Patent Document

BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The subject invention generally pertains to dental implants and more specifically to a method for adjusting the position of a drill bushing used for installing the implant. 
     2. Description of Related Art 
     Various dental implant methods and devices have been developed for replacing one or more missing teeth in a person&#39;s jaw with prosthetic teeth. For many prosthetic teeth, a final product comprises three basic components: an implant, an abutment, and a crown. The crown is the exposed portion of the prosthesis that resembles one or more teeth. The implant is an anchor that becomes attached to the jawbone, and the abutment couples the crown to the implant. 
     To install the implant, a hole is usually drilled into the patient&#39;s jawbone, and the implant is inserted into the hole. 
     A drill bushing attached to a stent can be used to help guide the drill bit, as disclosed in PCT Publication WO 99/26540 and U.S. Pat. Nos. 5,015,183; 5,133,660; 5,718,579. A drill bushing, unfortunately, can be difficult to align in the proper direction. 
     Although the image of implants have been tilted, translated and otherwise manipulated with respect to an image of a jawbone, such image manipulations fail to show how the orientation of an existing drill bushing may need to be adjusted to achieve a desired drill trajectory. 
     Thus, a need exists for a better method of aligning a drill bushing to a patient&#39;s jawbone. 
     SUMMARY OF THE INVENTION 
     To adjust the angular position of a drill bushing used in a dental implant process, it is an object of some embodiments of the invention to adjust a trajectory image of the drill bushing relative to a jaw image of the patient. 
     Another object of some embodiments is to allow a user to move the trajectory image relative to the jaw image to determine how far the actual drill bushing may need to be tilted. 
     Another object of some embodiments is to use a computer mouse to move the trajectory image of the drill bushing. 
     Another object of some embodiments is to use a computer keyboard to move the trajectory image of the drill bushing. 
     Another object of some embodiments is to use an electronic inclinometer to move the trajectory image of the drill bushing. 
     Another object of some embodiments to adjust the position of the trajectory image along two dimensional planes that are at right angles to each other. 
     Another object of some embodiments is to simultaneously adjust the trajectory image and the actual drill bushing, thereby achieving generally instantaneous feedback. 
     Another object of some embodiments is to use tomography in creating an overall image that depicts the trajectory image and the jaw image. 
     One or more of these and other objects of the invention are provided by creating an overall image that shows a trajectory of a drill bushing in relation to a patient&#39;s jaw, wherein the overall image shows a trajectory image that represents the trajectory of the drill bushing and a jaw image that represents the jaw; and moving the trajectory image relative to the jaw image. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is a perspective view of a tomograph system being used to help create at least one overall image of a drill bushing in relation to a patient&#39;s jaw. 
         FIG. 2  is a schematic view that illustrates moving a trajectory image relative to a jaw image. 
         FIG. 3  is a schematic view similar to  FIG. 2  but showing two trajectory images at another position. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  shows a tomograph or a series of X-rays being taken of a patient  10  that has a surgical dental stent  12  engaging the patient&#39;s jaw. The term, “jaw” refers to that part of a patient&#39;s body that comprises one or more of the following: teeth, gums, and/or jawbone (upper or lower). Stent  12  is a conventional surgical dental stent that mates with the patient&#39;s jaw and can be produced in various ways that are well known to those skilled in the art. A drill bushing  14  is attached to stent  12  in an area of a missing tooth. Bushing  14  can help guide a drill bit in drilling a hole into the patient&#39;s jaw. An implant can then be inserted into the hole and anchored to the jaw. 
