Abstract:
An orthodontic brace includes a set of orthodontic brackets for a dental arch that comprises at least one central incisor bracket, one lateral incisor bracket, and one cuspid bracket. Each bracket of the set lacks occlusal tiewings. Without occlusal tiewings, interferences with opposing teeth are substantially reduced and patient comfort, hygiene, and bracket aesthetics are enhanced.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention broadly relates to braces used in orthodontic treatment. More particularly, this invention relates to orthodontic braces that have a reduced profile. 
         [0003]    2. Description of the Related Art 
         [0004]    Orthodontic therapy is a specialized type of treatment within the field of dentistry, and involves movement of malpositioned teeth to improved locations along the dental arches. Orthodontic treatment often enhances the patient&#39;s facial appearance, especially in regions near the front of the oral cavity. Orthodontic treatment can also improve the patient&#39;s occlusion so that the teeth function better with each other during mastication. 
         [0005]    Many types of orthodontic treatment programs involve the use of a set of appliances and archwires that are commonly known collectively as “braces”. During such treatment programs, tiny slotted appliances known as brackets are fixed to the patient&#39;s anterior, cuspid and bicuspid teeth. The slots of these brackets receive an archwire, allowing the archwire to guide the teeth into orthodontically correct locations during the course of treatment. End sections of the archwires are often captured in tiny appliances known as molar tubes that are fixed to the patient&#39;s molar teeth. 
         [0006]    Orthodontic brackets often have small wings known as “tiewings” that are connected to a body of the bracket. Once the bracket has been attached to a tooth and an archwire has been received into the archwire slot of the bracket, a ligature is coupled to the bracket in order to retain the archwire in the archwire slot. One common type of commercially available orthodontic ligature is a small, elastomeric O-ring that is installed by stretching the O-ring along a path behind the tiewings and over the facial side of the archwire. Another option is to use stainless steel ligature wire, which can similarly be looped along a path behind the tiewings and over the facial side of the archwire and tightly secured by twisting together the ends. 
         [0007]    Certain types of orthodontic brackets known as self-ligating brackets are provided with a latch that allows an archwire to be coupled to the brackets without using ligatures or ligature wire. This latch may comprise a movable clip, spring member, cover, shutter, bail or other structure that is connected to the bracket body for retaining the archwire in the archwire slot. Self-ligating brackets can allow free and easy sliding of the archwire through the archwire slot, and this in turn can facilitate movement of teeth in early stages of treatment. While not required, tiewings are still used on many self-ligating brackets since they offer the practitioner increased flexibility in achieving specific treatment objectives. For example, a practitioner may elect to use ligatures for cases in which increased friction (i.e. resistance to sliding) is desirable. This in turn can help retain the teeth in their proper orthodontic positions when using a full sized archwire in the finishing stages of treatment. 
         [0008]    Self-ligating or otherwise, it is common for brackets with tiewings to have one or more tiewings residing on both the gingival and occlusal sides of the bracket. Such a design offers convenient paths for the ligature to cross over the facial side of the archwire. Brackets with four tiewings are especially common, and allow the ligature to secure the archwire in various configurations, including standard, double-over tie, figure- 8 , and corner-to-corner, each of which can be used advantageously by one skilled in the art. 
         [0009]    On occasion, a bracket on one arch (typically the lower arch) interferes with teeth on the opposite arch. In response, a practitioner may delay bonding of an appliance until the obstructive teeth have been safely moved out of the way. While this is one solution, this delay extends treatment time. Alternatively, orthodontic practitioners may elect to remove a portion or all of the tie wings from the problematic bracket, by grinding or some other means, to eliminate interferences. Using smaller sized appliances may help alleviate occlusal interferences. However, it can be challenging to reduce the size of an appliance without compromising its functionality. 
         [0010]    There is a present need in the art for an orthodontic brace that includes appliances that are smaller in size, especially a brace which can alleviate difficulties with occlusal interferences. 
       SUMMARY OF THE INVENTION 
       [0011]    This invention provides a brace for a dental arch that alleviates problems with occlusal interference and enhances patient comfort, hygiene, and bracket aesthetics. This brace comprises a set of orthodontic brackets and includes: at least one central incisor bracket, at least one lateral incisor bracket, and at least one cuspid bracket, wherein each bracket of the set includes a base, a body extending outwardly from the base, and an archwire slot extending across the body, wherein each bracket of the set includes at least one gingival tiewing and lacks any occlusal tiewing. 
         [0012]    Another aspect of the invention is directed towards a brace that comprises a set of orthodontic brackets that includes at least one central incisor bracket, at least one lateral incisor bracket, and at least one cuspid bracket, wherein each bracket of the set includes a base, a body extending outwardly from the base, an archwire slot extending across the body and a single gingival tiewing, while lacking occlusal tiewings. 
         [0013]    Yet another aspect of the invention is directed towards a brace that comprises a set of orthodontic brackets that includes at least one central incisor bracket, at least one lateral incisor bracket, and at least one cuspid bracket, wherein each bracket of the set includes a base, a body extending outwardly from the base, an archwire slot extending across the body, at least one gingival tiewing, and a latch for releasably retaining an archwire in the archwire slot of the bracket, while lacking occlusal tiewings. 
         [0014]    Still other aspects of the invention are directed towards extending the set of orthodontic brackets to include 1 st  bicuspid and 2 nd  bicuspid brackets. Yet still other aspects of the invention are directed towards extending the set of orthodontic brackets to include a bracket with a latch comprising a single centrally located clip, or with a latch comprising clips that also function as tiewings. 
         [0015]    In the aforementioned aspects of the invention, latches and/or gingival tiewings enable an archwire to be coupled to the brackets. Moreover, the absence of occlusal tiewings allows interferences between the bracket and teeth positioned on the opposite dental arch to be minimized or eliminated. This is especially useful in a “deep bite” situation in which the upper incisors descend over the lower anterior teeth in occlusion. With fewer bracket/tooth interferences, the likelihood of premature, spontaneous debonding of the interfering bracket and/or enamel damage are likewise reduced. 
         [0016]    The absence of occlusal tiewings also reduces potential irritation, swelling, and overall patient discomfort caused by brackets rubbing against the cheeks and lips of a patient throughout treatment. Hygiene is improved as well because less food and plaque is trapped beneath the tiewings during treatment. Improved patient hygiene in turn promotes improved gum health and reduced incidence of dental caries and/or decalcification. Lastly, this brace offers improved aesthetic appeal, since there are no occlusal tiewings protruding from the bracket body. The inventive orthodontic brace uses brackets that are visibly smaller. 
         [0017]    Aspects of the present invention are set out in the detailed description that follows and are illustrated in the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a front elevational view showing the lower teeth of an exemplary patient undergoing orthodontic treatment, wherein orthodontic appliances are fixed to the teeth and an archwire connected to the appliances by means of latches on said appliances. 
           [0019]      FIG. 2  is a front view of an individual bracket shown in  FIG. 1 , looking at the bracket towards its facial side. 
           [0020]      FIG. 3  is a side view of an individual bracket shown in  FIGS. 1 and 2 , looking at the bracket towards its mesial side. 
           [0021]      FIG. 4  is a perspective view of an individual bracket shown in  FIGS. 1-3 , looking at the bracket towards its mesial, facial, and occlusal sides. 
           [0022]      FIG. 5  is a side view of an assembly depicting the bracket shown in  FIGS. 1-3  coupled to an archwire by using an elastic ligature, looking at the assembly towards its mesial side. 
           [0023]      FIG. 6  is a perspective view of an assembly depicting the bracket shown in  FIGS. 1-3  coupled to an archwire by using an elastic ligature, looking at the assembly towards its mesial, facial, and occlusal sides. 
           [0024]      FIG. 7  is a front view of an orthodontic bracket according to another embodiment of the invention, looking at the bracket towards its facial side. 
           [0025]      FIG. 8  is a side view of the bracket shown in  FIG. 5 , looking at the bracket towards its mesial side. 
           [0026]      FIG. 9  is a perspective view of the bracket shown in  FIGS. 5 and 6 , looking at the bracket towards its mesial, facial, and occlusal sides. 
           [0027]      FIG. 10  is a perspective view of an orthodontic bracket according to another embodiment of the invention, looking at the bracket towards its mesial, facial, and occlusal sides. 
           [0028]      FIG. 11  is a front view of an orthodontic bracket according to another embodiment of the invention, looking at the bracket towards its facial side. 
           [0029]      FIG. 12  is a side view of the bracket shown in  FIG. 9 , looking at the bracket towards its distal side. 
           [0030]      FIG. 13  is a perspective view of the bracket shown in  FIGS. 9 and 10 , looking at the bracket towards its mesial, facial, and gingival sides. 
           [0031]      FIG. 14  is a perspective view of an orthodontic bracket according to another embodiment of the invention, looking at the bracket towards its distal, facial, and occlusal sides. 
       
    
    
     DEFINITIONS 
       [0032]    “Mesial” means in a direction toward the center of a patient&#39;s curved dental arch. 
         [0033]    “Distal” means in a direction away from the center of a patient&#39;s curved dental arch. 
         [0034]    “Occlusal” means in a direction toward the outer tips of a patient&#39;s teeth. 
         [0035]    “Gingival” means in a direction toward the patient&#39;s gum or gingiva. 
         [0036]    “Facial” means in a direction toward the patient&#39;s lips. 
         [0037]    “Lingual” means in a direction toward the patient&#39;s tongue. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0038]      FIG. 1  shows an example of a lower dental arch broadly designated by the numeral  2  of an orthodontic patient that is undergoing orthodontic treatment. An orthodontic brace  4  is connected to the teeth of the lower dental arch  2 . The brace  4  includes a set of appliances as well as an archwire that receives the appliances, as will be described in greater detail below. 
         [0039]    In this example, each tooth in the lower dental arch  2  is coupled to an orthodontic appliance. Specifically, lower central teeth  6  and lower lateral teeth  8  are coupled to lower anterior brackets  10 , cuspid teeth  12  are coupled to cuspid brackets  14 , 1 st  bicuspid teeth  16  are coupled to 1 st  bicuspid brackets  18 , 2 nd  bicuspid teeth  20  are coupled to 2 nd  bicuspid brackets  22 , first molars  24  are coupled to molar tube  26 , and second molars  28  are coupled to second molar tubes  30 . Appliances  10 ,  14 ,  18 , and  22  are of a type known as “self-ligating” brackets. Features associated with these brackets shall be described in detail in subsequent illustrations. For exemplary purposes, illustrated brackets  10 ,  14 ,  18 , and  22  and molar tubes  26  and  30  are metal appliances directly bonded to the patient&#39;s tooth enamel, although other appliances and/or methods of coupling could be used. An archwire  32  is received in the slots of brackets  10 ,  14 ,  18 , and  22 , and molar tubes  26  and  30 . 
         [0040]    The exemplary cuspid bracket  14  used in orthodontic brace  4  is shown from three different perspectives in  FIGS. 2-4 . The bracket  14  includes a base  42  and a body  44  that extends outwardly from base  42 . The body  44  includes a mesial side  46   a  along with a distal side  46   b . Body  44  also includes a pair of gingival posts  45  and a pair of occlusal posts  47 . An elongated archwire slot  38  extends in a generally mesial-distal direction across the body  44  from the mesial side  46   a  to the distal side  46   b  and between gingival posts  45  and occlusal posts  47 . Archwire slot  38  has an overall rectangular shape in transverse cross-sectional view. 
         [0041]    As previously mentioned, bracket  14  is of a type known as a “self-ligating” bracket. To this end, the bracket  14  has a latch that comprises a mesial spring clip  36   a  and a distal spring clip  36   b . Mesial spring clip  36   a  and distal spring clip  36   b  each includes a first section  37  and a second section  39  spaced from first section  37 . Between first section  37  and second section  39  resides archwire-receiving region  41 , which is aligned with archwire slot  38 . When an orthodontic archwire (not shown in  FIGS. 2-4 ) is urged in a direction toward the bottom of the archwire slot  38 , the clips  36   a  and  36   b  deflect and spread open to enable the archwire to be moved fully into archwire receiving region  41 , and hence also, archwire slot  38 . Once the archwire is seated into archwire slot  38 , the inherent resiliency of the clips  36   a  and  36   b  causes first section  37  and second section  39  to shift to their relaxed, closed position as depicted in  FIGS. 2-4  for retaining the archwire in archwire slot  38 . 
         [0042]    Preferably, the sides of the clips  36   a  and  36   b  deflect outwardly to a slot-open orientation and release the archwire from the archwire slot  38  whenever the force exerted by the archwire on the bracket  14  exceeds a certain minimum value. The minimum value is sufficiently high to prevent the archwire from unintentionally releasing from the archwire slot  38  during the normal course of orthodontic treatment. As such, the archwire can exert forces on the bracket  14  sufficient to carry out the intended treatment program and move the associated tooth as desired. Preferably, the clips  36   a  and  36   b  release the archwire from archwire receiving region  41 , and hence archwire slot  38 , in a direction perpendicular and away from the lingual side of the archwire slot  38  whenever the archwire exerts a force in the same direction on the bracket  14  that is in the range of about 0.2 lb (0.1 kg) to about 11 lbs (5 kg), more preferably in the range of about 0.4 lb (0.2 kg) to about 5.5 lbs (2.5 kg), and most preferably in the range of about 0.4 lb (0.2 kg) to about 2.7 lbs (1.25 kg). 
         [0043]    Preferably, the minimum value for self-release (i.e., self-opening) of the clips  36   a  and  36   b  is together substantially less than the force required in the same direction to debond the bracket  14  from the associated tooth in instances where the bracket  14  is directly bonded to the tooth surface. The minimum value for self-release of the clips  36   a  and  36   b  is preferably less than about one-half of the force required in the same direction to debond the bracket  14  from the associated tooth. For example, if the expected bond strength of the adhesive bond between the bracket  14  and the associated tooth is 16 lbs (7.3 kg) in the facial direction, the clips  36   a  and  36   b  are constructed to self-release the archwire whenever the archwire exerts a force in the same facial direction on the appliance  36   a  and  36   b  that is somewhat greater than about 8 lbs (3.6 kg). 
         [0044]    Each of clips  36   a  and  36   b  is preferably made from a flat annealed superelastic material having a pickled surface. Preferably, the superelastic material is nitinol having a nickel content of 55.97% by weight and an A f  of 10°±5° C. The nitinol is cold worked to 37.5% and has a thickness in the range of about 0.012 in. (0.3 mm) to about 0.016 in. (0.4 mm). The clips  36   a  and  36   b  are first cut in a rough cutting laser process, and then optionally cut along their edges for an additional one or more times using an laser cutting process in order to smooth the edges. 
         [0045]    Other details and features of the latch and the clips  36   a  and  36   b  are set out in applicants&#39; issued patents entitled, “ORTHODONTIC APPLIANCE WITH SELF-RELEASING LATCH”—U.S. Pat. Nos. 6,302,688 and 6,582,226, and “ORTHODONTIC APPLIANCE WITH FATIGUE-RESISTANT ARCHWIRE RETAINING LATCH”—U.S. Pat. No. 7,014,460, which are expressly incorporated by reference herein. 
         [0046]    The clips  36   a  and  36   b  are each held in place by mesial cap  40   a  and distal cap  40   b , respectively. In this embodiment, the caps  40   a  and  40   b  are considered as part of the body  44  and attached to the mesial side  46   a  and the distal side  46   b , respectively, as mentioned above. The caps  40   a  and  40   b  are fixed to protrusions that extend in a mesial-distal direction from the central section of the body  44 , and the protrusions are arranged to retain the clips  36   a  and  36   b  in place. For example, protrusions may be provided along the sides of the archwire slot  38  as well as along a portion or all of the lingual side of the clips  36   a  and  36   b . The protrusions may be integral with either the central section or the caps  40   a  and  40   b  and then fixed to the other of the central section or the caps  40   a  and  40   b  by a welding or brazing operation. Protrusions and caps can be integral with the bracket body using the metal injection molding process to fabricate the bracket. Bracket  14  also includes a pair of tiewings  48  that protrude from the gingival posts  45  of the body  44 . Tiewings  48  are parallel to each other and initially extend in the gingival direction from gingival posts  45  then bend in a gradual curve towards the lingual direction towards base  42 . 
         [0047]      FIGS. 5 and 6  demonstrate, in side view and perspective view, how tiewings  48  (designated here as  48   a  and  48   b ) can be advantageously used to provide an alternate route for coupling archwire  32  to bracket  14  in orthodontic brace  4 . 
         [0048]    Here, assembly  50  includes the bracket  14  and archwire  32  that is received in archwire slot  38 . Assembly  50  furthermore includes elastic ligature  52 , which travels along a continuous path over the facial, occlusal, and lingual sides of archwire  32  on the distal side  46   b  of bracket  14 , beneath distal tiewing  48   b , beneath mesial tiewing  48   a , over the lingual, occlusal, and facial sides of archwire  32  on the mesial side  46   a , beneath mesial tiewing  48   a , then finally beneath distal tiewing  48   b . To arrive at this configuration, elastic ligature  52  is first looped around mesial and distal tiewings  48   a  and  48   b  and gingival posts  45 . Archwire  32  is then received into archwire slot  38 . Then the portion of elastic ligature  52  located occlusal to archwire  32  is stretched up and over the labial side of archwire  32  and finally secured beneath mesial and distal tiewings  48   a  and  48   b , respectively. 
         [0049]    In such fashion, archwire  32  is securely retained in archwire slot  38 , demonstrating a secondary means for a practitioner to couple archwire  32  to bracket  14 . The configuration shown in assembly  50  for coupling archwire  32  to bracket  14  is easily extended to other types of ligatures such as stainless steel ligature ties. It is likewise straightforward to extend the configuration shown in assembly  50  to couple archwire  32  to other member brackets  10 ,  18 , and  22  of orthodontic brace  4  on dental arch  2 . Using bracket  14 , a practitioner has the option of coupling archwire  32  to bracket  14  using clips  36   a  and  36   b  alone, or in combination with an elastic ligature  52  (or similar ligature tie) looped around tiewings  48   a  and  48   b  as described above. 
         [0050]    Note here that bracket  14  lacks occlusal tiewings. The phrase “lacks occlusal tiewings” as used herein denotes that there is no recess, notch, protrusion or otherwise retaining feature present on the bracket that can be used to support a ligature on the occlusal side of the archwire slot during the course of orthodontic treatment. Preferably, the bracket  14  has no structure that has all of the following characteristics: (a) it is located in a facial direction relative to the base, (b) it is located in an occlusal direction relative to an occlusal reference plane passing through the center of the archwire slot, (c) it extends in an occlusal direction or in a generally occlusal direction, and (d) it is sufficiently large to support a ligature during the course of orthodontic treatment. 
         [0051]    In another embodiment, exemplary bracket  54  is used in place of bracket  14  in orthodontic brace  4 . Bracket  54  is shown in  FIGS. 7-9  in front view, side view, and perspective view, respectively. Bracket  54  includes a base  42   a  and a body  44   a  that extends outwardly from base  42   a . The body  44   a  includes a distal side  46   c  along with a mesial side  46   d . Body  44   a  also includes two gingival posts  45   a  and two occlusal posts  47   a . An elongated archwire slot  38   a  extends in a generally distal-mesial direction across the body  44  from the distal side  46   c  to the mesial side  46   d  and between gingival posts  45   a  and occlusal posts  47   a . Bracket  54  also includes a pair of tiewings  49  that are parallel and protrude from gingival posts  45   a  of body  44   a  initially in the gingival direction, then gradually curve towards the lingual direction. In this embodiment, an archwire (not shown) can be coupled to bracket  54  using an elastic ligature or stainless steel ligature tie as shown previously using the configuration depicted in  FIGS. 5 and 6 . 
         [0052]    In still another embodiment, exemplary bracket  56  is used in place of bracket  14  in orthodontic brace  4 . Bracket  56  is shown in  FIG. 10  in perspective view and is essentially identical to bracket  54  depicted in  FIGS. 7-9  except bracket  56  includes a single occlusal post  62 , single gingival post  65 , and single tiewing  68  that protrudes from gingival post  65 . Gingival tiewing  68  protrudes in a perpendicular fashion from gingival post  65  in the gingival direction and then curves in a gradual arc towards the lingual direction. An archwire (not shown) can be coupled to bracket  56  using an elastic ligature or stainless steel ligature tie using a configuration similar to that shown in  FIGS. 5 and 6  as described previously. 
         [0053]    Yet another embodiment uses exemplary bracket  69 , illustrated by  FIGS. 11-13  in front view, side view, and perspective view, respectively. Bracket  69  can be used in place of bracket  14  in orthodontic brace  4 , and is nearly identical to bracket  14  except tie wings  84  and  86  protrude not from the gingival posts but rather from clips  80  and  82 , respectively. Tiewings  84  and  86  are parallel and initially protrude from clips  80  and  82  in the gingival direction and then bend in a gradual curve towards the lingual direction. Bracket  69  has the ability to retain an archwire using clips  80  and  82  alone, or in combination with using an elastic ligature or stainless steel ligature tie (not pictured) guided around tiewings  84  and  86 , in a manner shown in  FIGS. 5 and 6  previously. 
         [0054]    An assembly  92  according to yet another embodiment of the invention is illustrated in  FIG. 14  in perspective view. Assembly  92  includes exemplary bracket  94  coupled to archwire  32 . In this embodiment, bracket  94  is used in place of bracket  14  of orthodontic brace  4 . Bracket  94  is essentially identical to bracket  14  except the latch includes only one centrally located spring clip  110 . Bracket  94  has the ability to retain an archwire using clip  110  alone or in combination with using an elastic ligature or stainless steel ligature tie (not shown) in a manner shown in  FIGS. 5 and 6  previously. 
         [0055]    While the embodiments described above were exemplified on a lower dental arch, it is straightforward to adapt these embodiments for use on an upper dental arch. It should also be understood that the brackets included in any of the above embodiments can be formed from a variety of materials, including metals, ceramics, polymers, or any combination therefrom. Examples of such materials include, but are not limited to, stainless steel, polycrystalline alumina, and fiber-reinforced polycarbonate. 
         [0056]    The examples described above are intended to exemplify the various aspects and benefits of the invention. However, those skilled in the art may recognize that a number of variations and additions to the appliances described above may be made without departing from the spirit of the invention. Accordingly, the invention should not be deemed limited to the specific embodiments set out above in detail, but instead only by a fair scope of the claims that follow, along with their equivalents.