Patent Publication Number: US-2018042700-A1

Title: Orthodontic bracket and method of correcting malpositioned teeth

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a divisional of U.S. patent application Ser. No. 15/292,794 filed Oct. 13, 2016, which is a continuation of U.S. patent application Ser. No. 14/682,453, filed Apr. 9, 2015, which is a continuation of U.S. patent application Ser. No. 12/689,145, now U.S. Pat. No. 9,004,916, filed Jan. 18, 2010, which claims the benefit of U.S. Provisional Patent Application Ser. No. 61/145,345 entitled “ORTHODONTIC BRACKET AND METHOD OF CORRECTING MALPOSITIONED TEETH,” filed on Jan. 16, 2009, the disclosures of which are incorporated by reference herein in their entirety. 
    
    
     BACKGROUND 
     Orthodontic treatment involves the application of mechanical forces to urge improperly positioned teeth into correct alignment. One form of orthodontic treatment includes the use of orthodontic brackets respectively fixed to individual teeth either by bands or, more commonly, fixed into place with adhesive. After the brackets are fixed to the teeth of the upper or lower arch, a resilient archwire is then seated in the archwire slots of the upper or lower brackets. The upper and/or lower teeth may be treated in this manner. The archwire(s) may then be secured in place with respect to each bracket by individual ligature wires or elastic bands. This results in active ligation or, in other words, ligation that forces the archwire to the base surface of the archwire slot. 
     Alternative bracket designs ligate the archwire into position by a movable closure member or cover. Such movable closure members may be permanently, but movably, coupled with the bracket body or may be a separate element non-permanently coupled with the bracket body. These types of archwire slot closure members may ligate the archwire either passively or actively. In passive designs, the closure member does not force the archwire to the base surface of the archwire slot but, instead, allows the archwire, or at least a portion thereof, to be spaced from the base of the archwire slot or from the movable closure member. In contrast, in active ligation, the movable closure member or other ligating element forces the archwire to the base surface of the archwire slot. The movable closure member is opened for inserting the archwire into the slot and then closed for retaining the archwire in the archwire slot. This movable closure member includes, but is not limited to, a ligating slide, a clip, an elastic or resilient cover, etc. Correction occurs as the archwire aligns the teeth to the shape of the archwire. 
     There is a need for an orthodontic bracket that provides consistent rotational control of the tooth and an improved method for controlling rotation of the tooth during treatment. 
     SUMMARY OF THE INVENTION 
     In one aspect, an orthodontic bracket is provided comprising a bracket body adapted to be secured to a tooth. The bracket body includes a mesial end, a distal end, a lingual side, a labial side, and an archwire slot extending generally in a mesial-distal direction. The archwire slot includes a base surface, opposing side walls extending in a labial direction from the base surface and an opening on the labial side opposite the base surface for receiving an archwire. The bracket further comprises a closure member movable between an open position and a closed position. The closure member is coupled to the bracket body in the closed position to retain the archwire in the archwire slot. The closure member includes a lingual side with archwire control structure including first and second projecting portions spaced apart in a mesial-distal direction and a recessed area therebetween. The recessed area and the first and second projecting portions overlie the archwire slot when the closure member is in the closed position, with first projecting portion being proximate the mesial end of the archwire slot and the second projecting portion being proximate the distal end of the archwire slot when the closure member is in the closed position, and at least one of the first or second projecting portions is adapted to contact the archwire when the closure member is in the closed position. 
     The closure member may further comprise various structures such as a slide member, a clip, a resilient closure, a pivoting member, etc. The recessed area and the first and second projecting portions may also take many forms. As examples, these elements of the closure member may generally form a generally rectangular cross sectional shape when viewed in an occlusal-gingival direction. Optionally, the recessed area may include a flat surface or a surface curved in a mesial-distal direction. The recessed surface and first and second projecting portions together define a radius of curvature that is less than the radius of curvature of the archwire portion that is seated in the associated slot of that bracket. This will ensure that the archwire contacts the first and/or second projecting portions instead of the recessed surface thereby resulting in a larger moment arm and better rotational control of the bracket with the force applied by the archwire. 
     More specifically, the lingual side or surface of the closure member can include a recess overlying the archwire slot when the closure member is in the closed position and the recess can have mesial and distal edges. At least one of the mesial edge or distal edge is adapted to contact the archwire when the closure member is in the closed position. 
     In another embodiment, the recessed area is defined by a mesial side wall, a distal side wall, and a surface therebetween. The surface is configured such that the archwire does not contact the surface when the clip is in the closed position and when the archwire is in contact with one or both of the mesial and distal projecting portions. 
     In another aspect, an orthodontic bracket is provided comprising a bracket body adapted to be secured to a tooth and a clip movable between an open position and a closed position. The bracket body includes a mesial end, a distal end, a lingual side, a labial side, an occlusal side, a gingival side, an occlusal-gingival slot extending generally from the occlusal side to the gingival side, and an archwire slot extending generally from the mesial end to the distal end. The archwire slot includes a base surface, opposing side walls extending in a labial direction from the base surface, and an opening on the labial side opposite the base surface for receiving an archwire. 
     The clip is coupled to the bracket body in the closed position to retain the archwire in the archwire slot. The clip includes a lingual leg and a labial leg connected by a lateral section and has a generally U-shaped cross section. The lingual leg is configured to slidably cooperate with the occlusal-gingival slot. The labial leg has a lingual side with archwire control structure that includes mesial and distal projecting portions having a recessed area therebetween. The archwire control structure overlies the archwire slot when the clip is in the closed position and at least one of the mesial and distal projecting portions is adapted to contact the archwire when the clip is in the closed position. In one embodiment, the clip is bifurcated. 
     In another embodiment, an orthodontic member is provided for use with an orthodontic bracket that is adapted to be secured to a tooth. The bracket includes a mesial end, a distal end, a lingual side, a labial side, an occlusal side, and a gingival side. The bracket further includes a viewing and an archwire slot that extends generally from the mesial end to the distal end. The archwire slot includes a base surface and gingival and occlusal side walls that extend in a labial direction from the base surface, and an opening on the labial side opposite the base surface that receives an archwire therein. 
     The member includes a main body that is configured to cover at least a portion of the bracket when the orthodontic member is coupled to the bracket. The main body has labial and lingual surface. The lingual surface includes archwire control structure. The archwire control structure includes mesial and distal projecting portions separated by a recessed area. The member further includes an engaging member that extends from the main body and that is configured to engage the tie wing to removably couple the orthodontic member to the bracket. When the archwire is positioned in the archwire slot and the orthodontic member is coupled to the bracket, the mesial and distal projecting portions overlie the archwire slot and are adapted to contact the archwire. 
     A method of correcting malpositioned teeth according to the invention can comprise applying a plurality of orthodontic brackets constructed in one or more of the manners discussed herein to the teeth of a patient. An archwire is then retained in the respective archwire slots of the orthodontic brackets with the ligating members coupled to the bracket such that the archwire contacts at least one of the first or second projecting portions or at least one of the mesial or distal edges, and without contacting another area of the ligating member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, with the general description given above, together with the detailed description given below, serve to explain various aspects of the invention. 