     Bushing  14  is preferably made of a material that can be detected by the X-rays, so at least one overall image  16   a  can be created which shows bushing  14  and/or its trajectory (i.e., the bushing&#39;s longitudinal centerline) in relation to the patient&#39;s jaw  18  as shown in  FIGS. 2 and 3 . Overall image  16   a , for example, shows a trajectory image  20   a  and a jaw image  22   a  that are displayed on a conventional computer monitor  24  controlled by a computer  26 . Trajectory image  20   a  represents the trajectory of bushing  14 , and jaw image  22   a  represents the patient&#39;s jaw. In some cases, monitor  24  also displays a second overall image  16   b  where the first overall image  16   a  presents a front view of the patient&#39;s jaw, and the second overall image  16   b  is a side view. Thus, the two views  16   a  and  16   b  are taken along planes that are intersecting and preferably perpendicular to each other. 
     The equipment and method for taking a tomographical scan is well known to those skilled in the art. Tomography generally involves creating a computer-generated image from a plurality of X-rays as indicated by lines  15  and  17 . Other terms used for tomography include, but are not limited to, CT scan (computed tomographical scan), EIT (electrical impedance tomography), CAT scan (computerized axial tomography). System  19  is schematically illustrated to represent all types tomography systems. Some examples of system  19  include, but are not limited to a CommCAT IS-2000, Panorex CMT, and a Panorex CMT Plus, all of which are products of Imaging Sciences International, Inc., of Hatfield, Pa. 
       FIG. 2  shows that the trajectory of bushing  14  is not aimed directly into the patient&#39;s jawbone  30 , so trajectory images  20   a  and  20   b  can be moved or tilted to correct the misalignment. Moving trajectory images  20   a  and  20   b  can be done in various ways. 
     In some cases, overall images  16   a  and  16   b  are created by importing, “cut-and-pasting,” or otherwise incorporating a tomograph into an appropriate software program. One example of such a program includes, but is not limited to, “Micrografx Designer, Technical Edition” by Micrografx, Inc. of Richardson, Tex. Using a standard “click-and-drag” technique, a conventional computer mouse  32  (or keyboard  34 , depending on the software) can be used to move or tilt trajectory images  20   a  and  20   b  (which can be a centerline drawn using the Micrografx software). An angular displacement or degree to which trajectory images  20   a  and  20   b  are tilted can be displayed in areas  36  and  38  and manually recorded for later reference. 
     Next, stent  12  with bushing  14  can be placed onto a model  36  of the patient&#39;s jaw. Model  36  can be cast or otherwise made in a conventional manner well known to those skilled in the art. A tool  38  or lever can be inserted into bushing  14 , and tool  38  can then be manually tilted based upon the angular displacement values displayed in areas  36  and  38 . The extent to which tool  38  tilts bushing  14  can be measured using a clinometer  40  (electronic or otherwise) that is mounted to or otherwise associated with tool  38 . The term, “clinometer” refers to any tool for measuring a change in inclination. 
     In some cases, clinometer  40  comprises two electronic levels  42  and  44  that are perpendicular to each other. The angle readings from levels  42  and  44  can be communicated to computer  26  so that trajectory images  20   a  and  20   b  tilt in response to tilting tool  38 . The angle reading from level  42  tilts trajectory image  20   b , and the angle reading from level  44  tilts trajectory image  20   a . In effect, tool  38  functions as a joystick with trajectory images  20   a  and  20   b  following the joystick&#39;s movements. The joystick inserted into bushing  14  can be tilted in various directions and angles until trajectory images  20   a ′ and  20   b ′ point directly into jawbone  30  as shown by images  16   a ′ and  16   b ′ of  FIG. 3 . Electronic levels  42  and  44  can be any inclination measuring instrument that provides an electronic signal whose value (analog or digital) can be inputted into a computer using a conventional appropriate I/O board or module. 
     Once drill bushing  14  is properly aimed, bushing  14  can be permanently affixed to stent  12  using a conventional bonding material. Stent  12  can then be returned to the patient&#39;s mouth where bushing  14  can help guide the drill bit in drilling the implant hole in the patient&#39;s jawbone. 
     Although the invention is described with reference to a preferred embodiment, it should be appreciated by those skilled in the art that various modifications are well within the scope of the invention. Therefore, the scope of the invention is to be determined by reference to the following claims.

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