Abstract:
An orthodontic bracket has a base with a slot configured to receive an archwire. A cover is hingedly fastened to the base and is operable between an open and closed position. The cover covers at least a portion of the slot on the base when in the closed position. A spring element extends between the base and the cover.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. The Field of the Invention  
           [0002]    The present invention relates to orthodontic brackets.  
           [0003]    2. The Relevant Technology  
           [0004]    Orthodontic brackets are secured to a patient&#39;s teeth for use in selectively straightening the patient&#39;s teeth. One type of orthodontic bracket known in the art includes a base having a slot formed thereon. The slot is configured to receive an archwire that extends between different teeth. A separate cover plate is removably attached to the base for use in securing the archwire to the base. One example of the above orthodontic bracket is disclosed in U.S. Pat. No. 4,712,999.  
         BRIEF SUMMARY OF THE INVENTION  
         [0005]    One object of the present invention is to develop an orthodontic bracket of the kind known in the prior art that is low-cost, simple to manufacture, and compact in construction.  
           [0006]    The above and other objects of the present invention are satisfied by the features of the present invention as claimed herein and in particular by an inventive orthodontic bracket having a cover and base that are integrally connected together as a single piece. The inventive orthodontic bracket is low-cost and simple to manufacture. This is due in part to the fact that the orthodontic bracket comprises only one single component which does not have to be assembled. In addition, in one embodiment the inventive orthodontic bracket is made from only one single material, preferably plastic. Furthermore, the cover is integrally formed with the base so as to prevent unwanted separation.  
           [0007]    Advantageous embodiments are described in the description, the dependent claims and the figures.  
           [0008]    In accordance with a first embodiment, a hinge between the base and the cover can be formed by a reduction in the material cross-sections in the hinge region. The orthodontic bracket can be formed in a compact manner by the use of such hinges, which are also known as integral hinges or living hinges.  
           [0009]    As an alternative to the integral one piece embodiment of the orthodontic bracket, the cover and the base can be connected to one another via a pluggable connection. This connection permits separation of the cover and the base without tools. The cover can, for example, be connected to the base via a grooved and tongued connection, for example in a dovetail form. It is possible in this way to put the cover onto the base via the pluggable connection, with the groove and tongue being formed so that a force fit is ensured with full insertion.  
           [0010]    This last-mentioned embodiment has the advantage that a subsequent fastening of the cover to the base is possible. This can be advantageous for certain positions of the teeth in tight space conditions. It is also possible with this embodiment to remove the cover from the base in a simple manner and, where required, to replace it with a further cover which is merely placed onto the base. Such a procedure is advantageous when it is not or is no longer possible to pivot the cover around the base due to tight space conditions.  
           [0011]    In accordance with a further advantageous embodiment, the orthodontic bracket includes a spring element which supports the closing and opening movement of the cover. This ensures that the cover is held in the open position by the spring element so that the opened cover does not hinder the insertion of the archwire. In one embodiment, the spring element is connected to the base and the cover via hinges. The hinges are preferably formed by a reduction of the material cross-sections in the hinge region. The resulting orthodontic bracket has a compact configuration despite the provision of the spring element. Low-cost manufacturing is ensured by the possibility of the bracket being made in one piece, for example, as an injection molded plastic part.  
           [0012]    It is particularly advantageous if the spring element is fully integrated in the cover so that the bracket does not have any protruding parts or edges when in the closed state. The comfort in wear is fairly significantly increased in this way since no edges are present which could have an irritating effect for the patient in the mouth region.  
           [0013]    In accordance with a further embodiment of the invention, the cover can have a recess which is open to the outside, but closed to the inside, and in which the spring element is completely received in the closed state of the cover. One advantage of this embodiment is that the spring element is completely integrated in the cover with respect to its outside so that a pleasant manner of wear results for the patient.  
           [0014]    At the same time, however, the cover is completely closed in the region of the spring element. As a result, no remnants of food or the like can penetrate the inside of the cover.  
           [0015]    In accordance with a further advantageous embodiment of the present invention, a reinforcement insert is provided on the base in the region of the slot. The reinforcement insert can be worked into the basic material of the bracket in the manufacturing process. This ensures that the forces acting in the region of the archwire are transferred without loss to the base and thus the tooth to be corrected. At the same time, the manufacturing costs are also reduced in this case since the bracket can be made of plastic in total and only the reinforcement part is made of a hard material, for example, metal.  
