US3729826A

US3729826A - Lock ring for edgewise bracket

Info

Publication number: US3729826A
Application number: US00163313A
Authority: US
Inventors: P Kesling
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-07-16
Filing date: 1971-07-16
Publication date: 1973-05-01
Anticipated expiration: 1990-05-01

Abstract

An orthodontic appliance for locking an archwire or archwires to an edgewise orthodontic bracket, and to provide movement control wherein the appliance is in the form of a ring that fits over the projections of the bracket and is locked in place on the projections to lock the archwire in the archwire slot. Lingual extensions may be provided on the ring for engagement with the archwire to provide mesio-distal inclination control when using round wire, and additionally labio-lingual control when using rectangular wire.

Description

United States Patent [1 1 Kesling LOCK RING FOR EDGEWISE BRACKET [76] Inventor: Peter C. Kesling, Green Acres, La

Porte, Ind

[22] Filed: July 16, 197] [2]] Appl. No.: 163,313

[52] US. Cl. ..32[l4 A [51] Int. Cl ..A6lc 7/00 [58] Field of Search .32/14 A [56] References Cited UNITED STATES PATENTS Gladstone ..32/ l 4 A Hoffman ..32/14 A [4 1 May 1, 1973 Primary ExaminerRobert Peshock Altorney-Lloyd L. Zickert 57] ABSTRACT An orthodontic appliance for locking an archwire or archwires to an edgewise orthodontic bracket, and to provide movement control wherein the appliance is in the form of a ring that fits over the projections of the bracket and is locked in place on the projections to lock the archwire in the archwire slot. Lingual extensions may be provided on the ring for engagement with the archwire to provide mesio-distal inclination control when using round wire, andwadditionally labiolingual control when using rectangular wire.

20 Claims, 14 Drawing Figures Patented May 1, 1973 3,729,826

2 Sheets-Sheet 2 ullml I My} 75 Inventor Peter C. Ke sling Y LOCK RING FOR EDGEWISE BRACKET This invention relates in general to orthodonticappliances, and more particularly to a lock ring for use with edgewise brackets to lock an archwire to the bracket, and still more particularly to a lock ring that may be constructed to additionally provide control movements effected by the archwire.

The present invention is intended for use with edgewise and edgewise-type brackets used in treating patients by the edgewise orthodontic technique, and where both the usual rectangular in cross-section edgewise archwire and round in cross-section archwire may be used in treatment.

The term edgewise herein is intended to apply to any bracket having a slot opening buccally or labially where the archwire may be inserted from the buccal or labial side of the bracket, and where both rectangular and round archwire may be used. Labial as used hereafter is intended to include buccal.

The usual edgewise bracket is defined by a pair of spaced occluso-gingivally aligned and labially extending lugs or projections defining therebetween a mesiodistally extending archwire slot. Notches are normally provided on the projections for locking the archwire to the bracket, such as illustrated in U. S. Pat. No. 3,391,461. The application of and removal of ligature wire is time consuming and troublesome. Further, ligature wire cannot provide axial inclination changes by its engagement with the arch wire.

It has been proposed to use caps or clips to lock archwires in place on edgewise brackets, such as in U. S. Pat. Nos. 3,128,552 and 3,256,602, but such do not have the ability to increase the control or tooth moving forces delivered from the archwire to the tooth. Moreover, they protrude labially from the bracket adding to the bulk of the appliance and the discomfort to the patient.

Heretofore, when it was desired to facilitate the control of root movements of teeth, edgewise brackets were provided having an angularly extending archwire slot, or were attached to the teeth with the slots at angles other than 90 to the long axis of the teeth, but such wouldnecessitate the removal of the band and bracket and replacement when in a later treatment state it was necessary to have a different slot-tooth relationship.

The lock ring of the invention in its most basic form includes a ring-shaped body, the center opening of which is adapted to receive the projections or lugs of an edgewise bracket. The lock ring may be made of dead soft metals, such as stainless steel or brass, in which case the ring is formed so that it may easily slip over the projections of the bracket and thereafter be deformed so the opposite ends are brought toward each other into locking engagement with the notched portions of the projections. In this position, the mesial and distal sides of the ring are arranged along the mesial and distal sides of the lugs and the labial surface of the lock ring is substantially flush or lingual to the outer ends of the lugs whereby the lock ring does not protrude labially beyond the projections. The mesial and distal sides of the lock ring function to hold the archwire in the archwire slot of the bracket, and to provide rotational control between the bracket and the wire.

In another form, the ring body may have lingually facing projections or notches to engage the wire thereby additionally providing mesial-distal inclination control between the wire and bracket. Where the wire is rectangular, these projections or notches may also provide labio-lingual torque control between the bracket and archwire.

The lock ring of the invention may also be made of resilient material (metallic or non-metallic) in the shape it would take when in locked position on a bracket wherein the lock ring would be deformed so that it may be applied to the bracket, and thereafter return to its original shape in locking position on the bracket.

Accordingly, it is an object of the present invention to provide a new and improved orthodontic appliance for locking archwires to edgewise type brackets.

Another object of this invention is in the provision of a lock ring for edgewise brackets that may be simply and easily installed and/or removed from a bracket for quickly and easily locking an archwire to or removing an archwire from a bracket.

Still another object of this invention is in the provision of a lock ring for an edgewise bracket wherein the lock ring includes means for obtaining control movements between the bracket and the archwire.

A further object of this invention is to provide a lock ring for an edgewise type bracket that eliminates the need of ligature wire for locking an archwire to the bracket.

A still further object of the invention is to provide a lock ring for an edgewise bracket capable of coacting with the bracket and archwire to provide rotational and mesio-distal inclination control with any round or rectangular wire and additionally labio-lingual torque control with rectangular wire.

Another object of the invention is to provide a lock ring for use with an edgewise bracket that coacts with the bracket to provide root control or changes in direction of root control without necessitating change of the bracket or modification of the archwire.

Other objects, features and advantages of the invention will be apparent from the following detailed disclosure, taken in conjunction with the accompanying sheets of drawings, wherein like reference numerals refer to like parts, in which:

FIG. 1 is a front, elevational view ofa lock ring in accordance with the invention arranged on an edgewise bracket, wherein the lock ring is shown in its form for initial placement on the bracket;

FIG. 2 is a vertical, sectional view taken through the embodiment of FIG. 1;

FIG. 3 is a perspective view of the embodiment of FIG. 1 but showing the lock ring in locking position on the bracket;

FIG. 4 is a perspective view of a modified lock ring according to the invention and which includes a lingual extension for obtaining mesio-distal control movement;

FIG. 5 is a perspective view of a still further modified lock ring in accordance with the invention and shown in association with an edgewise bracket and where lingually extending ears define a notch to engage the archwire to provide control of the mesio-distal inclination of the bracket or tooth, and where the wire is held perpendicularly to the occluso-gingival axis of the bracket;

FIG. 6 is a front, elevational view of a further embodiment which differs from the embodiment of FIG. in that the labially extending projections cause the archwire to be angularly disposed relative to the occluso-gingival axis of the bracket,

FIG. 7 is a side elevational view of a further embodiment illustrating the lock ring of the invention formed to provide a desired labial-lingual axial relationship between the arch wire and the bracket;

FIG. 8 is an exploded perspective view of a further modified lock ring and a bracket with an archwire in its slot, wherein the lock ring is illustrated in its form prior to being locked onto a bracket;

FIG. 9 is a perspective view of the embodiment of FIG. 8 wherein the lock ring is shown in looking engagement with the bracket;

FIG. 10 is a front, elevational view of the lock ring shown in FIGS. 8 and 9, but illustrated in combination with an edgewise bracket arranged to receive a rectangular in cross-section archwire.

FIG. 11 is a side, elevational view of the arrangement shown in FIG. 10;

FIG. 12 is a top plan view of the arrangement shown in FIGS. 10 and 11;

FIG. 13 is a perspective view of a further lock ring embodiment which differs from the embodiment of FIGS. 8-12 only in that lingual facing notches are provided to give mesio-distal inclination control; and

FIG. 14 is a perspective view of a lock ring and bracket arrangement, wherein the lock ring is of the same type as shown in FIGS. 8 to 12, but wherein the bracket is of a type that is capable of receiving an uprighting spring for applying an uprighting force to the bracket.

Referring now to the drawings, and particularly to FIGS. 1 to 3, the lock ring according to the invention, generally designated by the numeral 15, is illustrated with an edgewise bracket 16, and a round in cross-section archwire 17. FIGS. 5 to 7 illustrate a modification of the lock ring to coact with rectangular in cross-section archwire. It should be appreciated that round or rectangular ar'chwire may be used depending upon the choice of the operator and the desired stage of treatment.