         FIG. 1  is a schematic, cross-sectional view of a bracket body, closure member, and archwire of a conventional bracket and archwire assembly; 
         FIG. 2  is a perspective view of an orthodontic bracket holding an archwire in accordance with one embodiment of the invention; 
         FIG. 3  is a perspective view of a closure member in the illustrative form of a slide, as used in the orthodontic bracket shown in  FIG. 2 ; 
         FIG. 4A  is a cross-sectional view taken along section line  4 A- 4 A of  FIG. 2  that illustrates a position of the archwire in the archwire slot; 
         FIG. 4B  is a cross-sectional view taken along section line  4 - 4  of  FIG. 2  that illustrates a position of an archwire in the archwire slot; 
         FIG. 5  is a cross-sectional view similar to  FIG. 4B  that illustrates a finishing position of the archwire in accordance with the embodiment shown in  FIG. 2 ; 
         FIG. 6  is a perspective view of an orthodontic bracket holding an archwire in accordance with another embodiment of the invention; 
         FIG. 7A  is a perspective view of a closure member in the illustrative form of a U-shaped clip, as used in the bracket shown in  FIG. 6 . 
         FIG. 7B  is a plan view of the bracket of  FIG. 6  that illustrates one location of the U-shaped clip relative to the archwire and bracket body, which is shown in phantom line; 
         FIG. 8  is a cross-sectional view taken along section line  8 - 8  of  FIG. 6  that illustrates a position of an archwire in the archwire slot; 
         FIG. 9  is a cross-sectional view similar to  FIG. 8  that illustrates a finishing position of the archwire in accordance with the embodiment shown in  FIG. 6 ; 
         FIG. 10  is a perspective view of an orthodontic bracket holding an archwire in accordance with another embodiment of the invention; 
         FIG. 11  is a perspective view of a closure member in the illustrative form of a second U-shaped clip, as used in the bracket shown in  FIG. 10 ; 
         FIG. 12  is a cross-sectional view taken along section line  12 - 12  of  FIG. 10  that illustrates a position of an archwire in the archwire slot; 
         FIG. 13  is a plan view of the bracket of  FIG. 10  that illustrates one location of the U-shaped clip relative to the archwire and bracket body, which is shown in phantom line; 
         FIG. 14  is a cross-sectional view similar to  FIG. 12  that illustrates a finishing position of the archwire in accordance with the embodiment shown in  FIG. 10 ; 
         FIG. 15  is a perspective view of a removable ligating member coupled to a bracket for holding an archwire in accordance with another embodiment of the invention; and 
         FIG. 16  is a perspective view of the removable ligating member, as used on the bracket shown in  FIG. 15 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , the manner in which a ligated archwire  10  engages with a typical movable cover or closure member  12  of an orthodontic bracket  14  is depicted. As shown, the archwire  10  is passively ligated. That is, the archwire  10  is not secured to either of the closure member  12  or the bracket  14  and may, consequently, move or bend during treatment. Due to its radius of curvature, especially along anterior teeth, the archwire  10  can develop a point contact  16  with the underside or lingual side  18  of the closure member  12  at the apex  20  of its curvature. Where the archwire  10  also contacts the bracket  14  at the mesial or distal portions of the archwire slot (shown at  22 ), a moment arm  24  is formed. 
     The moment arm  24  allows application of torque  26  to the tooth (not shown) due to the force  28  generated by the archwire  10  contact on the closure member  12  at  16  and on the bracket  14  at  22 . The torque  26  causes the bracket  14 , and therefore the tooth, to rotate into a predetermined position. Unfortunately, this point contact  16  provides minimal control of bracket rotation since the apex  20 , and thus the point contact  16 , can easily shift or move along the lingual side  18  of the closure member  12  during treatment. Consequently, as the apex  20  moves, the moment arm  24  changes length. This in turn causes problems controlling tooth rotation because the torque  26  may change in an unpredictable manner. The practitioner, therefore, has less control over the movement of the tooth. It will be appreciated that a lack of control or limited control of tooth rotation may lead to extended treatment time. 
     With reference to  FIGS. 2 and 3 , in one exemplary embodiment, an orthodontic bracket  30  includes a bracket body  32  configured to be mounted to a tooth (not shown) using any suitable base structure  34  and a suitable ligating or closure member  36 , which in this illustration, is a slide member for captivating an archwire  38  within an archwire slot  40 . The closure member  36  is coupled to the bracket body  32  and in the closed position, retains the archwire  38  in the archwire slot  40 . 
     According to embodiments of the invention, the closure member  36  is designed with archwire control structure  72 , described below, that provides predictable, consistent contact between the archwire  38  and the orthodontic bracket  30 . In this regard, the archwire control structure limits contact between the archwire  38  and the closure member  36  to specific locations. Further, the specific locations may be predetermined and during treatment may not shift. By way of example, the archwire control structure may provide two-point contact between the orthodontic bracket  30  and the archwire  38 . The archwire  38  may contact both the bracket body  32  and the closure member  36 . In another configuration, two-point contact may occur at two locations on the closure member  36 . In one exemplary embodiment, the archwire control structure limits contact between the archwire  38  and the closure member  36  to one or two predetermined locations. In addition, three- and four-point contact between the archwire  38  and the orthodontic bracket  30  is also contemplated. 
     To that end, the orthodontic bracket  30 , unless otherwise indicated, is described herein using a reference frame with the orthodontic bracket  30  attached to a labial surface of a tooth on the upper jaw. Consequently, as used herein, terms such as labial, lingual, mesial, distal, occlusal, and gingival used to describe the bracket  30  are relative to the chosen reference frame. The embodiments of the invention, however, are not limited to the chosen reference frame and descriptive terms, as the orthodontic bracket  30  may be used on other teeth and in other orientations within the oral cavity. For example, the bracket  30  may also be located on an anterior tooth in the lower jaw or maxilla and be within the scope of the invention. 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 invention is intended to be independent of location and orientation within the oral cavity and the relative terms used to describe embodiments of the invention are to merely provide a clear description in conjunction with the drawings. As such, the relative terms labial, lingual, mesial, distal, occlusal, and gingival in no way limit the invention to a particular location or orientation. 
     Accordingly, and with reference to the bracket body  32  shown in  FIG. 2 , when the bracket body  32  is mounted to the labial surface of a tooth carried on the patient&#39;s upper jaw, the bracket body  32  has a lingual side  42 , a labial side  44 , an occlusal side  46 , a gingival side  48 , a mesial end  50 , and a distal end  52 . The archwire slot  40  extends generally in a mesial-distal direction, such as from the mesial end  50  to the distal end  52 . The archwire slot  40  includes a base surface  54 , opposing side walls  56 ,  58  extending in a labial direction from the base surface  54  and an opening  60  on the labial side  44  opposite the base surface  54  for receiving the archwire  38 . The lingual side  42  of the bracket body  32  is configured to be secured to a tooth in any conventional manner, including for example, by an appropriate orthodontic cement or adhesive or by a band around an adjacent tooth (not shown). 