           [0016]    The bracket in accordance with the invention is preferably formed in a self-ligating manner, i.e., the archwire is clamped between the cover and the base. It can be advantageous for this purpose for a plurality of locking recesses to be provided on the cover or the base in order to close the cover at different opening widths. Archwires having different cross-section sizes can be inserted into the slot in this way and be fixed there by closing the cover.  
           [0017]    In one embodiment the cover is designed to cover the base along the whole outer contour and to extend preferably to the bottom of the base. This ensures that no contamination (food remnants) can enter into the inside of the bracket. Furthermore, the comfort in wear is considerably improved by a smooth, edge-free shape of the cover.  
           [0018]    In accordance with a further aspect of the present invention, the invention comprises an orthodontic bracket kit. The kit includes at least one bracket having a cover integrally hinged to the base and a second, separate cover configured to attach to the base. The second cover does not have a shaped spring element, but rather locking elements for fastening the second cover to the base. In this embodiment, after the first integrally attached cover has been severed from the base, such as by use of a scalpel, the second cover can be put onto the base. Such a bracket kit allows the severing of the originally provided cover and the replacement of this cover with a separate cover. The second cover can be pressed onto the base in tight space conditions.  
           [0019]    These and other objects and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    The present invention is described below by means of example embodiments and with reference to the enclosed drawings, in which are shown:  
         [0021]    [0021]FIG. 1 is a cross sectional side view of an orthodontic bracket having an open cover;  
         [0022]    [0022]FIG. 2 is a cross sectional side view of the bracket shown in FIG. 1 with the cover closed;  
         [0023]    [0023]FIG. 3 is a cross sectional side view of the bracket shown in FIG. 1 with an alternative cover which is not connected to the base in one piece;  
         [0024]    [0024]FIG. 4 is a perspective view of a further embodiment of a bracket having an open cover; and  
         [0025]    [0025]FIG. 5 is a perspective view of the bracket shown in FIG. 4 with the cover closed.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    The orthodontic bracket shown in FIGS. 1 and 2 is manufactured in one piece as an injection molded plastic part. The orthodontic bracket has an approximately anvil-like base  10  to which a cover  20  is hingedly connected. A slot  11  open to the upper side of the base  10  is provided at the center of said base  10  and serves for the insertion of an archwire  15 . A reinforcement insert  13  is provided in the region of the slot  11 . The reinforcement insert  13  is formed from a metal material and has a U-shape in cross-section. The basic material of the bracket is molded round the reinforcement insert  13  in the manufacturing process. The archwire  15  with a square cross-section is arranged inside the slot  11  and serves to correct the teeth in a known manner.  
         [0027]    The cover  20  forms an approximately L-shaped hood in cross-section and is connected in one piece to the base  10  via an integral hinge  2   a.  Two exit apertures, which are not shown in FIGS.  1 - 4  and which are opposite to one another, are provided in each case in the cover  20 . The cover  20  also has an insertion slot (cf.  32 ″ and  34 ″ in FIG. 5) for the passage of the archwire  15  following on from the lower edge of the cover.  
         [0028]    A spring element  23  with an approximately L-shaped cross-section is hinged via a joint  8   a  in the region of the bottom  30  of the base  10 . That is, the spring element  23  is attached via an integral hinge which is formed in the same way as the integral hinge  2   a,  i. e., by a corresponding reduction in the material cross-sections during injection molding. The spring element  23  is further hinged to the outside of the cover  20  via a further integral hinge  8   b  of the same design. The spring element  23  is connected roughly at the middle of the cover  20 .  
         [0029]    As is shown in particular in FIG. 2, the spring element  23  is completely integrated in the cover  20 . As a result, the spring element  23  forms a hood-shaped, closed protective shell together with the cover  20  and said shell surrounds the complete outside contour of the base  10 . A recess  24 , open to the outside, but closed to the inside, is provided at the outside of the cover  20  for the integration of the spring  23  in the cover  20 . The spring element  23  is completely received in the recess  24  in the closed state of the cover  20  so that the upper sides of the cover  20  and the spring element  23  form a uniform, continuous surface.  
         [0030]    A plurality of locking recesses  16  are provided at the inside of the cover  20 . The locking recesses  16  enable the cover  20  to be able to latch onto a closing nose  17  of the base  10 .  
