Abstract:
A self-ligating orthodontic appliance including a base, one or more pivotally and movably mounted jaws on the base, and a spring member actuable to coact with the base and jaws and selectively move the jaws between open and closed positions.

Description:
This invention relates in general to an orthodontic appliance for connecting an archwire to a tooth, and more particularly to a self-ligating orthodontic bracket mountable on a tooth that may be opened for insertion or removal of an archwire and closed for retaining the archwire on a tooth, and still more particularly to a self-ligating bracket having at least one slidable and pivotal jaw connected to a spring and movable between open and closed positions by applying a force to the spring. 
   BACKGROUND OF THE INVENTION 
   Heretofore, it has been well known to provide self-ligating orthodontic brackets for use in orthodontic treatment of patients that eliminate the need to apply ligatures for retaining an archwire on a bracket. These brackets are intended to enhance the efficiencies of orthodontic treatment and also eliminate the problem sometimes encountered in ligature failure particularly with respect to use of elastomeric ligatures. Moreover, it is known that some self-ligating brackets, whether adapted for use labially or lingually, eliminate the need for tie wings. 
   It has also been known to provide self-ligating brackets that will release the archwire from the archwire slot whenever the forces on an archwire exceeds a certain minimum value, such as disclosed in U.S. Pat. No. 6,554,612 and U.S. Pat. No. 6,582,226. 
   Another example of a self-ligating bracket having a sliding archwire retaining member is disclosed in U.S. Pat. No. 5,711,666. 
   Heretofore known self-ligating brackets with complex mechanical configurations have a tendency to excessively trap food particles, and irritate the tissues of the mouth. Some are difficult to open and close for insertion and removal of the archwire, and are unreliable to withstand the masticatory forces of the mouth. 
   SUMMARY OF THE INVENTION 
   The self-ligating orthodontic appliance of the present invention provides a bracket having a configuration that minimizes the trapping of food particles and enhances patient comfort. Further, the self-ligating bracket of the present invention is compact and easy to operate between open and closed positions for insertion or removal of an archwire. 
   The self-ligating bracket of the invention includes a base adapted to be attached to a mounting pad or band, at least one jaw hingedly mounted on the base for selective movement between open and closed positions and defining an archwire slot in closed position, and a spring member engaging the jaw or jaws and coacting with the mounting of the jaws on the base to be engageable by a suitable tool for opening the jaws and allowing an archwire to be inserted or removed. The spring member is engageable by the archwire as the archwire is inserted, and application of a force to the archwire causes closure of the jaws. 
   Where the self-ligating bracket of the invention includes a pair of jaws, they are configured so that when they are in closed position, they coact to define an archwire slot for an archwire, and if the slot is rectangular for a rectangular archwire, a torquing force can be applied by the archwire to a tooth. 
   The jaws include hinge lugs that mate and coact with hinge lugs on the base and hinge pins. The hinge is similar to a piano hinge. The hinge pins are carried by lugs while coacting lugs on the jaws include kidney-shaped openings receiving the hinge pins such as to allow the jaws to slidably move relative to the base and pivot relative to the base during opening and closing of the bracket. The sliding movement locks or unlocks the jaws. 
   In order to further insure the locking of the jaws in closed position against opening, locking teeth may be provided on the base and the lugs of the jaws to interengage when the jaws are in closed and retaining position. 
   Preferably, the base is provided with a mounting pad in the form of cured plastic material of a suitable polymer resin to enable the bracket to be bonded to a tooth with a suitable bonding material. A foil/mesh bonding pad may also be attached to the base to allow bonding of the bracket to a tooth. It should also be appreciated that a band may be attached to the base for banding the bracket to a tooth. With respect to providing a cured polymer resin bonding pad, it should be appreciated that the bracket may also be provided with an uncured light-curable layer of polymer resin and shipped by the manufacturer to a user so that it may be directly mounted onto a tooth and where the uncured layer may be cured by a suitable light source to securely bond the bracket to a tooth. 
   Moreover, it should be appreciated with respect to the bracket of the invention to be adapted for the straight-wire technique and various prescriptions, functions or values may be built into the mounting pad and/or bracket configuration to provide tip or angulation, torque, rotation, and in/out values according to well known prescriptions for various systems. In this respect, the configuration of the mounting pad and the orientation of the bracket on the pad may attain a desired value, and/or the bracket may be rhomboidally shaped in the buccolingual (side) profile and/or labiobuccal (front) profile. Further, the rotation function or value and/or other functions may be built into the configuration of the archwire slot. For simplicity, the values for the bracket illustrated herein are zero. 
   It is therefore an object of the present invention to provide a new and improved self-ligating orthodontic appliance for use in the orthodontic treatment of patients that can be economically manufactured and easily handled by a professional user during treatment. 
   Another object of the present invention is to provide a new and improved self-ligating orthodontic bracket configured to minimize areas for trapping food particles and to enhance patient comfort. 
   A further object of the present invention is in the provision of a self-ligating orthodontic bracket having a pair of jaws pivotally and movably mounted to a base and connected to a spring member for coacting to drive the jaws to be selectively opened for insertion or removal of an archwire and closed for retention of an archwire. 
   A still further object of the present invention is to provide a new and improved self-ligating orthodontic bracket that will enhance the treatment of patients and reduce chair time for the professional user. 
   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. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an enlarged perspective view of the self-ligating orthodontic bracket of the present invention with a plastic bonding pad and mounted on a tooth, and illustrating the bracket in closed position for retaining a rectangular archwire that is shown in phantom; 
       FIG. 2  is an enlarged perspective view of the bracket of  FIG. 1  and showing the jaws in open position for removal or insertion of an archwire and showing the archwire in phantom; 
       FIG. 3  is an enlarged front elevational view of the bracket of  FIGS. 1 and 2  showing the jaws of the bracket in open position and underlying structure in dotted lines; 
       FIG. 4  is an enlarged exploded perspective view of the bracket of the present invention without a mounting pad to show the configuration of the bracket parts; 
       FIG. 5  is an enlarged vertical sectional view taken through the bracket of the invention with an archwire in phantom, and taken substantially along the line  5 — 5  of  FIG. 1  which shows the bracket closed to retain an archwire; 
       FIG. 6  is an enlarged vertical sectional view of the bracket to show the jaws slidably moved in an intermediate position during the opening cycle, and showing the application of a tool to the spring; 
       FIG. 7  is an enlarged vertical sectional view of the bracket with the jaws in fully open position to easily allow the insertion or removal of an archwire; 
       FIG. 8  is an enlarged top plan view of the bracket of the invention with the jaws in closed position and showing some underlying parts in dotted lines and an archwire retained by the archwire slot formed by the jaws; 
       FIG. 9  is a greatly enlarged side elevational view of one of the jaws of the bracket of the invention; and 
       FIG. 10  is an enlarged fragmentary sectional view of a jaw illustrating the series of movable and pivotal positions of the jaw between open and closed positions. 
   

   DESCRIPTION OF THE INVENTION 
   Referring now to the drawings, and particularly to  FIGS. 1 to 4 , the self-ligating bracketing of the present invention, generally indicated by the numeral  15 , includes generally a base  16 , a pair of jaws  18  and  20  hingedly mounted on the base for slidable and pivotal movement, hinge pins  22  and  24  connected to the base and coacting with the jaws, and a spring member  26 . 
   The bracket of the invention, where shown mounted on a tooth in  FIGS. 1 to 3  and  5  to  8 , includes a polymer resin bonding pad  28  bondable to the outer surface of a tooth at the labial. It will be appreciated that the bonding pad is preferably molded to the base  16  and serves to be adhesively bonded to a tooth such as the labial face of a tooth  29 . While the bracket of the invention is preferably labially mounted on teeth, it should be appreciated that it could be structured for mounting lingually if so desired. Further, it should be appreciated that while the mounting pad of the bracket is preferably a polymer resin mounting pad such as disclosed in copending application Ser. No. 10/285,742 filed Nov. 1, 2002, also owned by the assignee of the present application, the base could be attached to a foil/mesh bonding pad for bonding to a tooth or to a band for banding to a tooth. 
   It should be further appreciated that the bracket of the invention may be made of metal, whether it is cast or machined, or it may be made of ceramic or plastic. Moreover, it should be appreciated that the base may be made of metal, while the jaws could be made of ceramic or plastic in order to enhance the aesthetics of the bracket. Likewise, the hinge pins and the spring may also be made of metal or a suitable plastic. 
   Further, as above mentioned, it should be appreciated that the configuration of the bracket and/or mounting pad may be such as to provide tip or angulation, torque, rotation, or in/out compensation functions or values in accordance with the usual prescriptions or systems desired by users. One or more of the functions may be incorporated in any one bracket. Further, the bracket, together with the mounting pad, may be rhomboidally shaped along the buccolingual (side) profile to produce a torque value, or along the labiobuccal (front) profile to produce a tip or angulation profile. 