     The bracket body  32  may further include one or more tie wings. As shown best in  FIG. 2 , in one embodiment, the bracket body  32  may be formed with two occlusal tie wings  62   a ,  62   b  projecting from the occlusal side  46  and two gingival tie wings  62   c ,  62   d  projecting from the gingival side  48 . The tie wings  62   a - 62   d  permit coupling of other orthodontic elements such as, ligatures, power chains, among others, to the bracket body  32 . While tie wings are shown and described, embodiments of the invention are not so limited, as it will be appreciated that embodiments of the invention may or may not have one or more tie wings  62   a - 62   d.    
     Additionally, as shown in  FIG. 2 , the bracket body  32  may further include a horizontal slot  64  generally aligned parallel to the archwire slot  40  and configured for receiving temporary attachment devices, for example, a removable hook (not shown). The horizontal slot  64  may extend from the mesial end  50  to the distal end  52  of the bracket body  32  to form one continuous horizontal slot. 
     With reference to  FIGS. 2 and 3 , the closure member  36  has a labial surface  66  and a lingual surface  68 . As shown in  FIG. 3 , the lingual surface  68  of closure member  36  includes a retaining slot  70  that extends generally in the gingival-occlusal direction (e.g., in the direction of movement of closure member  36 ). A spring pin (not shown) in the bracket body  32  is received in retaining slot  70 . Additional details of the retaining slot  70  and spring pin can be found in co-owned U.S. application Ser. No. 12/147,877, the disclosure of which is incorporated by reference herein in its entirety. The closure member  36  may, therefore, be slid from an open position to a closed position without unintentional removal of the closure member  36  from bracket body  32 . However, other means for retaining the closure member  36  are known in the art and, as such, embodiments of the invention are not limited to those having a retaining slot/spring pin securing mechanism. 
     With reference to  FIG. 3 , in one embodiment, the lingual surface  68  of the closure member  36  is designed with archwire control structure, generally designated  72 . In the embodiment depicted in  FIGS. 3 and 4A , the archwire control structure  72  may include mesial and distal projecting portions  74 ,  76  or edges spaced apart in a mesial-distal direction with a recess or a recessed area  78  therebetween. The recessed area  78  may be defined by mesial, distal, and occlusal side walls  80 ,  82 ,  84  to define a rectangular shaped recessed area  78 . The recessed area  78  may also be defined by a recessed surface  86  that is inset or recessed into the lingual surface  68  or offset in the labial direction from the lingual surface  68 . Thus, the recessed area  78  may be a blind recessed area in the lingual surface  68  of the closure member  36 . However, the recessed area  78  may include a through-hole, cutout, or opening that extends through the closure member  36  from the lingual surface  68  to the labial surface  66  thereof. 
     Accordingly, as shown in  FIG. 4A , when the closure member  36  is in the closed or ligating position, the archwire control structure  72 , opposing side walls  56 ,  58  and base surface  54  of the archwire slot  40  form a four-sided boundary to retain the archwire  38  in the archwire slot  40 . As is known, the archwire  38  may have cross-sectional dimensions that are generally less than the corresponding cross-sectional dimensions of the four-sided boundary, as shown. In this way, the archwire  38  is not tightly restrained by the closure member  36  in the archwire slot  40 . Due to the relative size difference, the archwire  38  may bend and/or move in the archwire slot  40  relative to the orthodontic bracket  30 . 
     In particular, when the closure member  36  is in the closed position, the projecting portions  74 ,  76  with recessed area  78  are positioned labially of the archwire slot  40  and form the labial boundary thereof. Thus, movement of the archwire  38  may cause the archwire  38  to contact one or both of projecting portions  74 ,  76 . Since the projecting portions  74 ,  76  form the labial boundary, the archwire  38  may not contact another portion of the closure member  36  during treatment. 
     Further in this regard, and as shown in  FIG. 4A , the occlusal side wall  84  of the recessed area  78  may reside in the plane of opposing side wall  56 , as shown, or may be positioned occlusally thereof (labeled  84 ′). Thus, when the archwire  38  contacts the closure member  36 , it will not contact any portion of the closure member  36  other than one or both of the projecting portions  74 ,  76 . In other words, the recessed area  78  encompasses the labial boundary between the projecting portions  74 ,  76 . 
     Accordingly, due to the archwire control structure  72 , the rotational forces may be predetermined and controlled to a greater extent because the moment arm formed thereby may be both larger and more consistent throughout orthodontic treatment. By way of example and as illustrated in  FIG. 4B , the archwire  38  may be oriented such that it contacts both the bracket body  32  and the projecting portion  74 , thereby forming a moment arm  88  defined by the distance between the contact points. As shown, with the archwire  38  in this orientation, a force  90  generated by the archwire  38  may produce a torque  92 , due to the moment arm  88 , to rotate the bracket  30  (and tooth) into the desired position. By way of comparison with the bracket  14  shown in  FIG. 1 , the moment arm  88  may be at least as large as the moment arm  24  for equivalent bracket dimensions. In addition, with reference to  FIG. 4B , since the contact points between the archwire  38  and the bracket  30  are relatively constant, as the contact points on the closure member  36  (i.e., on the archwire control structure  72 ) remain consistent during treatment, the moment arm  88  remains relatively consistent compared to the moment arm  24  of  FIG. 1 , as described above. 
     With regard to consistency of the contact points, according to embodiments of the invention, the contact points between the bracket body  32  and the closure member  36  may not substantially shift as treatment progresses. Accordingly, the moment arm and thus the torque applied to the tooth are more consistent. Thus, the rotational forces are more predictable. By way of example, with reference to  FIGS. 2 and 4B , the archwire  38  may be oriented in a non-parallel manner relative to the archwire slot  40 . During treatment, where the archwire  38  bends, due to movement of the bracket  30 , such that an apex (not shown) of the bend forms between the projecting portions  74 ,  76 , and within the recessed area  78 , the apex does not contact another location. That is, the archwire  38  does not contact the surface  86 . Therefore, no forces develop between the surface  86  and the archwire  38  that would lead to an unpredictable moment arm. Rather, the archwire  38  remains in contact with one of the projecting portions  74 ,  76  and the moment arm  88  may remain substantially constant until the bracket  30  moves to an orientation where the archwire  38  does not contact the closure member  36 . At this point, the archwire  38  may be substantially aligned with the archwire slot  40 . While the embodiment shown illustrates the archwire  38  contacting the projecting portion  74  and the archwire slot  40  on the base surface  54  at the distal end  52  thereof, it will be appreciated that the orientation of the archwire  38  may be reversed. For example, the archwire  38  may have an orientation whereby contact occurs at the projecting portion  76  and at the mesial end  50  of the base surface  54 . Such a configuration will provide the benefits and advantages as described above related to a more consistent moment arm and torque, but provide rotation in a direction opposite to that described above. 
     In the finished state, as shown in  FIG. 5 , the archwire  38  may make two points of contact on the archwire control structure  72 . By way of example, the archwire  38  makes contact with each of the projecting portions  74 ,  76 . Near the end of treatment, this configuration mimics the fine rotation control provided by traditional methods of ligation, such as ligating an archwire to a bracket with traditional ligatures, and thereby improves finishing in clinical cases. It will be appreciated that for the anterior section of lower and upper jaws, the flat occlusal edges of the incisor teeth magnify distortions in rotation such that fine control is desired and fine control may be provided according to embodiments of the present invention. 
