Patent Publication Number: US-2002006595-A1

Title: Orthodontic tools

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates to tools for use in the area of orthodontics.  
       BACKGROUND  
       [0002] Certain self-ligating orthodontic brackets presently in use are opened by depressing a portion of the locking shutter that extends from the back of the bracket when in a closed position. These brackets are often difficult to open because the orthodontist is required to reach to the back of the bracket with an opening instrument. The back of the bracket can often be obstructed by food or other debris making it difficult to see the portion of the locking shutter that the orthodontist must depress to open the bracket. Also, it is difficult for those orthodontists whose vision may be slightly impaired to see the back portion of the bracket.  
       [0003] There is therefore a need for a tool for a self-ligating orthodontic bracket that enables orthodontists to open the bracket from a front portion of the bracket, which is easier to access. There is also need for a modified self-ligating orthodontic bracket that can be used in association with a tool that enables orthodontists to open the bracket from a front portion of the bracket.  
       [0004] Normally, a set of upper or lower teeth define a symmetrical and uniform archform. In many cases, however, one or more teeth can be either completely or partially displaced. When a patient requires orthodontic work, this displacement provides a challenge for the orthodontist. An orthodontic bracket must be placed on each tooth. An archwire must be seated in an archwire slot of each of the brackets. It is difficult to seat the archwire in the archwire slot of displaced teeth. It is helpful to use a tool for this purpose.  
       [0005] Previously, a very small fork-shaped tool has been used to seat the archwire. The tool is difficult to use because it can only engage one side of the archwire. Where a tooth is completely displaced, it is necessary to engage both sides of the archwire in order to seat the archwire. The small fork shaped tool is inconvenient for this purpose. There is therefore a need for an archwire-seating tool that is convenient to use and that can engage an archwire on both sides of the tooth.  
       [0006] Bracket placement is a very important orthodontic procedure. When fastening an orthodontic bracket to the tooth, the orthodontist must measure a predetermined distance between the bottom of the tooth and the bottom of the bracket depending on the type of tooth. This helps the orthodontist to place the bracket on the proper position on the tooth. Several instruments have been used in the past. A first instrument would be used to measure the height of the bracket from the cusp tip. A second instrument would be used to seat the bracket firmly on the tooth. A third instrument would be used to clean up the resin bonding material after seating the bracket. This system has the drawback of being unwieldy in view of the number of instruments that must be used. There is therefore a need for an instrument that can measure heights of brackets and can position the brackets on the tooth.  
       [0007] An orthodontic bracket is placed on each of a patient&#39;s upper and/or lower teeth. The brackets each receive an archwire that connects the brackets to apply a corrective force on the teeth. Most archwires that are presently used by orthodontists are wider buccolingually (from front to back) than they are occlusogingivally (top to bottom). With some types of self-ligating brackets, a locking shutter engages an exterior-facing portion of the archwire when the locking shutter is in a closed position. The force that the locking shutter applies to the archwire is translated to the tooth. When rectangular wires are used in self-ligating brackets on teeth that are tipped from profile view, the archwire occasionally does not seat properly in the upper corner of the archwire slot defined between the rear of the bracket and the locking shutter. There is therefore a need for an archwire that is proportioned to seat more effectively against a locking shutter in an archwire slot.  
       SUMMARY OF THE INVENTION  
       [0008] The present invention provides several tools that can be used in connection with orthodontic treatment using orthodontic brackets.  
       [0009] One of the tools has a first member that engages a notch of a self-ligating orthodontic bracket. The tool also has a second member engaged with the first member and adapted to engage a free end of a locking member in order to disengage the locking member when the first and second members are squeezed toward each other.  
       [0010] Another tool has a pair of notches that are adapted to engage an archwire on both sides of a tooth in order to seat an archwire in an archwire slot. In one embodiment, there is provided an instrument having a first end and a second end. The first end has a guiding member having two spaced-apart arms. Each of the arms defines a notch formed thereon capable of engaging an archwire whereby the guiding member can engage an archwire on both sides of a tooth to guide the archwire into an archwire slot of an orthodontic bracket.  
       [0011] A third tool is a positioning tool that helps position and seat an orthodontic bracket. The positioning tool is an elongated instrument having a planar positioning tool formed on an end thereof. The positioning tool has spaced demarcation or scribe lines formed thereon for measuring the height or position of an orthodontic bracket. The positioning tool is adapted to position the orthodontic bracket on a tooth.  
       [0012] The present invention also provides an archwire that is designed to have an enhanced interface with a locking member of a self-ligating bracket. More specifically, the archwire has a beveled edge to seat against a locking member when positioned in an archwire slot. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0013]FIG. 1 is a perspective view of an orthodontic tweezer tool embodying the present invention.  
     [0014]FIG. 2 is a perspective view of a self-ligating bracket.  
     [0015]FIG. 3 is a perspective view of the tweezer tool of FIG. 1 inserted insert the self-ligating bracket of FIG. 2.  
     [0016]FIG. 4 is a section view of the self-ligating bracket of FIG. 3 showing use of the tweezer tool.  
     [0017]FIG. 5 is a perspective view of a double-ended orthodontic multi-purpose tool.  
     [0018]FIG. 6 is an occlusal view of the multi-purpose tool used to seat an archwire in an orthodontic bracket.  
     [0019]FIG. 7 is an end view of an alternative way of using the multi-purpose tool to seat an archwire.  
     [0020]FIG. 8 illustrates use of a second end of the multi-purpose tool to open the locking member of the bracket.  
     [0021]FIG. 9 is a section view of FIG. 8.  
     [0022]FIG. 10 illustrates a placement instrument embodying an aspect of the present invention.  
     [0023]FIG. 11 illustrates use of the placement instrument to position an orthodontic bracket onto a tooth.  
     [0024]FIG. 12 illustrates an archwire having a beveled edge. 
    
    
     DETAILED DESCRIPTION  
     [0025] Tweezer Tool (FIGS.  1 - 4 )  
     [0026]FIG. 1 illustrates a tweezer tool  10  embodying one aspect of the present invention. The tweezer tool  10  has a first member  12  and a second member  14 . The first and second members are connected at junction  16 . The first member  12  has an end  18  that is preferably rectangular in cross-section although other shapes are within the purview of the present invention. The second member  14  has an end  20  that preferably has an inverted L shape, although other shapes are within the purview of the present invention.  
     [0027] As shown in FIGS.  2 - 4 , the tweezer tool  10  is used in association with a self-ligating orthodontic bracket  22 . The bracket  22  generally includes a base  24  having a lingual portion  26  for attachment to a tooth by means of a mounting pad  28  or other suitable means. A pair of gingival tie wings  30  and a pair of occlusal tie wings  32  extend from the base in a buccal-labial direction. An archwire slot  34  extends generally horizontally across the base  24  and opens for receiving an archwire  36 .  
     [0028] The bracket  22  further includes a sliding locking member  38  generally in the shape of a “U”. The locking member  38  curves at one end to form a generally hook-shaped catch  40  and at the opposite end a stopper  42  is attached for contacting the base  24 , thereby preventing the locking member  38  from sliding off of the base  24  in the open position. The locking member  38  is movable from a closed position (shown in solid lines in FIGS. 3 and 4) to an open position (shown in broken lines in FIG. 4). The general operation of the bracket and locking member is disclosed in more detail in European Patent Publication No. 1090604, which is incorporated herein by reference in its entirety.  
     [0029] In operation, the first end  18  engages a notch  44  formed in a front face of the bracket  22 . Preferably the notch is V-shaped. The second end  20  is engaged to the stopper  42  of the locking member  38 . The locking member becomes disengaged from the bracket when the second end  20  applies a force against the stopper  42 . The tweezer tool  10  is calibrated such that when the first end  18  is engaged to the notch  44 , the second end  20  engages the stopper  42  of the locking member  38 . Squeezing pressure on the stopper  42  causes the locking member  38  to move to the open position. A compression stop  46  prevents over stressing the tool  10 .  
     [0030] The tweezer tool  10  can be used in association with both upper tooth and lower tooth orthodontic brackets.  
     [0031] Double-ended Multi-Purpose Tool (FIGS.  5 - 9 )  
     [0032]FIG. 5 illustrates a multi-purpose tool  50  embodying another aspect of the invention. The multi-purpose tool  50  has a main shaft  52 , a first end  54 , and a second end  56 . The first end  54  has arms  58  that are substantially perpendicular to the shaft  52  and that preferably define a U shape. The arms  58  have fork-shaped ends  60  that each have prongs  62  defining a recess. Each of the arms further defines a notch  64  formed in an exterior surface of the ann near a midpoint of the arm.  
     [0033] The operation of the first end  54  of the tool  50  is shown in FIGS. 6 and 7. A completely displaced tooth  66  is shown in FIG. 6. The tool  50  engages an archwire  68  on both sides of the tooth  66 . The archwire  68  is received in notches  64  so that the tool can be used to direct the archwire  68  into an archwire slot of the orthodontic bracket. The substantially perpendicular angulation of the arms  58  allows the orthodontist to see the archwire slot clearly while directing the archwire  68  into the archwire slot.  
     [0034] Referring to FIG. 7, the fork shaped ends  60  and corresponding prongs  62  allow an orthodontist to seat only one side of an archwire  68  into an archwire slot. This is useful where a tooth is only partially displaced such that it is not necessary to direct the archwire  68  on both sides of the tooth into the archwire slot. It should be understood that the first end  54  of the tool  50  only needs one arm  58  to seat one side of the archwire  68 .  
     [0035]FIGS. 8 and 9 show the operation of the second end  56  of the tool  50 . The second end  56  defines a generally L-shaped tool having a flattened head  70 . The second end  56  is useful for opening a self-ligating orthodontic bracket by pressing vertically on a back end or stopper  42  of the locking member  38 .  
     [0036] Placement Instrument (FIGS.  10 - 11 )  
     [0037] Referring to FIGS. 10 and 11, the placement instrument  80  has a shaft  82  and planar positioning tool  84  formed at one end of the shaft. The planar positioning tool  84  has measured scribe lines  86  formed thereon for measuring the height of a bracket  88  on a tooth  90 . Preferably the scribe lines  86  are 1 mm apart. Preferably the planar positioning tool  84  is elongated and spade shaped as shown in the figures. The instrument  80  has a neck  92  that is bent such that the planar positioning tool  84  is substantially perpendicular to the shaft  82 .  
     [0038] In operation, the scribe lines  86  of the positioning tool  84  are used to measure the height of the bracket  88  from the edge of the tooth  90 , as shown in FIG. 11. The positioning tool  84  is aligned along the longitudinal axis of the tooth  90 . One can measure the height of the bracket  88  from the cusp tip to the bottom of the bracket pad using the scribe lines. The bend in the neck  68  makes the planar positioning tool  64  useful in accessing the posterior teeth for positioning the heights of the brackets on those teeth. The instrument  80  is also useful for seating the bracket  88  firmly against the tooth  90  by inserting the positioning tool  84  into the open archwire slot  94  when the locking member  96  is open. In addition, the tool  84  can be used to removed excess bonding material from around the edge of the bracket  88 .  
     [0039] Archwire with Beveled Edge (FIGS. 12 and 4)  
     [0040]FIG. 12 illustrates an archwire  100  embodying an aspect of the present invention. The archwire  100  has an upper edge  102 , a lower edge  104 , a front edge  106 , and a rear edge  108 . The archwire  100  is preferably square shaped or rectangular shaped in cross-section. The archwire  100  further includes a beveled edge  110  at the junction between the upper edge  102  and the front edge  106 . The archwire of the present invention is preferably made of nickel and titanium, stainless steel, TMA or elgiloy. Many other materials can also be used.  
     [0041]FIG. 4 shows the archwire  100  in an operational position. The archwire  100  is seated in an archwire slot  112  against the locking member  38  in a closed position. The locking member  38  engages the beveled edge  110  of the archwire  100 .  
     [0042] The foregoing description of the present invention has been presented for purposes of illustration and description. Furthermore, the description is not intended to limit the invention to the form disclosed herein. Consequently, variations and modifications commensurate with the above teachings, and the skill or knowledge of the relevant art, are within the scope of the present invention. The embodiments described herein are further intended to explain best modes known for practicing the invention and to enable others skilled in the art to utilize the invention in such, or other, embodiments and with various modifications required by the particular applications or uses of the present invention. It is intended that the appended claims be construed to include alternative embodiments to the extent permitted by the prior art.