Abstract:
An apparatus and method for guiding the formation of multiple, parallel holes in bone or implant in the mouth of a patient. A bar is engagable with a pivot and a slidable drill guide moves along the bar. Rotation of the bar about the pivot and radial movement of the drill guide relative to the bar permits selective positioning of the drill guide at different locations. The drill guide directs a drill bit to control hole formation of one or more holes parallel to the original reference. The angle, proximity and location of holes can be controlled.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to the field of dental surgery. More particularly, the invention relates to an apparatus and method for drilling parallel holes in a patient&#39;s jaw and other bone structures.  
           [0002]    Dental systems require anchor devices for establishing a firm attachment to bone. Holes are drilled in the bone structure to facilitate attachment of the anchor devices. Such holes are typically drilled “freehand” wherein the dentist&#39;s visual observations solely provide position and alignment control. To verify placement and alignment of a drill bit, a dental technician or other assistant typically provides visual alignment confirmation from a different viewing angle. Free-hand drilling should be performed only be skilled and experienced dental surgeons. If the bone is not homogeneous, the drill can be deflected and create a deformed or oversized hole. The incorrect drilling trajectory can damage nearby structures such as the patient&#39;s alveolar nerve and can lead to implant failures.  
           [0003]    In addition to free-hand drilling, other known practices include hole drilling through a prepared hole in a plastic matrix and hole drilling through a metal bushing supported by a plastic matrix. An acrylic resin mask is formed from the patient&#39;s dental arch so that the mask will fit over the patient&#39;s alveslar ridge. The correct position of the guide hole or cylinder is determined by an implantologist based on experience and with the assistance of a radiographic evaluation of the patient&#39;s jaw bone. After the template is made, however, the configuration of the resin mask and guide hole or cylinder is not easily moved.  
           [0004]    Numerous systems have been developed to permit alignment of a single device. As representative examples, U.S. Pat. No. 4,832,601 to Linden (1989) disclosed an adjustable support for changing the orientation of a prosthetic tooth. U.S. Pat. No. 5,133,662 to Metcalfe (1992) disclosed an anchoring member and tooth support for removable positioning. U.S. Pat. No. 5,302,126 to Wimmer et al. (1994) disclosed an adjustable post for a dental implant system. U.S. Pat. No. 6,135,773 to Lazzara (2000) disclosed a single tooth alignment system using an orientation tool for aligning an implant.  
           [0005]    Conventional dental practice assumes that two or more positioned pins will be nonparallel, and different techniques have been developed to align the attaching devices. Conventional “parallel” pins are manufactured and distributed with fifteen degree and twenty-five degree offsets to adjust for misaligned holes, confirming the expectation that multiple holes will be misaligned. As another example, U.S. Pat. No. 5,215,460 to Perry (1993) disclosed an alignment and fastening guide having articulated joints attachable to two nonparallel pins. A single jig provided for parallel alignment of the attached joints, and the joints were then glued into the aligned configuration. A different type of alignment guide was disclosed in U.S. Pat. No. 5,997,299 to Unger (1999), wherein a slotted guide facilitated placement of multiple devices each having an articulated joint for connection to the attached pins.  
           [0006]    These systems addressed the misalignment of pins within a patient&#39;s bone structure after the holes had been drilled. Various techniques have been developed to guide the drilling of holes in bone. U.S. Pat. No. 5,055,042 to Jansen (1991) disclosed a dental drill and template for drilling a second hole parallel to a first hole. U.S. Pat. No. 5,320,529 to Pompa (1994) disclosed a technique to modeling a template for a jaw. U.S. Pat. No. 5,718,579 to Kennedy (1995) disclosed a drill guide kit having a cylindrical metal sleeve in a splint for receiving a rotatable dowel. To form the splint, a cast model was formed of the patient&#39;s dentition. U.S. Pat. No. 5,636,986 to Pezeshkian (1997) disclosed a drill guide system having guides configured in the shape of teeth. U.S. Pat. No. 5,800,168 to Cascione et al. (1998) disclosed a dental implant guide formed with a radio opaque material having a cylindrical housing and guide cylinders with different sizes. U.S. Pat. No. 5,989,025 to Conley (1999) disclosed a drill guide having a tubular body with a screw thread and stent for removable attachment.  
           [0007]    Other techniques attempted to align multiple drill holes before placement of the pins. U.S. Pat. No. 5,842,859 to Palacci (1998) disclosed a bearing member having a free end for indicating placement of another hole. U.S. Pat. No. 5,888,065 to Sussman (1999) disclosed a jaw for attachment to one tooth and having an aperture for guiding drilling of an adjacent hole. U.S. Pat. No. 5,954,769 to Rosenlicht (1999) disclosed a string of drill bodies attached to one or more positioning bars. The drill body position was fixed along the positioning bars, and the positioning bar was deformable to permit movement of the drill bodies in two dimensions. Although the drill bodies permitted parallel drilling of multiple holes, the distance between holes was not easily adjusted. Additionally, the system required substantial bulk to be positioned within a patient&#39;s mouth. Such bulk encumbered drilling and other dental operations and increased discomfort to the patient. U.S. Pat. No. 5,967,777 to Klein et al. (1999) disclosed a computer aided template and drilling system.  
           [0008]    A need exists for an improved apparatus and method for directing a drill bit. The device should easily fit within a patient&#39;s mouth and should accurately and efficiently direct placement of parallel holes in the patient&#39;s bone.  
         SUMMARY OF THE INVENTION  
         [0009]    The invention provides an apparatus and method for directing a drill bit to form a hole in the bone of a patient. The apparatus comprises a pivot attachable to a first hole in the bone and having an axis, a bar pivotable about the pivot for rotation about the pivot in a plane substantially perpendicular to the pivot axis, and a guide slidably engaged with the bar to permit adjustment of the distance between the guide and the pivot, wherein the guide is formed to direct the drill bit in a direction substantially parallel to said pivot axis.  
           [0010]    The method of the invention comprises the steps of placing a pivot having an axis in a first hole formed within the bone, engaging a bar with the pivot, wherein the bar is slidably engaged with a guide for directing the drill bit in a selected direction parallel to the pivot axis, moving the guide into a selected location relative to the bone by rotating the bar relative to the pivot in a plane substantially parallel to the pivot axis and by moving the guide relative to the bar, and operating the drill bit in cooperation with the guide to drill a second hole in a location directed by the guide, wherein the second hole is substantially parallel to said pivot axis. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 illustrates an elevation view of the invention oriented relative to the lower jaw of a patient.  
         [0012]    [0012]FIG. 2 illustrates a plan view of a bar and engaged guide.  
         [0013]    [0013]FIG. 3 illustrates a side view of a bar and engaged guide.  
         [0014]    [0014]FIG. 4 illustrates another embodiment of the invention wherein a bar and integrated guide are slidable relative to a pin. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]    The invention provides a novel apparatus and method for drilling parallel holes in bone. Holes are accurately aligned to avoid the discomfort and liability associated with improper alignment. The invention is particularly useful in the field of dentistry wherein access to the patient&#39;s bone structure is confined, and wherein significant forces are exerted on pins and other devices mounted to the bone.  
         [0016]    [0016]FIG. 1 illustrates one embodiment of the invention wherein a pivot such as pin  10  is installed in hole  12  formed in bone structure  14 . Pin  10  has a longitudinal pivot axis as shown which functions as a pivot point. Bar  16  is pivotably engaged with pin  10  for rotation about pin  10  in a plane substantially perpendicular to the pivot axis. In one embodiment of the invention, such pivotable engagement is provided by inserting aperture  18  within bar  16  over an upper, exposed end of pin  10 . Although bar  16  is illustrated as a substantially linear member, bar  16  can be curved, formed with one or more pieces or sections, and can have numerous configurations and shapes. The cross-section of bar  16  can be rectangular, circular, elliptical, formed with two or more members, irregular, or formed in other shapes.  
