Abstract:
A self-ligating orthodontic bracket system is provided, comprising a bracket to be mounted on the lingual side of the tooth and a self-ligating insert. The insert comprises a retention arm and a lockarm pivotally engaged together. The retention arm includes: a retention spring; a topside arm; and a pivot ring connecting the retention spring to the topside arm. The lockarm includes: an attachment portion having a pivot bar configured to be received in the pivot ring of the retention arm; a strut portion connected to the attachment portion; and a clasp portion having a clasp lock and an unlocking opening. The clasp lock is configured to engage a chokebox stem of the bracket. A retention groove in the bracket retains the retention arm of the insert. The bracket includes slots for occlusal, edgewise and gingival archwires. A method of providing orthodontic treatment and an orthodontic system are also provided.

Description:
RELATED APPLICATION DATA 
     This application claims benefit of U.S. provisional patent application Ser. No. 60/984,312, filed Oct. 31, 2007, titled SELF-LIGATING ORTHODONTIC BRACKET, AND METHODS FOR MAKING AND USING THE SAME, the contents of which are herein incorporated by reference in their entirety. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present invention relates generally to methods and apparatus for orthodontic treatment. In another aspect, the present invention relates to methods of making and using the archwire bracket force delivery system, more commonly referred to as orthodontic braces or orthodontic appliances. In particular, the present invention relates to the conversion of the known labial art to lingual applications as well as original concepts designed to meet the unique demands of the lingual environment. 
     2. Description of the Related Labial Art 
     Generally, orthodontic treatment of the teeth is accomplished by applying force to the teeth with a series of archwires positioned in and across a number of brackets. Since the beginning of orthodontics, in the late 1800&#39;s, orthodontists have been pursuing the goals of increased appliance resiliency, control, comfort to the patient, and easier manipulation for the doctor. 
     Edward H. Angle is considered the father of modern orthodontics. Angle&#39;s U.S. Pat. No. 678,453 discloses a rigid outer archwire with teeth tied to the archwire to draw them into position. The bands on the teeth were attachments that were really simple cleats. In 1925, in U.S. Pat. No. 1,584,501, Angle added a rectangular slot to the bracket with wings to receive tiewires. Because the slot was perpendicular to the long axis of the tooth it was called the Edgewise Appliance. The initial heavy gold archwire was bent to the shape of the malocclusion and was gradually straightened out. The device produced very precise control but was extremely rigid and non-resilient. To provide increased resiliency the sequential use of a number of single archwires, beginning with relatively small diameter round wires, and finishing with large rectangular wires, was incorporated in the Edgewise technique. Angle&#39;s Edgewise bracket has evolved into the Edgewise technique that is in common use today. 
     Typically, the archwire was secured in the archwire slot using wire ligatures twisted around the wings extending laterally on opposite sides of the slot. The use of elastomer O-rings in place of the wire ligatures was described by Anderson and Klein in U.S. Pat. No. 4,382,782. The use of elastomers was a definite step forward in the Edgewise technique. By their very nature, the elastomers provided a gentler and longer acting force. They were softer and were easier to install. However, the elastomer O-rings did have one problem; they absorbed water and lost some of their elastic force over time, necessitating replacement of the O rings. 
     Also, in 1925, Angle was issued U.S. Pat. No. 1,552,413, which disclosed a bracket designed to receive a rectangular archwire that was called a ribbon arch because the long axis of the archwire cross section was in the same plane as the long axis of the tooth. This bracket was locked with a pin which was held in place by bending the pin after it was inserted in the locking position. This bracket was later used by Spencer Atkinson and was developed into what was known as the Universal Technique. Atkinson&#39;s art was taught in U.S. Pat. Nos. 1,821,171; 2,196,516; and 2,305,916. Wildman, in U.S. Pat. No. 3,854,207, offered a self-ligating version of the Universal Technique in 1974. 
     J. W. Ford, in 1933 in U.S. Pat. No. 2,011,575, described a sleeve and tube unit that was probably the first self-ligating lingual bracket. The locking device was a friction lock. 
     McCoy presented a different approach that still used the gold arch technology. McCoy&#39;s bracket was simply a gold tube opened up to allow a snap fit to securely hold an appropriate round arch. A wide variety of torquing spurs were soldered to the arch. The gold arch allowed a full range of movement. These early efforts produced some very nice cases, even by modern standards, but the process was very demanding and time consuming. McCoy described the details of this process in U.S. Pat. No. 2,023,849. This patent was in the same year as the Ford patent. Because McCoy lectured showing treated cases, some people call McCoy the originator of self-ligating brackets. 
