Abstract:
A palatal t-bar for preventing movement of selected teeth during corrective movement of other teeth through the use of an orthodontic appliance such as orthodontic braces. The t-bar comprises an elongate stem having an anchorage end arranged for affixation to the palatal bone of a patient by means of a temporary bone anchorage device, e.g., a miniscrew implant, and a free end extending in an anterior direction from the anchorage end. The stem is shaped to conform to the palatal surface of the patient. A cross-bar extends laterally from the free end of the stem and is arranged to engage one or more selected maxillary anterior teeth to retain the teeth non-mobile and non-rotational during corrective movement of other teeth utilizing an orthodontic appliance such as orthodontic braces.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    “Not Applicable” 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    “Not Applicable” 
       INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISK 
       [0003]    “Not Applicable” 
       FIELD OF THE INVENTION 
     Background of the Invention 
       [0004]    To clarify the description of the invention, certain dental terms should be understood. Upper and lower teeth are termed maxillary and mandibular teeth, respectively. Front teeth are anterior teeth and back teeth are posterior teeth. Anterior teeth are incisors and are named centrals, laterals, and cuspids in order from the anterior midline to the posterior. The posterior teeth, from anterior to posterior, are first and second premolars and first, second, and third molars. Distal refers to the direction towards the last posterior tooth, as opposed to mesial, which refers to the direction towards the anterior midline. 
         [0005]    Orthodontists and dental researchers are constantly searching for new and improved ways to correct malocclusion problems. Corrective movement of teeth may be accomplished utilizing a variety of orthodontic appliances. One such commonly used orthodontic appliance is orthodontic braces, wherein brackets are bonded to teeth and an arch wire is attached to the brackets in known ways. The arch wire exerts pressure on the brackets and teeth whereby the positioning of teeth relative to each other can be controlled and adjusted. The adjustment of the position of teeth is accomplished by providing forces in a desired direction. For many desired forces, there are unwanted reciprocal forces that often move teeth from their correct position. 
         [0006]    Attempts have been made to try to secure teeth from moving, rotating, or torquing from their correct positions in response to such unwanted forces. However, often these attempts are expensive, or involve surgery typically requiring significant healing time. Thus, there exists a need for an orthodontic system to position and adjust a tooth or teeth of a patient that is able to withstand occlusal, biomechanic or other reciprocal forces applied thereto, is less expensive and time consuming to install, and is less invasive to the patient. It is to the provision of such an improved orthodontic anchor system that the present invention is primarily directed. 
       SUMMARY OF THE INVENTION 
       [0007]    A palatal t-bar for preventing movement of selected teeth during corrective movement of other teeth through the use of an orthodontic appliance such as orthodontic braces is provided. The t-bar comprises an elongate stem having an anchorage end arranged for affixation to the palatal bone of a patient by means of a temporary bone anchorage device, e.g., a miniscrew implant, and a free end extending in an anterior direction from the anchorage end. The stem is shaped to conform to the palatal surface of the patient. A cross-bar extends laterally from the free end of the stem and is arranged to engage one or more selected maxillary anterior teeth to retain the teeth non-mobile and non-rotational during corrective movement of other teeth utilizing an orthodontic appliance such as orthodontic braces. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is an isometric view of a preferred embodiment of the palatal t-bar of the present invention; 
           [0009]      FIG. 2  is a view of the preferred embodiment of the palatal t-bar of the present invention installed in the roof of the mouth of a patient, the patient also wearing orthodontic braces; 
           [0010]      FIG. 3  is a view of the preferred embodiment of the palatal t-bar of the present invention installed within the roof of the mouth of a patient, the patient also wearing orthodontic braces; 
           [0011]      FIG. 4  is an elevational view, partially in cross-section, illustrating the preferred embodiment of the palatal t-bar of the present invention installed within the roof of the mouth of a patient; 
           [0012]      FIG. 5  is a view of the stem portion of the palatal t-bar of the present invention; 
           [0013]      FIG. 6  is another view of the stem portion of the palatal t-bar of the present invention; 
           [0014]      FIG. 7  is an elevational view, partially in cross-section, illustrating a second embodiment of the palatal t-bar of the present invention installed within the roof of the mouth of a patient; and, 
           [0015]      FIG. 8  is an isometric view of a third embodiment of the palatal t-bar of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0016]    Referring now in greater detail to the drawings in which like numerals represent like components throughout the several views,  FIGS. 1-4  illustrate a first preferred embodiment of the palatal t-bar  10  of the present invention. As best shown in these figures, the palatal t-bar  10  is intended for placement within the mouth of a patient to serve as an anchorage to prevent one or more selected teeth (as an example here shown on teeth  14 ) anchored within the t-bar  10  from rotating, torquing, or moving distally during corrective movement of other teeth. Such other teeth may include lateral incisors  18 , canines  22 , or posterior teeth  26 . As shown in  FIGS. 1-4 , corrective movement of teeth  14 ,  18 ,  22 , and  26  is shown as being accomplished utilizing orthodontic braces, wherein brackets  30  are bonded to teeth  14 ,  18 ,  22 , and  26  and an arch wire  34  is attached to the brackets  30  in known ways. The arch wire  34  exerts pressure on the brackets  30  and teeth  14 ,  18 ,  22 ,  26  whereby the positioning of teeth relative to each other can be controlled and adjusted. The adjustment of the position of the teeth is accomplished by providing forces in a desired direction. 
         [0017]    Referring now to  FIG. 2 , the orthodontic braces are shown mounted to the patient&#39;s maxillary teeth at the start of a corrective orthodontic procedure to provide corrective forces to move the posterior teeth  26 , e.g., premolars and molars, anteriorly in the direction of arrows  38  to fill in gaps  42  existing between the teeth  22  and  26 . During movement of the posterior teeth  26  in the mesial direction of arrows  38 , undesired forces may inadvertently be applied to the teeth  14  providing a tendency for them to rotate, torque, or move in an undesired direction. 
         [0018]    To prevent such unwanted rotation, torque or movement of these teeth  14 , the palatal t-bar  10  is provided. Referring again to  FIGS. 1-4 , the palatal t-bar  10  includes a cylindrical elongate stem  46  having a first end arranged to be affixed to the palatal surface  50  of the patient and a second end to which a cross-bar  54  is attached. Alternatively, the cross-bar  54  may be integral with the elongate stem  46 . As best shown in  FIGS. 1 and 4 , the elongate stem  46  is comfortable for the patient and generally cylindrical in shape. The elongate stem  46  can be contoured, molded or shaped to roughly match the palatal surface  50 . The cross-bar  54  is shaped to match the contour of the posterior surface of one or more anterior teeth  14 ,  18  and/or  22  in their correct position. In this manner, the cross-bar  54  will prevent movement, rotation and torquing of the anchored teeth. In addition, the cross-bar  54  includes curved ends  54   a  ( FIG. 1 ) arranged for bending around the edges of the anchored teeth  14  to prevent movement of the anchored teeth  14 . As best shown in  FIGS. 2 and 3 , the cross-bar  54  is bonded or held to one or more anchored teeth  14 ,  18  and/or  22  utilizing a suitable dental adhesive  57  to provide support for teeth  14  against the aforementioned undesired forces. 
         [0019]    Although the cross-bar  54  is illustrated in  FIGS. 1-4  as anchoring only the two frontmost teeth  14 , i.e., the upper central incisors, it should be understood that the cross-bar  54  could be configured to anchor a smaller or larger number of teeth during the application of corrective orthodontic forces to other teeth. For example, the cross-bar  54  could be lengthened and suitably configured to anchor the upper lateral incisors  18  in addition to the upper central incisors  14  to prevent unwanted distal movement, rotation or torquing of these teeth during the application of corrective forces. Likewise, the cross-bar  54  could be lengthened and configured to anchor upper canines  22  in addition to the central and lateral incisors,  14  and  18 . 
         [0020]    The palatal t-bar  10  is formed from a metal such as titanium, titanium alloys, stainless steel, a nickel-titanium alloy, titanium-molybdenum alloy, a chromium-nickel alloy, or combinations thereof, or alternatively, could be formed from synthetic polymer materials, such as an acrylic or by stereolithography. In the embodiment shown in  FIGS. 1-4 , the palatal t-bar  10  is illustrated as including an elongate stem  46  that is contoured to the shape of the maxilla, but it will be understood that other shapes or configurations can be used. 
         [0021]    As best shown in  FIG. 4 , the palatal t-bar  10  includes an anchor mechanism for anchoring the t-bar  10  to the patient&#39;s palatal surface  50 , i.e., the roof of the patient&#39;s mouth. As shown in  FIGS. 4 and 6 , under the present embodiment, the anchor mechanism includes an anchoring miniscrew implant  58  to which one end of the palatal t-bar is fixed. As an optional feature, in case it is necessary, a washer  62  can be used to provide a small amount of space or separation, e.g., 1 mm, between the palatal t-bar  10  and the palatal surface  50  when the t-bar  10  is anchored to the maxillary bone. In this manner, the palatal t-bar  10  will not contact the roof of the patient&#39;s mouth during use which will increase the patient&#39;s level of comfort, thus allowing for saliva to pass over the t-bar and facilitating hygiene around the miniscrew implant  58 . The anchoring miniscrew implant  58  and washer  62  are minimal in size so as to be unobtrusive of eating and to likewise minimize the trauma to the tongue and palate of the patient during insertion and thereafter while the palatal t-bar  10  is worn by the patient. Accordingly, the anchoring miniscrew implant  58  typically will be approximately 8 to 21 mm in length with approximately 2 to 6 mm of the anchoring miniscrew implant  58  being exposed outside the palatal surface  50  when inserted in the patient&#39;s mouth. However, it is possible to use anchors of other, varying dimensions and types. Therefore, while the present anchor mechanism is being disclosed with reference to a preferred range of sizes, such a preferred range is for illustrative purposes only and it will be understood by those skilled in the art that various other types of conventional dental implants and varying sizes also may be used. 
         [0022]    As shown, the anchoring miniscrew implant  58  typically includes a body  66  that is inserted or drilled into the palatal surface  50  of the mouth of the patient so as to be embedded into the palatal bone  70 , and a head or upper portion  74  exposed from the palate. The shank portion  66  of the anchoring miniscrew implant  58  further typically include threads to enable the anchoring miniscrew implant  58  to be drilled into the palatal surface  50 , although it will be understood by those skilled in the art that the anchoring miniscrew implant  58  also can have substantially smooth sided shanks. As best shown in  FIGS. 2-4 , a coating or bonding material  78  is utilized to mechanically hold the elongate stem  46  of the t-bar  10  to the miniscrew implant  58 . Also, a mechanical retention can be obtained by using metallic ligature wire to hold the elongate stem  46  of the t-bar  10  to the miniscrew implant  58 . 
         [0023]    As best illustrated in  FIGS. 3-6 , a portion of the elongate stem  46  may be configured as a bendable spine  82  formed in a notched or zig-zag pattern to provide a plurality of retention surfaces to enable mechanical retention with the bonding material  78 . The bendable spine  82  may be integral with or attached to the elongate stem  46  and may be fabricated of the same or different materials as the elongate stem  46 . The bendable spine  82  is bendable in proximity to the anchoring miniscrew implant  58 , which serves as a locator. As best shown in  FIGS. 4-6 , the spine  82  is bent around the head, neck or body  66  of the anchoring miniscrew implant  58 . Thereafter, it is secured to the miniscrew implant  58  by using a ligature wire, bonding material or composite  78 . The bonding material  78  flows within the retention grooves of the bendable spine  82  to create a solid mechanical retention between the t-bar  10  and the miniscrew implant  58 . By providing a bendable spine  82 , the palatal t-bar  10  is provided with a degree of adjustability to assure that anchorage can occur while the cross-bar  54  engages the teeth  14  to be anchored. 