The edgewise bracket 16 illustrated in FIGS. 1 to 3 includes a pad or base 18 which would be suitably secured directly to a tooth by adhesive, or to a band by welding or soldering. The band, in turn, would be suitably cemented to a tooth in a patients mouth. The occluso-gingival axis of the bracket is illustrated as being along the vertical and a pair of lugs, posts or

projections

19 and 20 extend labially of the pad 18 defining therebetween an ,archwire slot 21 which extends mesio-distally. In the embodiment of FIGS. 1 to 3, the archwire slot is illustrated as being wider than the diameter of the archwire which permits mesio-distal tipping action between the archwire and the bracket.

' However, it should be appreciated that if no tipping action is desired the archwire slot may have a width the same as the width of the archwire, that is, where essentially zero tolerance is provided between the slot and the archwire, such as shown in FIGS. 10 and 11.

The upper and lower sides of the

lugs

19 and 20 are notched at 22 and 23 respectively to permit purchase of the lock ring to the bracket. Heretofore, the notches have served as hooks or the like for receiving a ligature wire when locking the archwire in place on an edgewise bracket. The labio-lingual depth of the

lugs

19 and 20 may vary depending upon the desired usage of the bracket. For example, extensions are illustrated in phantom in FIG. 2 which would allow a further wire 17a to be secured to the bracket in the archwire slot labial of the lock ring by using a ligature wire retained by the openings 22a and 23a. The term edgewise used herein to define the bracket is intended to apply to any bracket having a mesio-distal archwire slot. It should be recognized the notches may be formed along the mesial and distal sides of the posts or along the occlusal and gingival sides of the posts as shown.

The bracket could be made of any suitable dead soft or resilient material, such as stainless steel or plastic. When made of stainless steel, it could be milled while when made of plastic it could be molded. It should also be appreciated that the bracket may be formed from a stamping. It should be further understood that the bracket forms no part of the present invention and that it is well known.

The lock ring 15 includes opposed sides 24 and 2S and opposed ends 26 and 27, all interconnected and formed as a body in the shape of a ring to define a central opening 28. The various sides are generally rectangular in cross-section, although they may take any other geometrical shape. The opposed sides 24 and 25 are oppositely, arcuately formed to insure proper deformation when the lock ring is compressed or squeezed along the occluso-gingival axis and locked to the bracket, and subsequently compressed or squeezed along the mesio-distal axis to be removed from the bracket. The upper and lower ends 26 and 27 are offset lingually from the opposed sides a sufficient distance so that they will enter the

notches

22 and 23 when the lock ring is squeezed into locking position. As shown in FIG. 3, the direction of squeeze is along the occlusogingival axis, as indicated by the

arrows

29 and 30, which brings the upper and lower ends 26 and 27 into locking engagement with the lugs, as seen in FIG. 3 and spreads the sides apart.

When the lock ring is made of a dead soft metal, the deformation of the ring will remain as shown in FIG. 3, where the upper and lower ends of the ringare hooked over the

lugs

19 and 20 so that the lock ring is locked into position. As noted in FIG. 2, the outer surface of the lock ring is substantially flush with the labial surface of the lugs so that the lock ring does not protrude labially from the bracket and into the mouth. This minimizes, if not eliminates, any possible irritation to the patients mouth, and the possible displacement of the ring when the patient is chewing on food. The lock ring, after positioning over the lugs, is locked in position by applying the jaws of a pliers to the upper and lower ends 26 and 27 and squeezing until the ends 26 and 27 are seated in the notches. It is a simple matter to remove the ring from the bracket by applying a pliers to the opposed sides 24 and 25 to force apart the

ends

26 and 27 thereby elongating the opening 28 and spreading apart the ends and allowing the lock ring to be withdrawn labially from the bracket lugs. When in locked position, it can be seen the

sides

26 and 25 coact with the base or pad 18 to, at the mesial and distal sides of the

lugs

19 and 20, contain the archwire to achieve rotational control between the bracket and archwire.

Where the lock ring may be molded of a resilient material, such as one of the many plastics available, like nylon, it would in its passive state take the form shown in FIG. 3 and be deformed during the application of the ring to the bracket. Deformation would involve the squeezing toward one another of the

opposite sides

24 and 25 until the opposite ends 26 and 27 are far enough apart so that they may slide over the

lugs

19 and 20.

In order to eliminate relative rotation between the lock ring and bracket, the opening at the top and bottom is narrowed to just clear the opposite sides of the lugs, and to this end guide faces 26a and 27a are provided.