     The ribbon arch bracket was modified by Dr. P. R. Begg and was used extensively in what was known as the Begg technique. The Begg technique was well-received because it produced gentle forces which made it easy to start a case. It fell out of favor though because it was difficult to adequately finish cases. Begg&#39;s modification is described in U.S. Pat. No. 3,123,553 and used the pin groove of the Angle ribbon arch to attach a wide variety of torquing and rotational auxiliaries. In some iterations, Begg used a secondary archwire to provide torque control. Coordinating all these complex torque vectors made finishing cases difficult and led to the demise of the Begg technique. 
     To further increase the resiliency of the archwires, orthodontists began incorporating all sorts of geometric bends in almost every conceivable shape. An extreme example of this approach is described by Brader in U.S. Pat. No. 3,593,421. The downside of this was the difficulty of putting precise bends in the archwire. These archwires became too flimsy to control, and were eventually abandoned. 
     To provide increased resiliency and still maintain control, orthodontists sometimes turned to multiple archwires. J. D. Berke, in U.S. Pat. Nos. 2,406,527 and 2,705,367, described a bracket which is essentially a button with two channels separated by the body of the bracket. The two archwires were connected by rigid connectors between two teeth. In one configuration connectors were fixed and in another configuration they were slidable. This was the first mention of slidable, rigid interarch connectors. The archwire was connected to the tooth by pulling the two archwires away from each other and snapping the two archwires over the tooth. The archwires, returning to shape, moved the tooth into the proper position by seating the archwires in the archwire slot. The rigid sliding connectors helped in manipulation of the archwires but the rigid construction made this system difficult to use. Thus, this bracket was never produced in any significant quantities commercially. 
     Another approach was described by Joseph Johnson in U.S. Pat. Nos. 1,952,320; 2,665,480; and 2,759,265. Johnson incorporated two small diameter archwires held together in a ribbon arch configuration with the long axis going through the two wires parallel to the long axis of the tooth. This twin wire did produce increased resiliency but placing any compensating bends was impossible. This was a friction lock. 
     In 1952 Russell described in U.S. Pat. No. 2,671,964, a two piece unit that closed off the slot locking in twin wires as proposed by Johnson. 
     In 1965, S. M. Bien, in U.S. Pat. No. 3,193,930, proposed an interesting approach using one, two or three separated archwires. The channels that accepted the archwires were in the shape of V&#39;s and did not provide an edgewise slot. 
     U.S. Pat. No. 3,302,288 to Teppler discloses a similar two wire bracket arrangement using parallel spaced crossbars interconnected by a rigid member. Since this interarch connector was rigid it made this arrangement difficult to use. The archwires cannot be pulled apart easily to allow insertion and release. 
     Another attempt at attaining precision with two wires was described by Northcott in U.S. Pat. No. 3,775,850. Northcott connected two and three archwires together with interarch connectors. These connectors were rigid cast or brazed metal, both fixed and slidable. This rigid system was tied into the corresponding slots in the labial bracket. The sliding rigid connectors had to be tied in with twisted steel ligatures, however. 
     The problem with all of the two-wire techniques is the difficulty in putting in compensating bends. In theory, if the bracket of the tooth is put on the tooth in such a position that the channel of the bracket is in an ideal position, a straight archwire placed in this channel would produce a tooth positioned in the ideal position. In actual practice this does not happen, though. To compensate for the fact that this is not an ideal position the orthodontist had to make compensating bends in the archwire. Compensating bends in even a single archwire are difficult and time consuming for the orthodontist. 
     This problem was addressed by Dr. Larry Andrews using methods described in U.S. Pat. Nos. 3,477,128 and 3,660,900. Andrews attempted to position the slots in the bracket in such a relation to the base of the bracket that was applied to the tooth so that the slot assumed an ideal position in the average tooth. Since the brackets were generally put on the tooth by the orthodontist in the mouth using the orthodontist&#39;s trained eye, errors in position were inevitable. Also, not all teeth are average, and this also increases errors. So, the orthodontist must still finish cases with compensating bends. This is much easier with Andrews&#39; straight arch system. Putting compensating bends in two wires is, from a practical point of view, impossible. 
     3. Description of the Related Lingual Art 
     Dr. A. J. Wildman&#39;s U.S. Pat. No. 3,842,503 in 1974 was the beginning of what is called lingual orthodontics. Wildman stated in this patent—“The archwires may be mounted on the lingual side of the teeth as well as the labial side, as previously done. This is possible because brackets may be secured directly to the teeth without bands. Thus, for cosmetic reasons or otherwise, it may be desired to mount a lingual archwire”. He also introduced the concept of cutting teeth off of a model of the teeth and placing them in an ideal position. The brackets could then be placed on the models and the resulting set-up could act as a means of making an ideal archwire. The brackets could then be transferred to the mouth in the ideal position by a variety of means, and the archwire could then be tied into the brackets on the teeth. This would produce an ideal position for the teeth. This technique was later refined and called the Class System. 
     This patent (&#39;503) suggested using cast gold bases as a means of indexing. The brackets were brazed to the bases in a perfect position. The castings and brackets were then transferred to the teeth and cemented or bonded in place just as a gold inlay would be seated. 
     Wildman has previously developed lingual orthodontic methods and brackets as described in U.S. Pat. Nos. 3,748,740, which was a self-ligating Begg bracket; 3,780,437, which was the production version of the Edgelok bracket; 3,842,503, which described for the first time the concept of “lingual orthodontics” and the concept of the Class System; 3,854,207, which was a self ligating version of the Universal System; 4,443,187; 4,484,931, which was a method of bonding using burnished index tabs; and U.S. Pat. No. 4,443,189, which was a lingual bracket which locked in a second or auxiliary archwire. This lingual bracket was called “The Kelly Bracket” after the first patient it was tried upon. These concepts were a good start but needed further development. 
     In U.S. Pat. Nos. 4,337,037, 4,386,908, and 4,669,981 (1982, 1983 and 1987 respectively), Kurz described a series of shapes that he felt fit best on the lingual anatomical surfaces of the teeth. These shapes were incorporated in brackets that had to be tied either with steel ligatures or with elastomer O&#39;s. The steel wires were very sharp and uncomfortable to the patient. When plastic O&#39;s were used it was often necessary to use a double tie arrangement, with O rings doubled back on themselves in order to apply enough force from the O ring to properly seat the archwire. Orthodontists complained that this method was difficult and inefficient. 
     U.S. Pat. No. 6,485,299 to Wildman describes an insert configured to convert a non-self-ligating lingual bracket into a self-ligating bracket. The insert is removably attachable to the non-self-ligating lingual bracket and includes a self-ligating mechanism. According to a preferred embodiment, the bracket insert includes a pin, a tube, and a lock arm. The pin is configured to be removably secured to the non-self-ligating bracket. The tube is attached to or formed from an occlusal end of the retention pin. The lockarm is partially mounted within the tube and is capable of rotation between a ligating and non-ligating position. In its ligating position the lockarm securely retains an archwire within the archwire slot of the non-self-ligating bracket using detents in the rotating lockarm that snap into corresponding architecture in the body. This approach works very well but it does not lock an occlusal auxiliary archwire. An interarch connector between the two wires opens up all sorts of opportunities. 
     Thus, there is a need for an improvement in the arrangement described in the above patent. Ideally, the body would have an auxiliary slot that would allow insertion from the incisal direction. There would also be a typical edgewise slot that would allow insertion from the lingual direction. In U.S. Pat. No. 5,791,897,  FIGS. 33-40B  and the accompanying description explain the virtues of the occlusal auxiliary archwire and the edgewise archwire used together as a working arch. Another improvement would be the ability to use an edgewise archwire alone to add any necessary compensating bends. 
     The orthodontic profession needs a lingual self-ligating bracket that could lock in a single, light occlusal archwire to begin the unraveling of teeth in the first phase of treatment. In this system, an edgewise archwire would complement the occlusal archwire to provide ideal control of roots in all planes of space. A third, gingival archwire could be used to provide additional control. Further, a single archwire could be used in the edgewise slot to provide the fine finishing details. Many combinations expressing the needs of various techniques could be met with this arrangement. Accordingly, a need remains for a multiple archwire bracket that overcomes the deficiencies in the prior art. 