         [0024]      FIG. 3  illustrates the patient&#39;s maxillary teeth at the conclusion of the corrective orthodontic procedure wherein the posterior teeth  26  have been moved mesially to eliminate gaps between teeth  22  and  26 . As illustrated in  FIG. 3 , the t-bar  10  anchoring the maxillary teeth  14  has prevented these teeth  14  from rotating, torquing, or moving distally during corrective mesial movement of the posterior teeth  26 . The above example illustrates use of the t-bar  10  for anchoring teeth  14  during mesial movement of other teeth, e.g., molars. However, it should be understood that the t-bar  10  would be equally effective for anchoring teeth  14  during distal movement of other teeth, such as molars, utilizing dental appliances such as braces. 
         [0025]    Referring now to  FIG. 7 , there is shown a second embodiment of the palatal t-bar of the present invention. As with the first embodiment, the second embodiment t-bar  100  is intended for placement within the mouth of a patient to prevent teeth  114  anchored within the second embodiment t-bar from rotating, torquing, or moving mesially or distally during corrective movement of other teeth  118 . As with the first embodiment, the second embodiment palatal t-bar includes a cross-bar  154  that is attached to, or integral with an elongate stem. The cross-bar  154  is bonded or held to one or more anchored teeth, e.g., the anchored teeth  114  shown in  FIG. 7 , utilizing a suitable dental adhesive  57  to provide support for the teeth against the undesired forces discussed above. 
         [0026]    However, under the embodiment  100 , the elongate stem is formed of a multi-piece construction, e.g., a two-piece construction, including an outer portion  146   a  and an inner portion  146   b  that are in telescoping relation to each other to enable adjustability of the overall length of the elongate stem to accommodate different sized palates. Once the overall length has been determined, the inner and outer portions may be crimped, glued or soldered together to retain the elongate stem at a defined length. The elongate stem includes a contour that roughly matches the maxilla  150  and includes a fixed end that is arranged to be anchored to the maxilla  150  utilizing anchoring hardware, e.g., an anchoring screw  158 . A washer  162  may be used to provide a small amount of separation between the second embodiment palatal t-bar and the maxilla  150  for the reasons previously discussed. Likewise, the anchoring screw  158  may be coated with a coating or bonding mechanism similar to that shown in the first embodiment for the reasons previously discussed. 
         [0027]    Referring now to  FIG. 8 , there is shown a third embodiment  200  of the present invention. This third embodiment  200  of the palatal t-bar is similar to prior embodiments in that it is intended for placement within the mouth of a patient to serve as an anchorage for preventing teeth anchored therein from rotating, torquing, or moving distally during corrective movement of other teeth. As with the prior embodiments, the third embodiment palatal t-bar  200  includes a cross-bar  254  that is attached to, or integral with an elonagate stem  246 . However, under this embodiment  200 , the elongate stem  246  includes an anchorage end that will fit two anchors, as opposed to one, and includes two semi-circular anchoring openings  258  that serve as points for anchoring the third embodiment palatal t-bar  200  within the maxilla utilizing suitable anchorage hardware as previously discussed. By providing two anchoring openings  258 , as opposed to one, lateral support for the anchored teeth will be increased to further reduce the possibility of torquing, rotation, or distal movement of the anchored teeth during application of corrective orthodontic forces. 
         [0028]    In the foregoing specification, specific embodiments of the present invention have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the present invention. Thus, while preferred embodiments of the invention have been illustrated and described, it is clear that the invention is not so limited. Numerous modifications, changes, variations, substitutions, and equivalents will occur to those skilled in the art without departing from the spirit and scope of the present invention. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present invention.