Patent Document

FIELD OF THE INVENTION 
     This invention relates to a novel form of intra-oral anchorage, for use in oral surgical procedures. 
     BACKGROUND OF THE INVENTION 
     Intra-oral anchorage refers to a stable point within the mouth, usually a tooth, such that traction may be applied to a less fixed or a moveable structure. Alternatively, two or more anchorage points may be used so that teeth may be held firmly together such that a fracture site nay be aligned and/or that some other surgical procedure may be performed which would necessitate the occlusion being consistent throughout and after the procedure. 
     This intra-oral anchorage is usually achieved by use of metal wires twisted tightly around the teeth (see FIG.  1 A). Additionally, metal bars (arch bars) may be used to create multiple hooks as easy anchorage for traction or fixation (see FIGS.  1 B and  1 C). Once an anchorage point has been established, traction is usually achieved by means of elastic bands while fixation is by use of more metal wires. 
     This system of wiring is time consuming and requires skill, dexterity and training. It is so uncomfortable for the patient that it is almost invariably done during a general anaesthesia. The removal of the wire several weeks later is usually under local anaesthesia and is generally distressing and destructive of delicate gingival (gum) structures. 
     As result of the wire cutting, there are many sharp ends of wire which present hazards to the patient, operator and his assistant, as gloves and skin are often punctured by the wire. This results in a risk of transmission of blood borne infections particularly hepatitis and the AIDS virus which is a well known risk associated with current techniques. 
     Additionally, wire work hardens and fractures in placement and often stretches with functional load requiring readjustment. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention provides anchorage for use in the treatment of oral fractures comprising a flexible belt of a dimension to extend around and between the teeth of a patient, the belt having locking means fixed thereon to receive a free end portion of the belt and lock said portion against retraction therefrom. 
     Preferably, the lock means is attached at one end to the belt, and may be generally in the form of a buckle. 
     Preferably, the locking means is in the form of a head having an aperture therethrough for receiving the end portion of the belt. 
     Preferably also the head has a one-way lock mechanism to allow advancement, but resist retraction of the belt in the aperture. 
     The belt may comprise two sections, a first section including the free end of the belt and typically being curved; and a second section between the first section and the locking means. 
     The second section is preferably profiled to co-operate and lockingly engage with the locking head. 
     Preferably, the first section has a smooth surface to facilitate passing the belt through inter-dental spaces. 
     The locking head may have on its outer face means for retaining a fixing member, for example an elastic band, a plastic tie, a wire or a bar, for inter-connecting and fixing to other locking heads. 
     Advantageously, there are no sharp edges on the anchorage which may be hazardous to the patient or the operator. 
     The locking means may comprise a plurality of inclined teeth on both the second section of the belt and an inner face of the locking head whereby the teeth co-operate such that the belt can only pass through the aperture in one direction. 
     The locking means may include an external plate to ensure a coherent fitting of the anchorage to a tooth; the plate may be concave, although it can be varied to suit any given tooth. 
     In use, where more than one anchorage is used, traction may be applied between the anchorages by wrapping elastic bands or other suitable means around retaining means such that the teeth or fracture points may be drawn into proper alignment and held in place. 
     The belt is typically between 10 and 14 centimeters in length and around 0.6 to 1.0 millimeters in width. 
     Said first section of the belt may be typically 1.5 to 3 centimeters long. 
     The locking head is preferably approximately 7 to 11 millimeters long and approximately 3 to 5 millimeters in width. 
     Further according to the invention there is provided a method of treating facial or law fractures or facilitating facial or jaw bone surgery, comprising extending a flexible belt around one or more of a patient&#39;s teeth, passing one end portion of the belt through locking means carried on the belt and tensioning the belt around the teeth by drawing it through the locking means, said locking means preventing retraction of the belt therefrom. 
     The belt is preferably of plastics material. 
     More preferably the belt is of Nylon having a tensile yield strength of between 50 to 80 MN/m 2  and a Rockwell hardness of between 100-140. 
     Optionally the belt, is of polyketone, having a tensile yield strength of between 50 to 80 MN/m 2  and a Rockwell hardness of between 100-140. 
     Optionally a portion of the belt, especially the first section of the belt may be of steel, having a tensile yield strength of between 175 to 2000 MN/m 2  and a modulus of elasticity of between 175 to 230 GN/m 2 . 
     The plastic ‘buckle’ preferably faces outwards from the face of the tooth and incorporates a hook and location point for an arch bar. The entire device can be produced with no sharp edges and may have minor modifications of shape to facilitate placement. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: 
     FIG.  1 A: Illustrates the prior art method of intra-oral wiring. 
     FIG.  1 B: Illustrates an arch bar of the prior art. 
     FIG.  1 C: Illustrates an arch bar of the prior art anchored by intra-oral wiring. 
     FIG.  2 A: Illustrates an anterior view of the first embodiment of the anchorage. 