     SUMMARY 
     The present invention provides a self-ligating orthodontic bracket system, composed of a bracket to be mounted on the lingual side of the tooth and a self-ligating insert. The first object of the present invention is the use of the lockable, occlusal archwire inserted from the incisal direction, and the use of a lockable edgewise archwire inserted parallel to the occlusal plane. The occlusal archwire would preferably be a light, round NiTi wire, which would be used to control gross rotations and to begin the leveling process. The occlusal locking mechanism would be opened up to allow insertion of the edgewise wire to provide precise root control. In this half-lock position the edgewise wire could be removed and adjusted without interference, because the occlusal wire is still locked in place in the half-lock position. Preferably, in most cases, once the occlusal wire is placed, it would not be removed for the duration of the treatment. 
     The two archwire system can handle most orthodontic situations well. The present invention also allows for use of a third, gingival archwire for additional flexibility and control. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and advantages of the disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1A  is a perspective view of a self-ligating insert in accordance with a first embodiment of the invention; 
         FIG. 1B  is a perspective view of a bracket in accordance with the first embodiment of the invention; 
         FIG. 1C  is a plan view of a lock arm prior to shaping in accordance with the first embodiment of the invention; 
         FIG. 2  is a side elevation view of a body pad ligating assembly in accordance with the first embodiment of the invention; 
         FIG. 3  is a plan view of the body pad ligating assembly of  FIG. 2 ; 
         FIG. 4  is an incisal end elevation view of the body pad ligating assembly of  FIGS. 2 and 3  showing the incisal surface; 
         FIG. 5  is a gingival end elevation view of the body pad ligating assembly of  FIGS. 2 and 3  showing the gingival surface; 
         FIG. 6  is a cross-section view of the body pad ligating assembly of  FIGS. 2 and 3  in the open position showing the occlusal archwire and the edgewise archwire positioned to be inserted into their respective slots; 
         FIG. 7  is a gingival end elevation view of the body pad ligating assembly in the open position; 
         FIG. 8  is a side elevation view of the body pad ligating assembly of  FIGS. 2 and 3  with the self-ligating insert in the half-lock position; 
         FIG. 9  is a gingival end elevation view of the body pad ligating assembly of  FIG. 8  in the half-lock position; 
         FIG. 9A  is a detailed view of portion A of  FIG. 9 , showing that, as forces continue along vector  87 , the locking clasps will begin to be forced from the lock open to the lock closed position; 
         FIG. 10  is a side elevation view of the body pad ligating assembly of  FIG. 8  with the self-ligating insert in the locked position locking in the occlusal and the edgewise archwires in their corresponding slots. 
         FIG. 11  is a gingival end elevation view of the body pad ligating assembly of  FIG. 10  showing the lock arm locked into the locking stem of the body; 
         FIG. 11A  is a detailed view of portion B of  FIG. 11 ; 
         FIG. 12  is a plan view of the body pad ligating assembly of  FIG. 10  showing a round occlusal archwire and an edgewise archwire locked into the occlusal and edgewise slots; 
         FIG. 13  is a perspective view of the self-ligating insert of  FIG. 10  locked into the bracket shown with the archwires removed; 
         FIG. 14A  is a perspective view showing a one piece retention arm-lockarm unit, in accordance with a second embodiment of the invention; 
         FIG. 14B  is a perspective view of a bracket body in accordance with the second embodiment of the invention; 
         FIG. 15  is a cross-sectional view of a one piece retention arm-lockarm unit of  FIG. 14A  locking an occlusal archwire and an edgewise archwire into the occlusal and edgewise slots of the bracket body of  FIG. 14B ; 
         FIG. 16  is a side view of a body pad ligating assembly in the open position showing the occlusal archwire, the edgewise archwire and the gingival archwire positioned to be inserted into their respective slots in accordance with a third embodiment of the invention; 
         FIG. 17  is a plan view of the lockarm of  FIG. 16 . 
         FIG. 18  is a side elevation view of the body pad ligating assembly of  FIG. 16  with the self-ligating insert in the half-lock position and the gingival archwire snapped into the gingival archwire snap-groove in accordance with the third embodiment of the invention, the archwires shown in cross section; 
         FIG. 19  is a gingival end elevation view of the body pad ligating assembly of  FIG. 18  in the half-lock position; 
         FIG. 20  is a side view of the body pad ligating assembly of  FIGS. 16-19  with the self-ligating insert in the locked position locking the occlusal archwire and the edgewise archwire in place in their slots, and the gingival archwire snap-locked in the gingival snap-groove in accordance with the third embodiment of the invention. 
         FIG. 21  is a gingival end elevation view of the body pad ligating assembly and a release tool inserted into the release notch to open the lockarm in accordance with the third embodiment of the invention; 
         FIG. 22  is a cross-section view of a body pad ligating assembly of  FIG. 20  in the closed position; 
         FIG. 23  is a cross-section view of a body pad ligating assembly of  FIG. 20  in the half-lock position. 
     
    
    
     DETAILED DESCRIPTION 
     Example embodiments of the invention are described below with reference to the accompanying drawings. Many different forms and embodiments are possible without deviating from the spirit and teachings of this disclosure and so the disclosure should not be construed as limited to the example embodiments set forth herein. Rather, these example embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. In the drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. 
     It will be understood that when an element or layer is referred to as being “on,” “connected to” or “coupled to” another element or layer, it can be directly on, connected or coupled to the other element or layer or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly connected to” or “directly coupled to” another element or layer, there are no intervening elements or layers present. Like numbers refer to like elements throughout. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one skilled in the art to which this disclosure pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
       FIGS. 1A through 13  illustrate the construction and operation of a lingual self-ligating bracket system in accordance with a first embodiment of the invention. Referring to  FIGS. 1A-1C , the lingual self-ligating bracket system includes a bracket  10  which is shown in  FIG. 1B  and a self-ligating insert  5  which is shown in  FIG. 1A . The self-ligating insert  5  consists of two main parts: a retention arm  14  and a lockarm  16 . The retention arm  14  includes a retention spring  14   a , a topside arm  14   b , and a pivot ring  18  which, when assembled, holds a pivot bar  16   d . The lockarm  16  is formed by three bends folding up the flat shape shown in  FIG. 1C . Bend  15   a  forms the clasp lock  40  which will engage the chokebox stem  38  when the self-ligating insert  5  is in the full lock position. This will securely lock an edgewise archwire and an occlusal archwire in place. The second bend  15   b  and the third bend  15   c  allow the lockarm  16  to conform to the shape of the bracket body  22 . Following the three bends, the lockarm  16  will include an attachment portion  16   a , a strut portion  16   b , and a clasp portion  16   c . The attachment portion  16   a  includes the pivot bar  16   d . The clasp portion  16   c  includes the clasp lock  40  and an unlocking slot  16   e . The bracket  10  includes a pad  20  and a bracket body  22 . The bracket body  22  includes a gingival hook  50 , a chokebox  39 , a chokebox stem  38  with perpendicular projections  44  on opposite lateral sides, topside head  24 , a curved hook stem  48 , and a retention groove  36 . 
       FIG. 2  shows a cross-sectional midline view of the retention groove  36  which is enclosed by brazing the bracket body  22  to the pad  20 . This construction forms the flat pad base  36   a  of the retention groove  36  and the irregular topside  36   b  of the retention groove  36 . The side walls  36   c  and  36   d  of the retention groove  36  are formed when the body  22  of the bracket  10  is brazed to the pad  20 . The side walls  36   c  and  36   d  of the retention groove  36  are parallel and equidistant from each other. The topside wall  36   b  of the retention groove  36  begins with an incisal opening (as shown in  FIG. 4 ). The top wall of the retention groove  36  inclines sharply in a gingival direction toward an apex that forms a pressure point  31  or constriction. The top wall of the retention groove  36  then extends gradually gingivally to form a gingival opening of the retention groove  36  (as shown in  FIG. 5 ). The incisal and gingival openings of the retention groove  36  are substantially identical in shape. The bracket  10  also includes an edgewise slot  30 , configured to receive an edgewise archwire  32 , an occlusal slot  29 , configured to receive an occlusal archwire  52 , and a gingival slot  91 , configured to receive a gingival archwire  62  (see  FIG. 6 ). As shown in  FIG. 2 , the angle of the edgewise slot  30  is about 50 degrees. In other words, the angle of the edgewise slot  30  with respect to a vector normal to the surface of the pad  20  is approximately 50 degrees. 
     The self-ligating insert  5  is assembled by sliding the lockarm  16  into the pivot ring  18  of the retention arm  14 . This is accomplished by mechanically spreading the retention spring  14   a  and the top side arm  14   b  wide enough to insert the incisal pivot bar  16   d  into the pivot ring  18 . When the mechanical spreading tool is released the pivot ring  18  will place a compressive force on the pivot bar  16   d . This allows the lockarm  16  to pivot within the confines of the pivot ring  18 . The center of rotation will be the center of the pivot ring  18  as shown in side views ( FIGS. 6 ,  8 , and  10 ) and in gingival elevation views ( FIGS. 7 ,  9  and  11 ). 