         [0031]    Furthermore, a holding cam  14  is provided at the inside and middle of the cover  20  and fixes the archwire  15  in the slot  11  in the closed state (FIG. 2). The fixing is effected here only by closing the cover  20  and latching the locking recess  16  via the closing nose  17 , i.e., the bracket is self-ligating.  
         [0032]    As is illustrated in particular by FIG. 1, the integral hinge  8   b,  which serves as a joint, moves on a circular arc with a radius R 1  when the cover  20  is opened and closed. If the spring element  23  were not connected to the cover  20 , the joint axis of the integral hinge  8   b  would move on a circular arc with a radius R 2  during rotation around the axis of the integral hinge  8   a.  However, due to hinge  8   b  being fixed at the cover  20 , it necessarily moves on the circular arc with the radius R 1 . The spring element  23  is elastically deformed in this way during the opening and closing process, with the maximum extension preferably being achieved in each case at approximately half the opening or closing angle. The spring force of the spring element  23  hereby supports the opening and closing of the cover  20  in the event of over- or underachievement of this angle in the one direction or the opposite one. When this angle is overachieved or underachieved, the spring element  23  is extended by the maximum path X.  
         [0033]    [0033]FIG. 3 shows a cross-section through a bracket in accordance with FIGS. 1 and 2, with, however, the cover  20  having been removed using a tool, for example a scalpel, by cutting through the integral hinges  2   a  and  8   a . Such a measure can be necessary in particular when it is not or no longer possible for the cover  20  to flip open due to a certain tooth position. In this case, a second, separate cover  20 ′ (FIG. 3) is provided. The cover  20 ′ is formed approximately in a U-shape in cross-section and has a plurality of peripheral locking recesses  16 ′ at its inside which can slide over the locking nose  17  of the base, whereby the cover  20 ′ latches on the base  10 . The cover  20 ′ is accordingly essentially formed in a hood-like manner and has, like the cover  20 , a holding cam  40  at its inside which holds the archwire  15 .  
         [0034]    A further embodiment of a bracket in accordance with the invention is shown in FIGS. 4 and 5. The base  10  shown corresponds here to the base  10  of FIGS.  1  to  3 . The base  10  in FIG. 4, however, includes a further slot  12  that is provided in addition to the slot  11  to receive the archwire  15 . The further slot  12  extends transversely to the slot  11  and is capable of use in a known manner to help fix the archwire. The cover  20 ″ is also formed in a hood-like manner and connected in one piece via an integral hinge  8 ″ b  to a joint element  23 ″. The joint element  23 ″ is formed in the same way as the spring element  23  of the embodiment in accordance with FIGS. 1 and 2. The element  23 ″ does not, however, act as a spring element in the embodiment of FIGS. 4 and 5, but as a joint part. A recess  24 ″, open to the outside, but closed to the inside, is, however, provided at the outside of the cover  20 ″ in the same way as in the embodiment in accordance with FIGS. 1 and 2. The element  23 ″ is completely received in said recess  24 ″ in the closed state of the cover  20 ″.  
         [0035]    The end of the joint part  23 ″ opposite the integral hinge  8 ″ b  is pushed into the groove of the base  10  in a form-locking manner, i.e., the joint part  23 ″, and thus also the cover  20 ″, are insertably fixed to the base  10 . At the same time, a further integral hinge is provided in this region so that the joint part  23 ″, and thus also the cover  20 ″, can be pivoted such that the cover  20 ″ can be placed onto the base  10 .  
         [0036]    Peripheral locking recesses (not shown) are in turn provided on the inside of the cover  20 ″ and are formed in accordance with the locking projections  16 ′ of FIG. 3. It is possible in this way to clip the cover  20 ″ onto the base  10  after flipping over. FIG. 5 shows such a state in which the cover  20 ″ is clipped onto the base  10 . The exit aperture  32 ″ already mentioned above can also be seen in this figure. An insertion slot  34 ″ extending to the lower edge of the cover  20 ″ and serving the passage of the archwire  15  follows on from said exit aperture  32 ″. The cover  20 ″ has two such insertion slots with connecting exit aperture, as do the covers  20  and  20 ′. These elements are, however, not shown in FIG. 4 for a more simplified representation.  
         [0037]    The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.  
         [0038]    What is claimed and desired to be secured by U.S. Letters Patent is: