLP
`123 WESTRIDGE DRIVE
`WATSONVILLE, CA 95076 (US)
`
`(21) Appl. No.:
`
`12/055,010
`
`(22) Filed:
`
`Mar. 25, 2008
`
`
`
`(51) Int. Cl.
`(2006.01)
`A6IC 7/08
`(52) U.S. Cl. ............................................................ 433A6
`(57)
`ABSTRACT
`A dental appliance is described herein. In one embodiment,
`the dental appliance comprises a concave trough conforming
`to a plurality of teeth when placed over the plurality of teeth.
`The concave trough is configured to transition from a first
`shape to a second shape if a deforming force is applied. The
`concave trough comprises a shape memory material. The
`shape memory material is configured to restore the concave
`trough to an approximate first shape upon an application of an
`external stimulus. The first shape is configured to apply a first
`force on a tooth when the trough conforms.
`
`ClearCorrect Exhibit 1052, Page 1 of 17
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`Patent Application Publication
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`Oct. 1, 2009
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`Sheet 1 of 11
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`US 2009/0246724 A1
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`
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`FIG. 1
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`Patent Application Publication
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`Oct. 1, 2009 Sheet 2 of 11
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`US 2009/0246724 A1
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`
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`120
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`-10
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`116
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`118
`
`FIG. 2
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`Patent Application Publication
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`Oct. 1,2009 Sheet 3 of 11
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`US 2009/0246724 Al
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`102
`
`FIG. 2A
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`ClearCorrect Exhibit 1052, Page 4 of 17
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`ClearCorrect Exhibit 1052, Page 4 of 17
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`Patent Application Publication
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`Oct. 1, 2009 Sheet 4 of 11
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`US 2009/0246724 A1
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`
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`FIG. 2B
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`ClearCorrect Exhibit 1052, Page 5 of 17
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`Patent Application Publication
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`Oct. 1, 2009 Sheet 5 of 11
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`US 2009/0246724 A1
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`
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`FIG. 3
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`Patent Application Publication
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`Oct. 1, 2009 Sheet 6 of 11
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`US 2009/0246724 A1
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`132
`134 1N 134
`
`FIG, 4A
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`Patent Application Publication
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`Oct. 1, 2009 Sheet 7 of 11
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`US 2009/0246724 A1
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`131
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`M
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`132
`134 /N 134
`
`FIG. 4B
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`Patent Application Publication
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`Oct. 1, 2009 Sheet 8 of 11
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`US 2009/0246724 A1
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`131 V
`132
`134 W 134
`
`FIG. 4C
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`Patent Application Publication
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`Oct. 1, 2009 Sheet 9 of 11
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`US 2009/0246724 A1
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`131
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`132
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`FIG. 4D
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`Patent Application Publication
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`Oct. 1, 2009 Sheet 10 of 11
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`150
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`152
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`
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`148
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`622&&.
`&stya) San
`
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`
`
`
`FIG. 5
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`Patent Application Publication
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`Oct. 1, 2009 Sheet 11 of 11
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`US 2009/0246724 A1
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`
`
`FORMING DENTAL
`APPLIANCETO FIRST SHAPE
`610
`
`APPLYING EXTERNAL
`STIMULUS TO TRANSITION
`TO FIRST SHAPE FROM
`SECOND SHAPE
`620
`
`FIG. 6
`
`ClearCorrect Exhibit 1052, Page 12 of 17
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`US 2009/0246724 A1
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`Oct. 1, 2009
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`RESTORATIVE DENTAL APPLIANCES
`
`FIELD
`0001 Embodiments of the present invention relate ingen
`eral to the field of orthodontics.
`
`BACKGROUND
`0002 An alternative to braces includes the use of aligner
`type dental appliances for realigning teeth. Such an appliance
`may be comprised of a thin concave trough of material that
`forms a receiving cavity geometry that generally conforms to
`a patient's teeth but is slightly out of alignment with the initial
`tooth configuration. Placement of the dental appliances over
`the teeth applies controlled forces in specific locations to
`gradually move the teeth into a new predetermined configu
`ration. Repetition of this process with Successive appliances
`comprising new configurations eventually moves the teeth
`through a series of predetermined intermediate arrangements
`along the most effective and efficient treatment path to a final
`predetermined arrangement.