     The lingual self-ligating bracket system is then assembled by inserting the retention arm  14  of the self-ligating insert  5  into the retention groove  36  of the bracket  10 . The retention spring  14   a  and top side arm  14   b  fit compressively into the retention groove  36  of the bracket  10  where they are kept in place by the pressure point  31 . As the retention spring  14   a  and top side arm  14   b  first enter the retention groove  36  they reach a position of maximum retention which is called the lock open position. 
     When the retention arm  14  is partially inserted into the retention channel  36 , it assumes the lock open position shown in  FIG. 6 .  FIG. 6  also shows the occlusal archwire  52  and the edgewise archwire  32  being placed in the occlusal slot  29  and the edgewise slot  30 , respectively. As seating pressure along the vector  87  is applied by the operator, the lockarm  16  begins to engage the edgewise archwire  32  and to collect the occlusal wire  52  into a half-locked position as shown in  FIG. 8 . Continued force along the seating vector  87  locks both archwires  32  and  52  as shown in  FIG. 10 . In other words, the lockarm  16  pivots from a lock open position shown in  FIGS. 6 and 7  to the half-lock position shown in  FIGS. 8 ,  9 , and  9   a . If pressure of the seating vector  87  is maintained in a clockwise manner the lockarm  16  will lock into the chokebox stem  38  beneath projections  44  as shown in  FIGS. 10 ,  11 , and  11   a . When the lockarm  16  is snapped into place it produces a very strong seating mechanism and thus the occlusal archwire  52  and the edgewise archwire  32  are securely locked in place (as shown in  FIGS. 10 ,  11  and  11   a ). 
     In actual practice the edgewise archwire  32  may not be placed at the beginning of treatment. In a typical approach, orthodontists could lock in a light, resilient occlusal archwire  52  initially that would begin the unraveling of rotations. The orthodontist then could add a second edgewise archwire  32  in the next phase of treatment. The occlusal archwire  52 , preferably round, could be made of soft, resilient Ni—Ti wire. This would allow the orthodontist to begin the case with gentle forces on the teeth. 
     The use of the occlusal archwire  52  and the edgewise archwire  32  together provides control of the roots in the working stage of treatment. The occlusal archwire  52  and the edgewise archwire  32  can be connected using interarch connectors. U.S. Pat. No. 5,791,897 describes the various forms and uses of interarch connectors. 
     A gingival slot  91 , as shown in  FIG. 6 , may be used to receive a third gingival archwire  62 . This could be used primarily with various interarch connectors that call for three archwire configurations. 
     According to embodiments of the invention, the strong chewing forces which the patient sometimes inflicts upon the lingual self-ligating bracket system will not unlock it. Finger pressure will not unlock the lockarm  16  either. However, the unlocking opening  16   e  is provided such that an adequate instrument, such as a scaler or an explorer, can be placed in the unlocking opening  16   e . Then, a gentle prying motion is all that is necessary to open the lockarm  16 . This is also shown in  FIG. 21 . 
       FIG. 12  is a plan view of the lingual self-ligating bracket system showing an incisal round archwire  52  and an edgewise archwire  32  locked into the occlusal and edgewise slots  29  and  30 , respectively. The gingival hook  50  includes two rounded protrusions  50   a  and  50   b . The gingival hook  50  is connected to the bracket  10  by the curved hook stem  48 .  FIG. 13  is a perspective view showing the lockarm  16  locked into the choke box  39  of the bracket  10 . For illustration purposes, the archwires  32  and  52  have been removed from the system in the view of  FIG. 13 . 
       FIGS. 14A through 15  illustrate the construction and operation of a lingual self-ligating bracket system in accordance with a second embodiment of the invention. 
