Abstract:
A permanently mounted orthodontic intermaxillary constant force system wherein the force producing portions are attached to the orthodontic appliance in one jaw and small flexible cables transmit the forces to the patient&#39;s opposite jaw.

Description:
FIELD OF THE INVENTION 
   The present invention is directed to a device for applying intermaxillary force from one jaw to another during orthodontic procedures where the intermaxillary connection is performed using fine cables. 
   BACKGROUND OF THE INVENTION 
   Orthodontic procedures for straightening teeth involve fixed orthodontic appliances wherein forces are often applied between the upper and lower jaws in order to correct the patient&#39;s bite. The predominant method used requires the patient&#39;s cooperation, wherein the patient repeatedly places latex rubber bands in selected positions. The latex rubber bands quickly lose their elasticity, thereby requiring the patient to repeatedly replace the latex bands. The patient&#39;s use of the bands affects treatment progress, length, and the results obtained. The uncooperative patient becomes a problem for the orthodontist. 
   The orthodontic profession has sought methods of applying the intermaxillary forces by seeking devices that could be permanently attached; thereby, eliminating patient cooperation. A primary requirement of a permanent force is that it maintain its elasticity. Latex loses 25% of its elasticity in the first 24 hours. The best non-latex material loses 40% of its elasticity in 24 hours. Coiled springs retain their elasticity and have been permanently placed. These springs have been open and closed coil in configuration. A close coiled spring is elongated to produce force wherein an open coiled spring is compressed to produce force. In order to produce force from one jaw to another the springs have been attached from one jaw to another, thus crossing the chewing plane of the teeth. The disadvantages of the coiled springs worn intermaxillary are that they are bulky, uncomfortable, and prone to damage during mastication. The bulkiness of the springs makes their use in the front of the mouth impossible. 
   SUMMARY OF THE INVENTION 
   In order to better understand the invention some dental terminology should be explained. An orthodontic appliance consists of a series of orthodontic brackets attached to a patient&#39;s teeth. The following dental terminology is used: buccal is towards the patient&#39;s teeth; lingual is towards the tongue; gingival is towards the gums; anterior is towards the front of the mouth; posterior is towards the back of the mouth; incisors are the front teeth; molars are the back teeth; maxilla is the upper jaw; mandible is the lower jaw; and intermaxillary is between the jaws. A bracket has a central slot which receives an archwire. The archwire is the force which actually aligns the teeth. The bracket has gingival and occlusal wings which are used to ligate the archwire to the bracket. 
   The present invention is directed to a permanently attached device wherein the force generating portion is attached to the orthodontic appliance within a single jaw, either the maxillary or the mandibular jaw. The intermaxillary force device comprises a longitudinal hollow tube with an inner and outer diameter and opposing ends, a first end and a second end. In the preferred embodiment, the longitudinal tube contains within its interior a longitudinal open coiled spring within its first and second ends extending almost the length of the longitudinal tube. The tube contains two v-grooved roller bearings, one at each end of the spring. A v-grooved pulley is mounted to the first end of the tube on a shaft mounted to the tube at a right angle to the tube&#39;s axis. Adjacent to the first end bearing the tube is constricted to form a seat for the first end of the internal coiled spring 
   At the second end of the spring a second v-grooved pulley is housed and mounted to a shaft within a ball which is seated within the second end of the internal spring. 
   A flexible cable is attached to the first of the spring and extends internally within the spring to the second end of the spring and encircles the v-groove of the second end pulley and returns internally within the spring to the v-groove at the first end of the spring. This is an important path for the string as the string travels twice the distance of compression of the spring. This allows for the opening and closing of the jaw. The jaw in the anterior opens as wide as 35 mm and moves sagitally 12 mm. The average open-coiled spring is 27 mm and will compress ⅔ of its length to 9 mm. The 18 mm of movement is not enough to allow for the 35 mm of jaw movement. The use of the second end pulley allows the cable to move twice the distance or 36 mm which is adequate for the jaw to open wide 
   The first end of the tube has an opening in the wall allowing the cable to circle the v-grooved pulley and exit the tube to the opposing arch of teeth. In a preferred embodiment, the first end v-grooved pulley is pivotally mounted allowing the pulley to swivel to accommodate the different cable directions due to different points of cable attachment in the opposite jaw end movement of the lower jaw. 
   The longitudinal tube is attached to the orthodontic appliance using, in a preferred embodiment, a locking clasp which allows easy placement and removal of the longitudinal tube. The locking clasp is attached to the orthodontic appliance using a configured wire. The clasps may also be attached to a separate heavier arch wire which is in turn ligated to the orthodontic appliance. 
   The flexible cable may be attached to the opposing arch by tying to to a bracket, button, arch wire, or an attachable hook. 