The embodiment of FIG. 4, generally designated by the numeral 35, differs from the embodiment of FIGS. 1 to 3 only in that a lingually extending ear is provided on one of the sides for the purpose of producing a control movement between the archwire and the bracket. This lock ring includes opposed

sides

36 and 37 and opposed ends 38 and 39. At the side 36 an ear or projection 40 extends lingually for the purpose of defining an archwire stop. For example, should the tooth on which the appliance is mounted require tipping movement and it be further desired that the tipping movement cease when the tooth is in an upright position, the lock ring could then be used and which would effectively provide a mesio-distal inclination control. If the ear were on the distal side of the bracket and occlusal to the archwire and the tooth were initially tipped with its occlusal end being mesial to the desired inclination, distal tipping would cease when the tooth reached the upright position where the archwire would engage the ear 40. It must be assumed here that the archwire will always tend to assume a perpendicular position with respect to the desired occluso-gingival position of the tooth. It should be appreciated here that the ear 40 extends from the lower end of the side 36, although for opposite control it could extend from the lower end of the side 37. Application and removal of the lock ring 35 would be accomplished in the same manner as above described with lock ring 15.

Another form of lock ring, according to the invention, is shown in FIG. 5 and generally designated by the numeral 42. This lock ring is especially useful for application to the bracket of FIG. 1 and to provide in addition to mesio-distal inclination control labio-lingual control by using rectangular in cross-section archwire 43. In this embodiment, the lock ring provides opposed sides 44 and 45 interconnected by opposed ends 46 and 47. The sides are like the embodiments of FIGS. 1 and 4 in that they are bowed outwardly to control deformation in the application to and removal of the lock ring from a bracket. At each of the opposed sides 44 and 45, a pair of lingually extending ears 48 coact to define an archwire slot 49 sized to receive the rectangular archwire 43 and to prevent rotation and tipping between the archwire and lock ring. The archwire is captured by the ears 48 which extend sufficiently toward the base 18 of the bracket so that it cannot slip around the ends of the ears. Application and removal of this lock ring may be accomplished in the same fashion as described in connection with the embodiment of FIG. 1. Further the ears 48 extending from the opposite sides 44 and 45 are positioned to place the archwire 43 perpendicularly with respect to the occluso-gingival axis of the bracket 16. It should be further appreciated that this lock ring could be used with round wire and the bracket 16 where no mesiodistal tipping would be desired.

The embodiment of FIG. 6 differs from the embodiment of FIG. 5 only in that the ears represented by Xs 50 are arranged to hold the archwire 43 in an angular relation to the bracket other than the perpendicular relation shown in FIG. 5. This bracket is generally designated by the numeral 420. While shown as used with rectangular wire, it could likewise be used with round wire.

The lock ring embodiment in FIG. 7, where the lock ring is generally designated 42B, differs from the lock ring 42 in the angulation of the slot 49b which is arranged to change the labial-lingual inclination of the tooth.

Another lock ring embodiment of the invention is illustrated in FIGS. 8 and 9 which differs from the embodiment of FIG. I only in the shape of the sides and initial positioning of the ends for illustrating another mode of application to a bracket. The bracket is the same as shown in FIGS. 1 to 5 and is therefore identified by the same numerals. This embodiment is also illustrated in use with a round archwire. The lock ring here is generally designated by the numeral 55 and includes parallel opposed and spaced

sides

56 and 57 and opposed ends 58 and 59 interconnected with the sides and defining a central opening 60. The opening 60 is initially sized when the lock ring is made of dead soft metal 50 that the lock ring may easily slip over the lugs of the bracket. Once the lock ring is in position, by using a pliers, the opposite ends 58 may be bent toward each other to engage in the

notches

22 and 23 of the lugs and lock the ring onto the bracket with the archwire in place, as shown in FIG. 9. In order to facilitate the bending of the

ends

58 and 59 toward each other and with respect to the opposed sides 56 and 57, the ends include

cross bar portions

58a and 59a having short end portions 58b and 59b forming continuations of the

sides

56 and 57. Further notches or scores 58c and 590 are provided at the junction of the sides with the end portions to facilitate bending and prevent fracturing when the lock ring is applied to a bracket. Again the

sides

56 and 57 of the lock ring capture the archwire at mesial and distal sides of the lugs against the base 18 to prevent rotation of the bracket relative the archwire while permitting tipping action. The labial faces of the lock ring are substantially flush with the labial faces of the lugs, although it should be appreciated that these lock ring faces could be recessed lingually with respect to the labial faces of the lugs. Removal of the lock ring 55 is accomplished by spreading the ends 58 until they clear the lugs. As with the embodiment of FIG. 1, if lock ring 55 were made of plastic, it would take the form shown in FIG. 9 and be deformed to spread the ends when applying and removing same from a bracket.

