Abstract:
A sinus bolt retention system includes a guide for precisely aligning a sinus support and an implant post for attachment through a bone. The sinus support is a bio-compatible material shaped to closely approximate the internal form of the sinus of the bone. The implant post extends from the outer surface of the bone through a bore hole to engage the sinus support. A denture may be immediately fitted to the implant post.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention is related to the field of dental implants.  
           [0003]    2. Description of the Prior Art  
           [0004]    Loss of teeth is generally followed by bone loss or resorption in the supporting anatomical structures. Osseointegrated implants have become the treatment of choice for the replacement of missing teeth. However, the primary prerequisite for using dental implants is the availability of supporting bone in adequate quantity (thickness) and quality (strength).  
           [0005]    Severe bone loss has been treated by bone regeneration techniques using bone grafts, with an acceptable degree of success. In the last few years synthetic materials have been used in place of bone. The loss of teeth coupled with severe bone resorption and pneumatization of the maxillary sinus precludes the use of endosseous implants without bone augmentation by grafting. The basic aim of the procedure referred to as a sinus lift is to introduce grafting material into the maxillary sinus by a surgical opening in the external wall of the sinus.  
           [0006]    After reflection of the sinus membrane, the grafting material is placed in direct contact with the bone. This is crucial because the graft must come in direct contact with the bone of the sinus floor in order to become a part of the bone. A sinus lift procedure is indicated when the height of the residual ridge is less than 8 mm.  
           [0007]    Permanent dental implants are obtained by attaching a fixture to the jaw bone or mandible to provide a mount for an artificial tooth. Implants may also be placed in the maxilla. Usually, a fixture is inserted into the bone and the denture is affixed to the fixture. However, in some cases the bone is so thin that the fixture may not remain stable under the normal forces of use. There are implant procedures for inserting different materials into the sinus of the bone to build up support for a denture.  
           [0008]    U.S. Pat. No. 5,456,601 issued to Sendax discloses a procedure to surgically access the sinus of the supporting bone to place a stabilized threaded post in the sinus to extend through the gum for mounting a denture. The stabilized post will eventually be incorporated within the bone and form a solid foundation for the denture. The surgical procedure described requires operating in the blind, without guidance, to drill or otherwise form an aperture medially through the bone into the sinus to connect with another pre-formed aperture cut laterally through the bone. A nut is inserted through he lateral opening and a post is inserted through the medial aperture and threaded together. After sufficient time has passed for the nut to become embedded in the bone, the post may serve as support for a denture.  
           [0009]    What is needed in the art is a device to obtain immediate fixation and loading of endosseous implants in the atrophic edentulous area below the sinus floor without the use of grafting material.  
         SUMMARY OF THE PRESENT INVENTION  
         [0010]    A sinus bolt retention system having a guide for precisely aligning a sinus support and an implant fixture for attachment through a bone. The sinus support is a bio-compatible material shaped to closely approximate the internal form of the sinus of the bone. The implant post extends from the outer surface of the bone through a bore hole to engage the sinus support. A denture may be immediately fitted to the implant post.  
           [0011]    The sinus bolt retention system of this invention is of particular benefit in placing implants in the maxilla with support in the maxillary sinus.  
           [0012]    Therefore, it is an objective of this invention to provide a surgical appliance for orienting the elements of a dental implant with each other and the recipient&#39;s anatomy.  
           [0013]    It is another objective of this invention to assure proper orientation of the aperture and post in relation to the gum line, the axis of the bone and the location of the denture. The device should also guide the connection of the post and support.  
           [0014]    It is a further objective, to provide a dental implant including a post and a support for the post that will maximize the surface contact between the wall of the sinus and the support to allow immediate placement of the denture.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a side view of the sinus bolt retention system of this invention in place within a cross section of the maxilla;  
         [0016]    [0016]FIG. 2 is a side view of the sinus bolt retention system with an implant mount aligned and a tool;  
         [0017]    [0017]FIG. 3 is a side view of the implant and support in place;  
         [0018]    [0018]FIG. 4 is an exploded side view of the components of the sinus bolt retention system;  
         [0019]    [0019]FIG. 5 is a side view of the sinus support; and  
         [0020]    [0020]FIG. 6 is a top view of the guide arm with a support.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    [0021]FIG. 1 illustrates the operational environment of the sinus bolt retention system with the guide  11  in place with the distal end  13  of the superior arm  12  inserted through the lateral maxilla flap F into the maxillary sinus S. The system is described in relation to the maxilla M but may be used to place implants in the mandible, also.  
         [0022]    The proximal end  14  of the superior arm  12  is connected to the upper end  16  of the vertical arm  15 . The distal end  13  of the superior arm  12  has an opening  18  to receive the support  30 . A set screw  19  extends through the superior arm with a head  20  and a distal end  21  securing support  30  in place.  
         [0023]    The bottom end  17  of the vertical arm  15  is movably attached with the proximal end  23  of lower arm  22 . The distal end  24  of the lower arm has a threaded aperture  25  with an axis parallel with the axis of the vertical arm  15 . The lower arm  22  is movable along the length of the vertical arm  15  to adjust the separation of the distal ends of the guide  11  to accommodate different anatomical sinus heights. A burr guide  26  is shown threaded into the aperture  25  to guide the drill. The burr guide  26  directs the formation of a bore through the bone to precisely align the sinus support  30  with the shaft of the implant  31  and, ultimately, the location of the denture.  
         [0024]    As shown in FIG. 2, an implant  31  is inserted through the bore and threaded into the sinus support  30 . The sinus support functions to create sufficient thickness for stabilizing a denture. The sinus support is shaped to closely engage the inner surface of the sinus. The shape of the support increases the area of contact between the implant and the bone and serves to spread the load over a larger area to further stabilize the implant. The tool  90 , which may be attached to a drill, is used to rotate the mount  100  fitted onto the implant  31 . Once the implant is connected with the support, the mount is removed from the implant. As shown, there may be more than one burr guide of different lengths to accommodate different bone structures. Also, the diameter of the burr guides and the implant may be the same or the implant may tap through the bone to screw into the sinus support  30 .  
         [0025]    [0025]FIG. 3 illustrates the final position of the sinus support  30  and the implant  31 . The denture may be immediately fitted if desired. Another option would be to add grafting material to the sinus about the sinus support.  
         [0026]    The sinus bolt retention system  10  is shown in FIG. 4. The system  10  includes the guide  11 , a sinus support  30 , burr guide  26  and other burr guides  26 ′ of different lengths, and a denture mount  100 . The lower arm may be angulated, as shown, to accommodate different bone thicknesses. The lower arm  22  is movable along the axis of the vertical arm  15  by sliding with a set screw  32  to lock the relative position and the distance between the superior arm and the lower arm. The arms may be adjustable by other devices, such as screw threads or rachet and pawl.  
         [0027]    The sinus support  30  is made from a biocompatible material, such as titanium, with suitable strength to withstand the forces of use. The support is shaped to complement the sinus surfaces closely. A bore  40  extends through the support  30  and is threaded to accept the threads of the implant  31 . The upper surface of the support has a shaped projection  41  for fitting into the opening  18  in the superior arm.  
         [0028]    The projection  41  is shown, in FIG. 6, as circular with flattened areas  42 ,  43  to prevent support  30  from rotation in the opening  18 . The distal end  21  of the set screw  19  is threaded through the wall of the opening  18  to contact and lock the support in the superior arm during connection of the support  30  and the implant  31 . The shape of the opening and the projection may take other forms, as long as there is no relative rotation between the components.  
         [0029]    Once the implant and the support are secured together, the guide is removed and the flap is closed by conventional procedures. Of particular importance in this procedure, is the location of the lateral surgical opening in the maxilla. The incision should provide an opening as close to the floor of the sinus as possible.  
         [0030]    A number of embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the invention is not to be limited by the specific illustrated embodiment but only by the scope of the appended claims.