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG.  2 B: Illustrates the first embodiment of the anchorage viewed from the right hand side. 
     FIG.  2 C: Illustrates the first embodiment of the anchorage viewed from the left hand side. 
     FIG.  2 D: Illustrates the posterior view of the first embodiment of the anchorage. 
     FIG.  3 A: Shows the first embodiment of the anchorage ‘open’. 
     FIG.  3 B: Shows the first embodiment of the anchorage ‘closed’. 
     FIG.  3 C: Shows the locking mechanism. 
     FIGS.  4 A-D: Illustrates the device being fitted to a tooth. 
     FIG.  5 : Shows traction being applied using elastic bands wrapped around the hooks. 
     FIG.  6 A: Shows an arch bar fitted in place. 
     FIG.  6 B: Shows an arch bar secured in place by an elastic band. 
     FIG.  7 A: Shows a fracture at two positions. 
     FIG.  7 B: Shows the fracture sites realigned with a screw plate in place. 
     FIG.  8 A: Illustrates a top view of the second embodiment of the anchorage. 
     FIG.  8 B: Illustrates the second embodiment of the anchorage viewed from the right hand side. 
     FIG.  8 C: Illustrates the second embodiment of the anchorage viewed from the left hand side. 
     FIG.  9 : Illustrates the second embodiment of the anchorage viewed from the left hand side. 
     FIG.  10 : Illustrates the pulling taut of the belt within the anchorage. 
     FIG.  11 A: Illustrates anchorages attached to teeth viewed from the front. 
     FIG.  11 B: Illustrates anchorages attached to teeth viewed from the side. 
     FIG.  11 C: Illustrates anchorages attached to teeth with an elastic band placed over the hooks, viewed from the side. 
     FIG.  12 A: Illustrates the second embodiment of the anchorage viewed from the right hand side. 
     FIG.  12 B: Illustrates the second embodiment of the anchorage viewed from the right hand side. 
     FIG.  12 C: Illustrates the second embodiment of the anchorage viewed from the right hand side. 
     FIG.  13 A: Illustrates the belt of the anchorage with teeth on its upper side viewed from the top, in cross section and from the side. 
     FIG.  13 B: Illustrates the belt of the anchorage viewed from the top and in cross section. 
     FIG.  13 C: Illustrates the belt of the anchorage with teeth on its aide viewed from above and from the right hand side. 
     FIG.  14 A: Illustrates the first section of the belt of the anchorage viewed from the side and in cross section. 
     FIG.  14 B: Illustrates the curvature of the first section of the belt of the anchorage viewed from the side. 
     FIG.  15 A: Illustrates how the teeth of the belt cooperate with the teeth of the anchorage. 
     FIG.  15 B: Illustrates the metal member locking system. 
     FIG.  15 C: Illustrates the third embodiment of the anchorage with the flap open and also closed, viewed from the front. 
     FIG.  15 D: Illustrates the fourth embodiment of the anchorage and also when in use, viewed from the front. 
     FIG.  15 E: Illustrates the fifth embodiment of the anchorage and also when in use attached to a belt, viewed from the front. 
     FIG.  16 : Illustrates the belt of the anchorage viewed in cross section. 
     FIG.  17 A: Illustrates a perspective view of the second embodiment of the anchorage. 
     FIG.  17 B: Illustrates the second embodiment of the anchorage viewed from the left hand side. 
     FIG.  17 C: Illustrates the second embodiment of the anchorage viewed from the top side. 
     FIG.  17 D: Illustrates the second embodiment of the anchorage viewed from the right hand side. 
     FIG.  18 A: Illustrates the second embodiment of the anchorage viewed from above. 
     FIG.  18 B: Illustrates the second embodiment of the anchorage viewed from the right hand side. 
    
    
     FIGS. 1A-1C shows the prior use method of wiring an arch bar to teeth to provide a plurality of anchor points for traction to be applied. 
     The oral anchorage of the first embodiment of the invention is formed from a single piece of plastics material  2 . The plastics material  2  is shaped to form a flat section  4  and a hook  6 , which adjoins flat section  4 . Between the flat section  4  and hook  6  there is a groove  8  for placement of arch bar  10 . Hook  6  has a belt  12  which runs perpendicular from hook  6 . Belt  12  may have teeth  14  on its upper and or side sections and is in sections  16  and  18 ; section  16  is linear and section  18  is curved. Hook  6  also has apertures  20  and  22  for entry and exit access for belt  12 , and has teeth  24  between apertures  20  and  22 , which cooperate with the teeth of belt  12 , to produce a one-way locking mechanism. Aperture  20  is funnelled for ease of belt entry. 
     In use the first embodiment of the oral anchorage of the invention is offered to outside face of tooth  26 . Belt  12  is pushed through the gap between teeth  26  and  28 , passed around the back of tooth  26  and through the gap between teeth  26  and  30 . Belt  12  is then threaded into aperture  20 , pulled through aperture  22  and pulled tight until taut around tooth  26 . Belt  12  is held in position by virtue of the cooperation of its teeth  14  with teeth  24 . The locking mechanism is of a one-way type such that once the belt  12  is passed through the apertures  20  and  22  it cannot be drawn back in the opposite direction. Any excess belt  12  which is left protruding from aperture  22  is cut away using any conventional technique. 
     The locking mechanism of the belt  12  between apertures  20  and  22  may vary. Teeth  14  on belt  12  may be on the longditudal side  32  or the vertical side  34  of belt  12 . 
     Alternatively a metal member  36 , positioned between the apertures  20  and  22  within the anchorage  2 , and angled so that the belt may pass one way over the metal member  36  may comprise the locking mechanism. 
     Once attached to tooth  26  the oral anchorage may cooperate with another oral anchorage, which has been similarly attached to tooth  38 . By virtue of an elastic band, plastic ties or ligature wires  40  traction can be provided between the two oral anchorages, fixing jaw  42  in position for healing to occur. 
     An arch bar  10  may be fixed into grooves  8  The arch bar is held in place by an elastic band  40  or by close adoptation to facets in the buckle. 
     The oral anchorage of the second embodiment of the invention is formed from a single piece of plastics material  2 . The plastics material  2  is shaped to form a hook  6  having a groove  8  for placement of elastic band  40 . Hook  6  has a belt  12  which runs perpendicular from hook  6 . Belt  12  has teeth  14  and is in sections  16  and  18 ; section  16  is linear and section  18  is curved. Hook  6  also has apertures  20  and  22  for entry and exit access for belt  12  with teeth  24  between apertures  20  and  22 , which cooperate with the teeth of belt  12  to produce a one-way locking mechanism. 
     The oral anchorage of the third embodiment of the invention is formed from a single piece of plastics material  2 . The plastics material  2  is shaped to form a hook  6  for placement of elastic band  40  and has a flap  42  hinged about the anterior end  44  of anchorage  2 . Hook  6  has a belt  12  which runs perpendicular from hook  6 . In use the anchorage is applied to a tooth  24  as in the first embodiment. The difference from the first embodiment is that belt  12  is restrained in anchorage  2  by closing flap  42  tight against anchorage  2 . 
     The oral anchorage of the fourth embodiment of the invention is formed from a single piece of plastics material  2 . The plastics material  2  is shaped to form a hook  6  for placement of elastic band  40  and has an incision  46  cut into the anchorage  2  toward its anterior end. Incision  46  is tapered from its point of incision. Hook  6  has a belt  12  which runs perpendicular from hook  6 . In use the anchorage is applied to a tooth  24  as in the first embodiment. The difference from the first embodiment is that belt  12  is restrained in anchorage  2  pulling the belt right in incision  46 . 
     The oral anchorage of the fifth embodiment of the invention is formed from a single piece of plastics material  2 . The plastics material  2  is shaped to form a hook  6  for placement of elastic band  40  and has an incision  48  cut into the side of anchorage  2 . Incision  48  is designed to cooperate with a belt  12 , which has a bulbous end  50 , The bulbous end  50  is restrained in incision  48  as the belt is pulled tight in its attachment to a another oral anchorage. 
     In the case of a fracture (see FIG.  7 A), once the teeth are brought into their correct relationship, the fracture sites will necessarily be correctly aligned. Using the hooks as anchorage points, ligature wires, strong elastic bands, or plastic ties would hold this stable for weeks to allow healing or briefly to allow placement of a rigid metal plate, fixed by screws (see FIG.  7 B). 
     The oral anchorage of embodiments of the present invention then provide anchorage points for the application of traction to teeth, particularly in the case of a broken jaw which is to be held in a fixed position. It offers a number of advantages over the conventional intra-oral anchorage method of metal wires as a result of its construction and ease of application. Particularly as there are no sharp ends of metal wires there is a much lower risk of “needle stick” injury to both patient and surgeon. 
     The present invention is easier to apply to a patient, resulting in lower operating time (and resultant lower costs) in applying and removing the anchorage and less damage to the delicate gum tissue in placement and removal. The anchorages are also sterile packed, are biologically inert and are compatible with other prosthetic and surgical technology/equipment. 
     REFERENCES 
     1. S. J. Wilson, A. Uy, D. Sellu and M. A. Jaffer, Ann. R. Coll. Surg. Engl., 1996, 78, 20-22. 
     2. M. I. Dauleh, A. D. Irving and N. H. Townell, J. R. Coll. Surg. Edinb., 1994, 39, 310-311. 
     3. D. J. Jeffries, J. Hospital Infection, 1995, 30, 140-155. 
     4. J. E. Carlton, T. B. Dodson, J. L. Cleveland, S. A. Lockwood, J. Oral. Maxillofac. Surg., 1997, 56, 553-556.

Technology Category: 1