The use of rectangular archwire with an edgewise bracket defining an archwire slot that will prevent mesio-distal and labio-lingual tipping movements between the archwire and bracket is illustrated in FIGS. 10 to 12 where the bracket is generally designated by the numeral 65. The lock ring 55 of the embodiment shown in FIGS. 8 and 9 is illustrated here although it should be appreciated that the lock ring of FIG. 1 could likewise be employed. The bracket 65 includes a base or pad 66 having a pair of

lugs

67 and 68 extending therefrom and which defines therebetween an archwire slot 69 of rectangular cross-section which is sized about the same as the archwire 43, allowing for tolerances, but which will not permit relative rotation between the archwire and lugs or relative tipping action between the archwire and lugs. Otherwise, the lock ring performs as with the other edgewise bracket.

The lock ring embodiment of FIG. 13, generally designated as 55A, differs from the lock ring of FIGS. 8 to 12 only in that lingually extending lugs 70 define a lingually facing archwire slot 71 to provide mesio-distal inclination control. Where rectangular archwire as shown is used which is sized to snugly fit in the slot, labio-lingual root control is also achieved.

FIG. 14 merely illustrates another form of edgewise bracket on which the lock ring of the present invention may be employed to emphasize that the lock ring is intended to be used on any type of edgewise bracket where the wire may be inserted from the labial side of the bracket into an archwire slot opening labially. This bracket is generally identified by the numeral 73 and is made from a stamping that is thereafter formed to the shape illustrated wherein a pair of lugs 74 and 75 extend labially from a pair of welding or attaching

flanges

76 and 77. An archwire slot 78 is defined between the lugs and which may be sized to receive round or rectangular wire that would permit relative tipping between the wire and the bracket. Further the lugs 74 and 75 are provided with occluso-gingival extending and aligned openings 74a and 750 which would permit the reception of one end of an uprighting spring, the other end of which would engage the archwire and where the uprighting spring would function to apply an uprighting force to the tooth on which the appliance is mounted. While the lock ring 55 is illustrated in connection with bracket 73, it should be appreciated that any of the lock rings illustrated may be used.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention, but it is understood that this application is to be limited only by the scope of the appended claims.

The invention is hereby claimed as follows:

1. The combination of an edgewise bracket and an appliance for locking an archwire to the bracket, wherein the bracket includes a pair of spaced occlusogingivally aligned projections defining therebetween a mesio-distally extending archwire slot and the projections are notched at the outer edges thereof, said appliance comprising a ring-shaped frame formed to slip over the projections when being first positioned on the bracket and thereafter be formed into locking position with the notches to lock an archwire in said slot and to be substantially flush with the labia] surface of the projections, and means at the occlusal and gingival ends of the frame closely fitting with the mesial and distal sides of the projections to prevent relative rotation between the frame and bracket.

2. The appliance of claim 1, wherein the projections are spaced apart a distance greater than the thickness of the archwire to enable tipping between the wire and bracket, and control means extending lingually of the frame to coact with the wire and control relative movement between the wire and bracket.

3. The appliance of claim 2, wherein said control means includes an ear at one side of the appliance extending lingually into the path of the archwire to limit mesio-distal tooth tipping thereby.

4. The appliance of claim 2, wherein said control means includes a plurality of ears at one side of the appliance capturing the archwire to provide relative mesio-distal tipping movement control between the wire and bracket.

5. The combination of a bracket and a lock ring for securing an archwire to said bracket, wherein said bracket includes a base and a pair of spaced and 0ccluso-gingivally aligned lugs labially projecting therefrom defining therebetween a mesio-distally extending archwire slot, each said lug having a notch at the side thereof opposite the archwire slot, said lock ring comprising opposed sides to be positioned on the mesial and distal sides of the lugs, means on the opposed sides coacting with the lugs to prevent relative rotation between the lock ring and bracket, opposed ends interconnected between the sides to be positioned at the occlusal and gingival sides of the lugs and formed to engage in the lug notches, said sides and ends defining therebetween an opening, said ends being initially spaced apart so the opening is sized to permit the lock ring to slip over the lugs to thereafter permit the ends of the lock ring to move toward one another into said notches and into locking engagement with said lugs.

