Patent Description:
Orthodontic appliances, such as orthodontic brackets, may be used in orthodontic treatments by dental practitioners for moving one or more teeth of a patient from a malposition to a desired position in a dentition of the patient. The orthodontic treatments may improve a facial appearance of the patient. In some cases, the orthodontic treatments may also improve function of the teeth by providing improved occlusion during mastication. However, in some cases, the orthodontic appliances may interfere with oral and dental hygiene of the patient. That is, the orthodontic appliances may cause oral and dental diseases, such as tooth decay, and white-spot lesioning on tooth surfaces that cannot be properly cleaned.

<CIT> relates to a fluoride-releasing dental composition which includes a polymeric compound selected from (meth)acrylate polymers, (meth)acrylate copolymers, ethylene vinyl acetate copolymers, and mixtures and combinations thereof, and a cariostatically effective amount of a fluoride compound. Further described is a dental appliance made from the fluoride-releasing dental composition.

The invention is defined in the appended claim.

In one aspect, the present disclosure provides an orthodontic appliance. The orthodontic appliance includes a body. The body includes a first portion defining a slot for receiving an archwire. The body further includes a second portion extending from the first portion along a longitudinal axis. The second portion includes a bottom surface opposite to the first portion. The second portion further includes a lateral surface extending from the bottom surface towards the first portion along the longitudinal axis. The bottom surface and the lateral surface at least partially form an external surface of the body. The second portion defines a cavity at least partially surrounded by the bottom surface. The cavity at least partially extends along a length of the second portion from the bottom surface. The cavity includes a reservoir and at least one passage disposed in fluid communication with the reservoir. The at least one passage extends from the reservoir to the lateral surface.

In another aspect, the present disclosure provides an orthodontic system for a plurality of teeth. The orthodontic system includes an archwire. The orthodontic system further includes a plurality of orthodontic appliances configured to be removably coupled to the archwire. Each orthodontic appliance from the plurality of orthodontic appliances includes a body. The body includes a first portion defining a slot for receiving the archwire. The body further includes a second portion extending from the first portion along a longitudinal axis. The second portion includes a bottom surface opposite to the first portion. The second portion further includes a lateral surface extending from the bottom surface towards the first portion along the longitudinal axis. The bottom surface and the lateral surface at least partially form an external surface of the body. The second portion defines a cavity at least partially surrounded by the bottom surface. The cavity at least partially extends along a length of the second portion from the bottom surface. The cavity includes a reservoir and at least one passage disposed in fluid communication with the reservoir. The at least one passage extends from the reservoir to the lateral surface. Each orthodontic appliance further includes a base. The base includes a first base surface configured to engage the bottom surface of the second portion of the body. The base further includes a second base surface opposite to the first base surface. The second base surface is configured to be attached to a corresponding tooth from the plurality of teeth.

In another aspect, the present disclosure provides a method which is not explicitly recited by the wording of the claims, but which is considered useful for understanding the invention. The method includes providing an orthodontic appliance including a body. The body includes a first portion defining a slot. The body further includes a second portion extending from the first portion along a longitudinal axis. The second portion includes a bottom surface opposite to the first portion. The second portion further includes a lateral surface extending from the bottom surface towards the first portion along the longitudinal axis. The bottom surface and the lateral surface at least partially form an external surface of the body. The second portion defines a cavity at least partially surrounded by the bottom surface. The cavity extends at least partially along a length of the second portion from the bottom surface. The cavity includes a reservoir and at least one passage disposed in fluid communication with the reservoir. The at least one passage extends from the reservoir to the lateral surface. The method further includes depositing a dental composition within the reservoir of the cavity.

Exemplary embodiments disclosed herein may be more completely understood in consideration of the following detailed description in connection with the following figures.

In the following description, reference is made to the accompanying figures that form a part thereof and in which various embodiments are shown by way of illustration. It is to be understood that other embodiments are contemplated and may be made without departing from the scope of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense.

The present disclosure relates to an orthodontic appliance, an orthodontic system, and a method. The orthodontic system, the orthodontic appliance, and the method may be used in orthodontic treatments for moving one or more teeth of a patient from a malposition to a desired position in a dentition of the patient.

The orthodontic appliance includes a body. The body includes a first portion defining a slot for receiving an archwire. The body further includes a second portion extending from the first portion along a longitudinal axis. The second portion includes a bottom surface opposite to the first portion. The second portion further includes a lateral surface extending from the bottom surface towards the first portion along the longitudinal axis. The bottom surface and the lateral surface at least partially form an external surface of the body. The second portion defines a cavity at least partially surrounded by the bottom surface. The cavity at least partially extends along a length of the second portion from the bottom surface. The cavity includes a reservoir and at least one passage disposed in fluid communication with the reservoir. The at least one passage extends from the reservoir to the lateral surface.

A patient undergoing an orthodontic treatment with conventional orthodontic appliances may experience oral and dental diseases, such as tooth decay, and white-spot lesioning on tooth surfaces that cannot be properly cleaned. Fluoride-releasing adhesives used with conventional orthodontic appliances may not be effective for fluoride delivery in an oral environment of the patient. In some cases, conventional methods may lead to excess fluoride release that can potentially cause fluoride toxicity.

The orthodontic appliance of the present disclosure may include a dental composition received within the reservoir of the orthodontic appliance. In some embodiments, a fluoride-releasing composition may be retained within the reservoir. The fluoride-releasing composition may diffuse into an oral environment of the patient from the reservoir via the at least one passage of the cavity. The orthodontic appliance of the present disclosure may provide safe, efficient, sustained and continuous release of fluoride from the fluoride-releasing composition into the oral environment during a course of the orthodontic treatment. Therefore, the orthodontic appliance may reduce or prevent white spot lesions on enamel of the teeth that are otherwise caused by re-mineralization on demineralized surfaces of the teeth. Moreover, the orthodontic appliance may prevent fluoride toxicity while providing a sustained release of fluoride.

Referring now to the Figures, <FIG> illustrates an orthodontic system <NUM> for a plurality of teeth <NUM> according to an embodiment of the present disclosure. The plurality of teeth <NUM> may be of a patient undergoing an orthodontic treatment. The plurality of teeth <NUM> may include one or more of a central incisor, a lateral incisor, a canine, a premolar, a first molar, a second molar, and a third molar. Further, the plurality of teeth <NUM> may be of a lower dental arch or an upper dental arch of the patient.

The orthodontic system <NUM> includes an archwire <NUM>. The archwire <NUM> may be configured to apply forces on the plurality of teeth <NUM> to move one or more teeth <NUM> from a malposition to a desired position in a dentition of the patient. In some embodiments, the archwire <NUM> may include a nickel-titanium (NiTi) alloy. In some other embodiments, the archwire <NUM> may include any suitable material for applying forces on the plurality of teeth <NUM>. For example, the archwire <NUM> may include a metal, a metal alloy, a composite, a non-metal alloy, and combinations thereof.

The orthodontic system <NUM> further includes a plurality of orthodontic appliances <NUM> configured to be removably coupled to the archwire <NUM>. Each orthodontic appliance <NUM> from the plurality of orthodontic appliances <NUM> may be removably coupled to the archwire <NUM> by removably receiving the archwire <NUM> within a slot of each orthodontic appliance <NUM>. Further, each orthodontic appliance <NUM> may be configured to be attached to a corresponding tooth <NUM> from the plurality of teeth <NUM>. The corresponding tooth <NUM> may be interchangeably referred to as "the tooth <NUM>". In some embodiments, each orthodontic appliance <NUM> further includes a base <NUM>. The base <NUM> may be configured to be attached to the corresponding tooth <NUM> from the plurality of teeth <NUM>. Specifically, each orthodontic appliance <NUM> may be attached to the corresponding tooth <NUM> by attaching the base <NUM> of each orthodontic appliance <NUM> to the corresponding tooth <NUM>.

In the illustrated embodiment of <FIG>, each orthodontic appliance <NUM> is attached to the corresponding tooth <NUM> on a labial surface of the corresponding tooth <NUM>, i.e., a tooth surface toward lips of the patient. In other words, each orthodontic appliance <NUM> is a labial orthodontic appliance. However, each orthodontic appliance <NUM> may be attached to the corresponding tooth <NUM> on a lingual surface of the corresponding tooth <NUM>, i.e., a tooth surface toward a tongue of the patient. In other words, each orthodontic appliance <NUM> may be a lingual orthodontic appliance. The orthodontic appliance <NUM> may include any appliance intended to be attached to the tooth <NUM> and the archwire <NUM>. For example, the orthodontic appliance <NUM> may include an orthodontic bracket (including self-ligating brackets), an orthodontic buccal tube, an orthodontic cleat, an orthodontic button (aligner attachment), and the like.

In some embodiments, the orthodontic system <NUM> may be referred to as an orthodontic brace, or "braces". However, in some other embodiments, the orthodontic system <NUM> may include aligners, retainers, mouthguards, and the like.

<FIG> illustrate the orthodontic appliance <NUM> according to an embodiment of the present disclosure. The orthodontic appliance <NUM> defines mutually orthogonal X, Y and Z-axes. The X and Z-axes are in-plane axes of the orthodontic appliance <NUM>, while the Y-axis is a transverse axis disposed along a thickness of the orthodontic appliance <NUM>. In other words, the X and Z-axes are disposed along a plane of the orthodontic appliance <NUM>, while the Y-axis is perpendicular to the plane of the orthodontic appliance <NUM>.

