Abstract:
The invention pertains to a tool or pliers for effecting a torque bends or twists to orthodontic rectangular arch wire. The pliers have two handles pivotally associated by a core, the core having a slot therein. One of the handles has a bifurcated head with the other handle having a single head adapted to fit within said bifurcated head and pivot on the core. The bifurcated headed handle has at least one slide reciprocally associated with a side of the bifurcated headed handle, the slide having a slot in an end thereof, the slide being manipulated so that its slot into aligned association with the slot in the core. The core is detachably secured to the single headed handle. Slots are in the single and bifurcated headed handles to access their bores so that all the slots can be aligned to accept an arch wire being passed through the slots in the handles and into the slots of the core and slide. Squeezing of the handles causes relative rotation between the core and slide to impart a twist to the wire. The degree of twist can be adjustably controlled. Preferably, there are two slides, one in each side of the bifurcated headed handle.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to orthodontic torque pliers and more particularly to pliers that enable an Orthodontist to effect torque bends or twists in arch wire in a calibrated specific and smooth manner without distortion to other parts of the arch wire. 
       BACKGROUNDS OF THE INVENTION 
       [0002]    An important challenge that faces Orthodontists is how best to apply a third arch bend (torque) or twist in the exact position and with exact angulation. Often the desired torque cannot be performed completely without affecting other parts of the arch wire that may result when in use in undesired teeth movement. 
         [0003]    This is particularly so if the Orthodontist attempts to effect the torque twists or bends with two or a pair of pliers, the pliers gripping the arch wire on either side of the desired location for the twist or bend. The hands and arms effect relative rotation of the pliers and the axis of rotation of the pliers is the wire itself. Due to the nature of the wire and the lack of rigidity to resist lateral dislodging forces that may accompany the relative rotation of the pliers, the result is not solely a torque twist, but most often a combination rotation and displacement movement. It is very difficult using two pliers to effect only a torque twist or bend without distortion of other parts of the wire. 
         [0004]    The U.S. patent to Sosnay U.S. Pat. No. 4,184,259 granted Jan. 22, 1980 discloses an orthodontic tool for placing bends or twists in orthodontic arch wires in order to place torquing forces in the wire. The tool includes indicator means to indicate the amount of twist or torque developed by the engaging means. The two engaging means are placed together and twisted around the arch wire with the indicator means, a pointer, indicating the amount of twist. The engaging means may comprise pliers and keyed members. 
         [0005]    The U.S. patent to Rose, U.S. Pat. No. 4,043,364 granted Aug. 27, 1997 discloses a wire bending plier set for permanently twisting a portion of orthodontic wire about the wire axis to enable application of a torque force to a malpositioned tooth. The plier is configured to grip the wire at spaced apart positions between which the twisting bend is to be made. A lever or key is then engaged with the wire between the gripped areas and the lever or key rotated about the wire axis to stress the wire and impart the desired twist. 
         [0006]    It would be desirable to provide a single tool or pliers which can be used to provide multi-torque bends in a single arch wire, each one specific to a single tooth and this can be accomplished in a single visit, which reduces chair time and treatment time. 
         [0007]    The elasticity of arch wire varies according to size and material used and it would be advantageous to have a single tool or pliers wherein the amount of real torque can be determined as well as the amount of torque that may be lost because of the elasticity of the wire. It would also be advantageous to provide pliers which can be controlled by one hand while the other hand supports the arch wire upon the pliers. 
         [0008]    It would also be advantageous to have a single tool or pliers which can be assembled and dismantled with ease. 
       SUMMARY OF THE INVENTION 
       [0009]    The invention pertains to a single tool or pliers for effecting a torque twist to orthodontic arch wire. 
         [0010]    The invention assists Orthodontists in the application of torque (third order bends) in exact position and exact angulation, and apply a torque bend without detrimentally affecting other parts of the arch wire. 
         [0011]    The pliers have a solid axis of rotation provided by a solid hinge upon which the handles of the pliers rotate. The solid hinge of the pliers permits the pliers to exert torque bends on a rectangular arch wire without affecting the ends of the wire on either side of the torque area. Multiple torque bends can be made on the single arch wire during a single visit of the patient and thereby reduces chair time. The pliers will also reduce the need to use pretorqued wires which are often more expensive. 
         [0012]    Further, the torque inclination, twist, or bend angle can be determined with precision with the use of the calibrated scale or ruler fixed to one handle of the pliers in co-operation with a pointer on the other handle of the pliers. The ability to determine with precision the bend angle will assist in reducing the risk of excessive force applied to a single tooth or group of teeth when installed and can enhance the aesthetics and appearance of the work. 
         [0013]    Further still, the pliers of the invention allow for standardization and repeatability of the torque applied to the arch wire, sometimes referred to in the profession as a “closing reference point” or “closing limit point”. An operator of the pliers can adjust a screw which permits adjustment to various degrees of angles and thereafter lock the screw, thereby enabling the operator to repeat the desired torque bend as often as required. This results in enabling the same degree of torque bend to be exerted to identical teeth in opposite arch wire halves, for example, upper left and right laterals or upper left and right premolars when a double torque technique is used. Single torque applications are applied at the beginning and at the end of the segment, and the pliers permit symmetry of the bends to reduce the possibility of differences in the torque angles. 
         [0014]    As noted, the pliers permit both single torque, as well as double torque bends, a single torque being applied to a group of teeth and involves using one of the supporting slides whereas the double torque bend uses both support slides. In either case, both are obtained in essentially one step. 
         [0015]    Further still, the pliers permit the arch wire to rotate around itself, i.e., around an imaginary line that passes through the center of the cross-section of the arch wire and not around points that are spaced from or away from the center. The results are symmetrical torque bends which avoid causing other movements of the teeth when the wire is in use. 
         [0016]    The pliers have two handles pivotally associated by a core, the core having a slot therein. One of the handles has a bifurcated head with the other handle having a single head adapted to fit within said bifurcated head and pivot on the core. The bifurcated headed handle has at least one slide reciprocally associated with a side of the bifurcated headed handle, the slide having a slot in an end thereof, wherein the slide can be manipulated so that its slot is in aligned association with the slot in the core. The core is detachably secured to the single headed handle. Slots are in the single and bifurcated headed handles to access their bores so that all the slots can be aligned to accept an arch wire being passed through the slots in the handles and into the slots of the core and slide. Squeezing of the handles causes relative rotation between the core and slide to impart a twist to the wire. The degree of twist can be adjustably controlled. Preferably, there are two slides, one in each side of the bifurcated headed handle. 
         [0017]    The parts are easily assembled and disassembled. 
         [0018]    More particularly, there is provided in one aspect orthodontic torque pliers for twists in orthodontic arch wire, comprising a first handle having a single headed portion with a bore therethrough and a rectangular slot. A second handle has a bifurcated headed portion, each bifurcation having a bore therethrough accessed by a slot, the bifurcated headed portion adapted to accommodate the single headed portion wherein the bores of both handles are in alignment and the slots of the bifurcated head are in axial alignment with the slot of the single headed portion. A core is provided for insertion within the bores of the single headed portion of the first handle and bores of the bifurcated headed portion of the second handle means and the core also acts as a pivot for the handles. The core has a rectangular slot therein adapted to accept a portion of the arch wire. The second handle has at least one slide means operatively associated with a side of the second handle wherein the slide means can be manipulated from a retracted position to an extended position. The slide means has a rectangular slot therein and in the extended position, the slot of the slide means in alignment with the core slots and the slots of the single and bifurcated headed portions of the handles. The slide slot is adapted to accept a portion of the arch wire. Squeezing the handles together about the core acting as a pivot causes the core slot and the slide slots to rotate relatively to each other to impart a twist to the arch wire. 
         [0019]    The invention also comprehends a method of creating a torque twist in orthodontic arch wire, comprising providing torque pliers having a first handle with a single head means having a bore and rectangular slot, and a second handle with a bifurcated head, each bifurcation having a bore and a slot, the handles pivotally connected by core means within the bores of the handle heads, the core means having a rectangular slot adapted to accept the arch wire when aligned with the slots of the handle heads. The second handle further has at least one slide slidingly associated with a side of the second handle, the slide having a rectangular slot in an end thereof and movable from a retracted position to an extended position. The method further comprises aligning the slide slot, the core slot and the handle slots, inserting the arch wire through the slots of the handle heads into both the slide slot and the core slot, squeezing the handles together to rotate the slide slot and core slot relative to each other, to cause torque twist in the arch wire, releasing pressure slightly on the handles and retracting the slide which disengages the arch wire from the slot of the slide, and removing the arch wire from the core slot and through the slots of the handle heads. 
         [0020]    Other aspects of the invention will become more apparent from the description of a preferred embodiment in conjunction with the drawings herein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a side view of the assembled pliers of the invention; 
           [0022]      FIG. 2  is a partial perspective exploded view of a part of the pliers showing the core and one slide. 
           [0023]      FIG. 3  comprises  FIG. 3   a , a side view of the single ended or headed handle,  FIG. 3   b  a front view thereof, and  FIG. 3   c  an opposite side view thereof; 
           [0024]      FIG. 4  comprises  FIG. 4   a , a side view of the double ended or bifurcated headed handle with a scale or ruler and  FIG. 4   b  is a front view thereof; 
           [0025]      FIG. 5  comprises  FIG. 5   a , a side view of the cylindrical core and  FIG. 5   b  is an end view thereof; 
           [0026]      FIG. 6  is a side view of the fixation pin; 
           [0027]      FIG. 7  comprises  FIG. 7   a , a side view of a slide and  FIG. 7   b  a front view thereof, both with views including a slide knob; 
           [0028]      FIG. 8  is a side view of the adjustment screw; 
           [0029]      FIG. 9  comprises  FIG. 9   a , an end view of a first portion of the fixation lock assembly and  FIG. 9   b  a side view thereof; 
           [0030]      FIG. 10  comprises  FIGS. 10   a , an end view of a second portion of the fixation lock assembly, and  10   b  a side view thereof; 
           [0031]      FIG. 11  is a side view of the opening spring; 
           [0032]      FIGS. 12 and 13  are schematic views of the pivot core and slides before and after application of torque; and 
           [0033]      FIG. 14  is an end view of the pivot core with arch wire inserted therein. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0034]    Turning to  FIG. 1  which illustrates the pliers or tool  10  assembled and  FIGS. 3-11  which illustrate parts of the tool, the tool includes two plier handles  20 ,  22 , which serve as a frame to carry the more active components. One of the plier handles  20  ( FIG. 3 ) is single ended or headed  26  with bore  28  and slot  29 . Handle  20  carries core  30  ( FIG. 5 ) as well as the adjustment screw  32  ( FIG. 7 ) in threaded aperture  100  with fixation lock nut assembly  104  and  108  ( FIGS. 9 and 10 ). The other handle  22  ( FIG. 4 ) is double ended or headed  34 , having bifurcations  36  and  38 . The bifurcated portions  36 ,  38  each have bore  37  and laterally aligned slots  39 . Handle  22  carries two supporting slides  40  ( FIG. 7 ) one on each side of handle  22  and carries a ruler  46 . 
         [0035]    The core  30  is the element, the articulation or pivot between the handles  20 ,  22 . The diameter of the bores  28 ,  37  is such that core  30  can be slid axially into the bores. The core  30  is cylindrical with radial slot  52  which is directed inwardly from the peripheral surface of the core to the axial center and past the center by half the depth of the arch wire that will be torqued. The width of the slot is substantially equal to the width of the arch wire to be torqued. The slot  52  in the core  30  is configured such that when the arch wire is at the inner end of the slot  52 , the center of the arch wire coincides with the axial center of the core  30 . The core is changeable, that is, cores with different sizes of slots are provided to take into consideration arch wires of different cross sectional dimensions. 
         [0036]    The core  30  is fixed to the handle  20  by means of a fixation pin  60  ( FIG. 6 ) in friction fit with bore  62  with its end entering recess  31  in pivot core  30 . When fixed, the slot  52  of core  30  is aligned with the slots  29  and  39  of handles  20  and  22 . The fixation pin secures the core  30  to handle  20 , but allows for easy and quick interchangeability of cores within bores  28 ,  37 . 
         [0037]    Each support slide  40 , there being two, but only one is shown ( FIGS. 2 and 7 ) has slots  70 ,  72  extending inwardly from opposite ends, the slots  70 ,  72 , the slots of different widths and adaptable to accept arch wire of different cross-sectional size. The slides  40  have ribs  74 ,  76  which are adapted to slide within grooves  78 ,  80  in the opposed sides  84  of a recess  86  in handle  22 . The slides  40  are held in position in relation to handle  22  so that they can be reciprocated whereby the slot  70  of each slide  40  can be lined up with the slot  52  in the core  30 . The slots are equal in depth. If the slides  40  are reversed side to side and end to end, the slot  72  of each slide would line up with the slot  52  with a different core  30 . The slides  40  have threaded holes  94  into which threaded knob element  98  can be secured to act as knobs for manipulation of the slides, whereby the Orthodontist&#39;s thumb can manipulate and reciprocate one or both slides  40  by the knobs during the process of torque application. The threaded knob element can be rotated so that the bottom thereof contacts the side of the handle and thereby fix the slide in a desired position. The slide slot  70  can be held against the arch wire on at least one side of core  30  during torquing and released from the wire after torquing. 
         [0038]    A threaded adjustment screw  32  is fixed to the single headed handle  20  through threaded bore  100  and rotatable threaded lock nut assembly  104 ,  108  is located on screw  32  and can be adjusted to set a limit to the angle of torque to be applied. In other words the adjustment screw  32  with threaded lock nut assembly  104 ,  108  sets a reference point or closing limit point between the handles  20 ,  22  which can be set and it will act as a repeatable point for torque application. This adjustment screw  32  with lock nut assembly  104 ,  108  can be used to assist the Orthodontist in a single torque exertion when there is a desire to torque an area greater than the width of the core of the pliers. The two points at the beginning and end of the span to be torqued can be made at the same angulation in order to provide symmetrical and a smooth torqued area without distortion. The adjustment screw  32  also provides for a reference point in double torque applications when the Orthodontist wishes to have the exact degree of angulation in identical teeth in opposite halves of an arch wire such as two laterals or two premolars. 
         [0039]    The curved ruler  46  is calibrated with scale  110  and is attached at end  112  to the handle  22  by screw  114  ( FIG. 1 ). Ruler  46  also has hook end  116  which is associated with handle  20  at  118  through slot  120 . Stop  122  in cooperation with hook end  116  limits the opening of the pliers. The limit of the opening of the pliers is where the slot  52  of core  30  is in line with and in parallel alignment with the slot  70  and/or  72  in the slides  40  and the access slots  29 ,  39  so that the arch wire can be inserted into the various slots at the opening limit or point of the pliers. The single headed handle  20  has a small pointer  124  which with closure of the pliers can indicate on the scale  110  the degree of torque angle applied to the arch wire. 
         [0040]    Finally, spring  130  fits around or encompasses curved ruler  46  (over hook end  116 ) and maintains the pliers normally in an open position where the core slots  52  and slide slot  70 , ( 72 ) are aligned as noted previously. 
         [0041]    In assembling the pliers, end  112  of curved ruler  46  is attached to handle  22  by screw  114 . The small knobs or screws  98  are attached at sides  74  of both slides  40  in threaded association with holes  94 . Spring  130  is fitted over hook end  116  and around ruler  46 . The hook end  116  of ruler  46  is angled through slot  120  and the two handles  20 ,  22  and their headed ends  26  and  34  are fitted together so that bores  28  and  37  are aligned. The core  30  can then be axially slid into the bores  28 ,  37  in the two handles. The core  30  is fixed in place by the fixation pin  60  in friction fit with bore  62  of handle  20  and its end in core recess  31 . 
         [0042]    The handles  20 ,  22  are locked together by virtue of the two headed handle  22 , with its bifurcations  36  and  38  on either side of single ended portion  26  of handle  20 . The core  30  acts as a hinge or pivot for relative rotation between the handles  20 ,  22 . The core hinge is solid and prevents distortion or bending. The adjustment screw  32  with the lock nut assembly  104 ,  108  thereon is threadably located in position in bore  100  and serves as a reference point to adjust the degree of angle to be applied to the arch wire. Once the adjusting screw  32  is used to adjust the desired angle, it is locked in place by adjusting lock nut assembly  104  and  108  so the position of screw  32  is fixed and the selected torque angle can be repeated and permits for both single and double torque applications as further noted herein. Both slides  40  are slid into position on handle  22  with the knobs  96  extending as shown in  FIG. 1  to complete the assembly of the pliers, ready for use. The slide  40  with knob  96  as seen in  FIG. 1  is shown with its slotted end spaced from the core  30 . Disassembly of the pliers for cleaning or repair is easily accomplished. Also by simply removing the fixation pin, a core with a different sized slot can be easily substituted. 
         [0043]      FIGS. 12 and 13  schematically illustrate core  30  and both slides  40  with pivot core slot  52  aligned with slots  70 . The headed ends of bifurcated handle  22  and the access slots  29 ,  39  are not shown. Pivot core  30  is shown in side view in  FIG. 14  with rectangular wire  150  therein, it being appreciated that the depth of the slot  52  is configured so that when wire  150  is fully inserted into the slot  52 , the axis  152  of the rectangular wire coincides with the axis of pivot core  30 .  FIG. 13  illustrates the relative position of the pivot core slot  52  and slots  70  of slide  40  after which torque may be applied to the wire by squeezing the handles to pivot the core relative to the slides. After the desired torque has been developed, pressure on the handles is released slightly, but sufficiently to allow the slots of the slide(s) to be retracted from the wire and then the handles are fully released so the slot  52  of the core realigns with the handle access slots  29  and  39  whereupon the wire  150  can be removed. 
         [0044]    In operation, the Orthodontist would take the pliers in one hand with the double ended handle  22  having a convex configuration, the convex configuration resting in the palm of the hand with the four fingers of the same hand around the single headed handle  20  which has a concave configuration. 
         [0045]    The pliers are capable of exerting torque on arch wire in two modes of operation. 
         [0046]    The first mode is the double torque technique (such as shown in  FIGS. 12 and 13 ) in which both slides  40  are in use to support the rectangular arch wire on both sides of the core  30 . Both slides  40  are pushed by thumb activity on knob  98  to their extended position and locked wherein the slots  70  are aligned with the slot  52  of core  30  (and access slots  29 ,  39  of the handles) so the slots form effectively one transverse slot. The access slots  29  and  39  of the handles  20 ,  22  are also in such alignment and are wider than the slots  52 ,  70 . It will be apparent that the slots  52 ,  70  must be of the same size or gauge. With the pliers held in one hand, the other hand is used to insert the arch wire through access slots  29 ,  39  and into the core slot  52  and slide slots  70 . Care is taken not to exert any pressure on the plier handles before the wire is completely inserted so as not to lose the opening limit point defined by the ruler hook  116  in cooperation with the stop  122 . The rectangular arch wire is supported on both sides of the pliers adjacent slides  40  by the other hand and once the wire is fully inserted into the slots  52  and  70  of the core and slides, the handles  20 ,  22  are squeezed together until the closing limit point is reached, as determined previously by adjustment of the lock nut assembly  104 ,  108  and the adjusting screw  32 . 
         [0047]    Hand pressure is released slightly and the slides  40  are both retracted by the thumbs in cooperation with knobs  96 . This releases the strain between the area torqued by the core and area supported by the slides. 
         [0048]    After the slides  40  are retracted and the slide slots  70  fully released from the wire, the handles are released further to the limit opening point and the wire pulled from the slot  52  of the core  30  and aligned handle access slots  29 ,  39 . This double torqued area is effectively equal to the width of the core which is confined to a specific single tooth. There is no affect on any other part of the arch wire and the process can be repeated for multiple positions as needed and as a result lead to reduced chair time. The double torque can be repeated effectively on lateral teeth because of the repeatable limiting points provided with the adjustment screw  32  and lock nut assembly  104 ,  108 . 
         [0049]    The pliers or tool  10  are also effective to apply a single torque area against a group of teeth. The torqued area is wider than one tooth and may torque an area of two teeth or more, for example. The area desired is marked on the arch wire by the Orthodontist with a marker, both at the beginning and the end of the area. One of the slides  40  is retracted or withdrawn completely from its operative position so that only one slide  40  is extended in operative position where it&#39;s slot  70  is aligned with the core slot  52 . The wire is manipulated (straightened) by the free hand and inserted through the access slots  29 ,  39 , core slot  52  and single slide slot  70  so that the wire is parallel to the axis of and within the core slot and is transverse to the axis of the slots of the core and the slide in operative use. Once the pliers are squeezed to the desired adjustment limitation point, slight release of the pliers reduces friction between the slide slot  70  and wire and the single slide  40  is retracted, allowing the pliers to then open to the opening limit point and permit withdrawal of the wire from the core slot  52  and access slots  29 ,  39 . There is thus formed a single torque bend to the wire. The wire is then reversed to the opposite side of the marked area and the process repeated. 
         [0050]    The torquing of the wire is effective without distortion. The pliers can apply multiple torques, single or double as desired without difficulty, to both the curved portion or straight portion of the arch wire. 
         [0051]    Accordingly, with my pliers, torquing arch wires can be performed in one step. There is ease of manipulation and the pliers frees the other hand to hold the arch wire. The degree of torque angle can be repeated easily whether double or single torques is required. Further, the assembly and disassembly of the pliers is provided wherein the core itself acts as the central point for the pliers and can be easily replaced by another core having a different slot gauge.