6. A lock ring as defined in claim 5, wherein said sides are bowed outwardly to facilitate deformation of the lock ring when locking and unlocking same to a bracket.

7. A lock ring as defined in claim 5, wherein said sides include means coacting with the lugs to provide relative mesio-distal rotation control between the bracket and lock ring.

8. The combination of claim 5, where the ring is of dead soft metal, and deformable into locking position on the bracket.

9. A lock ring as defined in claim 8, and scores between the sides and ends to facilitate bending of the ends toward each other.

10. The combination of claim 5, where the ring is of plastic, and snapable into locking position on the bracket.

11. A lock ring as defined in claim 6, and means extending lingually from one of said sides to effect labiolingual control between the bracket and archwire.

12. A lock ring as defined in claim 5, wherein the labial surfaces of said lock ring are substantially flush with the labial surfaces of said lugs, and the lingual surfaces of the lock ring coact with the base to capture the archwire and provide rotational control between the bracket and archwire while permitting relative tipping therebetween where the archwire slot is larger than the wire thickness.

13. A lock ring as defined in claim 5, and means extending lingually from at least one of said sides of the lock ring to provide mesio-distal inclination control between the bracket and archwire.

14. A lock ring as defined in claim 13, wherein said means includes an ear defining an archwire stop.

15. A lock ring as defined in claim' 13, wherein said means includes a pair of ears defining an archwire slot.

16. A lock ring as defined in claim 15, wherein said ears are positioned to hold the archwire normal to the occluso-gingival axis of the bracket.

17. A lock ring as defined in claim 15, wherein said ears are positioned to hold the archwire non-normal to the occluso-gingival axis of the bracket.

18. A lock ring as defined in claim 13, wherein said means includes a pair of ears on each of said sides defining an archwire slot.

19. A lock ring as defined in claim 18, wherein the slot defined by the ears is sized for rectangular wire and functions to provide relative mesio-distal and labio-lingual axial control between the wire and the bracket.

20. The combination of an edgewise bracket and an appliance for locking an archwire to the bracket, wherein the bracket includes a base for attachment to a band or tooth, a pair of occluso-gingivally aligned and spaced posts projecting labially and defining therebetween a mesio-distally extending archwire slot, and the posts formed to coact with the base and define notches, said appliance comprising a ring-shaped body sized to slip over the posts when being first positioned on the bracket and thereafter be formed into locking position with the posts by having means engaging into the notches to thereby lock an archwire in said slot, and means on the body coacting with the lugs to prevent relative rotation between the lock ring and bracket.

Claims

1. The combination of an edgewise bracket and an appliance for locking an archwire to the bracket, wherein the bracket includes a pair of spaced occluso-gingivally aligned projections defining therebetween a mesio-distally extending archwire slot and the projections are notched at the outer edges thereof, said appliance comprising a ring-shaped frame formed to slip over the projections when being first positioned on the bracket and thereafter be formed into locking position with the notches to lock an archwire in said slot and to be substantially flush with the labial surface of the projections, and means at the occlusal and gingival ends of the frame closely fitting with the mesial and distal sides of the projections to prevent relative rotation between the frame and bracket.

5. The combination of a bracket and a lock ring for securing an archwire to said bracket, wherein said bracket includes a base and a pair of spaced and occluso-gingivally aligned lugs labially projecting therefrom defining therebetween a mesio-distally extending archwire slot, each said lug having a notch at the side thereof opposite the archwire slot, said lock ring comprising opposed sides to be positioned on the mesial and distal sides of the lugs, means on the opposed sides coacting with the lugs to prevent relative rotation between the lock ring and bracket, opposed ends interconnected between the sides to be positioned at the occlusal and gingival sides of the lugs and formed to engage in the lug notches, said sides and ends defining therebetween an opening, said ends being initially spaced apart so the opening is sized to permit the lock ring to slip over the lugs to thereafter permit the ends of the lock ring to move toward one another into said notches and into locking engagement with said lugs.

11. A lock ring as defined in claim 6, and means extending lingually from one of said sides to effect labio-lingual control between the bracket and archwire.

15. A lock ring as defined in claim 13, wherein said means includes a pair of ears defining an archwire slot.