Referring to <FIG>, the orthodontic appliance <NUM> includes a body <NUM>. The body <NUM> includes a first portion 102a defining a slot <NUM> for receiving the archwire <NUM> (shown in <FIG>). The body <NUM> further includes a second portion 102b extending from the first portion 102a along a longitudinal axis <NUM>-<NUM>. In some embodiments, the longitudinal axis <NUM>-<NUM> may be substantially aligned with the Y-axis. The second portion 102b includes a bottom surface <NUM> (best shown in <FIG>) opposite to the first portion 102a. The second portion 102b further includes a lateral surface <NUM> extending from the bottom surface <NUM> towards the first portion 102a along the longitudinal axis <NUM>-<NUM>.

As discussed above, in some embodiments, the orthodontic appliance <NUM> further includes the base <NUM>. The base <NUM> includes a first base surface 112a and a second base surface 112b opposite to the first base surface 112a. The first base surface 112a is configured to engage the bottom surface <NUM> (best shown in <FIG>) of the second portion 102b of the body <NUM>. Furthermore, the second base surface 112b is configured to be attached to the tooth <NUM> (shown in <FIG>). In other words, the second base surface 112b is configured to be attached to the corresponding tooth <NUM> from the plurality of teeth <NUM> (shown in <FIG>). For example, the second base surface 112b of the base <NUM> may have a concave contour that matches a convex contour of a surface of the tooth <NUM>. Optionally, the second base surface 112b may be provided with grooves, particles, recesses, undercuts, chemical bond enhancement materials, or any other materials and structures to facilitate bonding or attachment of the second base surface 112b to the tooth <NUM>. The second base surface 112b may be attached to the tooth <NUM> by an orthodontic adhesive, an orthodontic cement, or any other suitable bonding agent. Moreover, in some embodiments, the base <NUM> may be integral with the body <NUM>. In some other embodiments, the base <NUM> may be manufactured separately and attached to the body <NUM> by a suitable process (for example, by a laser welding process).

The orthodontic appliance <NUM> may be made of any suitable material as per desired application attributes. For example, the orthodontic appliance <NUM> may include metals (such as, stainless steel, titanium, and cobalt-chromium alloys), plastic materials (such as, fiber-reinforced polycarbonate), ceramic materials (such as, fine-grained polycrystalline alumina), polymeric materials, composite materials (such as, glass-fiber reinforced polymeric composites), and combinations thereof. Furthermore, various methods of making the orthodontic appliance <NUM> may be employed depending upon the materials selected for manufacturing the orthodontic appliance <NUM>. For example, the orthodontic appliance <NUM> may be manufactured by processes, such as die pressing, slurry casting, injection molding, extrusion processes, rapid prototyping, and the like.

<FIG> illustrates an exploded perspective view of the orthodontic appliance <NUM>. As shown in <FIG>, the bottom surface <NUM> and the lateral surface <NUM> at least partially form an external surface <NUM> of the body <NUM>. Specifically, each of the bottom surface <NUM> and the lateral surface <NUM> form at least a portion of the external surface <NUM> of the body <NUM>. In other words, the external surface <NUM> of the body <NUM> includes the bottom surface <NUM> and the lateral surface <NUM>. The second portion 102b defines a cavity <NUM> at least partially surrounded by the bottom surface <NUM>. The cavity <NUM> at least partially extends along a length of the second portion 102b from the bottom surface <NUM>. The cavity <NUM> may at least partially extend along the length of the second portion 102b from the bottom surface <NUM>. Specifically, the cavity <NUM> extends substantially along the longitudinal axis <NUM>-<NUM>. In the illustrated embodiment of <FIG>, the cavity <NUM> at least partially extends along the length of the second portion 102b from the bottom surface <NUM>. Further, the cavity <NUM> extends from the bottom surface <NUM> substantially along the Y-axis.

The cavity <NUM> includes a reservoir <NUM>. As shown in <FIG>, in some embodiments, the reservoir <NUM> has a circular shape in a plane normal to the longitudinal axis <NUM>-<NUM> of the second portion 102b. In some embodiments, the plane normal to the longitudinal axis <NUM>-<NUM> may be the X-Z plane. However, in some other embodiments, the reservoir <NUM> has at least one of a circular shape, a rectangular shape, a square shape, and a polygonal shape in the plane normal to the longitudinal axis <NUM>-<NUM> of the second portion 102b. The reservoir <NUM> may have other shapes in the plane normal to the longitudinal axis <NUM>-<NUM> of the second portion 102b, and is not limited thereto.

The cavity <NUM> further includes at least one passage <NUM> disposed in fluid communication with the reservoir <NUM>. The at least one passage <NUM> extends from the reservoir <NUM> to the lateral surface <NUM>. Therefore, the at least one passage <NUM> may fluidly communicate the reservoir <NUM> with the external surface <NUM> of the body <NUM>, and hence an oral environment in which the orthodontic appliance <NUM> is disposed. In some embodiments, the at least one passage <NUM> may extend from the reservoir <NUM> to the lateral surface <NUM> substantially along the Z-axis. In some embodiments, the at least one passage <NUM> has a width 118W. The width 118W of the at least one passage <NUM> may be orthogonal to the longitudinal axis <NUM>-<NUM>. In the illustrated embodiment of <FIG>, the width 118W of the at least one passage <NUM> may be substantially along the X-axis. Further, the width 118W of the at least one passage <NUM> may be substantially uniform along a length of the at least one passage <NUM>. The length of the at least one passage <NUM> may be substantially along the Z-axis.

In some embodiments, the at least one passage <NUM> is substantially U-shaped in a plane parallel to each of the longitudinal axis <NUM>-<NUM> and the width 118W of the at least one passage <NUM>. In the illustrated embodiment of <FIG>, the plane parallel to each of the longitudinal axis <NUM>-<NUM> and the width 118W of the at least one passage <NUM> may be the X-Y plane. The X-Y plane may include both the longitudinal axis <NUM>-<NUM> and the width 118W. In some other embodiments, the at least one passage <NUM> may be substantially V-shaped in the plane parallel to each of the longitudinal axis <NUM>-<NUM> and the width 118W of the at least one passage <NUM>. However, a shape of the at least one passage <NUM> in the plane parallel to each of the longitudinal axis <NUM>-<NUM> and the width 118W of the at least one passage <NUM> may change as per desired application attributes.

As shown in <FIG>, in some embodiments, the orthodontic appliance <NUM> further includes a dental composition <NUM> (shown by hatching) received within the reservoir <NUM>. In some embodiments, the reservoir <NUM> is configured to retain the dental composition <NUM> within the reservoir <NUM>. The reservoir <NUM> may retain the dental composition <NUM> within the reservoir <NUM> by mechanical interaction of the dental composition <NUM> and the reservoir <NUM>. The reservoir <NUM> may secure the dental composition <NUM> within the cavity <NUM>. That is, the reservoir <NUM> may prevent the dental composition <NUM> to be removed from the cavity <NUM>. Therefore, the reservoir <NUM> may prevent the dental composition <NUM> from being dislodged into an oral environment of a patient from the cavity <NUM>. In some embodiments, a size of the reservoir <NUM> may be adjusted according to a volume of the dental composition <NUM> required, as per desired application attributes.

The dental composition <NUM> may be exposed to saliva of the patient via the at least one passage <NUM>. Therefore, the dental composition <NUM> may diffuse (shown by arrows) into the oral environment of the patient from the reservoir <NUM> via the at least one passage <NUM> of the cavity <NUM>. The orthodontic appliance <NUM> may provide safe, efficient, sustained and continuous release of elements from the dental composition <NUM> into the oral environment of the patient during a course of orthodontic treatments. The elements (for example, fluoride, calcium, strontium, phosphate) released into the oral environment may further deposit on surfaces of the teeth <NUM> (shown in <FIG>). Therefore, the orthodontic appliance <NUM> may reduce or prevent oral and dental diseases.

In some embodiments, the dental composition <NUM> is at least one of a fluoride-releasing composition, a calcium-releasing composition, a strontium-releasing composition, and a phosphate-releasing composition. The fluoride-releasing composition may diffuse into the oral environment via the at least one passage <NUM> of the cavity <NUM>. Specifically, the fluoride-releasing composition may be exposed to saliva of the patient via the at least one passage <NUM>. Therefore, fluoride may be released into the oral environment of the patient. Consequently, the orthodontic appliance <NUM> may reduce white spot lesions on enamel of the teeth <NUM> that are otherwise caused by re-mineralization on demineralized surfaces of the teeth <NUM>. Examples of the dental composition <NUM> include, but are not limited to, glass ionomer cement and filling materials, resin modified glass ionomer cement and filling materials, dental sealants, aqueous coating materials, and solvent based polymeric coating materials, and the like. In some embodiments, the dental composition <NUM> may release fluoride, calcium, strontium, phosphate, buffer, and other elements to manage oral and dental diseases. In some embodiments, the dental composition <NUM> may be additionally coated on the body <NUM> of the orthodontic appliance <NUM>. For example, at least a portion of the external surface <NUM> of the body <NUM> may be additionally coated with the dental composition <NUM>.

<FIG> is perspective view of the orthodontic appliance <NUM>. <FIG> is a bottom view of the orthodontic appliance <NUM>. Furthermore, <FIG> is a sectional side view of the orthodontic appliance <NUM> taken along the longitudinal axis <NUM>-<NUM>. Specifically, the sectional side view of the orthodontic appliance <NUM> is taken along the Y-Z plane. The base <NUM> shown in <FIG>, and the dental composition <NUM> shown in <FIG> are not shown in <FIG> for illustrative purposes.

Referring to <FIG>, in some embodiments, the bottom surface <NUM> includes a first region 106a and a second region 106b. In some embodiments, the cavity <NUM> is disposed between the first region 106a of the bottom surface <NUM> and the second region 106b of the bottom surface <NUM>. In other words, the cavity <NUM> separates the first region 106a from the second region 106b.

In some embodiments, the second portion 102b further includes a cavity surface <NUM> offset from the bottom surface <NUM>. The cavity surface <NUM> may be offset from the bottom surface <NUM> substantially along the longitudinal axis <NUM>-<NUM>. In some embodiments, the cavity <NUM> extends from the bottom surface <NUM> towards the cavity surface <NUM> along the longitudinal axis <NUM>-<NUM>. Furthermore, in some embodiments, the cavity surface <NUM> is substantially planar. For example, the cavity surface <NUM> is disposed along the X-Z plane.

In some embodiments, at least a portion of the cavity <NUM> is tapered from the bottom surface <NUM> to the cavity surface <NUM>. In the illustrated embodiment of <FIG>, the reservoir <NUM> is tapered from the bottom surface <NUM> to the cavity surface <NUM>. Specifically, the reservoir <NUM> is defined by a first reservoir wall 117a and a second reservoir wall 117b. The first and second reservoir walls 117a, 117b may extend from the bottom surface <NUM> to the cavity surface <NUM> along the longitudinal axis <NUM>-<NUM>. As discussed above, the reservoir <NUM> is tapered from the bottom surface <NUM> to the cavity surface <NUM>. Consequently, each of the first and second reservoir walls 117a, 117b is tapered from the bottom surface <NUM> to the cavity surface <NUM>. The first reservoir wall 117a may have a first taper slope, and the second reservoir wall 117b may have a second taper slope. In some embodiments, the first taper slope and the second taper slope may be substantially equal. However, in some other embodiments, the first taper slope may be different than the second taper slope.

In some embodiments, the at least one passage <NUM> includes a plurality of passages <NUM> spaced apart from each other. Each passage <NUM> from the plurality of passages <NUM> extends from the reservoir <NUM> to the lateral surface <NUM>. In the illustrated embodiment of <FIG>, the at least one passage <NUM> includes two passages. Specifically, the at least one passage <NUM> includes a first passage <NUM>-<NUM> and a second passage <NUM>-<NUM>. The first passage <NUM>-<NUM> and a second passage <NUM>-<NUM> may be interchangeably referred to as "the at least one passage <NUM>-<NUM>" and "the at least one passage <NUM>-<NUM>", respectively.

The first passage <NUM>-<NUM> extends from the reservoir <NUM> to the lateral surface <NUM>. Furthermore, the second passage <NUM>-<NUM> extends from the reservoir <NUM> to the lateral surface <NUM>. In some embodiments, each of the first and second passages <NUM>-<NUM>, <NUM>-<NUM> extends from the reservoir <NUM> to the lateral surface <NUM> substantially along the Z-axis. However, in some other embodiments, each of the first and second passages <NUM>-<NUM>, <NUM>-<NUM> may extend from the reservoir <NUM> to the lateral surface <NUM> substantially along the X-axis. In some other embodiments, each of the first and second passages <NUM>-<NUM>, <NUM>-<NUM> may be inclined obliquely to each of the X-axis and Z-axis.

In the illustrated embodiment of <FIG>, the second passage <NUM>-<NUM> is spaced apart from the first passage <NUM>-<NUM>. Specifically, the first passage <NUM>-<NUM> is angularly spaced from the second passage <NUM>-<NUM> by about <NUM> degrees. However, in some other embodiments, the first passage <NUM>-<NUM> and the second passage <NUM>-<NUM> are obliquely inclined to each other. For example, the first passage <NUM>-<NUM> may be inclined to the second passage <NUM>-<NUM> by about <NUM> degrees to about <NUM> degrees. In other example, the first passage <NUM>-<NUM> may be inclined to the second passage <NUM>-<NUM> by about <NUM> degrees to about <NUM> degrees.

In the illustrated embodiment of <FIG>, the first passage <NUM>-<NUM> is defined by two passage walls, specifically, a first passage wall 120a and a second passage wall 120b. Further, the second passage <NUM>-<NUM> is defined by two passage walls, specifically, a third passage wall 120c and a fourth passage wall 120d. Each of the first, second, third and fourth passage walls 120a, 120b, 120c, 120d may extend from the bottom surface <NUM> to the cavity surface <NUM> substantially along the longitudinal axis <NUM>-<NUM>. In some embodiments, each of the first, second, third and fourth passage walls 120a, 120b, 120c, 120d may be substantially planar. In some other embodiments, at least one of the first, second, third and fourth passage walls 120a, 120b, 120c, 120d may be curved.

As shown in <FIG>, in some embodiments, the reservoir <NUM> has a maximum width 116W<NUM> at the bottom surface <NUM>. Further, the reservoir <NUM> has a maximum width 116W<NUM> at the cavity surface <NUM>. The maximum widths 116W<NUM>, 116W<NUM> may be orthogonal to the longitudinal axis <NUM>-<NUM>. In the illustrated embodiment of <FIG>, the maximum widths 116W<NUM>, 116W<NUM> are substantially along the X-axis. The maximum width 116W<NUM> at the bottom surface <NUM> is greater than the maximum width 116W<NUM> at the cavity surface <NUM>. The maximum width 116W<NUM> at the bottom surface <NUM> may be greater than the maximum width 116W<NUM> at the cavity surface <NUM> because of the taper of the reservoir <NUM>.

In some embodiments, the reservoir <NUM> has an average width 116Wavg. The average width 116Wavg of the reservoir <NUM> may be orthogonal to the longitudinal axis <NUM>-<NUM>. In the illustrated embodiment of <FIG>, the average width 116Wavg of the reservoir <NUM> is substantially along the X-axis. Furthermore, the at least one passage <NUM> has an average width 118Wavg orthogonal to the longitudinal axis <NUM>-<NUM>. Specifically, the first and second passages <NUM>-<NUM>, <NUM>-<NUM> have the average width 118Wavg. The average width 118Wavg of the at least one passage <NUM> is substantially along the X-axis. In some embodiments, the average width 116Wavg of the reservoir <NUM> orthogonal to the longitudinal axis <NUM>-<NUM> is greater than or equal to the average width 118Wavg of the at least one passage <NUM> orthogonal to the longitudinal axis <NUM>-<NUM>.

Referring to <FIG>, in some embodiments, the cavity <NUM> extends between a first end 122a and an opposing second end 122b. The cavity <NUM> has a first height <NUM><NUM> at the first end 122a along the longitudinal axis <NUM>-<NUM>. Furthermore, the cavity <NUM> has a second height <NUM><NUM> at the second end 122b along the longitudinal axis <NUM>-<NUM>. The first height <NUM><NUM> of the cavity <NUM> is less than the second height <NUM><NUM> of the cavity <NUM>. Furthermore, a height of the cavity <NUM> along the longitudinal axis <NUM>-<NUM> increases monotonically from the first height <NUM><NUM> to the second height <NUM><NUM> with respect to a length <NUM> of the cavity <NUM>. In the illustrated embodiment of <FIG>, the length <NUM> of the cavity <NUM> is substantially along the Z-axis.

In the illustrated embodiment of <FIG>, the at least one passage <NUM>-<NUM> has a first height <NUM>-<NUM><NUM> along the longitudinal axis <NUM>-<NUM> at the reservoir <NUM> and a second height <NUM>-<NUM><NUM> along the longitudinal axis <NUM>-<NUM> at the lateral surface <NUM>. Specifically, the first passage <NUM>-<NUM> has the first height <NUM>-<NUM><NUM> and the second height <NUM>-<NUM><NUM> at opposing ends of the first passage <NUM>-<NUM>. The first height <NUM>-<NUM><NUM> is different from the second height <NUM>-<NUM><NUM>. Specifically, the first height <NUM>-<NUM><NUM> is less than the second height <NUM>-<NUM><NUM>. Furthermore, the second height <NUM>-<NUM><NUM> of the first passage <NUM>-<NUM> is substantially equal to the second height <NUM><NUM> of the cavity <NUM> at the second end 122b.

Moreover, in the illustrated embodiment of <FIG>, the at least one passage <NUM>-<NUM> has a first height <NUM>-<NUM><NUM> along the longitudinal axis <NUM>-<NUM> at the reservoir <NUM> and a second height <NUM>-<NUM><NUM> along the longitudinal axis <NUM>-<NUM> at the lateral surface <NUM>. Specifically, the second passage <NUM>-<NUM> has the first height <NUM>-<NUM><NUM> and the second height <NUM>-<NUM><NUM> at opposing ends of the second passage <NUM>-<NUM>. The first height <NUM>-<NUM><NUM> is different from the second height <NUM>-<NUM><NUM>. Specifically, the first height <NUM>-<NUM><NUM> is greater than the second height <NUM>-<NUM><NUM>. However, in some embodiments, the at least one passage <NUM>-<NUM> has a substantially uniform height along the longitudinal axis <NUM>-<NUM>. That is, the first height <NUM>-<NUM><NUM> may be substantially equal to the second height <NUM>-<NUM><NUM>. Furthermore, in the illustrated embodiment of <FIG>, the second height <NUM>-<NUM><NUM> of the second passage <NUM>-<NUM> is substantially equal to the first height <NUM><NUM> of the cavity <NUM> at the first end 122a.

In some embodiments, the first passage <NUM>-<NUM> has a first length <NUM>-<NUM>, and the second passage <NUM>-<NUM> has a second length <NUM>-<NUM>. The second length <NUM>-<NUM> of the second passage <NUM>-<NUM> is greater than the first length <NUM>-<NUM> of the first passage <NUM>-<NUM>. However, in some other embodiments, the first length <NUM>-<NUM> of the first passage <NUM>-<NUM> may be equal to or greater than the second length <NUM>-<NUM> of the second passage <NUM>-<NUM>. The first and second lengths <NUM>-<NUM>, <NUM>-<NUM> may be normal to the longitudinal axis <NUM>-<NUM>. In the illustrated embodiment of <FIG>, the first and second lengths <NUM>-<NUM>, <NUM>-<NUM> may be substantially along the Z-axis. Further, first and second lengths <NUM>-<NUM>, <NUM>-<NUM> are measured along the cavity surface <NUM> and may correspond to maximum lengths of the first and second passages <NUM>-<NUM>, <NUM>-<NUM>. Due to a taper of the reservoir <NUM> in the Y-Z plane, respective lengths of the first and second passages <NUM>-<NUM>, <NUM>-<NUM> may vary along the longitudinal axis <NUM>-<NUM>.

<FIG> illustrate an orthodontic appliance <NUM> according to another embodiment of the present disclosure. The orthodontic appliance <NUM> may have a function substantially similar to that of the orthodontic appliance <NUM> (shown in <FIG>). The orthodontic appliance <NUM> defines mutually orthogonal X, Y and Z-axes substantially similar to the orthodontic appliance <NUM>. Further, the orthodontic appliance <NUM> may include a base substantially similar to the base <NUM> of the orthodontic appliance <NUM>. However, the base of the orthodontic appliance <NUM> is not shown in <FIG> for illustrative purposes. Furthermore, the dental composition <NUM> (shown in <FIG>) is not shown in <FIG> for illustrative purposes.

Referring to <FIG>, the orthodontic appliance <NUM> includes a body <NUM>. The body <NUM> defines a first portion 202a and a second portion 202b. The first portion 202a defines a slot <NUM> for receiving the archwire <NUM> (shown in <FIG>). The second portion 202b includes a bottom surface <NUM> opposite to the first portion 202a. The second portion 202b further includes a lateral surface <NUM> extending from the bottom surface <NUM> towards the first portion 202a along a longitudinal axis <NUM>-<NUM>. The longitudinal axis <NUM>-<NUM> may be equivalent to the longitudinal axis <NUM>-<NUM> shown in <FIG>. The bottom surface <NUM> and the lateral surface <NUM> at least partially form an external surface <NUM> of the body <NUM>.

The second portion 202b defines a cavity <NUM> at least partially surrounded by the bottom surface <NUM>. The cavity <NUM> at least partially extends along a length of the second portion 202b from the bottom surface <NUM>. The cavity <NUM> may at least partially extend along the length of the second portion 202b from the bottom surface <NUM> substantially along the longitudinal axis <NUM>-<NUM>. In the illustrated embodiment of <FIG>, the cavity <NUM> at least partially extends along the length of the second portion 202b from the bottom surface <NUM>. Further, the cavity <NUM> extends from the bottom surface <NUM> substantially along the Y-axis. In some embodiments, the second portion 202b further includes a cavity surface <NUM> offset from the bottom surface <NUM>. The cavity surface <NUM> may be offset from the bottom surface <NUM> substantially along the longitudinal axis <NUM>-<NUM>. In some embodiments, the cavity <NUM> extends from the bottom surface <NUM> towards the cavity surface <NUM> along the longitudinal axis <NUM>-<NUM>.

The cavity <NUM> includes a reservoir <NUM> and at least one passage <NUM> disposed in fluid communication with the reservoir <NUM>. The at least one passage <NUM> extends from the reservoir <NUM> to the lateral surface <NUM>. In some embodiments, the at least one passage <NUM> includes a plurality of passages <NUM> spaced apart from each other. Each passage <NUM> from the plurality of passages <NUM> extends from the reservoir <NUM> to the lateral surface <NUM>. In the illustrated embodiment of <FIG>, the plurality of passages <NUM> includes four passages <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, and <NUM>-<NUM>. Specifically, the plurality of passages <NUM> includes a first passage <NUM>-<NUM>, a second passage <NUM>-<NUM>, a third passage <NUM>-<NUM>, and a fourth passage <NUM>-<NUM>. The first and third passages <NUM>-<NUM>, <NUM>-<NUM> extend from the reservoir <NUM> to the lateral surface <NUM> substantially along the X-axis, and the second and fourth passages <NUM>-<NUM>, <NUM>-<NUM> extend from the reservoir <NUM> to the lateral surface <NUM> substantially along the Z-axis.

As shown in <FIG>, in some embodiments, the reservoir <NUM> is located at an intersection of the four passages <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>. Furthermore, the reservoir <NUM> is centrally located with respect to the bottom surface <NUM>. Moreover, the reservoir <NUM> has a square shape in a plane normal to the longitudinal axis <NUM>-<NUM> of the second portion 202b. The plane normal to the longitudinal axis <NUM>-<NUM> of the second portion 202b may be the X-Z plane.

In some embodiments, adjacent passages from the plurality of passages <NUM> are angularly spaced apart from each other by about <NUM> degrees. In the illustrated embodiment of <FIG>, the first passage <NUM>-<NUM> is adjacent to the second passage <NUM>-<NUM> and is angularly spaced apart from the second passage <NUM>-<NUM> by about <NUM> degrees. Further, the second passage <NUM>-<NUM> is adjacent to the third passage <NUM>-<NUM> and is angularly spaced apart from the third passage <NUM>-<NUM> by about <NUM> degrees. Furthermore, the third passage <NUM>-<NUM> is adjacent to the fourth passage <NUM>-<NUM> and is angularly spaced apart from the fourth passage <NUM>-<NUM> by about <NUM> degrees. Moreover, the fourth passage <NUM>-<NUM> is adjacent to the first passage <NUM>-<NUM> and is angularly spaced apart from the first passage <NUM>-<NUM> by about <NUM> degrees.

In the illustrated embodiment of <FIG>, the first passage <NUM>-<NUM> is defined by a first passage wall 220a and a second passage wall 220b. Further, the second passage <NUM>-<NUM> is defined by a third passage wall 220c and a fourth passage wall 220d. The third passage <NUM>-<NUM> is defined by a fifth passage wall 220e and a sixth passage wall 220f. Furthermore, the fourth passage <NUM>-<NUM> is defined by a seventh passage wall <NUM> and an eight passage wall <NUM>. In some embodiments, each of the first, second, third, fourth, fifth, sixth, seventh, and eighth passage walls 220a, 220b, 220c, 220d, 220e, 220f, <NUM>, and <NUM> may be substantially planar. In some other embodiments, at least one of the first, second, third, fourth, fifth, sixth, seventh, and eighth passage walls 220a, 220b, 220c, 220d, 220e, 220f, <NUM>, and <NUM> may be curved.

In some embodiments, as shown in <FIG>, the four passages <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> include a pair of opposing first passages <NUM>-<NUM>, <NUM>-<NUM> and a pair of opposing second passages <NUM>-<NUM>, <NUM>-<NUM> substantially orthogonal to the first passages <NUM>-<NUM>, <NUM>-<NUM>. In some cases, the first and third passages <NUM>-<NUM>, <NUM>-<NUM> may be interchangeably referred to as "the first passages <NUM>-<NUM>, <NUM>-<NUM>". Further, the second and fourth passages <NUM>-<NUM>, <NUM>-<NUM> may be interchangeably referred to as "the second passages <NUM>-<NUM>, <NUM>-<NUM>".

In some embodiments, the first passage <NUM>-<NUM> and the third passage <NUM>-<NUM> may have substantially equal lengths. Therefore, in some embodiments, the first passages <NUM>-<NUM>, <NUM>-<NUM> have a first length <NUM><NUM>. Furthermore, at least one of the second passages <NUM>-<NUM>, <NUM>-<NUM> has a second length <NUM><NUM>. Specifically, the fourth passage <NUM>-<NUM> has the second length <NUM><NUM>. The first and second lengths <NUM><NUM>, <NUM><NUM> may be orthogonal to the longitudinal axis <NUM>-<NUM>. Specifically, in the illustrated embodiments of <FIG>, the first length <NUM><NUM> of the first passages <NUM>-<NUM>, <NUM>-<NUM> may be substantially along the X-axis, and the second length <NUM><NUM> of the at least one of the second passages <NUM>-<NUM>, <NUM>-<NUM> may be substantially along the Z-axis. In some embodiments, the first length <NUM><NUM> of the first passages <NUM>-<NUM>, <NUM>-<NUM> is greater than the second length <NUM><NUM> of at the least one of the second passages <NUM>-<NUM>, <NUM>-<NUM>. Specifically, in the illustrated embodiment of <FIG>, the first length <NUM><NUM> of the first passages <NUM>-<NUM>, <NUM>-<NUM> is greater than the second length <NUM><NUM> of the fourth passage <NUM>-<NUM>.

Furthermore, in some embodiments, a width of the four passages <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> orthogonal to the longitudinal axis <NUM>-<NUM> may be substantially equal. Specifically, a width 218W<NUM> of the first passages <NUM>-<NUM>, <NUM>-<NUM> substantially along the Z-axis may be substantially equal to a width 218W<NUM> of the second passages <NUM>-<NUM>, <NUM>-<NUM> substantially along the X-axis.

In some embodiments, the orthodontic system <NUM> (shown in <FIG>) includes the orthodontic appliance <NUM>. In some embodiments, the orthodontic appliance <NUM> further includes the dental composition <NUM> (shown in <FIG>) received within the reservoir <NUM>. In some embodiments, the reservoir <NUM> is configured to retain the dental composition <NUM> within the reservoir <NUM>. The reservoir <NUM> may retain the dental composition <NUM> within the reservoir <NUM> by mechanical interaction of the dental composition <NUM> and the reservoir <NUM>. Specifically, a crossed configuration of the cavity <NUM>, i.e., the reservoir <NUM> and the first, second, third and fourth passages <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> may retain the dental composition <NUM> within the reservoir <NUM>. The reservoir <NUM> may secure the dental composition <NUM> within the cavity <NUM>. That is, the reservoir <NUM> may prevent the dental composition <NUM> to be removed from the cavity <NUM>. Therefore, the reservoir <NUM> may prevent the dental composition <NUM> from being dislodged into an oral environment of a patient from the cavity <NUM>. Furthermore, the orthodontic appliance <NUM> may provide safe, efficient, sustained and continuous release of elements from the dental composition <NUM> into the oral environment of the patient during a course of orthodontic treatments. The elements (for example, fluoride, calcium, strontium, phosphate) released into the oral environment may further deposit on surfaces of the teeth <NUM> (shown in <FIG>). Therefore, the orthodontic appliance <NUM> may reduce or prevent oral and dental diseases. In some embodiments, the dental composition <NUM> may be additionally coated on the body <NUM> of the orthodontic appliance <NUM>.

Referring to <FIG>, the orthodontic appliance <NUM> includes a body <NUM>. The body <NUM> defines a first portion 302a and a second portion 302b. The first portion 302a defines a slot <NUM> for receiving the archwire <NUM> (shown in <FIG>). The second portion 302b includes a bottom surface <NUM> opposite to the first portion 302a. The second portion 302b further includes a lateral surface <NUM> extending from the bottom surface <NUM> towards the first portion 302a along a longitudinal axis <NUM>-<NUM>. The longitudinal axis <NUM>-<NUM> may be equivalent to the longitudinal axis <NUM>-<NUM> shown in <FIG>. The bottom surface <NUM> and the lateral surface <NUM> at least partially form an external surface <NUM> of the body <NUM>.

The second portion 302b defines a cavity <NUM> at least partially surrounded by the bottom surface <NUM>. The cavity <NUM> at least partially extends along a length of the second portion 302b from the bottom surface <NUM>. The cavity <NUM> may at least partially extend along the length of the second portion 302b from the bottom surface <NUM> along the longitudinal axis <NUM>-<NUM>. In the illustrated embodiment of <FIG>, the cavity <NUM> at least partially extends along the length of the second portion 302b from the bottom surface <NUM>. Further, the cavity <NUM> extends from the bottom surface <NUM> substantially along the Y-axis. In some embodiments, the second portion 302b further includes a cavity surface <NUM> offset from the bottom surface <NUM>. The cavity surface <NUM> may be offset from the bottom surface <NUM> substantially along the longitudinal axis <NUM>-<NUM>. In some embodiments, the cavity <NUM> extends from the bottom surface <NUM> towards the cavity surface <NUM> along the longitudinal axis <NUM>-<NUM>.

In the illustrated embodiment of <FIG>, the bottom surface <NUM> includes a first region 306a and a second region 306b. In some embodiments, the cavity <NUM> is disposed between the first region 306a of the bottom surface <NUM> and the second region 306b of the bottom surface <NUM>.

The cavity <NUM> includes a reservoir <NUM>. In the illustrated embodiment of <FIG>, the reservoir <NUM> is defined by a first reservoir wall 317a and a second reservoir wall 317b. The first and second reservoir walls 317a, 317b may extend from the bottom surface <NUM> to the cavity surface <NUM> substantially along the longitudinal axis <NUM>-<NUM>. In some embodiments, each of the first and second reservoir walls 317a, 317b may be substantially planar. In some other embodiments, at least one of the first and second reservoir walls 317a, 317b may be curved. Furthermore, in the illustrated embodiment of <FIG>, the reservoir <NUM> is centrally located with respect to the bottom surface <NUM>.

The cavity <NUM> further includes at least one passage <NUM> disposed in fluid communication with the reservoir <NUM>. The at least one passage <NUM> extends from the reservoir <NUM> to a lateral surface <NUM>. In the illustrated embodiment of <FIG>, the at least one passage includes a plurality of passages <NUM> spaced apart from each other. Each passage <NUM> from the plurality of passages <NUM> extends from the reservoir <NUM> to the lateral surface <NUM>.

In the illustrated embodiment of <FIG>, the at least one passage <NUM> includes two passages. Specifically, the at least one passage <NUM> includes a first passage <NUM>-<NUM> extending from the reservoir <NUM> to the lateral surface <NUM>. The at least one passage <NUM> further includes a second passage <NUM>-<NUM> spaced apart from the first passage <NUM>-<NUM> and extending from the reservoir <NUM> to the lateral surface <NUM>. Furthermore, the first passage <NUM>-<NUM> is angularly spaced from the second passage <NUM>-<NUM> by about <NUM> degrees. The first passage <NUM>-<NUM> and a second passage <NUM>-<NUM> may be interchangeably referred to as "the at least one passage <NUM>-<NUM>" and "the at least one passage <NUM>-<NUM>", respectively.

As shown in <FIG>, the at least one passage <NUM>-<NUM> includes a first passage portion <NUM>-<NUM> and a second passage portion <NUM>-<NUM>. Specifically, the first passage <NUM>-<NUM> includes the first and second passage portions <NUM>-<NUM>, <NUM>-<NUM>. The first passage portion <NUM>-<NUM> is disposed between the reservoir <NUM> and the second passage portion <NUM>-<NUM>. The first passage portion <NUM>-<NUM> includes a first width <NUM>-1W orthogonal to the longitudinal axis <NUM>-<NUM>. Further, the second passage portion <NUM>-<NUM> is adjacent to the first passage portion <NUM>-<NUM> and includes a second width <NUM>-2W orthogonal to the longitudinal axis <NUM>-<NUM>. In the illustrated embodiments of <FIG>, the first and second widths <NUM>-1W, <NUM>-2W may be substantially along the X-axis. In some embodiments, the first width <NUM>-1W is greater than the second width <NUM>-2W.

Furthermore, in some embodiments, the at least one passage <NUM>-<NUM> includes a first passage portion <NUM>-<NUM> and a second passage portion <NUM>-<NUM>. Specifically, the second passage <NUM>-<NUM> includes the first and second passage portions <NUM>-<NUM>, <NUM>-<NUM>. The first passage portion <NUM>-<NUM> is disposed between the reservoir <NUM> and the second passage portion <NUM>-<NUM>. The first passage portion <NUM>-<NUM> includes a first width <NUM>-3W orthogonal to the longitudinal axis <NUM>-<NUM>. Further, the second passage portion <NUM>-<NUM> is adjacent to the first passage portion <NUM>-<NUM>. The second passage portion <NUM>-<NUM> includes a second width <NUM>-4W orthogonal to the longitudinal axis <NUM>-<NUM>. In the illustrated embodiments of <FIG>, the first and second widths <NUM>-3W, <NUM>-4W may be substantially along the X-axis. In some embodiments, the first width <NUM>-3W is greater than the second width <NUM>-4W.

In some embodiments, the first passage portions <NUM>-<NUM>, <NUM>-<NUM> and the second passage portions <NUM>-<NUM>, <NUM>-<NUM> are substantially planar. In some other embodiments, at least one of the first passage portions <NUM>-<NUM>, <NUM>-<NUM> and the second passage portions <NUM>-<NUM>, <NUM>-<NUM> may be curved. Further, the reservoir <NUM> includes a width 316W. In some embodiments, the width 316W of the reservoir <NUM> is greater than each of the first widths <NUM>-1W, <NUM>-3W and the second widths <NUM>-2W. <NUM>-4W of the first passage portions <NUM>-<NUM>, <NUM>-<NUM> and the second passage portions <NUM>-<NUM>, <NUM>-<NUM>, respectively.

<FIG> illustrates a sectional side view of the orthodontic appliance <NUM> taken along the longitudinal axis <NUM>-<NUM>. Specifically, the sectional side view of the orthodontic appliance <NUM> is taken along the Y-Z plane. Referring to <FIG>, in some embodiments, the cavity <NUM> extends between a first end 322a and an opposing second end 322b. The cavity <NUM> has a first height <NUM><NUM> at the first end 322a along the longitudinal axis <NUM>-<NUM>. Furthermore, the cavity <NUM> has a second height <NUM><NUM> at the second end 322b along the longitudinal axis <NUM>-<NUM>. As shown in <FIG>, in some embodiments, the first height <NUM><NUM> of the cavity <NUM> is less than the second height <NUM><NUM> of the cavity <NUM>. In some embodiments, a height of the cavity <NUM> along the longitudinal axis <NUM>-<NUM> increases monotonically from the first height to <NUM><NUM> the second height <NUM><NUM> with respect to a length <NUM> of the cavity <NUM>. The length <NUM> of the cavity <NUM> may be substantially along the Z-axis. Furthermore, a rate of change of the height of the cavity <NUM> with respect to the length <NUM> of the cavity <NUM> changes along at least a portion of the cavity <NUM>. Specifically, in the illustrated embodiment of <FIG>, the rate of change of the height of the cavity <NUM> with respect to the length <NUM> of the cavity <NUM> from the second passage portion <NUM>-<NUM> of the cavity <NUM> to the first passage portion <NUM>-<NUM>. Furthermore, the rate of change of the height of the cavity <NUM> with respect to the length <NUM> of the cavity <NUM> changes from the first passage portion <NUM>-<NUM> to the reservoir <NUM> of the cavity <NUM>. Moreover, the rate of change of the height of the cavity <NUM> with respect to the length <NUM> of the cavity <NUM> changes from the first passage portion <NUM>-<NUM> to the second passage portion <NUM>-<NUM>. In some embodiments, the rate of change of the height of the cavity <NUM> with respect to the length <NUM> may be substantially constant in each of the first passage portion <NUM>-<NUM>, the second passage portion <NUM>-<NUM>, the reservoir <NUM>, the first passage portion <NUM>-<NUM>, and the second passage portion <NUM>-<NUM>. In other words, the height of the cavity <NUM> with respect to the length <NUM> may increase substantially linearly in each of the first passage portion <NUM>-<NUM>, the second passage portion <NUM>-<NUM>, the reservoir <NUM>, the first passage portion <NUM>-<NUM>, and the second passage portion <NUM>-<NUM>.

In some embodiments, a height <NUM>-<NUM> of the first passage portion <NUM>-<NUM> increases along a length <NUM>-<NUM> of the first passage portion <NUM>-<NUM>. Further, a height <NUM>-<NUM> of the second passage portion <NUM>-<NUM> increases along a length <NUM>-<NUM> of the second passage portion <NUM>-<NUM>. The lengths <NUM>-<NUM>, <NUM>-<NUM> of the first and second passage portions <NUM>-<NUM>, <NUM>-<NUM>, respectively, may be substantially along the Z-axis. Furthermore, the heights <NUM>-<NUM>, <NUM>-<NUM> of the first and second passage portions <NUM>-<NUM>, <NUM>-<NUM>, respectively, may be substantially along the Y-axis.

As shown in <FIG>, in some embodiments, the first passage portion <NUM>-<NUM> has a first rate of change of the height <NUM>-<NUM> with respect to the length <NUM>-<NUM> of the first passage portion <NUM>-<NUM>. Further, the second passage portion <NUM>-<NUM> has a second rate of change of the height <NUM>-<NUM> with respect to the length <NUM>-<NUM> of the second passage portion <NUM>-<NUM>. The first rate of change of the height <NUM>-<NUM> is different from the second rate of change of the height <NUM>-<NUM>. Specifically, the first rate of change of the height <NUM>-<NUM> is less than the second rate of change of the height <NUM>-<NUM>.

Moreover, the first passage portion <NUM>-<NUM> has a first rate of change of the height <NUM>-<NUM> with respect to the length of the first passage portion <NUM>-<NUM>. The second passage portion <NUM>-<NUM> has a second rate of change of the height <NUM>-<NUM> with respect to the length of the second passage portion <NUM>-<NUM>. The first rate of change of the height <NUM>-<NUM> is different from the second rate of change of the height <NUM>-<NUM>. Specifically, the first rate of change of the height <NUM>-<NUM> is greater than the second rate of change of the height <NUM>-<NUM>.

In some embodiments, the orthodontic system <NUM> (shown in <FIG>) includes the orthodontic appliance <NUM>. In some embodiments, the orthodontic appliance <NUM> further includes the dental composition <NUM> (shown in <FIG>) received within the reservoir <NUM>. In some embodiments, the reservoir <NUM> is configured to retain the dental composition <NUM> within the reservoir <NUM>. The reservoir <NUM> may retain the dental composition <NUM> within the reservoir <NUM> by mechanical interaction of the dental composition <NUM> and the reservoir <NUM>. The reservoir <NUM> may secure the dental composition <NUM> within the cavity <NUM>. That is, the reservoir <NUM> may prevent the dental composition <NUM> to be removed from the cavity <NUM>. Therefore, the reservoir <NUM> may prevent the dental composition <NUM> from being dislodged into an oral environment of a patient from the cavity <NUM>. Furthermore, the orthodontic appliance <NUM> may provide safe, efficient, sustained and continuous release of elements from the dental composition <NUM> into the oral environment of the patient during a course of orthodontic treatments. The elements (for example, fluoride, calcium, strontium, phosphate) released into the oral environment may further deposit on surfaces of the teeth <NUM> (shown in <FIG>). Therefore, the orthodontic appliance <NUM> may reduce or prevent oral and dental diseases. In some embodiments, the dental composition <NUM> may be additionally coated on the body <NUM> of the orthodontic appliance <NUM>.

The orthodontic appliance <NUM> includes a body <NUM>. The body <NUM> defines a first portion 402a and a second portion 402b. The first portion 402a defines a slot <NUM> for receiving the archwire <NUM> (shown in <FIG>). The second portion 402b includes a bottom surface <NUM> opposite to the first portion 402a. The second portion 402b further includes a lateral surface <NUM> extending from the bottom surface <NUM> towards the first portion 402a along a longitudinal axis <NUM>-<NUM>. The longitudinal axis <NUM>-<NUM> may be equivalent to the longitudinal axis <NUM>-<NUM> shown in <FIG>. The bottom surface <NUM> and the lateral surface <NUM> at least partially form an external surface <NUM> of the body <NUM>.

The second portion 402b defines a cavity 414a at least partially surrounded by the bottom surface <NUM>. The cavity 414a at least partially extends along a length of the second portion 402b from the bottom surface <NUM>. Furthermore, the cavity 414a is substantially T-shaped in a plane orthogonal to the longitudinal axis <NUM>-<NUM>. The plane orthogonal to the longitudinal axis <NUM>-<NUM> may be the X-Z plane. The cavity 414a includes a reservoir 416a and at least one passage 418a disposed in fluid communication with the reservoir 416a. The at least one passage 418a extends from the reservoir 416a to the lateral surface <NUM>.

In some embodiments, the at least one passage 418a includes a plurality of passages 418a spaced apart from each other. Each passage 418a from the plurality of passages 418a extends from the reservoir 416a to the lateral surface <NUM>. In the illustrated embodiment of <FIG>, the at least one passage 418a includes three passages. Specifically, the at least one passage 418a includes a first passage <NUM>-<NUM> extending from the reservoir 416a to the lateral surface <NUM>. The at least one passage 418a further includes a second passage <NUM>-<NUM> spaced apart from the first passage <NUM>-<NUM> and extending from the reservoir 416a to the lateral surface <NUM>. In some embodiments, the first and second passages <NUM>-<NUM>, <NUM>-<NUM> may extend from the reservoir 416a to the lateral surface <NUM> substantially along the Z-axis. Therefore, in some embodiments, the first passage <NUM>-<NUM> is angularly spaced from the second passage <NUM>-<NUM> by about <NUM> degrees. In some embodiments, the at least one passage 418a further includes a third passage <NUM>-<NUM> spaced apart from the first passage <NUM>-<NUM> and extending from the reservoir 416a to the lateral surface <NUM>. In some embodiments, the third passage <NUM>-<NUM> may extend from the reservoir 416a to the lateral surface <NUM> substantially along the X-axis. Therefore, in some embodiments, the third passage <NUM>-<NUM> is angularly spaced from each of the first and second passages <NUM>-<NUM>, <NUM>-<NUM> by about <NUM> degrees.

In some embodiments, the second portion 402b further defines a cavity 414b at least partially surrounded by the bottom surface <NUM>. The cavity 414b at least partially extends along the length of the second portion 402b from the bottom surface <NUM>. Furthermore, the cavity 414b is substantially T-shaped in a plane orthogonal to the longitudinal axis <NUM>-<NUM>. The plane orthogonal to the longitudinal axis <NUM>-<NUM> may be the X-Z plane. The cavity 414b includes a reservoir 416b and at least one passage 418b disposed in fluid communication with the reservoir 416b. The at least one passage 418b extends from the reservoir 416b to the lateral surface <NUM>.

In the illustrated embodiment of <FIG>, the at least one passage 418b includes a plurality of passages 418b spaced apart from each other. Each passage 418b from the plurality of passages 418b extends from the reservoir 416b to the lateral surface <NUM>. In the illustrated embodiment of <FIG>, the at least one passage 418b includes three passages. Specifically, the at least one passage 418b includes a first passage <NUM>-<NUM> extending from the reservoir 416b to the lateral surface <NUM>. The at least one passage 418b further includes a second passage <NUM>-<NUM> spaced apart from the first passage <NUM>-<NUM> and extending from the reservoir 416b to the lateral surface <NUM>. In some embodiments, the first and second passages <NUM>-<NUM>, <NUM>-<NUM> may extend from the reservoir 416b to the lateral surface <NUM> substantially along the Z-axis. Therefore, in some embodiments, the first passage <NUM>-<NUM> is angularly spaced from the second passage <NUM>-<NUM> by about <NUM> degrees. In some embodiments, the at least one passage 418b further includes a third passage <NUM>-<NUM> spaced apart from the first passage <NUM>-<NUM> and extending from the reservoir 416b to the lateral surface <NUM>. In some embodiments, the third passage <NUM>-<NUM> may extend from the reservoir 416b to the lateral surface <NUM> substantially along the X-axis. Therefore, in some embodiments, the third passage <NUM>-<NUM> is angularly spaced from each of the first and second passages <NUM>-<NUM>, <NUM>-<NUM> by about <NUM> degrees.

In some embodiments, the orthodontic system <NUM> (shown in <FIG>) includes the orthodontic appliance <NUM>. A configuration of the cavities 414a, 414b of the orthodontic appliance <NUM> may be suitable for an orthodontic appliance that cannot accommodate a cavity in a central area of a bottom surface. For example, the orthodontic appliance <NUM> may be used with a cuspid tooth where a cavity may not be accommodated in a central region of the bottom surface <NUM>. As shown in <FIG>, the cavities 414a, 414b may be provided proximal to edges of the orthodontic appliance <NUM>.

In some embodiments, the orthodontic appliance <NUM> further includes the dental composition <NUM> (shown in <FIG>) received within each of the reservoirs 416a, 416b. In some embodiments, each of the reservoirs 416a, 416b is configured to retain the dental composition <NUM> within each of the reservoirs 416a, 416b. The reservoirs 416a, 416b may retain the dental composition <NUM> within the reservoirs 416a, 416b by mechanical interaction of the dental composition <NUM> and the reservoirs 416a, 416b. Specifically, a T-shaped configuration of the cavities 414a, 414b may retain the dental composition <NUM> within the reservoirs 416a, 416b, respectively. The reservoirs 416a, 416b may secure the dental composition <NUM> within the cavities 414a, 414b, respectively. That is, the reservoirs 416a, 416b may prevent the dental composition <NUM> to be removed from the cavities 414a, 414b, respectively. Therefore, the reservoirs 416a, 416b may prevent the dental composition <NUM> from being dislodged into an oral environment of a patient from the cavities 414a, 414b, respectively. The orthodontic appliance <NUM> may provide safe, efficient, sustained and continuous release of elements from the dental composition <NUM> into the oral environment of the patient during a course of orthodontic treatments. The elements (for example, fluoride, calcium, strontium, phosphate) released into the oral environment may further deposit on surfaces of the teeth <NUM> (shown in <FIG>). Therefore, the orthodontic appliance <NUM> may reduce or prevent oral and dental diseases. In some embodiments, the dental composition <NUM> may be additionally coated on the body <NUM> of the orthodontic appliance <NUM>.

<FIG> illustrates a method <NUM>. The method 50C which is not explicitly recited by the wording of the claims, but which is considered useful for understanding the invention, may be a method of use of each of the orthodontic appliances <NUM>, <NUM>, <NUM>, <NUM>. The method <NUM> will be described with reference to <FIG>. The method <NUM> includes the following steps:
At step <NUM>, the method <NUM> includes providing an orthodontic appliance. The orthodontic appliance includes a body. The body includes a first portion defining a slot. The body further includes a second portion extending from the first portion along a longitudinal axis. The second portion includes a bottom surface opposite to the first portion. The second portion further includes a lateral surface extending from the bottom surface towards the first portion along the longitudinal axis. The bottom surface and the lateral surface at least partially form an external surface of the body. The second portion defines a cavity at least partially surrounded by the bottom surface. The cavity extends at least partially along a length of the second portion from the bottom surface. The cavity includes a reservoir and at least one passage disposed in fluid communication with the reservoir. The at least one passage extends from the reservoir to the lateral surface.

For example, the method <NUM> may include providing the orthodontic appliances <NUM>, <NUM>, <NUM>, <NUM> including the bodies <NUM>, <NUM>, <NUM>, <NUM>, respectively. The bodies <NUM>, <NUM>, <NUM>, <NUM> include the first portions 102a, 202a, 302a, 402a defining the slots <NUM>, <NUM>, <NUM>, <NUM>, respectively. The second portions 102b, 202b, 302b, 402b extend from the first portions 102a, 202a, 302a, 402a along the longitudinal axes <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, respectively. The second portions 102b, 202b, 302b, 402b include the bottom surfaces <NUM>, <NUM>, <NUM>, <NUM> opposite to the first portions 102a, 202a, 302a, 402a, respectively. The second portions 102b, 202b, 302b, 402b further include the lateral surfaces <NUM>, <NUM>, <NUM>, <NUM> extending from the bottom surfaces <NUM>, <NUM>, <NUM>, <NUM> towards the first portions 102a, 202a, 302a, 402a along the longitudinal axes <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, respectively. The bottom surfaces <NUM>, <NUM>, <NUM>, <NUM> and the lateral surfaces <NUM>, <NUM>, <NUM>, <NUM> at least partially form the external surfaces <NUM>, <NUM>, <NUM>, <NUM> of the bodies <NUM>, <NUM>, <NUM>, <NUM>, respectively.

The second portions 102b, 202b, 302b define the cavities <NUM>, <NUM>, <NUM> at least partially surrounded by the bottom surfaces <NUM>, <NUM>, <NUM>, respectively. Further, the second portion 402b defines the cavities 414a, 414b at least partially surrounded by the bottom surface <NUM>.

The cavities <NUM>, <NUM>, <NUM> extend at least partially along the lengths of the second portions 102b, 202b, 302b from the bottom surfaces <NUM>, <NUM>, <NUM>, respectively. Further, the cavities 414a, 414b extend at least partially along the length of the second portion 402b from the bottom surface <NUM>.

The cavities <NUM>, <NUM>, <NUM> include the reservoirs <NUM>, <NUM>, <NUM> and the at least one passages <NUM>, <NUM>, <NUM> disposed in fluid communication with the reservoirs <NUM>, <NUM>, <NUM>, respectively. Further, the cavities 414a, 414b include the reservoirs 416a, 416b and the at least one passages 418a, 418b disposed in fluid communication with the reservoirs 416a, 416b, respectively.

The at least one passages <NUM>, <NUM>, <NUM> extend from the reservoirs <NUM>, <NUM>, <NUM>, to the lateral surfaces <NUM>, <NUM>, <NUM>, respectively. Further, the at least one passages 418a, 418b extend from the reservoirs 416a, 416b to the lateral surface <NUM>, respectively.

At step <NUM>, the method <NUM> includes depositing a dental composition within the reservoir of the cavity. For example, the method <NUM> may include depositing the dental composition <NUM> within the reservoirs <NUM>, <NUM>, <NUM> of the cavities <NUM>, <NUM>, <NUM>, respectively. Further, the method <NUM> may include depositing the dental composition <NUM> within the reservoirs 416a, 416b of the cavities 414a, 414b, respectively.

In some embodiments, the dental composition <NUM> is at least one of the fluoride-releasing composition, the calcium-releasing composition, the strontium-releasing composition, and the phosphate-releasing composition. The dental composition <NUM> may be deposited within the reservoirs <NUM>, <NUM>, <NUM>, 416a, 416b by various methods. In some embodiments, the dental composition <NUM> may be directly injected into the reservoirs <NUM>, <NUM>, <NUM>, 416a, 416b. In some embodiments, the dental composition <NUM> may include a self-cure glass ionomer and/or a resin modified glass ionomer (RMGI). The self-cure glass ionomer and the RMGI may cure itself after injection into the reservoirs <NUM>, <NUM>, <NUM>, 416a, 416b and may be secured within the cavities <NUM>, <NUM>, <NUM>, 414a, 414b, respectively. Examples of self-cure glass ionomer and RMGI include, but are not limited to, RelyX™ Luting plus, Ketac™ Cem, Fujicem®, Fuji IX, and the like.

Some RMGI products, such as Ketac™ Nano, Varnish™ XT, and Fuji LC, may need to be cured by light. The resin in such products may be cured with redox curing agents, such as tertial amine and benzyl peroxide. In some embodiments, the resin in such products may alternatively be cured with thermal initiators at an elevated temperature (for example, <NUM>° C). Examples of the thermal initiators include, but are not limited to, benzyl peroxide, potassium persulfate, and the like. However, due to shelf-life concern, a paste of the product with the redox curing agents and the thermal initiators may need to be compounded and used within several days. The paste with the redox curing agents and the thermal initiators may be injected into the cavities <NUM>, <NUM>, <NUM>, of the orthodontic appliances <NUM>, <NUM>, <NUM>, respectively. Further, the paste with the redox curing agents and the thermal initiators may be injected into the cavities 414a, 414b of the orthodontic appliance <NUM>.

The RMGI products, such as Ketac™ Nano, Varnish™ XT, and Fuji LC, may also be cured in molds similar in shape to the cavities <NUM>, <NUM>, <NUM> outside of the orthodontic appliances <NUM>, <NUM>, <NUM> and then transferred into the cavities <NUM>, <NUM>, <NUM> of the orthodontic appliances <NUM>, <NUM>, <NUM>, respectively. Further, the RMGI products, such as Ketac™ Nano, Varnish™ XT, and Fuji LC, may also be cured in molds similar in shape to the cavities 414a, 414b outside of the orthodontic appliance <NUM> and then transferred into the cavities 414a, 414b of the orthodontic appliance <NUM>.

The glass ionomers and resin modified glass ionomers curable compositions according to the present disclosure may include one or more additional components, such as, for example, solvent, antioxidants, flavorants, fluoridating agents, buffering agents, numbing agents, remineralization agents, basic fillers, desensitization agents, colorants, indicator(s), viscosity modifiers, surfactants, stabilizers, preservative agents (e.g., benzoic acid), or a combination thereof. The buffering agents can be selected from phosphate buffer, citrate buffer, and carboxylate buffer. The remineralization agents can be selected from calcium salts, such as calcium phosphate, calcium hydrogen phosphate, calcium dihydrogen phosphate, calcium chloride, calcium nitrite, calcium carbonate, calcium lactate, and strontium salts, such as strontium chloride, strontium nitrite, strontium lactate, etc. The fluoridating agents can be selected from sodium fluoride, ammonium fluoride, potassium fluoride, zinc fluoride, silver diamine fluoride, and fluosilane. The basic fillers may be selected from Portland cement and mineral trioxide aggregate (MTA).

In some embodiments, the dental composition <NUM> may include fluoride varnish. In such embodiments, a fluoride coating may be injected into the cavities <NUM>, <NUM>, <NUM>, 414a, 414b, and then dried under various conditions to remove solvents and form solids with active ingredients in the solids. This process may be repeated to completely fill the cavities <NUM>, <NUM>, <NUM>, 414a, 414b. Such dental compositions may be additionally coated over the bodies <NUM>, <NUM>, <NUM>, <NUM> of the orthodontic appliances <NUM>, <NUM>, <NUM>, <NUM>, respectively.