     Given that the archwire-closure member contact points are limited to specific, predetermined locations in the embodiments shown, e.g., the projecting portions  74 ,  76 , the clinician may be more likely to be able to assess the clinical result of a change in treatment for a given orthodontic bracket, archwire, and tooth orientation or may be able to effect a certain rotational motion more quickly. Furthermore, the moment arm formed by contact between the archwire and the archwire control structure may be maximized to rotate the bracket  30  and tooth in more efficient and optimal manner. 
     Various modifications may be made to the archwire control structure  72  in accordance with the description set forth above. For example, the desired contact locations between the archwire  38  and the closure member  36  may be adjusted to allow for a particular torque or to allow use of archwires of differing dimension. In this regard, the depth of the recessed area  78  may be changed to accommodate changes in the bracket and/or archwire dimensions. In one embodiment, the recessed area  78  has minimum depth such that the apex or deepest central point thereof together with the projecting portions  74 ,  76  on the mesial and distal ends thereof form or define a radius of curvature, r 1 , that is less than the radius of curvature, R 1 , of the archwire  38 . Further in this regard, to change the radius of curvature, r 1 , it will be appreciated that while the surface  86  is depicted as a near-planar surface having side walls  80 ,  82 ,  84 , embodiments in accordance with aspects of the invention are not so limited. By way of example, the surface  86  may be a generally non-planar surface, such as a uniform arc (labeled  86 ′ in  FIG. 4B ) that extends from the mesial to the distal sides of the closure member  36  with or without side walls  80 ,  82 ,  84 . The radius of curvature, r 1 , may then be defined by the configuration of the arc. By way of additional example, the radius of curvature, r 1 , may also be defined by other regular and/or irregular-shaped recessed areas. It will be appreciated that, regardless of the shape of the recess, the concepts employed and features described remain similar. 
     Additionally, to change the magnitude of the moment arm  88 , the recessed area  78  may be extended to cover a larger portion of the lingual surface  68  of the closure member  36 . It will be appreciated that moving the projecting portions  74 ,  76  apart in the mesial-distal direction may further improve the length of the moment arm  88 . Maximizing the distance between the two points of contact (e.g., one on the base surface  54  of the archwire slot  40  and the other on the lingual surface  68  of the closure member  36 ), maximizes the moment arm  88  and, consequently, maximizes the torque for a given force. Accordingly, smaller forces may be used to provide the same amount of torque. In one embodiment, the recessed area  78  extends a sufficient dimension along the lingual surface  68  such that projecting portions  74 ,  76  reside on the mesial-most and distal-most edges of the closure member  36 . In this case, the projecting portions  74 ,  76  may each appear to be pointed edges oriented toward the archwire slot  40 . 
     In another embodiment in accordance with aspects of the invention and with reference to  FIGS. 6-9 , in which like reference numerals refer to like features, an orthodontic bracket  100  similar to those illustrated in  FIGS. 2-5  is depicted. With reference specifically to  FIG. 6 , the orthodontic bracket  100  has a bracket body  102  having an occlusal-gingival slot  104  positioned lingually of the archwire slot  40  and a ligating member, closure member, or a U-shaped clip  106  for sliding movement in the occlusal-gingival direction within slot  104  for retaining/releasing the archwire  38  from the archwire slot  40 . 
     Referring to  FIGS. 6 and 7 , the clip  106  captivates the archwire  38  within the archwire slot  40  when it is in a closed position. The clip  106  moves within the occlusal-gingival slot  104  from an open position to allow the archwire  38  to be removed from the archwire slot  40  to a closed position (as shown in  FIG. 6 ). The clip  106  includes archwire control structure  108  (described in more detail below) that provides predictable, consistent contact between the archwire  38  and the orthodontic bracket  100  similar to that described above. 
     With reference to  FIG. 7 , the clip  106  may be generally U-shaped and may be made from a resilient, flat spring material, such as a cobalt-chrome (Co—Cr) alloy, nickel-titanium (Ni—Ti) alloy, other shape memory alloys, or another suitable material. The clip  106  may be formed from a single sheet of the material and thus the through-thickness of the clip  106  may be uniform. However, it will be appreciated that the clip  106  need not be uniform in thickness depending on, for example, the bracket design and the material from which the clip  106  is made, among other factors. 
     In one embodiment, the clip  106  has a lingual leg  110  and a labial leg  112  that are connected by a generally lateral section  114 . The lingual leg  110  may be of a generally uniform thickness that fits within the occlusal-gingival slot  104  (as shown in  FIG. 6 ). The lingual leg  110  may include a tab  116  that projects from the labial surface thereof generally toward the lateral section  114  or otherwise provides a discontinuity in the overall thickness of the lingual leg  110 . Where the lingual leg  110  extends through the occlusal-gingival slot  104 , the clip  106  resists unintentional removal because tab  116  may abut a portion of the gingival side  48  of the orthodontic bracket  100  once the clip  106  is moved to the open position. Alternatively, the tab  116  may abut the surface  56  of the archwire slot  40  when in the open position and thereby resist removal of the clip  106  from the bracket body  32 . 
     The lateral section  114  may form a generally smooth arc, as shown, and may cooperate with a portion the occlusal side  46  and/or labial side  44  of the bracket body  102  and may, for example, reside in a channel  115  between the two occlusal tie wings  62   a ,  62   b . The channel  115 , in cooperation with other portions of the bracket  100 , such as the slot  104 , may stabilize mesial-distal movement of the clip  106  when contacted by the archwire  38 . The resilient properties of the clip  106 , particularly of the lateral section  114 , together with the configuration of the lateral section  114  may provide spring-like clamping forces on the bracket body  102  along the occlusal and labial surfaces thereof to resist unintentional movement of the clip  106  in such a way as to expose the archwire slot  40 . 
     With reference to  FIGS. 7A and 7B , the labial leg  112  is oriented in a direction generally in the gingival direction at an angle to the lingual leg  110 . The labial leg  112  has a lingual surface  118  that projects labially over the archwire slot  40  when the clip  106  is in the closed position and a labial surface  120 . In addition, the labial leg  112  may widen relative to the lingual leg  110  and/or lateral section  114 , as shown, and may extend the mesial-distal dimension of the archwire slot  40 , though the width of the labial leg  112  may be less or more than the length of the archwire slot  40 . 
     In one embodiment and with reference to  FIGS. 7A and 8 , the labial leg  112  includes archwire control structure  108  that may include mesial and distal projections or wings  128 ,  130  that extend mesially and distally, respectively, from the labial leg  112 . In addition, each of the mesial wing  128  and the distal wing  130  has a tip  132 ,  134  that may extend generally lingually therefrom to form a mesial projecting portion  138  and a distal projecting portion  140 , respectively. 
     As shown in  FIG. 8 , the tips  132 ,  134  may be oriented toward the lingual leg  110  such the labial leg  112  may be generally curved in the form of an arc that is convex in the labial direction. By way of example, the labial leg  112  may be curved in the mesial-distal direction over the archwire slot  40 , the curve or arc may extend from the mesial projecting portion  138  to the distal projecting portion  140 . In one embodiment, the curved form of the clip  106  may be made by bending a flat spring metal such that the clip  106  has a permanent curvature in the mesial-distal direction in the labial leg  112  thereof. 