`0003. Some dental appliances are made using polymers,
`Such as thermoplastic polyurethane. Polymers may deform
`overtime and/or use due to external and internal forces. Some
`deforming external forces may include repeated insertion/
`removal and biting/wearing. An internal deforming force may
`include material stress relaxation. The deformation may
`reduce tooth moving forces, thereby reducing the usefulness
`of the dental appliance. Once the usefulness of the aligner
`dental appliance is reduced, the dental appliance is typically
`disposed of, and either a replacement dental appliance is
`made or the next dental appliance in the treatment series is
`used. Hence, the shorter the effective usefulness of the dental
`appliance, the more frequently the dental appliance needs to
`be changed. Consequently, an extension of the effective use
`fulness of the dental appliance is desirable.
`
`SUMMARY
`0004. A dental appliance is described herein. In one
`embodiment, the dental appliance comprises a concave
`trough conforming to a plurality of teeth when placed over the
`plurality of teeth. The concave trough is configured to tran
`sition from a first shape to a second shape ifa deforming force
`is applied. The concave trough comprises a shape memory
`material. The shape memory material is configured to restore
`the concave trough to an approximate first shape upon an
`application of an external stimulus. The first shape is config
`ured to apply a first force on a tooth when the concave trough
`conforms.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`0005 FIG. 1 illustrates the lower jaw of a patient together
`with a dental appliance upon which embodiments of the
`present invention may be implemented.
`0006 FIGS. 2, 2A, and 2B are cross-sectional views of an
`embodiment for securing the appliance of FIG. 1 on to the
`teeth, in accordance with embodiments.
`0007 FIG.3 illustrates a cross-sectional view of an attach
`ment device for securing the appliance of FIG. 1 on to the
`teeth, in accordance with embodiments.
`0008 FIGS. 4A-4D illustrates layering geometry, in
`accordance with embodiments.
`
`0009 FIG. 5 illustrates a cross-sectional view of a dental
`appliance transforming shapes, in accordance with embodi
`mentS.
`0010 FIG. 6 is a flow chart of a method for restoring a
`dental appliance, in accordance with embodiments.
`
`DESCRIPTION OF EMBODIMENTS
`0011. In the following description, numerous specific
`details are set forth in order to provide a thorough understand
`ing. However, it will be recognized by one of ordinary skill in
`the art that embodiments may be practiced without these
`specific details. In other instances, well known methods, pro
`cedures, and components have not been described in detail as
`not to unnecessarily obscure aspects of the present invention.
`
`Overview
`0012 Embodiments in accordance with the present inven
`tion transition the dental appliance from a deformed and/or
`relaxed shape to an original shape upon an application of an
`external stimulus thereby extending the useful lifespan of the
`dental appliance.
`0013 The dental appliance comprises a concave trough
`conforming to a plurality of teeth when placed over the plu
`rality of teeth. In other words, upon placement, controlled
`forces are applied to the teeth as the appliance conforms in
`specific locations to gradually move the teeth into a new
`predetermined configuration. The concave trough comprises
`a shape memory material being transitionable to the approxi
`mate original shape from the relaxed shape upon an applica
`tion of an external stimulus. The original shape is configured
`to apply a desired force on a tooth when the trough conforms.
`The deformed shape may have less than desirable forces
`acting on a tooth and may obtain this shape due to deforming
`forces, such as biting the dental appliance.
`System and Method for Positioning Teeth
`0014 Referring to FIG. 1, the lower jaw 114 of a patient
`together with a dental appliance 100 is illustrated upon which
`embodiments of the present invention may be implemented.
`The dental appliance 100 is removable and replaceable over
`the teeth. In some embodiments, appliance 100 is one of a
`plurality of incremental position adjustment appliances.
`0015 The dental appliance 100 may comprise a polymeric
`concave trough 102 having an inner cavity 120, a proximal
`edge 116, and a distal edge 118. The inner cavity is shaped to
`receive and resiliently reposition teeth from one tooth
`arrangement to a Successive tooth arrangement. In some
`embodiments, the polymeric concave trough 102 fits over all
`teeth present in the upper jaw (not depicted) or lower jaw 114.