These compositions from fluoride varnishes and other coating material that can be dried in the structure according to the present disclosure may include one or more additional components such as, for example, solvent, antioxidants, flavorants, fluoridating agents, buffering agents, numbing agents, remineralization agents, basic fillers, desensitization agents, colorants, indicator(s), viscosity modifiers, surfactants, stabilizers, preservative agents (e.g., benzoic acid), or a combination thereof. The buffering agents can be selected from phosphate buffer, citrate buffer, and carboxylate buffer. The remineralization agents can be selected from calcium salts, such as calcium phosphate, calcium hydrogen phosphate, calcium dihydrogen phosphate, calcium chloride, calcium nitrite, calcium carbonate, calcium lactate, and strontium salts, such as strontium chloride, strontium nitrite, strontium lactate, etc. The fluoridating agents can be selected from sodium fluoride, ammonium fluoride, potassium fluoride, zinc fluoride, silver diamine fluoride, and fluosilane. The basic fillers may be selected from Portland cement and mineral trioxide aggregate (MTA).

In some embodiments, the dental composition <NUM> may be inserted/injected into the cavities <NUM>, <NUM>, <NUM>, 414a, 414b before different parts of the orthodontic appliances <NUM>, <NUM>, <NUM>, <NUM> are assembled together by a suitable process (e.g., laser welding). Specifically, in some embodiments, the method <NUM> further includes engaging a base with the bottom surface of the second portion of the body, and attaching the base to a tooth. For example, the method <NUM> may further include engaging the base <NUM> with the bottom surfaces <NUM>, <NUM>, <NUM>, <NUM> of the second portions 102b, 202b, 302b, 402b of the bodies <NUM>, <NUM>, <NUM>, <NUM>, respectively, and attaching the base <NUM> to the tooth <NUM>.

In some embodiments, the method <NUM> further includes at least partially receiving an archwire within the slot of the first portion of the body. For example, the method <NUM> may further include at least partially receiving the archwire <NUM> within the slots <NUM>, <NUM>, <NUM>, <NUM> of the first portions 102a, 202a, 302a, 402a of the bodies <NUM>, <NUM>, <NUM>, <NUM>, respectively.

<FIG> illustrates a graph <NUM> depicting a cumulative fluoride release (in parts per million) in <NUM> of <NUM> water based on an experiment conducted on the orthodontic appliance <NUM> (shown in <FIG>) of the present disclosure. The <NUM> of <NUM> water was used to replicate an oral environment of a patient. An equal amount of a fluoride-releasing composition (RelyX™ Luting Plus cement) was provided on different regions of the orthodontic appliance <NUM>.

Particularly, the fluoride-releasing composition was:.

The cumulative fluoride release from the fluoride-releasing composition provided on the different regions of the orthodontic appliance <NUM> was observed for <NUM> days, and the experiment was repeated three times for each of the different coating regions.

An average cumulative fluoride release (in ppm) for each of the different coating regions is depicted in the graph <NUM>. Specifically, in the graph <NUM>, an average cumulative fluoride release from the fluoride-releasing composition coated on the top of the orthodontic appliance <NUM> is depicted by triangles and by a curve <NUM>. Furthermore, an average cumulative fluoride release from the fluoride-releasing composition coated on the edges of the orthodontic appliance <NUM> is depicted by squares and by a curve <NUM>. Moreover, an average cumulative fluoride release from the fluoride release composition injected within the reservoir <NUM> of the orthodontic appliance <NUM> is depicted by circles and by a curve <NUM>.

The average cumulative fluoride release along with a standard deviation (in brackets in Table <NUM>) for each of the different coating regions of the cumulative fluoride release is provided in Table <NUM> below.

Referring to <FIG> and Table <NUM>, as shown by the curve <NUM>, the average cumulative fluoride release from the fluoride-releasing composition coated on the top of the orthodontic appliance <NUM> was observed to be high. A high cumulative fluoride release may result in fluoride toxicity. Additionally, coating the fluoride-releasing composition on the top of the orthodontic appliance <NUM> may reduce an application life of the fluoride-releasing composition. In some cases, the application life of the fluoride-releasing composition coated on the top of the orthodontic appliance <NUM> may be less than a period of an orthodontic treatment. In some cases, the fluoride-releasing composition coated on the top of the orthodontic appliance <NUM> may be dispensed substantially before the period of the orthodontic treatment has lapsed.

Furthermore, as shown by the curve <NUM>, the average cumulative fluoride release from the fluoride-releasing composition coated on the edges of the orthodontic appliance <NUM> was observed to be less than the average cumulative fluoride release from the fluoride-releasing composition coated on the top of the orthodontic appliance <NUM> (shown by the curve <NUM>). Particularly, coating the fluoride-releasing composition on the edges of the orthodontic appliance <NUM> may result in a longer application life of the fluoride-releasing composition. However, the cumulative fluoride release from the fluoride-releasing composition coated on the edges of the orthodontic appliance <NUM> may be difficult to control. Specifically, a volume of the fluoride-releasing composition coated on the orthodontic appliance <NUM> may be limited by a size of the orthodontic appliance <NUM>. Therefore, the volume of the fluoride-releasing composition may not be selected as per desired application attributes. In other words, a desired volume of the fluoride-releasing composition may not correspond to an available area on the edges of the orthodontic appliance <NUM>.

As shown by the curve <NUM>, the average cumulative fluoride release from the fluoride-releasing composition injected within the reservoir <NUM> of the orthodontic appliance <NUM> was observed to be sustained and continuous throughout the experiment. Furthermore, coating the fluoride-releasing composition within the reservoir <NUM> of the orthodontic appliance <NUM> may result in a long application life of the fluoride-releasing composition. A volume of the fluoride-releasing composition may be selected as per desired application attributes. Further, the volume of the fluoride-releasing composition may be reliably injected within the reservoir <NUM>. Moreover, a risk of fluoride toxicity may be substantially reduced. These findings were further verified with another experiment.

<FIG> illustrates a graph <NUM> depicting a variation between a cumulative fluoride release from the fluoride-releasing composition injected within the reservoir <NUM> of the orthodontic appliance <NUM> and time (days) in <NUM> water based on an experiment conducted on the orthodontic appliance <NUM> over a period of two years (<NUM> days). The experiment was performed three times. An average cumulative fluoride release is depicted in the graph <NUM>. The average cumulative fluoride release along with a standard deviation (stdev) of the cumulative fluoride release is provided in Table <NUM> below.

Referring to <FIG> and Table <NUM>, a curve <NUM> depicts the average cumulative fluoride release from the fluoride-releasing composition injected within the reservoir <NUM> of the orthodontic appliance <NUM> over the period of two years. It may be noted that fluoride release continued for the period of two years. Therefore, the orthodontic appliance <NUM> may provide safe, sustained and continuous fluoride delivery in an oral environment of a patient throughout a period of an orthodontic treatment.

Another experiment was performed to verify whether the fluoride released from the fluoride-releasing composition (RelyX™ Luting Plus cement) injected within the reservoir <NUM> of the orthodontic appliance <NUM> interacted with an enamel of a tooth. In a first sample, an enamel was submerged in an artificial saliva. In a second sample, an identical enamel was submerged in water along with four of the orthodontic appliances <NUM> with the fluoride-releasing composition injected within the reservoirs <NUM> placed near the enamel. The experiment was conducted three times, and an average fluoride uptake along with a standard deviation of the fluoride uptake by the enamel was calculated.

<FIG> illustrates a graph <NUM> depicting the average fluoride uptake on the enamel from the two samples. The experiment was performed three times. A mean fluoride uptake and a standard deviation of the fluoride uptake (in brackets) was calculated and is tabulated in Table <NUM> provided below.

Referring to <FIG> and Table <NUM>, the average fluoride uptake on the enamel from four of the orthodontic appliances <NUM> with the fluoride-releasing composition injected within the reservoirs <NUM> is more than the average fluoride uptake on the enamel surface treated with the artificial saliva. Therefore, the orthodontic appliance <NUM> may provide efficient fluoride uptake on enamels of the plurality of teeth <NUM> (shown in <FIG>).

In the orthodontic system <NUM> (shown in <FIG>), <NUM> of the orthodontic appliances <NUM>, <NUM>, <NUM>, <NUM> may require an amount of the fluoride-releasing composition about the same as the amount required for cementation of a single crown. Furthermore, a total fluoride releasing area of <NUM> orthodontic appliances <NUM>, <NUM>, <NUM>, <NUM> may be about <NUM> times more than that of the single crown. Therefore, the orthodontic system <NUM> may be more efficient in fluoride delivery than the single crown.

It will be appreciated that the arrangements presented herein may be varied in any number of aspects while still remaining within the scope of the disclosures herein.

Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.

Claim 1:
An orthodontic appliance (<NUM>, <NUM>, <NUM>, <NUM>) comprising:
a body (<NUM>, <NUM>, <NUM>, <NUM>) comprising a first portion (102a, 202a, 302a, 402a) defining a slot (<NUM>, <NUM>, <NUM>, <NUM>) for receiving an archwire (<NUM>) and a second portion (102b, 202b, 302b, 4022b) extending from the first portion along a longitudinal axis (<NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>), wherein the second portion comprises a bottom surface (<NUM>, <NUM>, <NUM>, <NUM>) opposite to the first portion and a lateral surface (<NUM>, <NUM>, <NUM>, <NUM>) extending from the bottom surface towards the first portion along the longitudinal axis, the bottom surface and the lateral surface at least partially forming an external surface of the body, wherein the second portion defines a cavity (<NUM>, <NUM>, <NUM>, 414a) at least partially surrounded by the bottom surface and at least partially extending along a length of the second portion from the bottom surface, wherein the cavity comprises a reservoir (<NUM>, <NUM>, <NUM>, 416a) and at least one passage (<NUM>, <NUM>, <NUM>, 418a) disposed in fluid communication with the reservoir and extending from the reservoir to the lateral surface, and
a dental composition (<NUM>) injected within the reservoir, wherein the reservoir is configured to retain the injectable dental composition.