Abstract:
An orthodontic bracket having opposite nonparallel surfaces and further incorporating one or more gripping portions to provide stability in gripping and handling. The gripping portion or portions may be formed as various types of small notches or shelves in the bracket body and preferably enable gripping to take place on opposite parallel surfaces even though surrounding surfaces are nonparallel and may be convergent. Methods of installation and removal involve gripping the appliance with a tool having movable jaws with at least one jaw engaging a gripping portion.

Description:
TECHNICAL FIELD 
     The present invention relates to orthodontic appliances, such as brackets and buccal tubes for fixation to the teeth of a patient. More particularly, the invention relates to such appliances with non-parallel opposite surfaces adapted to be gripped by a tool during installation and/or removal procedures. 
     BACKGROUND OF THE INVENTION 
     Improperly positioned teeth may be forced into desired positions through the use of a flexible wire, referred to by orthodontists as an archwire, and a series of appliances affixed to respective upper and lower teeth. The appliances currently take the form of specialized brackets and buccal tubes formed from suitable metallic or ceramic or plastic material. The orthodontist typically adheres the appliances to the teeth with an adhesive, although other fixation methods are known as well. Each appliance includes a slot or a hole to receive and control the position of the archwire. 
     The design of orthodontic appliances involves the balancing of several considerations. The appliance must adequately retain and position the archwire and further allow for adjustments to the archwire. Preferably, appliances are compatible with other dental attachments with minimal complexity and are strong yet compact. The most common bracket design is the so-called tie-wing bracket. This bracket includes a slot for insertion of the archwire and a plurality of projections referred to as wings. After the archwire is set in the slot of the bracket, either a tie wire or an O-ring is affixed beneath the wings and over the archwire at each end of the archwire slot. The tie-wing bracket is a simple design and provides excellent control of the archwire. Brackets of this type typically have parallel upper and lower surfaces of adequate size to be easily gripped with conventional orthodontic pliers. However, some orthodontic appliances are generally tubular in shape or otherwise have nonparallel, opposite surfaces. These appliances include buccal tubes used on rear molars to anchor and hold the archwire ends in proper alignment. 
     In one prior buccal tube design, for example, one outer surface slopes downwardly from a position close to the base or tooth mounting surface and an opposite outer surface extends essentially perpendicular from the base. A small gripping ledge is contained on the body of the buccal tube and intersects the sloped surface. In addition to facilitating patient comfort, one of the main functions of the sloping surface is to deflect food particles which may become lodged between respective buccal tubes of the upper and lower teeth as the patient chews food, especially hard foods such as hard candy, etc. Unfortunately, the sloping surface also impedes the ability of the orthodontist to grasp the buccal tube with a pair of conventional pliers during installation or removal procedures. The small gripping ledge on the body of the buccal tube is not easily grasped at all times and the orthodontist may therefore experience “shoot-out” of the buccal tube from the tool as one of the gripping jaws of the tool slides down the sloping surface. 
     While it would be desirable to continue providing one or more sloping surface in many orthodontic appliances, it would also be desirable to provide a orthodontic appliance, such as a buccal tube or other orthodontic bracket or appliance, with better gripping ability despite the presence of opposite, nonparallel appliance surfaces. 
     SUMMARY OF THE INVENTION 
     The present invention is therefore directed to an orthodontic appliance having nonparallel opposite surfaces, such as upper and lower surfaces, but having at least one specialized portion that may be securely gripped with an orthodontic tool during installation. The appliance generally includes a body with a plurality of outer surfaces. One surface is a mounting surface or base which is affixed against a tooth, such as with an adhesive or in another suitable manner. The body also includes a passage, such as an open-ended hole or an open channel, for receiving an archwire. Two opposed outer surfaces are nonparallel in that at least one of the outer surfaces generally slopes toward the other. The slope may be angular and planar or may be rounded. Other nonparallel configurations may derive benefit from this invention as well. In accordance with the present invention, a gripping portion is located on the body such that it intersects one of the nonparallel outer surfaces, such as the sloping outer surface. This portion creates a gripping surface which, in conjunction with the opposite outer surface, is used to grasp the body with much greater stability than previous appliance configurations having nonparallel opposite surfaces. 
     In one particular example, the upper outer surface of a buccal tube, as used on a lower molar, begins generally at an upper edge and slopes downward. The slope of this surface aids in patient comfort and causes food particles to be deflected away from the tooth and the corresponding upper buccal tube. The gripping portion may comprise at least two alternative forms. First, a notch or recess may be formed into the sloping outer surface. Second, the gripping portion may take the form of a small shelf which projects slightly outward from the sloping outer surface. Each form of the gripping portion creates a generally parallel gripping surface relative to the opposite gripping surface which may or may not also be formed as a notch or shelf. Ideal gripping is achieved when the gripping surfaces are parallel. However, the gripping portion of one nonparallel surface may be only substantially parallel with an opposite gripping surface and still achieve the objective of this invention. 
     A method of using the appliance is also contemplated by the present invention. Generally, an orthodontic gripping tool having movable jaws is positioned with its jaws on opposite sides of the appliance. The jaws are then closed and thus become seated on the body of the appliance. Seating is accomplished on a first gripping surface portion of one nonparallel surface and the opposing gripping surface which may or may not be another gripping surface portion formed on an otherwise nonparallel surface relative to the first gripping surface portion. The compressive force exerted by the tool is increased to ensure the appliance is firmly held. Then, the appliance is directed into the patient&#39;s mouth and affixed to the patient&#39;s tooth. The gripping tool is then released from the appliance after the appliance has been fixed to the tooth. A similar method, which is essentially the reverse of the installation method, may be used during a removal procedure. 
     Other features, objects and advantages of the invention will become more readily apparent to those of ordinary skill in the art upon review of the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a perspective view showing an orthodontic appliance in the form of a buccal tube of the prior art being applied to a tooth. 
     FIG. 1A is a cross-sectional view taken along line  1 A— 1 A of FIG.  1  and showing the orthodontic gripping tool engaging the prior art buccal tube. 
     FIG. 2 is a perspective view showing an orthodontic appliance in the form of a buccal tube of the present invention being applied to a tooth. 
     FIG. 2A is a cross-sectional view taken along line  2 A— 2 A of FIG.  2  and showing the orthodontic gripping tool engaging the preferred buccal tube. 
     FIG. 3 is a perspective view showing the preferred buccal tube mounted on a tooth. 
     FIG. 4 is a perspective view showing another embodiment of the present invention. 
     FIG. 5 is a perspective view of another alternative embodiment of the present invention. 
     FIG. 6 is a perspective view of another alternative embodiment of the present invention. 
     FIG. 6A is a cross sectional view taken along line  6 A— 6 A of FIG.  6 . 
     FIG. 7 is a perspective view of another alternative embodiment of the invention. 
     FIG. 7A is a cross sectional view taken along line  7 A— 7 A of FIG.  7 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The advantages of the present invention and its preferred embodiments described herein are best revealed by briefly considering the prior art. It will be appreciated that terms of orientation, such as “upper”, “lower” and other similar terminology, are used for purposes of clarity with respect to the illustrative drawings. These terms are not meant to be limiting in any manner as orientations of orthodontic appliances may vary in practice. It should also be understood that, although the preferred and alternative embodiments of the invention are specifically directed to buccal tubes, the inventive concepts herein may be applied to other forms of orthodontic appliances exhibiting similar problems and deriving similar benefits from the inventive concepts. 
     Referring first to FIG. 1, an orthodontic gripping tool  10  is shown as typically used to position a buccal tube body  12  and attached base  13  on a tooth  14 . A hole  15  is provided for an archwire (not shown). The gripping tool  10  has jaws  16  which seat upon a narrow upper ledge  18  of the body  12  and a parallel lower surface  20 . The upper ledge  18  must be as narrow as possible to prevent undesirable contact with food during chewing. The engagement of jaws  16  on upper ledge  18  and lower outer surface  20  is shown in cross section in FIG.  1 A. As especially evident from FIG. 1A, upper ledge  18  provides substantially less area for gripping than lower surface  20 . This can cause the body  12  to shoot out of jaws  16  during installation procedures. Particularly, the upper jaw  16  can quickly slide down angled surface  19 , which converges toward surface  20 , if the grip with narrow ledge  18  is lost. 
     An orthodontic appliance constructed according to the present invention helps minimize the shoot-out problem mentioned above while also maintaining the provision of nonparallel upper and lower surfaces, for example, in cases in which it is necessary or desirable to have at least one rounded or angled surface sloping toward an opposite surface. Such a sloped surface can aid patient comfort and minimize forceful contact with food during chewing. Turning to FIGS. 2,  2 A and  3 , the preferred embodiment of the invention is shown mounted to tooth  14 , with other like numerals in these figures representing like structure or elements in FIGS. 1 and 1A. A buccal tube  22  is shown and incorporates a gripping portion  24  which, in this case, comprises a notch. Notch  24  thereby forms an upper gripping surface  28 . As FIGS. 2 and 2A illustrate, gripping tool  10  applies a compressive force on buccal tube  22  through jaws  16  which seat upon gripping surface  28  and the opposed lower surface  20 . 
     Increased and more secure gripping force may be applied due to the extended gripping dimension, in a direction away from tooth  14 , provided by surface  28 . Surfaces  20  and  28  are at least substantially parallel to each other and thereby ensure positive gripping by tool  10 . Gripping portion or notch  24  extends downwardly from the narrow upper ledge  18  and intersects angled surface  19 . As further shown in FIG. 3, after buccal tube  22  is mounted on tooth  14 , an archwire  30  may be inserted through buccal tube  22  in a conventional manner. As is also conventional, at least one auxiliary attachment  32  can form part of buccal tube  22  and may be used to hold auxiliary devices, such as rubber bands. Buccal tube  22 , as well as other appliances formed in accordance with the invention, may be made of any suitable orthodontic material. As examples, these may include ceramic materials, metals such as stainless steel or titanium, or metal alloys. 
     Turning now to FIG. 4, an alternative embodiment of a buccal tube  40  includes a body  42  and a base  44  for attachment to a tooth. Buccal tube  40  may again include an auxiliary attachment  46  and a throughhole  48  for receiving an archwire. It will be appreciated that certain orthodontic appliances will not require a throughhole, but instead will utilize an open channel. Body  42  again includes a narrow upper ledge  50  and a lower surface  52 . In this embodiment, however, ledge  50  includes a first end  50   a  which is at a different elevation than a second end  50   b.  In a conventional buccal tube of this shape, this creates a slope from one end  50   b  toward the other end  50   a  of ledge  50 . For this reason, gripping with a conventional tool, such as tool  10  of FIG. 1, is even more difficult as the jaws of the tool will tend to slide downwardly on the sloped ledge  50 . Thus, there is even a greater tendency for the tool to lose its grip on body  42  by having a jaw slide down on upper ledge  50  and subsequently move down angled surface  54 . This embodiment again utilizes a notch  56  to solve this problem. Notch  56  extends downward from ledge  50  and intersects angled surface  54  at a wider gripping surface  58  thereby creating more gripping area for a tool of the general type shown in FIG.  1 . Jaws  16  of tool  10  may securely grip body  42  by engaging surface  58  and the opposite, parallel surface  52 . 
     FIG. 5 illustrates another alternative embodiment of a buccal tube  60  which is very similar to the embodiment of FIGS. 2-3, however, the upper narrow ledge  18  has been eliminated to further decrease the potential for undesirable contact with food during chewing. More specifically, buccal tube  60  includes a body  62  and a base  64  for attachment to a tooth  14  (FIG.  1 ). Upper angled surface  66  intersects with a lower surface  68  which is adapted to extend substantially normal to the outer surface of tooth  14  after attachment thereto. As is conventional, buccal tube  60  includes a throughhole  70  for receiving a conventional archwire. In accordance with the invention, a notch  72  is formed in the upper angled surface  66  in order that a gripping surface  74  is formed at least substantially parallel to lower surface  68 . In this manner, a conventional tool  10  (FIG. 1) may be used to firmly grip surfaces  68 ,  74  during an installation or removal procedure. 
     FIGS. 6 and 6A illustrates another alternative configuration in which a buccal tube  80  generally includes a body  82  and a base  84 . The body includes a generally rounded outer surface  86 . Like the other appliance configurations disclosed and discussed herein, this would normally create gripping problems in that the generally sloped and converging upper and lower surface portions of the body  82  are nonparallel in a manner that promotes shoot-out problems. Body  82  again includes a conventional throughhole or archwire hole  88 . In accordance with the invention, an upper notch  90  forming an upper gripping surface  92  is formed within body  82  along with an opposed lower notch  94  forming a lower gripping surface  96 . As best shown in FIG. 6A, notches  90 ,  94  and, more specifically, parallel gripping surfaces  92 ,  96  form a gripping area on body  82  that may be securely and forcefully gripped with the jaws  16  of a conventional tool  10  (FIG.  1 ). 
     Turning now to FIGS. 7 and 7A, another alternative appliance configuration and gripping area configuration is shown. Specifically, a buccal tube  100  includes a body  102  and a base  104 . Body  102  includes upper and lower angled surfaces  106 ,  108  converging toward one another. Alternatively, these surfaces  106 ,  108  may be rounded. Normally, this type of configuration would be virtually impossible to grip with conventional gripping tools, however, in accordance with the invention, a notch  112  formed with a gripping surface  114  is contained in upper surface  106  and a shelf  116  formed with a gripping surface  118  projects from lower angled surface  108 . In this manner, gripping surfaces  114 ,  118  are formed at least substantially parallel to one another and provide a gripping area sufficiently sized to allow secure and forceful compressive gripping by a conventional tool, such as tool  10  (FIG.  1 ). It will be understood that other forms and/or combinations of gripping portions may be used in place of these specifically disclosed herein. 
     The methods of this invention are best illustrated with reference to FIGS. 2 and 2A. A method of installing an orthodontic appliance, such as buccal tube  22  formed in accordance with the invention, includes positioning one of the jaws  16  of a gripping tool  10  on gripping surface  28  of notch  24  and positioning the other of the jaws  16  on the opposite surface  20 . Compression may then be applied to jaws  16  by the orthodontist to securely grip buccal tube  22  as it is directed into the patient&#39;s mouth toward tooth  14 . Base  13  of buccal tube  22  is then affixed to tooth  14 , such as with a conventional orthodontic adhesive. Once the buccal tube  22  is adequately adhered to tooth  14 , jaws  16  may be released and the orthodontist may move on to apply the next appliance. Removal of buccal tube  22  may involve similar steps as described above. For example, orthodontists may remove appliances by heating the appliance sufficiently to soften the adhesive between base  13  and tooth  14 . When the adhesive is sufficiently softened, tool  10  and, specifically, jaws  16  may again be used to engage surfaces  20 ,  28  to compressively grip buccal tube  22  and then remove buccal tube  22  from tooth  14 . It will further be appreciated that the remaining embodiments of this invention, as well as other orthodontic appliances configured in accordance with the invention, may be installed and removed in a similar manner by engaging the gripping portion or portions of the appliance with a suitable plier-type orthodontic tool such as tool  10 . 
     While the present invention has been illustrated by a description of the preferred embodiment and while this embodiment has been described in some detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Many different orthodontic appliance configurations may benefit from the inventive concepts disclosed herein. As only one of many alternatives, appliances of this invention may also including weldable bases, i.e., for welding to bands or crowns. This has been a description of the present invention, along with the preferred methods of practicing the present invention as currently known. However, the invention itself should only be defined by the appended claims, wherein I claim: