WO2017087533A1

WO2017087533A1 - Self-ligating orthodontic bracket

Info

Publication number: WO2017087533A1
Application number: PCT/US2016/062295
Authority: WO
Inventors: Fabio BEGGIORA; Renan G. JUNG
Original assignee: 3M Innovative Properties Company
Priority date: 2015-11-19
Filing date: 2016-11-16
Publication date: 2017-05-26
Also published as: BR112018010320A2

Abstract

A self-ligating appliance including a door rotatable about a hinge structure on the appliance body. The door and body include multiple interfering surfaces, which can arrest the door in a desired open or closed position.

Description

SELF-LIGATING ORTHODONTIC BRACKET

Background Orthodontic appliances are devices used in the professional supervision, guidance and correction of a patient's malpositioned teeth. The many benefits of orthodontic treatment include the attaining and maintaining of a proper bite function, enhancement of facial aesthetics, and easier maintenance of dental hygiene. Orthodontic appliances are placed in mechanical engagement with the patient's teeth and apply gentle mechanical forces that gradually move the teeth toward corrected positions to achieve a proper bite (or occlusion).

A very common type of orthodontic treatment uses tiny slotted appliances called orthodontic brackets, which are adhesively attached to either the front or back surfaces of the patient's teeth. To move the teeth within an upper or lower arch, a resilient arch-shape wire ("archwire") is mechanically engaged, or "ligated," into the slot of each bracket. The ends of the archwire are generally captured in appliances called molar tubes, which are bonded to the patient's molar teeth. As the archwire slowly returns to its original shape, it acts as a track that guides the movement of teeth toward their desired positions. The brackets, tubes, and archwire are collectively known as "braces."

Conventional brackets are ligated to the archwire with the help of opposing tie wings, which are cleat-like projections on the bracket body. After the archwire is placed in the archwire slot, either a tiny elastomeric "0"-ring ligature or a metal ligature wire is looped over the archwire and beneath the undercut portions of tiewings located on opposite sides of the archwire slot. By tightly encircling the undercut portions of the tiewings, the ligature (or ligature wire) can secure the archwire within the archwire slot of each bracket, while still allowing the archwire to slide longitudinally along the slot. Depending on the relative sizes and shapes of the archwire and the slot, it is possible to achieve a precise mechanical coupling between the two bodies. This enables the practitioner to control the position and orientation of each individual tooth in the arch.

Both of the ligating mechanisms above have certain drawbacks. For example, the frictional contact between O-ring ligatures and the archwire can increase resistance to archwire sliding within the slot. Moreover, the elastic properties of these ligatures can degrade over time, resulting in unpredictable sliding mechanics. While these ligatures can be made from translucent polymers for aesthetic treatment, these same ligatures also tend to stain in the presence of dark-colored foods and liquids. Ligature wire poses its own problems, since the process of tying and trimming the wire can be cumbersome and time- consuming for the orthodontic professional. Being made of metal, ligature wire is also considered non- aesthetic.

Self-ligating brackets present a solution to at least some of the above problems. These appliances generally use a clip, spring member, door, shutter, bail, or other ligation mechanism built into the bracket itself to retain the archwire in the slot, thereby obviating use of a separate ligature. Several advantages can derive from the use of these ligation mechanisms. For example, these appliances can decrease friction between the archwire and the bracket compared with appliances ligated with elastomeric ligatures, potentially providing faster leveling and aligning of teeth in early stages of treatment. Depending on the mechanism, these appliances can also simplify the installation and removal of an archwire, significantly reducing chair time for the treating professional. Finally, self-ligating brackets can provide better hygiene than conventional brackets, which use elastomeric ligatures and ligature wires that can trap food and plaque.

Summary of the Invention

The present disclosure provides self-ligating appliances featuring a door rotatably engaged to an appliance body, with the door and body including rotation locking surfaces. The interfering components of the door and body reduce, minimize, or prevent rotation of the occlusal edge of the door towards the archwire slot while the door is in the open orientation, keeping the door from obscuring access to the archwire slot as long as the locking surfaces are engaged. This can dramatically reduce the risk to the practitioner of the door inadvertently closing during seating of the archwire. Similarly, the interfering components of the door and body reduce, minimize, or prevent inadvertent opening when an archwire is secured in the archwire slot during treatment. The door of the present disclosure accordingly grants dynamically enhanced control over access to the archwire slot.

In one aspect, the present disclosure provides a self-ligating orthodontic bracket comprising, a base for bonding the appliance to a tooth surface; a body extending outwardly from the base, the body defining an archwire slot extending in a mesial-distal direction across the body and including a hinge structure on a first side of the archwire slot; a clip coupled to the hinge structure and rotatable about the first reference axis between an open state and a closed state, wherein an archwire is insertable into the archwire slot in the open state and the door retains the archwire in the archwire slot in the closed state, the clip including a deformable region; and; a locking mechanism on the body engaging the clip and impeding rotation of the door to the open state when the door is in the closed state, and wherein the deformable region is deformed by the locking mechanism as the clip is rotated between the closed state and the open state.

In another aspect, the present disclosure provides a self-ligating orthodontic appliance comprising, a base for bonding the appliance to a tooth surface; a body extending outwardly from the base, the body defining an archwire slot extending in a mesial-distal direction across the body; a hinge structure defining a first reference axis and including an arcuate surface, the structure disposed on the first side of the archwire slot; a channel extending between the hinge structure and the base; and a door coupled to the hinge structure and rotatable about the first reference axis between an open state and a closed state, wherein an archwire is insertable into the archwire slot in the open state and the door retains the archwire in the archwire slot in the closed state; wherein the door is generally C-shaped and includes a compound curvature at a base of the C-shape, the compound curvature including a first radius of curvature and a second radius of curvature, the portion of the door having the second radius of curvature interfering with the arcuate surface of hinge structure to impede rotation of the door between the open state and the closed state, and wherein a portion of the door is disposed in the channel in both the open state and the closed state.

The words "preferred" and "preferably" refer to embodiments of the disclosure that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the disclosure.

In this application, terms such as "a", "an", and "the" are not intended to refer to only a singular entity, but include the general class of which a specific example may be used for illustration. The terms "a", "an", and "the" are used interchangeably with the term "at least one." The phrases "at least one of and "comprises at least one of followed by a list refers to any one of the items in the list and any combination of two or more items in the list.

As used herein, the term "or" is generally employed in its usual sense including "and/or" unless the content clearly dictates otherwise.

The term "and/or" means one or all of the listed elements or a combination of any two or more of the listed elements.

Also herein, all numbers are assumed to be modified by the term "about" and preferably by the term "exactly." As used herein in connection with a measured quantity, the term "about" refers to that variation in the measured quantity as would be expected by the skilled artisan making the measurement and exercising a level of care commensurate with the objective of the measurement and the precision of the measuring equipment used.

Also herein, the recitations of numerical ranges by endpoints include all numbers subsumed within that range as well as the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

As used herein as a modifier to a property or attribute, the term "generally", unless otherwise specifically defined, means that the property or attribute would be readily recognizable by a person of ordinary skill but without requiring absolute precision or a perfect match (e.g., within +/- 20 % for quantifiable properties). The term "substantially", unless otherwise specifically defined, means to a high degree of approximation (e.g., within +/- 10% for quantifiable properties) but again without requiring absolute precision or a perfect match. Terms such as same, equal, uniform, constant, strictly, and the like, are understood to be within the usual tolerances or measuring error applicable to the particular circumstance rather than requiring absolute precision or a perfect match.

The above summary of the present disclosure is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The description that follows more particularly exemplifies illustrative embodiments. In several places throughout the application, guidance is provided through lists of examples, which examples can be used in various combinations. In each instance, the recited list serves only as a representative group and should not be interpreted as an exclusive list.

Brief Description of the Drawings

FIG. 1 is a perspective view of an orthodontic appliance according to one embodiment of the present disclosure in a closed configuration, looking toward its labial, distal, and gingival surfaces.

FIG. 2 is a top down, labial view of the appliance of FIG. 1 in a closed configuration, looking toward its labial surfaces.

FIG. 3 is a gingival view of the appliance of FIGS. 1-2, looking toward its gingival-facing surfaces.

FIG. 4 is an occlusal view of the appliance of FIGS. 1-3, looking toward its occlusal-facing surfaces.

FIG. 5 is a mesial side view of the appliance of FIGS. 1-4, looking toward its mesial-facing surfaces.

FIG. 6 is a cross-sectional view of the appliance of FIGS. 1-5 including a door in a closed position, looking toward its mesial side;

FIG. 7 is a cross-sectional view of the appliance of FIGS. 1-5 including a door in an open position, looking towards its mesial side;

FIG. 8 is an exploded perspective view of the appliance of FIGS. 1-7, looking toward its looking toward its labial, mesial, and gingival surfaces. While the above -identified figures set forth several embodiments of the disclosure other embodiments are also contemplated, as noted in the description. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the invention.

Directional Definitions

As used herein:

"Mesial" means in a direction toward the center of the patient's curved dental arch.

"Distal" means in a direction away from the center of the patient's curved dental arch.

"Occlusal" means in a direction toward the outer tips of the patient's teeth.

"Gingival" means in a direction toward the patient's gums or gingiva. "Facial" means in a direction toward the patient's lips or cheeks.

"Lingual" means in a direction toward the patient's tongue.

Detailed Description of Illustrative Embodiments

An orthodontic appliance 10 according to one embodiment of the present disclosure is shown in FIGS. 1-8, and represents an orthodontic bracket. Referring to FIG. 1, the appliance 10 has a base 12 having an outer surface 14 adapted for adhesive bonding to a patient's tooth. Preferably and as shown, the outer surface 14 is concave and substantially conforms to the convex outer surface of the tooth. In certain embodiments, the outer surface 14 may feature a compound contour, with curvature in both the mesial-distal and occlusal-gingival direction.

The orthodontic bracket 10 of this embodiment and the orthodontic appliances of other embodiments, unless otherwise indicated, are described herein using a reference frame attached to a labial surface of a tooth on the upper or lower jaw. Consequently, terms such as labial, lingual, mesial, distal, occlusal, and gingival used to describe the orthodontic bracket 10 are relative to the chosen reference frame. The embodiments, however, are not limited to the chosen reference frame and descriptive terms, as the orthodontic bracket 10 may be used on other teeth and in other orientations within the oral cavity. For example, the orthodontic bracket 10 may also be coupled to the lingual surface of the tooth. Those of ordinary skill in the art will recognize that the descriptive terms used herein may not directly apply when there is a change in reference frame. Nevertheless, the embodiments are intended to be independent of location and orientation within the oral cavity and the relative terms used to describe embodiments of the orthodontic bracket are to merely provide a clear description of the embodiments in the drawings. As such, the relative terms labial, lingual, mesial, distal, occlusal, and gingival are in no way limiting the embodiments to a particular location or orientation.

The outer surface 14 may include mesh, holes, bumps, recesses, undercuts, a microetched surface, glass grit, bonded particles, an organo-silane treated surface, or any other known mechanical or chemical modification to enhance adhesive bonding between the base 12 and the underlying tooth. Alternatively, the base 12 could also have a banded configuration in which the base 12 fully encircles the tooth to provide an even stronger bond. In other implementations, the base may include a fixed, compressible material to assist in filling gaps between the base 12 and the tooth structure. Suitable compressible materials are described in US Publication No. 2009/0233252 (Cinader).

A body 20 extends outwardly from the base 12 in a facial direction, away from the outer surface 14. Optionally and as shown, the base 12 and body 20 are integral components. In certain embodiments, the base 12 and body 20 may be integrally made, for example, via machine or mold from a polymeric material as disclosed in U.S. Patent No. 4,536,154 (Garton, et al.), a ceramic material such as a finegrained polycrystalline alumina as disclosed in U.S. Patent No. 6,648,638 (Castro, et al.), or a polymer- ceramic composite such as glass-fiber reinforced polymeric composites as disclosed in U.S. Patent Nos. 5,078,596 (Carberry, et al.) and 5,254,002 (Reher, et al.). Other suitable materials include, for example, metallic materials (such as stainless steel, titanium, and cobalt-chromium alloys) and plastic materials (such as fiber-reinforced polycarbonate).

The body 20 has a facial surface 21 and an elongated archwire slot 30 extending in a generally mesial-distal direction across the facial surface 21 of the body. Referring to the mesial view in FIG. 5, the archwire slot 30 includes a bottom, lingual wall 34 along with gingival and occlusal side walls 32, 36. An archwire (not shown) is received in the archwire slot 30 and typically has a generally rectangular cross-section that substantially corresponds with the dimensions of walls 32, 34, 36 of the archwire slot 30. A close correspondence between the dimensions of the archwire and the archwire slot can provide for a precise coupling between the archwire and appliance 10, giving the treating practitioner a high degree of control over the movement of teeth. In appliances of the present disclosure, other archwire geometries can be used that do not closely approximate the dimensions of the lingual and gingival walls. In certain embodiments, the side walls 32 and 36 can include a substantially equal facial-lingual height in relation to the lingual wall 34.

The appliance 10 has a structure that also allows for traditional methods of ligation, including occlusal tiewings 15, gingival tiewings 16, and undercuts 18. A treating professional can elect to manually ligate an archwire with the assistance of the undercuts 18 and tiewings 15, 16. Ligation can be achieved, for example, by securing an elastomeric o-ring or ligature wire beneath the undercuts 18, over an archwire received in the slot 30, and beneath the tiewings 15, 16. The undercuts 18 and tiewings 15, 16 may also be used to secure a power chain to two or more teeth if so desired. One or more of the tie wings can include a rotation stop surface 17 located in a facial direction from the archwire slot 30. The rotation stop surfaces are designed to control the position of a door 40 relative to the slot 30, as described in further detail below.

As shown in FIG. 1 , a hinge is provided proximate gingival wall 32, and a door 40 is rotatably coupled to the hinge. The door 40 is rotatable about the hinge between open and closed orientations, so that when the door 40 is closed an archwire is held captive in the archwire slot 30. In the configuration shown in FIG. 1, the archwire would be securely ligated to the appliance 10 such that the archwire will not become accidently dislodged as a result normal chewing and brushing activity that occurs in a patient's mouth. However, the archwire can, and should typically be capable of sliding along the length of the archwire slot 30, thereby allowing the archwire to function as a track that guides the movement of maloccluded teeth. Such sliding is especially prominent as the teeth unravel during the leveling and aligning stages of treatment.

In more detail, the hinge in this embodiment is provided by an arcuate surface 71 of the body 20 having a radius of curvature. The arcuate surface 71 extends along a portion of the archwire slot 30 between the gingival tiewings 16 and defines a longitudinal hinge axis 72 that extends in a generally mesial-distal direction. The hinge axis 72 as illustrated is generally coplanar with the lingual wall 34 of the archwire slot 30. In other embodiments, the hinge axis 72 may be located above (i.e., in a facial direction from) or below (i.e., in a lingual direction from) the lingual wall 34. The hinge axis 72 positions the axis of rotation of the door 40 within or adjacent the archwire slot 30, limiting the necessary rotation of the door 40 in transitioning between the open and closed positions. Accordingly, placing the arcuate surface 71 near the archwire slot 30 can, in certain implementations, result in a lower profile for the appliance 10 and a resultant increase in patient comfort.

The resilient, generally "C"-shaped door 40 is rotatably engaged to the arcuate surface 71 and, as best shown in FIGs. 6-8, includes a labial section 41 and a lingual section 44 joined to the labial section 41 via a curved section 45. The lingual section 44 includes one or more legs 43 and is received in a passageway 28 extending through the body 20 and beneath the archwire slot 30 in a generally occlusal- gingival direction. The labial section 41 extends over the archwire slot 30 when the door is in the closed position. The curved section 45 is generally convex relative to the arcuate surface 71, registering and matingly engaging with the arcuate surface 71. The curved section 45 includes a first portion 46 with a first radius of curvature that is substantially the same as the radius of curvature of the arcuate surface 71, allowing the door 40 to reversibly rotate between open and closed positions thus permitting or blocking access to the archwire slot 30, respectively.

The curved section 45 further includes a second portion (locking section 47) proximate the labial section 41 with a second radius of curvature, creating a compound contour in the base of the "C". In presently preferred embodiments, the second radius of curvature is smaller than the first radius of curvature, meaning that the second radius of curvature is also smaller than the radius of curvature of the arcuate surface 71. This mismatch in curvature creates interference with the rotation of the door between the open and closed positions. For example, if the radius of curvature of curved surface 71 is 0.7 mm, the radius of the locking section 47 can be 0.3 mm. Those skilled in the art will appreciate that other dimensions and relationships between the locking section 47 and the arcuate surface 71 are possible and can be tailored to a desired offset and force necessary to overcome resistance to rotation.

In some or all embodiments, the arcuate surface 71 may include compound curvature as well. In such implementations, the compound curvature includes at least one radius of curvature that is: a) larger than the second radius of curvature of the locking section 47; and b) exhibited by a sufficient portion of the arcuate surface so as to interfere with locking section 47 over a desired arc of rotation. The interaction of locking section 47 with the arcuate surface 71 is, in certain implementations, alone sufficient to arrest the rotation of the door 40 in the desired state. The door 40 can be made to transition between open and closed position with application of force sufficient to deflect the locking section 47 relative to (e.g., away from) the arcuate surface 71.

In lieu of or in addition to the disparate curvatures of the door 40 and body surfaces, the door 40 may interact with certain features on the body 10 to further inhibit unwanted rotation. In the embodiments depicted in FIGs 1-7, the labial section 41 includes a resilient, deformable frame 48. The frame 48 includes mesial and distal edges 49, 50 positioned at opposite ends of the archwire slot 30 when the door is in the closed position. As can be appreciated by reference to FIG. 2, the frame 48 includes a greater maximum mesial-distal width than the maximum mesial-distal width between the gingival tiewing structures 16a, 16b. A portion of the frame 48 is disposed above the tie wings 15, 16.

In the depicted embodiment, the frame 48 defines an first open region 52 extending between the mesial and distal edges 49, 50 and a second open region 54 disposed generally where the labial section 41 transitions to the curved section 45. The second open region 54 provides a purchase point for a hand instrument useful in operating the door 40. In other embodiments, the frame 48 may include smaller open regions 52, 54. In yet other embodiments, the labial section 41 of the door may include a continuous surface between the mesial and distal edges 49, 50; the continuous surface may be curved, planar, or possess other geometry as will be apparent to those skilled in the art.

Rotation stop surfaces 17 on at least one of the tiewing structures 16a, 16b abut the edges 49, 50 of the frame 48 when the door 40 is in the closed position (See e.g., FIG. 2). The tiewings structures 16a, 16b may also include deliberate features (e.g., protrusions) that engage with the edges 49 of the frame 48 to deter rotation of the door between closed and open positions. Rotational force applied to the door 48 will cause deformation the mesial and distal edges 49, 50 of the frame 48 towards the mesial-distal center of the archwire slot 30 as the labial section 41 is drawn against rotation stop surfaces 17. In other embodiments, the labial section 41 may deform (e.g., buckle) in a facial or lingual direction. In presently preferred embodiments and as depicted in FIG. 2, the stop surfaces 17 include an angled region to assist in deformation of the frame 48 and as a structure to hold the door in the open position.

The operation of the door 40 relative to the body 10 is shown in the cross-sectional illustrations of FIGS. 6 and 7. FIG. 6 shows the door in its stable closed position, in which the labial section 41 of the door 40 extends over the archwire slot 30 and the edges 49, 50 of the frame 48 abut the rotation stop surfaces 17 of the gingival tie wing structures 16a, 16b. By virtue of at least one of a) the frame 48 having an overall mesial-distal width that is greater than the gap between the tie wing structures 16a, 16b, and b) the locking section 47 of the door 40 having a radius of curvature smaller than the curvature of the arcuate surface 71 to an extent suitable to interfere with rotation, the door 40 is held captive during the normal course of treatment.

To open the door 40, a practitioner can insert the tip of an explorer or other suitable hand instrument into the second open region 54, and apply a rotational force in the direction of the base 12 to the door 40. As the door 40 rotates to the position shown in FIG. 7, resistance to further sliding increases as a result of the interference between locking surface 47 and arcuate surface 71 of the body, as well as rotation stop surfaces 17 and frame 48. When urged against the rotation stop surface 17 and arcuate surface 71 with sufficient force, the frame 48 and locking section 47 of the door 40 can resiliently deflect, and traverse the arcuate surface 71 and/or stop surface 17 to reach an opened clip configuration as shown in FIG. 7.

The door 40 of the present disclosure is uniquely capable of serving at least two functions, separately or in combination. The interfering components of the door 40 and body 20 minimize or prevent rotation of the occlusal edge of the door 40 towards the archwire slot while the door 40 is in the open orientation, keeping the door 40 from obscuring access to the archwire slot 30 as long as the locking surfaces are engaged. This can dramatically reduce the risk to the practitioner of the door 40 inadvertently closing during seating of the archwire. Similarly, the interfering components of the door 40 and body 20 minimize or prevent inadvertent opening when an archwire is secured in the archwire slot 30 during treatment. The door 40 of the present disclosure accordingly grants dynamically enhanced control over access to the archwire slot 30.

In certain particularly advantageous implementations, interaction of the door and a body surface (e.g., tie wing protrusion 17 or curved surface 71) substantially prevents the door 40 from rotating in directions away from the lingual wall 34 at any position of the door 40 along arc R. As used herein, backward rotation is substantially prevented if the door 40 is only capable of rotating in directions away from the lingual wall 34 about the hinge axis 72 in an arc of no greater than 5 degrees. In some implementations, the permissible arc of rotation away from the lingual wall 34 is no greater than 4 degrees, in some embodiments no greater than 3 degrees, in some embodiments, no greater than 2 degrees, in yet other embodiments no greater than 1 degree, and in yet other embodiments no greater than 0.5 degrees.

In presently preferred circumstances, the force required to open and close the door 40 is sufficiently low to enable easy operation by a practitioner but also sufficiently high such that the door 40 does not spontaneously disengage during normal patient activity that occurs during treatment, such as chewing and toothbrushing. Preferably, the threshold amount of force applied to open the door 40 is at least about 0.45 Newtons (0.1 lbf), at least about 0.9 Newtons (0.2 lbf), at least about 2.2 Newtons (0.5 lbf), or at least about 4.4 Newtons (1 lbf). The threshold force is no greater than about 5.3 Newtons (1.2 lbf), about 6.7 Newtons (1.5 lbf), or no greater than about 8.9 Newtons (2 lbf).

The door 40 may be either assembled or unitary in construction and can be made from any of a number of resilient materials known to the skilled artisan. As shown, the labial section 41 and lingual section 43 are formed from a single flat sheet of resilient material. In presently preferred circumstances, the door 40 is made from a shape memory metal such as an alloy of nickel and titanium (i.e., nitinol, available from NDC Fremont, CA), but in other embodiments is made from a metal such as stainless steel, titanium, cobalt-chromium alloy (such as manufactured by Elgiloy Specialty Metals, Elgin, IL). It is also preferred that the door 40 is sufficiently resilient so that the shape of the door 40 when relaxed does not significantly change during the course of treatment. Optionally and as shown in FIG. 8, the lingual section 44 can have a trailing edge 55 and one or more bumps 56 adjacent the trailing edge 55 and protruding in mesial and/or distal directions, respectively. The bumps 56 engage with a rotation stop surface located in the passageway 28 when the door 40 rotates toward its closed position. The stop surface arrests the rotation of the lingual section 44 through the passageway 28 and prevents the door 40 from becoming dislodged during normal operation of the appliance 10. Similarly, the bumps 56 may engage undercuts 18 on the occlusal side of the body to prevent excess rotation in the open position.

Having multiple mating, locking surfaces on the door 40 and body 20 can be beneficial when deflection of an archwire 50 causes contact with the door 40 and urges the outer end of the door 40 toward the labial direction. In conventional self-ligating appliances, such forces could cause the outer end of the door to slip out of the retaining recess and cause spontaneous disengagement of the archwire from the slot. As shown, the engagement between all cooperative surfaces of the door and body creates an interference that restricts sliding between these components, providing for a more secure ligation of the archwire.

Embodiments

1. A self-ligating orthodontic bracket comprising,

a base for bonding the appliance to a tooth surface;

a body extending outwardly from the base, the body defining an archwire slot extending in a mesial-distal direction across the body and including a hinge structure on a first side of the archwire slot; a door coupled to the hinge structure and rotatable about the first reference axis between an open state and a closed state, wherein an archwire is insertable into the archwire slot in the open state and the door retains the archwire in the archwire slot in the closed state, the door including a deformable region; and;

a locking mechanism on the body engaging the door and impeding rotation of the door to the open state when the door is in the closed state, and wherein the deformable region is deformed by the locking mechanism as the door is rotated between the closed state and the open state.

2. The self-ligating orthodontic bracket of embodiment 1 and further including a channel between the base and archwire slot, wherein a portion of the door is received in the channel.

3. The self-ligating bracket of any of the previous embodiments, wherein the body includes a mesial tie wing and a distal tie wing, and wherein the locking mechanism comprise a surface on the mesial tie wing or the distal tie wing, or surfaces on both the mesial tie wing and the distal tie wing.

4. The self-ligating bracket of embodiments 1-3, wherein the body includes rotation stop surfaces proximate the channel on a second side of the archwire slot, and wherein the door engages the rotation stop surfaces in the closed state. 5. The self-ligating bracket of embodiments 1-4, wherein the door is generally C-shaped and includes a compound curvature at a base of the C-shape, the compound curvature including a first radius of curvature and a second radius of curvature, the portion of the door having the second radius of curvature interfering with the arcuate surface of hinge structured to impede rotation of the door between the open state and the closed state.

6. The self-ligating bracket of any of the previous embodiments, wherein the door includes an open region that extends over at least a portion the archwire slot when the door is in the closed state.

7. The self-ligating bracket of any of previous embodiments, wherein the door comprises a shape memory material.

8 The self-ligating bracket of any of the previous embodiments, wherein the body comprises a mesial-distal center, and wherein the door is deformed in the direction of the mesial-distal center by the locking mechanism as the door is rotated between the closed state and the open state.

9. The self-ligating bracket of any of the previous embodiments wherein the locking mechanism comprises a protrusion on a tie wing.

10. The self-ligating bracket of any of the previous embodiments, wherein the body includes a mesial tie wing and a distal tie wing, and wherein a portion of the door extends in a generally facial direction from an outer surface of the mesial tie wing.

11. The self-ligating bracket of any of the previous embodiments, wherein body includes a mesial tie wing on a second side of the archwire slot, and wherein the door engages a surface on the underside of a mesial tie wing when the door is in the open state.

12. A self-ligating orthodontic appliance comprising, a base for bonding the appliance to a tooth surface; a body extending outwardly from the base, the body defining an archwire slot extending in a mesial-distal direction across the body; a hinge structure defining a first reference axis and including an arcuate surface, the structure disposed on the first side of the archwire slot; a channel extending between the hinge structure and the base; and a door coupled to the hinge structure and rotatable about the first reference axis between an open state and a closed state, wherein an archwire is insertable into the archwire slot in the open state and the door retains the archwire in the archwire slot in the closed state; wherein the door is generally C-shaped and includes a compound curvature at a base of the C-shape, the compound curvature including a first radius of curvature and a second radius of curvature, the portion of the door having the second radius of curvature interfering with the arcuate surface of hinge structure to impede rotation of the door between the open state and the closed state, and wherein a portion of the door is disposed in the channel in both the open state and the closed state.

13. The self-ligating bracket of embodiment 12, and wherein the door includes a deformable region proximate the portion having the second radius of curvature.

14. The self-ligating bracket of embodiment 13 and further including a locking mechanism on the hinge structure engaging the door and impeding rotation of the door to the open state when the door is in the closed state, and wherein the deformable region is deformed by the locking mechanism as the door is rotated between the closed state and the open state.

15. The self-ligating bracket of embodiment 14, wherein the body includes a mesial tie wing and a distal tie wing, and wherein the locking mechanism comprise a surface on the mesial tie wing or the distal tie wing, or surfaces on both the mesial tie wing and the distal tie wing.

16. The self-ligating bracket of any of the previous embodiments, wherein the body includes rotation stop surfaces proximate the channel on a second side of the archwire slot, and wherein the door engages the rotation stop surfaces in the closed state.

