Abstract:
A plurality of self-ligating orthodontic brackets for use in orthodontic treatment wherein varying progressive forces against an archwire occur. In one variant, the varying forces are a result of the angle of the locking shutter. In another variant, the varying forces are a result of the curvature of the locking shutter. In a third variant, the varying forces are a result of a combination of the two.

Description:
RELATED APPLICATION DATA 
       [0001]    This application claims priority from U.S. Provisional Application No. 62/039,623 filed on Aug. 20, 2014, and U.S. Provisional Application No. 62/112,957 filed on Feb. 6, 2015; all of which are herein incorporated by reference in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to the field of orthodontic brackets, and more particularly to biocompatible self-ligating brackets. 
       BACKGROUND OF THE INVENTION 
       [0003]    As is known, orthodontic treatment is effected by fixing small appliances called orthodontic brackets to a patient&#39;s teeth. Namely, the orthodontic brackets are most commonly used by being fixed to the patient&#39;s teeth in an appropriate manner so as to correct the misaligned teeth by applying an external force thereto through an arch wire extending between the fixed orthodontic brackets. As to the structure of these orthodontic brackets, they are constructed of a body having small slots and are adhered directly on the labial or lingual sides of the teeth or welded to such as metal bands attached to the teeth by cementing or by some other method. 
         [0004]    It is well known that the front incisor teeth have single roots that are thin and that these roots are generally more tapered roots susceptible to root resorption or shortening during orthodontic treatment. Often times, when root resorption or shortening is observed in a patient with orthodontics, it is attributed to the magnitude of orthodontic force exerted on the roots by the braces. 
         [0005]    In contrast, the middle premolar teeth have larger and thicker roots and the back molars have even larger, and multiple roots that can absorb the generally higher normal orthodontic forces for dental movement than the smaller front teeth. Heretofore, prior art orthodontics, and in particular, prior art self-ligating brackets have been unable to accommodate the varying root sizes and strengths to reduce the risk of root resorption and/or shortening during orthodontic treatment. 
       SUMMARY OF THE INVENTION 
       [0006]    In accordance with the invention there is provided a set of self-ligating orthodontic brackets that exert progressively lighter forces from the back molars to the front incisor teeth, by altering the angle at which a locking shutter engages an archwire used in the orthodontic treatment. The invention provides for a number of exemplary embodiments for effecting a set of orthodontic brackets having progressively lighter forces. 
         [0007]    It is an object of the invention to provide a set of biocompatible self-ligating orthodontic brackets. It is a further object of the invention to provide a set of orthodontic brackets that are adaptable to exert different forces on different types of teeth to mitigate one or more of the problems with the prior art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The novel features which are believed to be characteristic of the present invention, as to its structure, organization, use and method of operation, together with further objectives and advantages thereof, will be better understood from the following drawings in which a presently preferred embodiment of the invention will now be illustrated by way of example. It is expressly understood, however, that the drawings are for the purpose of illustration and description only, and are not intended as a definition of the limits of the invention. In the accompanying drawings: 
           [0009]      FIG. 1  shows a set of self-ligating brackets having a flat, angled locking shutter as contemplated by the invention. 
           [0010]      FIG. 2  shows a set of self-ligating brackets having a curved locking shutter according to another embodiment of the invention. 
           [0011]      FIGS. 3 to 5  shows a set of self-ligating brackets having a curved angled locking shutter according to another embodiment of the invention. 
           [0012]      FIG. 6  shows occlusal view of the clip in a closed position where only the bottom end of the thin low profile and active clip is visible. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0013]    According to one embodiment of the invention, there is provided a set of self-ligating orthodontic brackets adapted to exert progressively lighter forces from the back of the mouth towards the front of the mouth, whereby the forces applied to the molar teeth are higher than those applied to the premolar teeth, which are themselves higher than those applied to the canines, which are themselves higher than those applied to the front incisor teeth. Referring now to  FIG. 1 , there is shown a set of such brackets. The general structure and arrangement of brackets according to the first embodiment is as disclosed in United States Patent Publication No. 2013/0260329 to John Voudouris, the contents of which are herein incorporated in their entirety by reference. In the &#39;329 publication, an orthodontic bracket is shown having an angled locking shutter. 
         [0014]    With reference to  FIG. 1 , the first embodiment of the invention provides for a set of these orthodontic brackets  100 ,  120 ,  140 ,  160 . The brackets have a pair of gingival tie wings  110  and a pair of occlusal tie wings  112  shown in profile. A bonding pad  114  is used for attachment to the tooth (not shown). An archwire slot  104  extends mesio-distally across the body of the bracket permitting placement of an archwire  106  therein. The brackets in the set have the slidable locking shutter  102  placed in one or more tracks or channels  108  either internal to the occlusal tie wings  112  or on the exterior surface of the occlusal tie wings  112 . The tracks  108  extend at progressively smaller angles, θ, such that a distance from the base of the archwire slot  104  to the locking shutter  102  in a direction perpendicular to the surface of the tooth is progressively greater from the molar bracket  100  to the premolars bracket  120  to the canine bracket  140 , and to the incisors bracket  160 . This arrangement in the kit provides for progressively lighter forces to be applied depending on the type of tooth, as illustrated in  FIG. 1 . In preferred embodiments, the slidable locking shutter  102  for the molar bracket  100  is angled between about 15-18 degrees from a straight vertical line perpendicular to a horizontal line to the bottom of the archwire slot  104  when viewed from the side as shown in  FIG. 1 . The locking shutter  102  associated with a premolar bracket  120  is angled between about 9-14 degrees, while the locking shutter  102  associated with the canine bracket  140  is angled between about 7-8 degrees, and finally the locking shutter  102  associated with the incisor bracket  160  is angled between about 1-7 degrees. All angular references are made with respect to the reference planes as earlier described. 
         [0015]    Accordingly, as will be understood by a person skilled in the art, that in varying the angle, θ, of the locking shutter of the self-ligating brackets as described with respect to the first embodiment, as shown in  FIG. 1 , in a set or kit of orthodontic treatment brackets, varying forces can be placed on individual teeth to accommodate for different root sizes and thickness and therefore, mitigate the risk of root resorption. 
         [0016]    According to a second embodiment of the invention, as illustrated in  FIG. 2 , there is provided a set or kit of self-ligating brackets for orthodontic treatment having the general shape and structure as described in United States Patent Publication No. 2014/0134563 to OrthoArm, Inc., incorporated herein by reference. These brackets are of the structure having a curved locking shutter as described in the &#39;563 publication, and in various prior applications. The general structure of this type of orthodontic bracket to which the invention is applied is also known in the art. The invention lies in the provision of brackets in a kit as herein described. 
         [0017]    With reference to  FIG. 2 , the second embodiment of the invention provides for a set of these orthodontic brackets  200 ,  220 ,  240 ,  260 . The brackets have gingival tie wings  110  and occlusal tie wings  112  and an archwire slot  104  having an archwire  106  therein. The brackets in the set have a curved locking shutter  102 , having a clip portion  202  which engages the archwire  106  at progressively smaller angles, θ, such that a distance from the base of the archwire slot  104  to the clip portion  202  in a direction perpendicular to the surface of the tooth is progressively greater from the molars to the premolars to the canines, and to the incisors. This arrangement in the kit provides for progressively lighter forces to be applied depending on the type of tooth, as illustrated in  FIG. 2 . The shutter  102  passes through one or more channels  108  that retain the shutter  102  in the occlusal tie wings  112 . In preferred embodiments, the locking shutter  102  for the molar bracket  200  has an end portion  202  that is angled between about 15-18 degrees from a straight vertical line perpendicular to a horizontal line to the bottom of the archwire slot  104  when viewed from the side as shown in  FIG. 1 . The locking shutter  102  associated with a premolar bracket  220  is angled between about 9-14 degrees, while the locking shutter  102  associated with the canine bracket  240  is angled between about 7-8 degrees, and finally the locking shutter associated with the incisor bracket  260  is angled between about 1-7 degrees. All angular references are made with respect to the reference planes as earlier described. 
         [0018]    With reference to  FIGS. 3 to 6 , the third embodiment of the invention provides for a set of orthodontic brackets  300 ,  320 ,  340 ,  360  having a curved locking shutter  102  similar to the brackets of  FIG. 2 . Similar numbered elements have been omitted from brackets  320 ,  340 , and  360  for clarity. The brackets in the set have a curved locking shutter  102  with a clip portion  202  and a curved portion  302 . The curved portion  302  does not extend completely through the channel  108  towards the bonding pad  114  as in the second embodiment. The material between the bonding pad  114  and the archwire slot  104  is reduced or minimized in order to lower the profile of the brackets  300 ,  320 ,  340 ,  360  as more clearly shown in  FIG. 6 . The channels  108  may have one or more recesses  304  and  306  wherein the uppermost recess  304  holds the shutter  102  within the occlusal tie wing  112  while the shutter  102  is in an open position (shown in  FIG. 5 ). The bottommost recess  306  holds the shutter  102  in position while the shutter  102  is in a closed position (shown in  FIGS. 3 and 4 ). 
         [0019]    Accordingly, various embodiments of the invention have been described above, that have the effect of a progressive, graduated force being applied on the dentition consistent with the respective root anatomy for more highly effective, efficient and biocompatible tooth movement that reduces the risk for root resorption. The invention is not limited to the embodiments herein described. Rather, variations on the above-described embodiments that produce a kit or set of self-ligating brackets for orthodontic treatments having clips that differ from each other to apply light, medium and normal forces to the front, middle and back teeth, respectively, are also contemplated by the invention.