   The attachable hook, in its preferred embodiment, is 3-4 mm in length and is attached to a configured 0.016 inch stainless steel wire adapted to an orthodontic bracket archwire combination. 
   In an alternative embodiment of the present invention, the cable returns to the arch it originated from, producing a maxillary mandibular vertical pull, as in a force in the front of the patient&#39;s mouth to close an anterior open bite. 
   In an alternative embodiment of the present invention, the cable is attached directly to the second end of the spring, eliminating the bearing at the second end of the spring. 
   In a further alternative embodiment of the invention, the spring is a close coiled spring attached to the second end of the tube. 
   In a further alternative embodiment of the invention, the force system, such as the coil springs, can be used without the horizontal tube. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a prospective view of the intermaxillary force system; 
       FIG. 2  is an internal view of the intermaxillary force system of  FIG. 1 ; 
       FIG. 3  is a view of the intermaxillary force system mounted to an orthodontic appliance; 
       FIG. 4  is an end view of the of the mounted first end v-shaped pulley; 
       FIG. 5  is a side view of the v-shaped pulley; 
       FIG. 6  is an internal view of the pivotally mounted first end v-shaped pulley; 
       FIG. 7  is a view of the spherically mounted second end v-shaped pulley resting on the second end of the coiled spring; 
       FIG. 8  is another view of the pulley of  FIG. 7 ; 
       FIG. 9  is an interior view of the mounted first end v-shaped pulley; 
       FIG. 10  is the circular clasp mounted to a wire configuration; 
       FIG. 11  the configured wire of  FIG. 10  mounted on an orthodontic bracket archwire combination; 
       FIG. 12  is a cross-sectional view  FIG. 11 ; 
       FIG. 13  is a view of the clasp wire configuration mounted in the mouth; 
       FIG. 14  is a view of the clasps mounted to a heavy archwire; 
       FIG. 15  is a view of the apparatus of  FIG. 14  mounted in the mouth; 
       FIG. 16  is a view of the configured wire with a hook as it is placed in the mouth; 
       FIG. 17  is a view of the horizontal tube mounted with the first end in the front of the mouth; 
       FIG. 18  is a view of the locking clamp in an open position; and 
       FIG. 19  is a view of the locking clamp of  FIG. 18  in a closed position. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIGS. 1-3  the intermaxillary force appliance has a longitudinal hollow tubular body  5  having sufficient length to extend from the patient&#39;s posterior molar area  25  to the anterior cuspid area  26 . The tube is preferably metal. The diameter of the horizontal tube  5  may be 2-6 mm, preferably 4 mm to be comfortably worn by the patient. The horizontal tube  5  has a first  8  and second  9  end. An open coiled longitudinal spring  10  is enclosed in the horizontal tube  5  extending from the first tube end  8  to the second tube end  9 . The spring  10  has a first  18  and second  19  end to correspond to the first  8  and second end  10  of the tube  5 . The external diameter of the spring is less than the internal diameter of the tube  5 , allowing the spring  10  to be compressed. A sphere  14  the same diameter as the spring  10  rests at the second spring end  19 . The horizontal tube  5  is externally threaded at the first  16  and second  15  ends. An internally threaded cap, the first end cap  12 , is threaded onto the first horizontal tube end external thread  16 . A second end cap  4  is threaded over the second horizontal tube threaded end  15 . The first and second end caps have eyelets  6 - 7  for ligation. Referring to  FIG. 6 , in a preferred embodiment, the first end cap  3  has an interior wherein a 4 mm shaft  38 , 1-2 mm in diameter, is mounted centrally in the long axis of the horizontal tube  5 . Pivotally mounted upon the shaft is a v-shaped roller bearing  36  mounted to mounting brackets  35  attached to a pedestal base  49 . The pedestal base  49  has a central hole  40  which receives the shaft  38 . The shaft  38  has an end  39  which extends into the horizontal tube  5  wherein the end  39  is enlarged locking the pedestal base  49  to the first end cap  3 . Spherical bearings  37  may be placed between the pedestal base  49  and the first end cap  3 , enhancing the rotation of the v-shaped roller bearing  36 . Adjacent to the pivotally mounted first end roller bearing  11  is an opening  2  in the wall of the horizontal tube  5 . The first end spherical bearing  36  is mounted offset  35  towards this opening  2 . In  FIG. 9 , adjacent to the tube opening  12 , the horizontal tube  5  is circumferentially narrowed  77  to form a seat for the first end  18  of the spring  10 . 
   Referring to  FIG. 4 , another embodiment of the first end pulley  30  is mounted to a central shaft  32  mounted to the walls of the horizontal tube  5 . The v-shaped pulley is shown in  FIGS. 30-31   4 ,  5 , and  8 . A central shaft housing  34  is surrounded by roller bearings  33 . The pulley is v-shaped to receive a cable. 
   Referring to  FIGS. 1-3  a flexible cable  1  0.015-0.030 inch in diameter is attached at the first tube end  8  and extends through the center of the spring to the second end of the spring  19 , wraps around the v-grooved pulley  14  at the second end and returns to through the center of the spring to the first horizontal tube end  8 , wraps around to his first end v-shaped pulley  11 , and exits the horizontal tube through the opening  2  in the wall of the horizontal tube  5 . 
   A preferred embodiment of the cable is a 0.016 inch diameter 60 pound test microfilament line called POWER PRO® sold by Innovative Textiles, inc. The cable is made from SPECTRA® FIBER from Honeywell International. 
   The horizontal tube  5  assembly is mounted, as shown in  FIGS. 3 and 12 , positioned between the orthodontic brackets and the patient&#39;s cheek. The horizontal tube  5  is positioned slightly gingival  FIG. 12  to the central position of the bracket  56  to keep the tube out of occlusal contact with the patient&#39;s opposing teeth. Referring to  FIG. 3 , the cable I is shown exiting the first end of the tube  8  and attaching to the patient&#39;s upper arch in the cuspid area  24 . The length of the cable is adjusted to compress the spring sufficiently to apply pressure from the patient&#39;s lower dental arch to the anterior of the patient&#39;s upper arch. This force would move patient&#39;s upper teeth inward, correcting the bite. 
   Referring to  FIGS. 2 and 7 , in a preferred embodiment, there is a v-shaped roller bearing  41  embedded within a sphere  14  mounted on the second end  19  of the coiled spring  10 . The sphere  14  and v-shaped pulley  41  are mounted on an axial mounting shaft  43 . The cable  1  originates at first end of the horizontal tube  8  and travels through the interior of the coiled spring, engages the second end pulley  14  and returns to the first end pulley  11 . This pulley arrangement allows the cable to have twice the movement of the compression distance of the spring, allowing for full motion of the lower jaw. 
   The advantage of this appliance is that it is permanently attached eliminating the variable of patient cooperation. The continuous force reduces the time the patient will spend in orthodontic appliances, reduces the orthodontist&#39;s chair time, and increases the success rate of the orthodontic treatment. 
   Referring to  FIGS. 10-13  a configured wire  50 - 54  attaches the horizontal tube  5  to the orthodontic bracket  56  archwire  52  combination. An orthodontic bracket has a central horizontal slot for the archwire and occlusal  59  and gingival  58  wings for ligating the archwire  52 . The configured wire has a clasp portion  50  and a portion  51  which engages the archwire and bracket. 
   The horizontal tube assembly  5  is mounted to the orthodontic appliance, in a preferred embodiment, using clasps  50  and  53  which grip the horizontal tube  5  combination. The clamps are secured to the bracket archwire combination. The mounting of the clasp  50  and  53  to the bracket is done by using a 0.016 inch wire which is attached to the clasp and is configured to engage the occlusal tie wings  59  of the orthodontic bracket, pass over the buccal surface of the archwire, and return under the gingival tie wings  58  of the orthodontic bracket  56  to be attached to the clasp  50  and  53 . The wire has a break in it where it passes over the archwire, resulting in two ends. Each wire is configured as a small C-hook  53  which rests over and engages the buccal of the archwire. 
   Referring to  FIGS. 14-15  another embodiment in mounting the horizontal tube assembly  5  to the orthodontic appliance is to mount the horizontal tube  5  by soldering or attaching the tube to an overlay archwire  60 . The overlay archwire  60  is bent to the same arch form as the archwire  52  using the same tie-wires used for the existing archwire  52   
   A preferred embodiment of the horizontal tube clasp is in  FIGS. 18-19  wherein the clasp is a locking clasp comprising a c-clasp  70  with a lip at one end  71 . The other end of the c-clasp  70  is hinged  80  to a first smaller curved section  72  which is in turn hinged at its free end  81  to a smaller second curved section  73  to which is hinged at its free end  82  to the center of a third c-section  74  which has a lip at its free end  75  adjacent the c-hook lip  71 .  FIG. 18  shows the clasp open allowing easy insertion or removal of the horizontal tube.  FIG. 19  shows the clasp closed to a locked position. 
   Referring to another configuration of the intermaxillary force appliance in  FIG. 17  the horizontal tube  5  ends are reversed wherein the cable  1  exits the horizontal tube  5  at the front of mouth. The cable would be used in this configuration for class III, or underbite correction. This embodiment can also be used by attaching the cable straight upwards to the anterior of the patient&#39;s mouth  FIG. 17 , for use in closing an anterior open bite.