     With continued reference to  FIG. 8 , the curvature defined by the orientation of the mesial and distal wings  128 ,  130  and tips  132 ,  134  forms a recessed area  136  with projecting portions  138 ,  140  being spaced apart in the mesial-distal direction over the archwire slot  40 . The recessed area  136  may be defined by a recessed surface  146  that is formed by curvature of the lingual surface  118  of the labial leg  112 . As with projecting portions  74 ,  76  of the embodiment shown in  FIGS. 2-5 , the projecting portions  138 ,  140  with recessed area  136  are positioned labially of the archwire slot  40  and form the labial boundary thereof to restrain or limit movement of the archwire  38  beyond a certain amount in the labial direction. In other words, the archwire  38  may move mesially or distally but only a limited direction in any of the gingival, occlusal, lingual, or labial directions, with the projecting portions  138 ,  140  limiting the movement in the labial direction. However, the recessed area  136  may include a through-hole, cutout, or opening that extends through the clip, as shown in the exemplary embodiment of  FIG. 11 , for example. 
     Since the archwire control structure  108  forms the labial boundary, the archwire  38  may not contact any other portion of the clip  106  during orthodontic treatment. In other words, and in the embodiment shown, the archwire  38  may contact only one or both of the projecting portions  138 ,  140  of the clip  106 . 
     The archwire control structure  108 , similar to the archwire control structure  72 , described above, may provide more consistent contact points between the archwire  38  and the bracket  100  during orthodontic treatment. With reference to  FIGS. 8 and 9 , the archwire  38  may be oriented in a non-parallel manner relative to the archwire slot  40 . By way of example, the archwire  38  may be oriented such that it contacts both the bracket body  102  and the clip  106  thereby forming the moment arm  148 , which is defined by the distance between the two contact points. For example, the archwire  38  may contact the distal end  52  of the bracket body  102  at  150  and the projecting portion  138  at  152 . As illustrated in  FIG. 8 , a force  154  having moment arm  148  produces a torque  156  to rotate the bracket  100  (and tooth) into the desired position. By way of comparison with the bracket  14  shown in  FIG. 1 , the moment arm  148  may be at least as large as the moment arm  24  for equivalent bracket dimensions. In any event, in one embodiment and with reference to  FIG. 8 , since the contact points between the archwire  38  and the bracket  100  are relatively constant, the moment arm  148  remains relatively consistent compared to the moment arm  24  of  FIG. 1 . 
     Furthermore, according to embodiments of the invention, the two-point contact configuration shown in  FIG. 8  between archwire  38  and both of the bracket body  102  and the clip  106  may not substantially shift as treatment progresses. Therefore, no forces may develop other than at one or both of the projecting portions  138 ,  140 . While the embodiment shown illustrates the archwire  38  contacting the projecting portion  138  and the archwire slot  40  on the base surface  54  at the distal end  52  thereof, it will be appreciated that the orientation of the archwire  38  may be reversed. For example, the archwire  38  may have an orientation whereby contact occurs at the projecting portion  140  and the mesial end  50  of the base surface  54 . Therefore, the moment arm  148  may remain substantially constant until the bracket body  102  moves to an orientation where the archwire  38  does not contact the clip  106 . In this situation, the archwire  38  may be substantially aligned with the archwire slot  40 . 
     As shown in  FIG. 9 , the archwire  38  may make two points or locations of contact with the bracket  100 , for example, two-point contact may include contact at  158  and  160  between the archwire  38  and the archwire control structure  108 . In particular, the archwire  38  makes contact with each of the projecting portions  138 ,  140 . To provide the desired contact locations between the archwire  38  and the clip  106 , for example, at both projecting portions  138 ,  140 , the shape of the recessed area  136  may be changed to accommodate changes in the bracket and/or archwire dimensions. In one embodiment, as shown in  FIG. 9 , the recessed area  136  has minimum curvature such that the apex thereof or deepest central point in combination with the projecting portions  138 ,  140  form or define a radius of curvature, r 2 , that is less than the radius of curvature, R 2 , of the archwire  38 . In this regard, the radius of curvature, r 2 , may decrease by increasing the depth of the recessed area  136 . Other configurations of the recessed area  136  may produce similar results, for example, the recessed area  136  may be defined by other regular and irregular-shaped recessed areas that define a radius of curvature that is less than the radius of curvature, R 2 , of the archwire  38 . 
     Various additional or alternative modifications may be made to the archwire control structure  108  in accordance with the description set forth above. For example, the dimensions of the clip  106 , particularly the distance between the projecting portions  138 ,  140  may affect the length of the moment arm  148 . Maximizing the distance between the two points of contact, maximizes the moment arm  148  and, consequently, maximizes the torque available to rotate the tooth. The length of the moment arm  148  may be increased by increasing the width of the labial leg  112 , and particularly increasing the distance between the projecting portions  138 ,  140 ; by increasing the overall width of the labial leg  112 ; by increasing the size of the wings  128 ,  130 ; or by changing the orientation between the wings  128 ,  130  and tips  132 ,  134 . In one embodiment, the projecting portions  138 ,  140  approach or are proximate the respective mesial distal sides of the archwire slot  40 . 
     Additionally, the recessed area  136  may form a rectangular shape such that the tips  132 ,  134  are nearly perpendicular to the archwire slot  40 . In addition, the recessed area  136  is sufficiently deep for a given archwire and archwire slot dimension such that the apex of the archwire  38  may not reach the surface  146  or contact another portion of the clip  106  during orthodontic treatment. However, even where the apex in the archwire  38  may shift, possibly due to movement of the teeth, the two-point contact between the archwire and the clip  106  shown in  FIG. 8  may not change. 
     The labial leg  112  may further include an extension  122  that extends generally in the same direction as the lingual leg  110 . The extension  122  fits within a retention slot formed  124  by a labial stop  126  (shown in  FIG. 6 ) that extends between tie wings  62   c ,  62   d . The extension  122  may be narrower, the same width, or wider than the lingual leg  110  or labial leg  112  or the lateral section  114 . When the clip  106  is in the closed position, the extension  122  may also stabilize the clip  106  against mesial-distal movement when in contact with the archwire  38 . Furthermore, the extension  122  may contact the labial stop  126  to substantially prevent the clip  106  from unintentionally releasing the archwire  38 . In this way, the extension  122  may further stabilize the contact locations between the archwire control structure  108  and the archwire  38  when the archwire  38  is in a non-parallel orientation with respect to the archwire slot  40 . Labial movement of the archwire  38  may be further limited by the extension  122  such that the contact points between the archwire  38  and projecting portions  138 ,  140  are more consistent because the clip  106  may not significantly flex or distort. While  FIGS. 6 and 7  depict the clip  106  as including extension  122 , it will be appreciated that clip  106  need not have extension  122  and be designed to not substantially flex or distort under the loads that may be experienced during use of the clip  106 . 
     In another embodiment of the invention shown in  FIGS. 10-14 , in which like reference numerals refer to like features of  FIGS. 6-9 , the orthodontic bracket  200  is similar to the bracket  100  illustrated in  FIGS. 6-9 . With reference specifically to  FIG. 10 , the orthodontic bracket  200  includes a bracket body  202  and a ligating or closure member which in this illustration is a U-shaped clip  204  for sliding movement in the occlusal-gingival direction within slot  104 . 
     The clip  204  is similar in some respects to clip  106  depicted in  FIG. 7 . Accordingly, as shown in  FIG. 10 , the clip  204  captivates the archwire  38  within the archwire slot  40  when it is in a closed position. The clip  204  moves within the occlusal-gingival slot  104  to an open position to allow the archwire  38  to be removed from the archwire slot  40 . 
     The clip  204  includes archwire control structure  206  (described in more detail below) that provides more predictable, consistent contact between the archwire  38  and the orthodontic bracket  200 . In this regard, the archwire control structure  206  limits contact between the archwire  38  and the clip  204  to specific locations. Further, the specific locations may be predetermined and may not substantially shift during orthodontic treatment. By way of example, the archwire control structure  206  may provide two-point contact between the orthodontic bracket  200  and the archwire  38 . In this case, the archwire  38  may contact both the bracket body  202  at one location and the clip  204  at one location. Specifically, the contact points may include a contact point on the archwire control structure  206  and one at the mesial end  50  or distal end  52  of the base surface  54  of the archwire slot  40 . In one embodiment, the archwire control structure  206  limits contact between the archwire  38  and the clip  204  to one or two predetermined locations. Two-point contact may also include contact between the archwire  38  and two locations on the archwire control structure  206 . That is, the archwire  38  does not contact the bracket body  202 . In addition, three- and four-point contact between the archwire  38  and the orthodontic bracket  200  is also contemplated according to embodiments of the present invention. 
     With reference to  FIG. 11 , the clip  204  may be generally U-shaped and may be made from a single sheet of a resilient, spring material, such as a suitable metal. The metal may be cobalt-chrome (Co—Cr) alloy, nickel-titanium (Ni—Ti) alloy, other shape memory alloys, or other suitable material. Thus, the through-thickness of the clip  204  may be uniform. The clip  204  may be formed by bending the flat spring metal to have the U-shape. However, it will be appreciated that the clip  204  need not be uniform in thickness depending on, for example, the bracket design and the material from which the clip  204  is made, among other factors. In one embodiment, the clip  204  is made from a flat spring metal. 
     In the exemplary embodiment shown in  FIG. 11 , the clip  204  has a lingual leg  208  and a labial leg  210  that are connected by a lateral section  212 . The lingual leg  208  is generally uniform in thickness and fits within the occlusal-gingival slot  104 . The lingual leg  208  may include a tab  216  that functions similar to tab  116  shown in  FIG. 7 . 
     The lateral section  212  may form a generally smooth arc, as shown, and may cooperate with a portion of the occlusal side  46  and/or labial side  44  of the bracket body  202 . In one embodiment, the resilient properties of the clip  204  together with the configuration of the lateral section  212  may provide spring-like clamping forces that improve friction between the clip  204  and the bracket body  202  along a portion of the occlusal and labial surfaces thereof to resist unintentional movement of the clip  204  in such a way as to expose the archwire slot  40 . 
     In one embodiment, the clip  204  may be formed such that the labial leg  210  projects gingivally from the lateral section  212  to form a U-shaped cross section. In this configuration, the labial surface  218  forms a portion of the labial side  44  of the bracket  200 , though embodiments of the present invention are not so limited, as a portion of the labial leg  210  and/or the lateral section  212  may extend through a slot or other recess formed in the bracket body  202  on the occlusal side  46  thereof. Furthermore, the lingual surface  220  of the labial leg  210  projects labially over the archwire slot  40  when the clip  204  is in the closed position, as shown in  FIG. 13 , and forms the labial boundary thereof. 
     In the exemplary embodiment illustrated in  FIGS. 10-14 , the labial leg  210  includes a mesial portion  222  and a distal portion  224 . Rather than a recessed area between the mesial portion  222  and distal portion  224 , the mesial and distal portions  222 ,  224  may define a generally U-shaped cutout  230  such that labial leg  210  appears bifurcated, i.e., the clip  204  may be a so-called bifurcated clip. The cutout may have a depth D from the end of the mesial and distal portions  222 ,  224  to the apex of the cutout  230  that is greater than the occlusal-gingival dimension of the archwire slot  40 . It will be appreciated, however, that the mesial and distal portions  222 ,  224  may define other configurations, such as a rectangular notch, having a similar depth D. 
     In addition, as shown best in  FIGS. 11 and 13 , the labial leg  210  may widen relative to the lingual leg  208  and lateral section  212 . In this regard, the mesial portion  222  and distal portion  224  of the labial leg  210  may be spaced apart in the mesial-distal direction along the archwire slot  40 . Specifically, the mesial-distal dimension from the mesial edge of mesial portion  222  to the distal edge of distal portion  224  may be greater than the width of the lateral section  212  and/or the lingual leg  208 . However, the maximum mesial-distal dimension of the labial leg  210  may be less or more than the dimension of the archwire slot  40 . In one embodiment, the maximum width of the labial leg  210  may extend the full width of the mesial-distal dimension of the archwire slot  40  or be proximate thereto. 
     As shown in  FIGS. 11, 12, and 13 , in one embodiment, the labial leg  210  includes archwire control structure  206 . The archwire control structure  206  may include mesial and distal lingual surfaces  232   a ,  232   b  of mesial portion  222  and distal portion  224 , respectively. As with projecting portions  74 ,  76  and projecting portions  138 ,  140 , described above, the mesial and distal lingual surfaces  232   a ,  232   b  are positioned labially of the archwire slot  40  when the clip  204  is in the closed position. The surfaces  232   a  and  232   b  form the labial boundary of the archwire slot  40  to restrain or limit movement of the archwire  38  beyond a certain amount in the labial direction. In one embodiment, the archwire  38  may not contact another portion of the clip  204  during orthodontic treatment. In other words, and in the embodiment shown, the archwire control structure  206  limits contact between the archwire  38  and clip  204  to one or both of the mesial and distal lingual surfaces  232   a ,  232   b . Since the contact points are limited to two specific, predetermined locations, e.g., the mesial and distal lingual surfaces  232   a ,  232   b , the clinician may be more likely to be able to assess the clinical result of a change in treatment for a given orthodontic bracket, archwire, and tooth orientation. Furthermore, as set forth in more detail below, a moment arm is formed by contact between the archwire  38  and the archwire control structure  206  and the archwire  38  and the bracket body  202  are more consistent over the course of treatment. 
     By way of example and with reference to  FIG. 12 , the archwire  38  may be oriented in a non-parallel manner relative to the archwire slot  40  such that it contacts both the bracket body  202  and the archwire control structure  206  of the clip  204 . This orientation forms a moment arm  236  defined by the distance between the two contact points. Specifically, the archwire  38  may contact the bracket body  202  at the base surface  54  at location  238  of the archwire slot  40  and the mesial lingual surface  232   a  at location  240  of the archwire control structure  206  to form moment arm  236 . Where the archwire  38  exerts a force  244  having moment arm  236 , a torque  246  is created to rotate the bracket  200  and tooth. 
     Furthermore, according to embodiments of the invention, the two-point contact configuration shown in  FIGS. 12 and 13  between the bracket body  202  and the clip  204  may not shift as orthodontic treatment progresses even though the archwire may move or bend within the archwire slot  40 . For example, during treatment, where the archwire  38  bends such that an apex (not shown) of the bend forms between the mesial portion  222  and distal portion  224  of the labial leg  210 , i.e., in the cutout  230 , the archwire  38  does not contact the clip  204  other than at one or both of the mesial and distal lingual surfaces  232   a ,  232   b . Because the archwire control structure  206  limits contact to two locations on the clip  204 , the moment arm  236  may not change significantly during treatment. Thus, adjustments to the force  244 , for example, by changing the archwire  38 , may produce more predictable rotational movement of the bracket  200 . While the embodiment shown illustrates the archwire  38  contacting the mesial lingual surface  232   a  and the archwire slot  40  on the base surface  54  at the distal end  52  thereof, it will be appreciated that the orientation of the archwire  38  may be reversed. For example, the archwire  38  may have an orientation whereby contact occurs at the distal lingual surface  232   b  and the mesial end  50  of the base surface  54 . 
     In view of the above and with reference to  FIG. 13 , various configurations of the archwire control structure  206  may be used to control the contact points. For example, the depth D of the cutout  230  may be sufficient to prevent contact between the archwire  38  and surfaces other than the surfaces  232   a  and  232   b . That is, the cutout  230  may be sufficient to allow a bend or apex of the archwire  38  to pass between the mesial and distal portions  222 ,  224  should a bend develop during treatment. In particular, in one embodiment, the depth D of the cutout  230  is sufficient to position the apex  242  of the cutout  230  in the plane of opposing side wall  56 , or gingivally thereof, as shown, for a given archwire and archwire slot dimensions. However, the depth D may depend on the shape of the lateral section  212  and the labial leg  210 . In any case, even where the apex in the archwire  38  may shift, possibly due to movement of the teeth or installation of the archwire  38 , the two-point contact between the archwire  38  and the clip  204 , as shown in  FIGS. 12 and 13 , may not significantly change. Therefore, the moment arm  236  may remain substantially constant until the bracket  200  moves to an orientation where the moment arm  236  ceases to exist, i.e., when the tooth reaches the selected position. 
     Additionally, changes to the moment arm  236  may be selected by changing the configuration of the mesial and distal portions  222 ,  224 . For example, while the mesial and distal portions  222 ,  224  are shown to have an axis of symmetry about the longitudinal axis of the clip  204  (i.e., a symmetrical bifurcation), the embodiments of the invention are not so limited. Accordingly, the positions of the mesial and distal portions  222 ,  224  may not be equally spaced relative to the mesial-distal dimension of the archwire slot  40 . Similarly, the mesial and distal portions  222 ,  224  may vary in width relative to one another and change the moment arm  236 . By way of additional example, by increasing the width of the labial leg  210  and particularly the distance between the mesial and distal portions  222 ,  224 ; by increasing the overall mesial-distal width of the labial leg  210 ; or by decreasing the individual size of one or both of the mesial and distal portions  222 ,  224 , the length of the moment arm  236  may be increased. In other words, the dimensions of the clip  204 , particularly the distance between mesial and distal lingual surfaces  232   a ,  232   b  may affect the length of the moment arm  236 . 
     It will be appreciated that maximizing the distance between the two points of contact (e.g., between contact on the base surface  54  of the archwire slot  40  and contact on the archwire control structure  206  of the clip  204 ), maximizes the moment arm  236  and, consequently, maximizes rotation control. It will be further appreciated that with a consistently larger moment arm, smaller forces may generate an equivalent amount of torque. By way of comparison with the bracket  14  shown in  FIG. 1 , the moment arm  236  of the embodiment shown in  FIG. 10  may be at least as large as the moment arm  24  for equivalent bracket dimensions. In addition, with reference to  FIG. 12 , since the contact locations, (e.g. at  238  and  240 ) between the archwire  38  and the bracket  200  are relatively constant, the moment arm  236  remains relatively consistent compared to the moment arm  24  of  FIG. 1 , as described above. 
     With reference to  FIGS. 10, 11, and 13 , in one embodiment, the mesial and distal portions  222 ,  224  may further include opposing extensions  226 ,  228 , respectively. Opposing extensions  226 ,  228 , extend generally in the same direction as the lingual leg  208  from the mesial and distal portions  222 ,  224 , respectively. The opposing extensions  226 ,  228  may be configured to contact a portion of the bracket body  202  to substantially prevent the clip  204  from unintentionally releasing the archwire  38  during treatment. For example, the opposing extensions  226 ,  228  may fit within mesial and distal retention slots (not shown) formed in the opposing side wall  58  of the archwire slot  40  in the bracket body  202 . In this regard, the opposing extensions  226 ,  228  may further stabilize the contact locations between the archwire control structure  206  and the archwire  38  when the archwire  38  is in a non-parallel orientation with respect to the archwire slot  40 . Furthermore, opposing extensions  226 ,  228  may allow the force  244  at contact to be greater and therefore the torque  246  on the bracket  200  to be greater, to rotate the tooth more quickly. As with the extension  122  of the clip  106  of  FIG. 7 , when the clip  204  is in the closed position, the opposing extensions  226 ,  228  may also stabilize the clip  204  against mesial-distal movement due to sliding contact with the archwire  38 . While  FIGS. 10 and 11  depict the clip  204  as including opposing extensions  226 ,  228 , it will be appreciated that clip  204  need not have opposing extensions  226 ,  228  and be designed to not substantially flex or distort under the loads that may be experienced during use of the clip  204 . 
     As set forth above and shown in  FIG. 14 , the archwire  38  may make two points of contact on the archwire control structure  206 . For example, the archwire  38  may make contact with each of the mesial and distal lingual surfaces  232   a ,  232   b  at locations  248  and  250 . Similar to the previous embodiments, near the end of treatment this configuration may mimic the fine rotation control provided by traditional methods of ligation and thereby improve finishing in clinical cases. 
     To that end, to provide the desired contact locations between the archwire  38  and the clip  204 , the dimensions of the clip  204  may be changed similar to that described above. For example, the distance between the mesial and distal portions  222 ,  224  of the labial leg  210 , may be changed to accommodate changes in the bracket and/or archwire dimensions. In one embodiment, the distance between the mesial and distal portions  222 ,  224  allows the archwire  38  to bend to a minimum curvature. However, unlike the embodiments of the invention described above, the radius of curvature, r 3 , of the clip  204  is not limited by a third location between the mesial and distal portions  222 ,  224  since the cutout  230  is open. Therefore, where an archwire forms an apex between the mesial and distal portions  222 ,  224 , the apex may pass without any contact with another portion of the clip  204 . Thus, the radius of curvature, r 3 , will be smaller than the radius of curvature R 3  of the archwire  38 , as shown in  FIG. 14 . 
     While the above-described exemplary embodiments include orthodontic brackets that are so-called self-ligating brackets, i.e., the bracket includes a moveable closure member, such as a ligating slide or clip, embodiments of the invention are not limited to brackets that are designed with a moveable closure member coupled thereto. In this regard, and by way of example, embodiments of the present invention include a removable ligating member, such as an elastic or resilient cover that is not meant to be permanently coupled to the bracket but is configured to be a separate element selectively coupled to or removed from the bracket. 