17. The self-ligating bracket of any of the previous embodiments wherein the door includes an open region that extends over at least a portion the archwire slot when the door is in the closed state.

18. The self-ligating bracket of any of the previous embodiments, wherein the door comprises a shape memory material.

19. The self-ligating bracket of any of the previous embodiments, wherein body includes a mesial tie wing on a second side of the archwire slot, and wherein the door engages a surface on the underside of a mesial tie wing when the door is in the open state.

20. The self-ligating bracket of any of the previous embodiments, wherein the arcuate surface has a radius of curvature that is substantially the same as the first radius of curvature of the door.

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

Claims

CLAIMS:

1. A self-ligating orthodontic bracket comprising,

a base for bonding the appliance to a tooth surface;

2. The self-ligating orthodontic bracket of claim 1 and further including a channel between the base and archwire slot, wherein a portion of the door is received in the channel.

3. The self-ligating bracket of claim 1, wherein the body includes a mesial tie wing and a distal tie wing, and wherein the locking mechanism comprise a surface on the mesial tie wing or the distal tie wing, or surfaces on both the mesial tie wing and the distal tie wing.

4. The self-ligating bracket of claim 2, wherein the body includes rotation stop surfaces proximate the channel on a second side of the archwire slot, and wherein the door engages the rotation stop surfaces in the closed state.

5. The self-ligating bracket of claim 3, wherein the door is generally C-shaped and includes a compound curvature at a base of the C-shape, the compound curvature including a first radius of curvature and a second radius of curvature, the portion of the door having the second radius of curvature interfering with the arcuate surface of hinge structure to impede rotation of the door between the open state and the closed state.

6. The self-ligating bracket of claim 4, wherein the door includes an open region that extends over at least a portion the archwire slot when the door is in the closed state.

7. The self-ligating bracket of claim 1, wherein the body comprises a mesial-distal center, and wherein the door is deformed in the direction of the mesial-distal center by the locking mechanism as the door is rotated between the closed state and the open state.

8. The self-ligating bracket of claim 1, wherein the locking mechanism comprises a protrusion on a tie wing.

9. A self-ligating orthodontic appliance comprising,

a base for bonding the appliance to a tooth surface;

a body extending outwardly from the base, the body defining an arch wire slot extending in a mesial-distal direction across the body;

a hinge structure defining a first reference axis and including an arcuate surface, the structure disposed on the first side of the arch wire slot;

a channel extending between the hinge structure and the base; and

a door coupled to the hinge structure and rotatable about the first reference axis between an open state and a closed state, wherein an arch wire is insertable into the arch wire slot in the open state and the door retains the arch wire in the arch wire slot in the closed state;

wherein the door is generally C-shaped and includes a compound curvature at a base of the C- shape, the compound curvature including a first radius of curvature and a second radius of curvature, the portion of the door having the second radius of curvature interfering with the arcuate surface of hinge structure to impede rotation of the door between the open state and the closed state,

and wherein a portion of the door is disposed in the channel in both the open state and the closed state.

10. The self-ligating bracket of claim 9, and wherein the door includes a deformable region proximate the portion having the second radius of curvature.

11. The self-ligating bracket of claim 10 and further including a locking mechanism on the hinge structure engaging the door and impeding rotation of the door to the open state when the door is in the closed state, and wherein the deformable region is deformed by the locking mechanism as the door is rotated between the closed state and the open state.

12. The self-ligating bracket of claim 11, wherein the body includes a mesial tie wing and a distal tie wing, and wherein the locking mechanism comprise a surface on the mesial tie wing or the distal tie wing, or surfaces on both the mesial tie wing and the distal tie wing.

13. The self-ligating bracket of claim 9, wherein the body includes rotation stop surfaces proximate the channel on a second side of the archwire slot, and wherein the door engages the rotation stop surfaces in the closed state.

14. The self-ligating bracket of claim 9, wherein body includes a mesial tie wing on a second side of the archwire slot, and wherein the door engages a surface on the underside of a mesial tie wing when the door is in the open state.

15. The self-ligating bracket of claim 9, wherein the arcuate surface has a radius of curvature that is substantially the same as the first radius of curvature of the door.