   While the bracket of the invention is illustrated as having a rectangular slot for receiving a rectangular archwire, it will be appreciated that a round archwire could be retained by the bracket in such a slot if desired. Round archwires are often used in early stages of treatment, while rectangular archwires are used in the final stages of treatment in order to provide final positioning of the teeth. Further, the shape of the archwire slot could be other than rectangular if desired. 
   The base  16  of the bracket, as particularly seen in  FIG. 4 , includes a base plate  30  having a series of spaced apart lugs or ears  32  at the gingival end of the base plate and in opposing relation a series of lugs or ears  34  at the occlusal end of the base plate. The lugs  32  are spaced from the lugs  34  but preferably in identically opposite positions on the base plate  30 . Each of the lugs or ears  32  includes hinge pin bores or holes  36 , while each of the lugs  34  includes hinge pin bores or holes  38 . When assembling the bracket parts as further explained below, the hinge pin holes  36  will receive a hinge pin  22 , while the hinge pin holes  38  will receive a hinge pin  24 . 
   Each of the jaws  18  and  20  is L-shaped and provided with lugs or ears that coact with the lugs or ears on the base. These jaws are identical, but placed in opposing relation when mounted on the base. The upper or gingival jaw  18  includes a leg  44  having lugs or ears  46  at one end and an arm  48  at the other end extending substantially perpendicular to the leg  44  such that an L-shaped face  50  is defined for contact with the rectangular archwire as shown by the rectangular archwire  52  in phantom in  FIG. 1 . Each of the lugs or ears  46  includes a hinge pin opening  56  configured to allow movement of the jaw laterally and pivotally with respect to the base, as further explained below. The openings are substantially kidney-shaped. 
   The opposing or occlusal jaw  20  is essentially identical to the jaw  18  but functions oppositely to the jaw  18 , while both jaws coact to open or close the bracket and collectively define a rectangular archwire slot when closed. The jaw  20  includes a leg  58  having ears or lugs  60  at one end and an arm  62  at the other end extending perpendicular to the leg to coact with the leg and form an L-shaped face  64 . Hinge pin openings or holes  66  are provided in the lugs  60 . The shape of the openings is substantially kidney-shaped to permit the jaw to have a movable and pivotal relation with respect to the base. The pin openings  36  align with each other axially as do the pin openings  38  on the base. Similarly, the pin openings  56  align with each other on the jaw  18 , while the pin openings  66  on the jaw  20  align with each other. 
   The spring  26  includes an elongated flat body  68  and tangs  70  and  72  at opposite edges engageable in slots formed in the lugs or ears of the jaws, as seen particularly in  FIGS. 5 to 7 . The tangs  70  are received in slots or notches  74  at the inwardly facing side of the lugs  46 , while slots or notches  76  of the jaw  20  receives tangs  72  of the spring. Between the lugs  46  on the jaw  18  and the lugs  60  on the jaw  20  and adjacent thereto and at the same ends of the legs  44  and  58 , arcuately formed surfaces  78  and  80  are formed to accommodate the arcuately formed ends of the lugs  32  and  34  on the base  16 . 
   Locking teeth or serrations are provided on the base plate  30  of the base  16  and the ends of the lugs of the jaws to serve to assure locking of the jaws when in closed position to resist opening of the jaws due to the masticatory forces generated during chewing. More particularly, as seen in the figures and particularly in the vertical sectional views  5 ,  6  and  7 , teeth or serrations  82  are provided on the base plate  30  between the lugs  32 , while teeth or serrations  84  are provided on the base plate  30  between the lugs  34 . Coacting with the teeth  82  on the base plate are teeth or serrations  86  on the ends of the lugs  46  of the jaw  18 . Coacting with the teeth  84  on the base plate  30  are teeth or serrations  88  on the ends of the ears  60  of the jaw  20 . The teeth may be slanted in either direction or not at all. Alternatively, the interengaging teeth may be located on the base plate lugs and the arcuate faces  78  and  80  on the jaws. 
   When the jaws, hinge pins, and spring are assembled with the base, preferably the hinge pins, which extend through the holes in the ears on the base and the holes in the ears on the jaws, are fitted to the base such that they cannot be removed. It is not necessary that the pins be rotatable in the holes on the base as they serve to provide anchorage for the ears of the jaws. The tangs of the spring are preferably connected to the slots or notches in the ears of the jaws. For example, the tangs may be adhesively bonded, staked or tack-welded to the ears. It is also possible that the spring may be cast integrally with the casting of the lugs. 
   The operation of the bracket between open and closed positions is particularly illustrated in  FIGS. 5 ,  6  and  7 , where in  FIG. 5  the jaws of the bracket are shown in closed and locked position, and in  FIG. 6  the jaws are shown slidably moved to an intermediate position during the opening cycle, and in  FIG. 7  the jaws are pivoted to the fully open position. In the closed position the jaws retain the archwire in the archwire slot, while in the open position the jaws allow the archwire to be inserted or removed. Starting with the closed position in  FIG. 5 , it will be particularly noted that the ends of the jaw arms  48  and  62  are slightly spaced apart to facilitate the opening and closing of the jaws as they move along and pivot on the hinge pins  40  and  42 . A greatly enlarged view of the jaw  20  is shown in  FIG. 9  to emphasize the shape and orientation of the pin hole  66  of an ear  60 . As above mentioned, the pin hole is kidney-shaped, and when viewing the longitudinal axis of the pin hole as indicated by the numeral  90  in  FIG. 9 , the axis is inclined relative to the leg  58  toward the arm  62 . 
   The kidney-shaped openings of the jaw lugs include a bump or node  92  centrally between the opposite ends of the opening and configured such that the hinge pin  24  will be disposed on one side of the bump when the jaw is in closed position and on the other side of the bump when the jaw is in open position. These positions apply to all of the ears of each of the jaws, but for clarity will only be described relative to the ears  60  of the jaw  20 . The elongated kidney-shaped hole  66  may be considered as a cam hole, and bump  92  may be referred to as a cam lobe where the hinge pin  24  with the jaw in closed position is at the top of the cam opening, while in the open position the hinge pin is in overcenter position at the bottom of the cam opening. Thus, the configuration of the kidney-shaped opening allows slidable movement of the jaw along the axis  90  and pivotal movement when the ears of the jaws are positioned such that the pins are at the bottom of the cam openings. 
   The spring moves away from the base during opening of the jaws and toward the base during closing of the jaws and in each position respectively holds the jaws in open or closed position. Manipulation of the spring  26  causes operation of the jaws. Opening of the jaws is produced by use of a tool such as a dental explorer  94 , as seen in  FIG. 6 , to engage against the underside of the spring  26  and apply a force outward of the bracket. The force initially causes the spring to buckle and then the jaws to slide outwardly away from the base  16  as the cam openings in the jaw lugs move overcenter of the hinge pins. Also, the locking teeth on the base and the jaw lugs disengage. When the jaws reach the position where the bottom ends of the cam openings or slots of the jaw lugs align with the hinge pins as shown in  FIG. 7 , the spring causes the jaws to open fully and allow easy insertion or withdrawal of the archwire. 
   Closing of the jaws to form the archwire slot for connecting the archwire to the bracket is produced by inserting the archwire to engage against the spring and then applying pressure on the archwire on opposite sides of the bracket to drive the spring inwardly toward the base of the bracket, and causing first the pivoting of the jaws inwardly toward each other and then sliding of the jaws along the hinge pins into the closed position, as shown particularly in  FIG. 5 , where the jaws are locked in overcenter position as to the cam holes and hinge pins and in closed position by the spring with the teeth in matching engagement to fully retain the archwire on the bracket. Again, the slots move overcenter of the hinge pins. Because there is a slight movement of the jaws toward each other during the opening cycle, clearance is provided between the ends of the jaw arms, as shown in exaggerated form in  FIG. 5 , so that they will be able to come toward each other during that sliding movement of the jaws until the lug slots move overcenter relative to the hinge pins. It will be appreciated that a tool could be applied at either or both sides of the bracket to engage under the spring for exerting a force to open the jaws while closing of the jaws is accomplished by applying a force to the archwire to drive the spring toward its inner closed position, as shown in  FIG. 5 . 
   The outer corners and surfaces of the jaws are suitably rounded and smooth in order to eliminate any sharp edges and enhance patient comfort. It will also be appreciated that when the jaws are in closed position, food particles will just move on over the smooth surface of the jaws and not become lodged in any cavities. 
   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 the invention in this application is to be limited only by the scope of the appended claims.