`Typically, only certain one(s) of the teeth will be repositioned
`while others of the teeth will provide a base or anchor region
`for holding the dental appliance in place as it applies the
`resilient repositioning force against the tooth or teeth to be
`repositioned. Certain areas of the appliance will confer orth
`odontic forces on the teeth due to the intentional mismatch
`built into the appliance between the tooth's current position
`and the desired position built into the appliance. These are the
`inherently “active' regions of the appliance. Certain areas of
`the appliance will conform to the teeth nearly exactly as they
`are, without introducing orthodontic forces onto the teeth to
`which they conform. These are the inherently “passive' areas
`of the appliance which retain the teeth as they are in their
`Current State.
`
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`US 2009/0246724 A1
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`Oct. 1, 2009
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`0016. The planning and fabrication of such dental appli
`ances as an example elastic polymeric positioning appliance
`is described in detail in U.S. Pat. No. 5,975,893, and in
`published PCT application WO 98/58596 which designates
`the United States and which is assigned to the assignee of the
`present application, and which is herein incorporated by ref
`erence for all purposes. Systems of dental appliances employ
`ing technology described in U.S. Pat. No. 5,975,893, are
`commercially available from Align Technology, Inc., Santa
`Clara, Calif., under the tradename, Invisalign System. Align
`Technology, Inc., is the assignee of the present application.
`0017. Throughout the body of the Description of Embodi
`ments, the use of the terms “aligner or “dental aligner' is
`synonymous with the use of the terms “appliance' and “den
`tal appliance' in terms of dental applications. For purposes of
`clarity, embodiments are hereinafter described within the
`context of the use and application of appliances, and more
`specifically “dental appliances.”
`Securing Dental Appliance to Teeth
`0018. As may be understood with reference to the cross
`sectional views of embodiment for securing the appliance of
`FIG. 1, in FIGS. 2, 2A, and 2B, the concave trough 102 is
`forced down over teeth T, typically by the patient biting down
`on the concave trough or by other forms of manual pressure
`being applied to the concave trough. Edges 116 and 118 are
`made to engage what is known as the undercut U of the teeth.
`Typically, this type of engagement is helpful in that it allows
`for specific tooth movements. Such as extrusions (e.g.,
`upward movement of the tooth).
`0019. The concave trough 102 is made of a material that
`has a predetermined modulus, also referred to as the stiffness,
`of the material. Generally, the modulus is a measurement of
`the inherent stiffness of a material determined by conducting
`stress and strain tests on a material specimen and plotting the
`results. The value of the slope of the line generated by the
`results is the modulus. The modulus can be predetermined to
`match the compliance required to reposition the teeth based
`on requirements set by an individual patient's repositioning
`needs. In one example, the concave trough may have a modu
`lus in the range of between about 0.1 GPa to 4 GPa, usually
`0.5 GPa to 3 GPa, and preferably about 0.8 GPa to 1.5 GPa.
`0020. In various embodiments, the concave trough 102 is
`formed from a material that has uniform properties, such as
`stiffness, over the entire area. In some embodiments, the
`concave trough has varying stiffness, thickness, or other
`material properties at different points or segments. In other
`embodiments, other layers, reinforcement elements, holes, or
`components may be added to the concave trough 102 to vary
`the stiffness and/or other mechanical properties. The stiffness
`of the concave trough 102 may keep edges 116 and 118
`engaged with undercut U, which is configured to hold the
`appliance in place and effect tooth repositioning.
`0021. The concave trough 102 may include a single or a
`plurality of polymeric material layers. In some embodiments,
`each layer may have shape memory materials, as discussed
`further herein. The layers may consist of similar and/or dif
`ferent materials. The shape memory materials may undergo a
`property change independent of one another or simulta
`neously. The layer or layers may also be made of a cross
`linked polymer capable of undergoing a joint change in
`shape.
`0022 FIG.3 illustrates a cross-sectional view of an attach
`ment device for securing the appliance of FIG. 1 on to the
`
`teeth, in accordance with embodiments. In another alternative
`embodiment, concave trough 102 may also be held or
`anchored to the teeth through an engagement between con
`cave trough 102 and an attachment device 124. Such as an
`anchor. The attachment device 124 may be anchored to a
`distal surface (between tooth and cheek) and/or a proximal
`Surface (between tooth and tongue) of the teeth using an
`adhesive or similar bonding Substance. In various embodi
`ments, the anchors may have any of a variety of material
`properties with the objective being to point a force-transmit
`ting interface between the appliance and the tooth when the
`appliance is in place. The anchors may be formed from most
`Solid, physiologically acceptable materials, particularly met
`als, ceramics, and polymers. The materials may be rigid,
`resilient, and/or programmable, e.g. shape memory polymers
`or metal alloys. In some instances, it is also possible that the
`anchors would be mechanically complex, e.g. articulated,
`rotatable, or otherwise repositionable to facilitate mounting
`or removal of the appliance from the teeth.
`0023 Several techniques for securing the dental appliance
`to the teeth, Such as, anchoring, use of adhesive, and gripping
`are described in U.S. Pat. No. 6,390,812 B1, which is herein
`incorporated by reference for all purposes.
`
`Deforming Forces
`0024. Although the dental appliance 100 may be designed
`to resist deformation, Some regions of the dental appliance
`100 may experience deformation. Deformation may reduce
`the forces to reposition the teeth. Deformation may becaused
`by inserting the dental appliance, removing the dental appli
`ance, wearing the dental appliance, biting the dental appli
`ance, material stress relaxation, heating, cooling, or any force
`that stresses the dental appliance.
`
`Dental Appliance Material Properties
`0025. In various embodiments, the dental appliance uses
`shape memory material to restore the dental appliance to the
`approximate original shape upon the application of an exter
`nal stimulus or stimuli. Some shape memory materials that
`may be used include shape memory polymers, methacrylate
`containing polymers, acrylate containing polymers, elas
`tomer polymers, thermoplastic polymers, thermoplastic elas
`tomer polymers, thermoset polymers, thermoplastic polymer
`blends, cross-linked thermoplastic polymers, and cross
`linked thermoplastic polymer blends.
`0026. The dental appliance 100, in some embodiments,
`has a polymeric material layer fabricated into at least two
`segments, one segment harder than the other segment. In
`other embodiments, a softer segment is fabricated using a
`polymeric material and the harder segment is made using
`polymeric material and/or non-polymeric material. The
`softer segment may be designed more Susceptible to deform
`under deforming forces than the harder segment. The harder
`segment may be designed to control a restoration of an origi
`nal shape. Upon an application of an external stimulus, the
`softer segment controlled by the harder segment's forces
`returns the dental appliance 100 to the approximate original
`shape.
`0027. The external stimulus may be a non-oral applica
`tion. A non-oral application is any application outside of a
`mouth as the application may be damaging to the mouth
`and/or Surrounding region.
`
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`0028. The dental appliance 100 may be configured with a
`reinforcement structure, such as a wire, a filament, a mesh, a
`ring, and/or a braid. The reinforcement structure may also be
`capable of undergoing a change in material property and/or a
`change in shape, Such that the change facilitates the restora
`tion of the original shape. For example, dental appliance 100
`may be fabricated with a polymeric outer layer and a metal
`inner wire embedded in at least a portion of the appliance
`proximate to either the engagement with the undercut or the
`engagement with the anchor. The metal inner wire may be
`made of a shape memory metal, such as Nitinol R, Bimetal(R),
`Memotal(R) or similar alloy. The wire undergoes a change in
`material property (and/or shape) as it is Subjected to a thermal
`stimulus or other external stimulus. In this example, the wire
`changes geometry. Since the wire is embedded within the
`dental appliance, the appliance also changes shape, which
`may restore the appliance to an approximate original shape.
`0029. The changes described above may be provided
`through use of various polymers which undergo a glass tran
`sition at a preselected temperature. The glass transition may
`occur by using a plastic, such as a polymer, that has a molecu
`lar transition incorporated in the same. The polymeric mate
`rial is biocompatible and is formulated so that the achieved
`transition can be activated upon Subjecting the appliance to
`thermal stimuli as herein explained. The molecular transi
`tions, which are incorporated in the appliance, are typically in
`the form of thermotransitions, as for example, a crystalline
`melting point, above about 37 degrees Celsius, preferably
`between 40 degrees Celsius and 55 degrees Celsius, of the
`polymer side chain, the polymer main chain, or a liquid
`crystal (mesophase)transition of the polymerchain. The ther
`motransitions may also be accessed via a glass transition
`phenomenon or a local mode molecular transition.
`Dental Appliance Layers
`0030 FIGS. 4A-4D illustrates layering geometry, in
`accordance with embodiments. In various embodiments, an
`original shape restoration mechanism may comprise the con
`cave trough 102 with a single layer as shown in FIG. 4D or a
`plurality of layers, as shown in FIGS. 4A, 4B and 4C. In
`various embodiments, the layer 132 of FIG. 4D includes a
`single material with a thickness ranging from about 1 mill to
`60 mils, and preferably 10-40 mils.
`0031. The concave trough 102 may include a variable
`number of inner layers 132. For example, four, three or two
`inner layers 132, as shown in FIGS. 4A, 4B, and 4C, respec
`tively. More than four inner layers (not depicted) may also be
`used. The inner layers 132, as well as the outer layers 134,
`may each have different thickness, such as 5 or 10 mils, and/or
`variable glass transition temperatures. The layers may be
`formed in various orientations and configurations to Suit the
`modulus and application requirements. The layers may be
`formed by a process, such as thermoforming or similar pro
`cess, Such as co-extrusion, lamination, or any other process
`where layers are formed. The layers may be formed with
`cavities and indentations used as repositioning forces on the
`teeth.
`0032. An example embodiment is to have Polycarbonate
`outer layers 134 and the PVC inner layers 132. Here, while
`under a glass transition temperature of both materials, the
`forces of all layers have a combined modulus that may be used
`as forces to grab hold of and reposition the teeth. If desired to
`restore the dental appliance to an original shape, heat may be
`applied to obtain the glass transition temperature of the inner
`
`layers. The forces of the inner layers will relax, transition, and
`may eventually return to a previous alignment, thereby allow
`ing the dental appliance to return to an approximate original
`shape. Alternatively, the inner layers may be configured with
`a higher transition temperature than that of the outer layers.
`By reversing the threshold glass transition temperatures
`between the layers, the rolls of the inner and outer layers may
`be reversed.
`0033. In various embodiments, the softer segment may
`consist of one or more layers and the harder segment may
`consist of one or more layers. In still further embodiments, the
`softer segment may consist of multiple layers with different
`glass transition temperatures, thereby allowing different lev
`els of restoration depending on different degrees of deforma
`tion.
`0034 Several examples using glass transition materials
`and layers are described in U.S. Pat. No. 6,390,812B1, which
`is herein incorporated by reference for all purposes.
`
`Cross-Sectional View of the Dental Appliance
`0035 FIG. 5 illustrates cross-sectional view of a dental
`appliance 148 transforming shapes, in accordance with
`embodiments. The cross section view of the dental appliance
`148 shows several layers, such as inner layers 150 and an
`outer layer 152. The dental appliance is shown in an original
`shape. Deforming forces 154, as discussed herein, may
`deform the dental appliance 148 to a shape as shown by dotted
`lines 156.
`0036. In various embodiments, a plurality of inner layers
`150 is sandwiched between the outer layer 152. The inner and
`outer layers may have variable thickness and variable glass
`transition temperatures depending on the modulus require
`ments. The inner layers 150 and outer layer 152 may be made
`from a homopolymer, cross-linked homopolymer, copoly
`mer, polycarbonate, cross-linked copolymer, a copolymer
`blend of thermoplastics, and/or similar material. The outer
`layer 152 may have a higher (or lower) glass transition tem
`perature than the inner layers 150. The inner and outer layers
`are formed with the desired surface features and indentations
`necessary for proper application of the repositioning forces to
`the teeth. The layer or layers with the lower glass transition
`temperature may be the softer segment, as discussed herein.
`The layer or layers with the higher glass transition tempera
`ture may be the harder segment, as discussed herein.
`0037. During an application of an external stimulus, the
`softer segment heats to a temperature higher than or equal to
`the glass transition temperature of the Softer segment. The
`temperature of the harder segment is maintained at a tempera
`ture below the glass transition temperature of the harder seg
`ment. This is desirable as the harder segment may be used to
`control the shape of the dental appliance 148. As the softer
`segment reaches the glass transition temperature, the material
`softens, repositions, and remolds to the shape of the harder
`segment. The harder segment via returning forces 158
`restores the dental appliance 148 to the approximate original
`shape. As the dental appliance 148 cools below the glass
`transition temperature of the Softer segment, the softer seg
`ment hardens and increases the stiffness of the dental appli
`ance 148.
`0038 Although the glass transition temperature is
`described as the threshold temperature for activating the state
`change process of the appliance, alternatively, the melting
`point temperature may be used as the threshold temperature.
`An advantage to using the melting point temperature is a
`
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`greater change in properties from one state to another. Also,
`the change in properties occurs over a smaller temperature
`range.
`
`External Stimulus
`0039. Depending on the shape memory material, some
`external stimuli may include heat, chemicals, light, magnetic
`forces, cleaning, and a pH agent. The external stimulus may
`be used to initiate the State changes in various embodiments
`described herein. For example, the heat may be supplied to
`the appliance by introducing a source of heat energy, such as
`a liquid with high heat transfer capacity. High heat transfer
`capacity may allow for uniform heating of the dental appli
`ance, thereby more effectively returning the appliance to the
`original shape. In various embodiments, two or more external
`stimuli may be used, for example, using a cleaning device for
`cleaning that applies a magnetic force and/or heat and/or uses
`chemicals and hydraulic forces.
`0040 Similarly magnetism, electricity, and radio waves
`can be used as secondary Sources of heat to cause the desired
`state changes. Such external heat can also be applied by using
`an infrared, microwave, or radio frequency sources as well as
`resistive heating. Use of pH agents on pH sensitive materials
`and other stimuli having an effect on shape memory materials
`are described in U.S. Pat. No. 6,390,812 B1, which is herein
`incorporated by reference for all purposes.
`
`Restoring the Dental Appliance's Original Shape
`0041
`FIG. 6 is a flow chart of a method for restoring a
`dental appliance, in accordance with embodiments. In step
`610, the dental appliance is formed to an original shape. The
`dental appliance may consist of one or a plurality of poly
`meric layers and/or non-polymer materials. Deforming
`forces may deform the dental appliance.
`0042. In step 620, an external stimulus is applied to the
`dental appliance to transition to the approximate original
`shape from the deformed shape. In various embodiments, the
`external stimulus heats the softer segment to a temperature
`greater than the glass transition of the softer segment. As the
`softer segment is heated, the deformed forces deforming the
`softer segment are relaxed, thereby allowing the harder seg
`ment to mold the softer segment and restore the dental appli
`ance to an approximate original shape. In various embodi
`ments, the approximate original shape is within Zero to five
`mils of the original shape. In other embodiments, the approxi
`mate original shape is effectively the original shape regarding
`desirable teeth aligning forces. After the dental appliance
`cools below the glass transition temperature of the softer
`segment, the Softer segment aligns and strengthens the stiff
`ness of the dental appliance.
`0043. While the embodiments illustrated in steps 610-620
`show specific sequences and quantity of steps, the present
`invention is suitable to alternative embodiments. For
`example, not all the steps provided for in the methods are
`required for the present invention. Furthermore, additional
`steps may be added to the steps presented in the present
`embodiment. Likewise, the sequences of steps can be modi
`fied depending upon the application.
`0044 Various alternatives, modifications, and equivalents
`may also be used. For example, a non-polymeric material,
`such as a metal, may be used for the softer and/or harder
`
`segment. Therefore, the above description should not be
`taken as limiting the scope of the invention which is defined
`by the appended claims.
`0045 Embodiments of the present invention, a restorative
`dental appliance, have been described herein. While the
`invention is described in conjunction with various embodi
`ments, it is understood that they are not intended to limit the
`invention to these embodiments. On the contrary, the inven
`tion is intended to cover alternatives, modifications and
`equivalents, which may be included within the spirit and
`Scope of the invention as defined by the appended claims.
`What is claimed is:
`1. A dental appliance comprising:
`a concave trough conforming to a plurality of teeth when
`placed over the plurality of teeth, the concave trough
`configured to transition from a first shape to a second
`shape ifa deforming force is applied, the concave trough
`comprising shape memory material, the shape memory
`material configured to restore the concave trough to an
`approximate first shape upon an application of an exter
`nal stimulus, the first shape configured to apply a first
`force on a tooth when the concave trough conforms.
`2. The dental appliance of claim 1, wherein the shape
`memory material comprises a material selected from the
`group consisting of shape memory polymers, methacrylate
`containing polymers, acrylate containing polymers, elas
`tomer polymers, thermoplastic polymers, thermoplastic elas
`tomer polymers, thermoset polymers, thermoplastic polymer
`blends, cross-linked thermoplastic polymers, cross-linked
`thermoplastic polymer blends, metal alloys, and shape
`memory metals.
`3. The dental appliance of claim 1, wherein the shape
`memory material comprises a first segment, the first segment
`configured to reach a glass transition temperature upon the
`application of the external stimulus.
`4. The dental appliance of claim 3, further comprising a
`second segment coupled to the concave trough and config
`ured to control the restoration of the first shape.
`5. The dental appliance of claim 3, wherein the shape
`memory material further comprises a second segment
`coupled to the first segment and configured to control the
`restoration of the first shape.
`6. The dental appliance of claim 1, wherein the concave
`trough comprises a plurality of polymeric layers.
`7. The dental appliance of claim 1, wherein the external
`stimulus is selected from the group consisting of heat, chemi
`cals, light, magnetic forces, cleaning, and a pH agent.
`8. The dental appliance of claim 1, wherein the second
`shape is configured to apply a second force on the tooth, the
`first force is greater than the second force.
`9. The dental appliance of claim 1, wherein the deforming
`force comprises a force from the group consisting of inserting
`removing, wearing, biting, heating, cooling the dental appli
`ance, and material stress relaxation of the dental appliance.
`10. The dental appliance of claim 1, wherein the external
`stimulus is a non-oral application.
`11. The dental appliance of claim 1, wherein the external
`stimulus is induced using a cleaning device.
`12. A method for restoring a dental appliance comprising:
`forming the appliance with a plurality of polymeric layers
`to have a concave trough in a first shape to conform to a
`plurality of teeth, the concave trough includes a shape
`memory material configured to transition from the first
`shape to a second shape if a deforming force is applied;
`
`ClearCorrect Exhibit 1052, Page 16 of 17
`
`

`

`US 2009/0246724 A1
`
`Oct. 1, 2009
`
`restoring the concave trough to an approximate first shape
`upon an application of an external stimulus, the first
`shape configured to apply a first force on at least one
`tooth of the plurality of teeth.
`13. A method for restoring a dental appliance comprising:
`forming a concave trough in a first shape to conform to a
`plurality of teeth when placed over the plurality of teeth,
`the concave trough configured to transition from the first
`shape to a second shape if a deforming force is applied,
`the concave trough comprising shape memory material,
`the first shape configured to apply a first force on a tooth
`when the trough conforms; and
`applying an external stimulus to transition the concave
`trough to an approximate first shape from the second
`shape.
`14. The method of claim 13, wherein the shape memory
`material comprises a material selected from the group con
`sisting of shape memory polymers, methacrylate containing
`polymers, acrylate containing polymers, elastomer polymers,
`thermoplastic polymers, thermoplastic elastomer polymers,
`thermoset polymers, thermoplastic polymer blends, cross
`linked thermoplastic polymers, cross-linked thermoplastic
`polymer blends, metal alloys, and shape memory metals.
`15. The method of claim 13, wherein the shape memory
`material comprises a first segment and a second segment, the
`
`first segment configured to reach a glass transition tempera
`ture upon the application of the external stimulus, the second
`segment coupled to the first segment and configured to con
`trol the restoration of the first shape.
`16. The method of claim 13, wherein the concave trough
`comprises a plurality of polymeric layers.
`17. The method of claim