     Accordingly, in another embodiment of the invention shown in  FIGS. 15 and 16 , in which like reference numerals refer to like features of  FIGS. 2-14 , an orthodontic member  300 , which, in this illustration, is a removable ligating member or cover, may be secured to a conventional edgewise bracket. By way of example, such members are described (albeit in the context of self-ligating brackets) in commonly-owned, co-pending U.S. application Ser. No. 12/622,090, which is incorporated by reference herein in its entirety. Member  300  may be attached to an edgewise bracket  302  having viewings  311   a - d  and may be made from an elastomeric material or hard plastic, though the member  300  may be made from other suitable materials. 
     As shown in  FIG. 15 , the member  300  is configured to be releasably coupled to the bracket  302  and, when coupled to bracket  302 , captures the archwire  38  within archwire slot  40 . The member  300  includes archwire control structure  304  that provides predictable, consistent contact between the archwire  38  and the member  300 . As with the archwire control structures  72 ,  108 ,  206 , each described above, the archwire control structure  304  may provide two-point contact between the edgewise bracket  302  and the archwire  38  or two-point contact between the archwire  38  and the member  300 . 
     To this end, in one exemplary embodiment shown in  FIGS. 15 and 16 , the member  300  includes a main body  306  having labial and lingual surfaces  308 ,  310 . In one embodiment, the lingual surface  310  includes archwire control structure  304  thereon. By way of example, the archwire control structure  304  may include a first projecting portion  312  and second projecting portion  314  separated by a recessed area  316 . Projecting portions  312 ,  314  are configured similarly to projecting portions  74 ,  76  or projecting portions  138 ,  140 , described above, and have similar functions. Similarly, recessed area  316  is configured similar to the recessed area  78 ,  136 , as well as having similar functions thereof. Accordingly, the recessed area  316  may include a blind recess (as shown) or may include a through-hole or cutout. In one embodiment, the recessed area  316  is defined by a mesial side wall  322 , a distal side wall  324 , an occlusal side wall  326 , and gingival side wall  328  and a recessed surface  330 . The recessed surface  330  being similar to surfaces  86 ,  146  described above. 
     The member  300  also includes an engaging member, such as engaging members  318 ,  320  extending from the main body  306 , which are configured to releasably couple the member  300  with bracket  302 . For example, in one embodiment, the engaging members  318 ,  320  may include a pair of stretchable closed loops. The engaging members  318 ,  320  may be stretched over and secured with the viewings  311   a - d . It will be appreciated that the member  300  or a portion thereof may not protrude into the archwire slot  40 . 
     When secured to the bracket  302 , a portion of the lingual surface  308  of the main body  306  extends over the archwire slot  40 , as shown. Accordingly, the archwire control structure  304  forms the labial boundary of the archwire slot  40 . As set forth in the exemplary embodiments above, the archwire  38  may move in the mesial and distal directions. However, the archwire control structure  304  limits movement beyond a certain distance in the labial direction. By way of example, the first and second projecting portions  312 ,  314  may form the labial boundary of the archwire slot  40 . Accordingly, the archwire  38  may contact either or both projecting portions  312 ,  314  should the archwire  38  be in sufficient non-parallel alignment. By controlling the contact locations, a moment arm formed by contact between the archwire control structure  304  and the archwire  38  and between the base surface  54  and the archwire  38  may be controlled. In order to control the contact locations, in one embodiment, the occlusal side wall  326  resides in the same lingual-labial plane as the occlusal side wall  56  of the archwire slot  40  or occlusally thereof. In another embodiment, the gingival side wall  328  is in the same lingual-labial plane as the gingival side  58  of the archwire slot  40  or gingivally thereof. It will be appreciated that it may be desirable to form a cavity or through hole in the main body  306  rather than the blind recessed area  316 . 
     In another embodiment of the invention, a method of correcting malpositioned teeth includes applying a plurality of orthodontic brackets constructed according to at least one of the embodiment of the invention as shown in  FIGS. 2, 6, 10, and 15  to teeth of a patient, and retaining an archwire  38  in the respective archwire slot  40  of the orthodontic bracket with the closure members, for example, closure member  36 , clip  106 , clip  204 , or removable ligating member  300  in the closed positions such that the archwire  38  contacts archwire control structure, such as at least one of the first or second projecting portions  74 ,  76 ; at least one of first or second projecting portions  138 ,  140 ; at least one of first or second lingual surfaces  232   a ,  232   b ; or at least one of projecting portions  312 ,  314  and without contacting another portion of the closure member  36 , clip  106 , clip  204 , or member  300 . For example, the archwire  38  may not contact the recessed area  78 , recessed area  136 , or recessed area  316 . 
     In one embodiment, the recessed area  78 ,  136 , or  316  and the first and second projecting portions  74 ,  76  or  138 ,  140  or  312 ,  314  of closure member  36 , clip  106 , or member  300 , respectively, define respective curved surfaces, and the respective curves of the curved surfaces each have a radius of curvature that is less than a radius of curvature of the portion of the archwire  38  retained in the respective bracket. 
     In another embodiment, the method includes retaining the archwire  38  by contacting the archwire  38  with, for example, both the first projecting portion  74 ,  138 , or  312  or surface  232   a  and the second projecting portion  76 ,  140 ,  314 , or surface  232   b  of at least one of the brackets. 
     In yet another embodiment, the method of correcting malpositioned teeth includes applying a plurality of orthodontic brackets constructed according to at least one of the orthodontic brackets  30 ,  100 ,  200 , and  302  to teeth of a patient, and retaining an archwire  38  in the respective archwire slot  40  of the orthodontic brackets  30 ,  100 ,  200 ,  302  with the closure member  36 , clip  106 , clip  204 , or member  300 , for example, in the closed positions such that the archwire  38  contacts at least one of the projecting portions  74 ,  76 ,  138 ,  140 ,  312 ,  314  and without contacting a surface  86 ,  146 ,  330  in the recessed area  78 ,  136 ,  316  respectively. 
     In yet another embodiment, the surfaces  86 ,  146 ,  330  in the recessed areas  78 ,  136 ,  316  and the projecting portions  74 ,  76 ;  138 ,  140 ; or  312 ,  314  of the closure member  36 , clip  106  or  204 , or member  300 , respectively, define respective curves, and the respective curves each have a radius of curvature less than a radius of curvature of the portion of the archwire retained in the associated bracket. In addition, retaining the archwire  38  may further include contacting the archwire  38  with both the mesial end  50  and the distal end  52  of at least one of the brackets, such as the mesial end  50  or the distal end  52  of the base surface  54  of the archwire slot. 
     While the present invention has been illustrated by a description of various embodiments and while these embodiments have been described in some detail, it is not the intention of the Applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those of ordinary skill in the art. The various features discussed herein may be used alone or in any combination depending on the needs and preferences of the user. This has been a description of illustrative aspects and embodiments of the present invention, along with the methods of practicing the present invention as currently known. However, the invention itself should only be defined by the appended claims.