       FIG. 14A  is a perspective view showing a one-piece retention arm-lockarm unit  60 . The one-piece retention arm-lockarm unit  60  includes a clasp portion  68 , for engaging with the chokebox stem  38  of the bracket  10 , and a retention portion  62 , for engaging with the retention groove  36 . The one-piece retention arm-lockarm unit  60  may also include a shoulder  65  configured to aid in positioning of the retention portion  62  in the retention groove  36 . The one-piece retention arm-lockarm unit  60  can be folded out of a one piece blank of material which would most desirably be a heat treated stainless steel such as 17/7-condition A. Tooling for this embodiment may be complicated and require a progressive die and perhaps a second operation. Although the tooling may be expensive it might produce a very inexpensive part.  FIG. 15  shows this solid self-ligating unit  60  locked into the bracket  10  of  FIG. 14B . The bracket  10  of  FIG. 14B  can be similar to or identical to the bracket  10  of  FIG. 1B . As shown in  FIG. 15 , an occlusal archwire  52  and an edgewise archwire  32  can be locked into place in the bracket  10  using the one-piece retention arm-lockarm unit  60 . Also, as shown in  FIG. 15 , the angle of the edgewise slot  30  can be about 50 degrees. 
       FIGS. 16 through 23  illustrate the construction and operation of a lingual self-ligating bracket system in accordance with a third embodiment of the invention. 
     The lingual self-ligating bracket system in accordance with the third embodiment includes a much stronger, rounded, and smoother lockarm  102  formed using Metal Injection Molding (MIM) technology that replaces the stamped lockarm  16  of the first embodiment. The general function and shape is the same, however. In the third embodiment, the same bracket  10  can be used, as shown in  FIG. 1B . The same retention arm  14  can also be used and the same general shape and form of the first embodiment can be retained. The locking mechanism should be gentle, but also capable of the necessary precision and strength. Because the lock has a stronger locking action and it moves in a narrower range it should also be much more precise. The MIM process provides the necessary close tolerances to make this possible. The MIM process also provides much greater design flexibility. 
       FIG. 16  shows the MIM lockarm  102  pivoting around the pivot ring  18  of the retention arm  14 . When the lockarm  102  is locked into the chokebox stem  38  the edgewise archwire  32  and the occlusal archwire  52  are securely locked into place.  FIG. 16  also illustrates a gingival archwire  62  that can engage with the gingival hook  50 . 
       FIG. 17  is a plan view of the MIM lockarm  102 . The flat pivot bar  16   d  of the first embodiment is replaced by a round molded pivot bar  103  that is molded into the lock arm  102 , making a solid part. This is designed to be assembled inside the pivot ring  18  of the retention arm  14 . A round bar inside a circular ring provides smoother movement and easier use. The smooth flowing rounded edges are shown in  FIGS. 16  thru  21 . 
     The strong chewing forces which the patient sometimes inflicts upon the lingual self-ligating bracket system will not release the lockarm  102 . Finger pressure will not unlock the lockarm  102  either. An unlocking opening  106  is provided to release the lockarm  16 . An adequate instrument, such as a scaler or explorer, can be placed in the unlocking opening  106 . The leverage is such that a gentle prying motion is all that is necessary to open the lockarm  16 , as shown in  FIG. 21 . 
     One other feature of the third embodiment is the release lock  107  (see  FIG. 23 ) that keeps the self-ligating insert from sliding into the mouth when the lockarm  102  is in the open position.  FIG. 22  shows the lockarm  102  in the closed position such that the retention arm  14  is under gentle compression in the retention groove  36 . When the lockarm  102  is open, however, the retention arm  14  is gradually compressed by pressure point  31 . Because of the release lock  107 , when the lockarm  102  is partially withdrawn from the bracket  10 , the retention arm  14  reaches a point where it will not withdraw any farther except under heavy force. This condition is shown in  FIG. 23 . Thus, the release lock  107  prevents the self-ligating insert from sliding into the mouth when the lockarm  102  is in the open position. 
     Although the above description has been directed to a single self-ligating insert, one of ordinary skill in the art would appreciate that various self-ligating inserts may be used in order to provide various forces on the archwires. According to embodiments of the invention, these different self-ligating inserts can be used universally with the bracket to accommodate different treatment options. 
     Some embodiments of the invention have been described above, and in addition, some specific details are shown for purposes of illustrating the inventive principles. However, numerous other arrangements may be devised in accordance with the inventive principles of this patent disclosure. Further, well known processes have not been described in detail in order not to obscure the invention. Thus, while the invention is described in conjunction with the specific embodiments illustrated in the drawings, it is not limited to these embodiments or drawings. Rather, the invention is intended to cover alternatives, modifications, and equivalents that come within the scope and spirit of the inventive principles set out in the appended claims.