         [0017]    Guide  20  can be slidably engaged with bar  16  for adjusting the distance between the pivot axis and guide  20 . The slidable engagement between bar  16  and guide  20  can be accomplished in many different ways and is shown in FIG. 1 as comprising an aperture  22  through which bar  16  is inserted. If desired, lock  24  in the form of a set screw or other mechanical device can selectively connect guide  20  to bar  16 . Guide  20  can be moved inwardly or outwardly relative to pin  10  by moving guide  20  relative to bar  16 , by moving bar  16  relative to pin  10  as discussed below, or combination of both.  
         [0018]    Guide  20  can be shaped or formed in different ways to direct the path of a drill bit into the patient&#39;s bone. This function can be accomplished by an aperture  26  as shown in FIG. 1 or can be accomplished by a shoulder, surface, protrusions, or other modified form integral within or attached to guide  20 . Aperture  26  can be lined with a hard faced material such as metal or can accommodate a bushing attachment integrated with or independent from a drill. FIGS. 2 and 3 show alternative view of these components and possible configurations for the moving components.  
         [0019]    [0019]FIG. 4 illustrates another embodiment of the invention wherein pin  28  includes aperture  30  for slidable engagement with bar  16 . Distal end  32  provides the function provided by guide  20  in FIG. 1, and can comprise a separate component or can be integrated within bar  16 . Lock  24  can selectively retain bar  16  in a fixed position relative to pin  28 .  
         [0020]    Operation of the inventive method can be accomplished in several different ways. In one method, pin  10  is temporarily or permanently set within hole  12  and bar  16  is pivotably engaged with pin  10 . Guide  20  is slidably moved along bar  16  so that the pivotable movement of bar  16  and the sliding movement of guide  20  cooperates to reach a selected position adjacent the bone. Because such movement occurs in a plane substantially perpendicular to the pivot axis through pin  10 , subsequent operation of a drill bit relative to guide  20  generates a second hole substantially parallel to the first hole and pin  10 . Proper orientation of guide  20  relative to pin  10  axis controls the axial orientation of the resulting holes in a parallel or selectively nonparallel orientation.  
         [0021]    In various embodiments of the invention lock  24  can be operated to retain guide  20  in a fixed location relative to bar  16 . In another embodiment of the invention using the embodiment shown in FIG. 4, rotation of bar  16  and radial movement of bar  16  and attached distal end  32  relative to pin  28  provides selective control for positioning the second hole in the bone. Lock  24  can lock the movement of bar axially relative to pin  10 , and can also lock the rotation of bar  16  relative to pin  10  in another embodiment of the invention.  
         [0022]    After the second hole is drilled, the apparatus can be unlocked or otherwise operated in a similar fashion to drill a third hole in the bone parallel to the first and second holes. In this fashion multiple parallel holes can be drilled without the alignment errors customary in conventional practice.  
         [0023]    The device is compact, contains few components, and is especially suited for the narrow confines within a patient&#39;s mouth in dental practice. The apparatus can operate from a pin such as pin  10  previously set within the patient&#39;s bone or can be used as a template to guide the angle of the first hole before pin  10  is set. In dentistry, the apparatus is equally adaptable to either side of a patient&#39;s mouth, and to the upper and lower bone structures within a patient&#39;s mouth. The invention can be attached to existing implants or other structures within the patient&#39;s mouth. As used herein references to forming a hole in the bone of a patient are equally to the act and process of forming a hole in an existing implant or other structure within the patient&#39;s mouth. One innovative benefit of the invention provides the same consistent anchor in bone, implant, or other stable structure within the mouth. These features of the invention minimize the work within the mouth and provide less trauma to patients. Although the invention is particularly suited for the narrow confines within a patient&#39;s mouth, the invention is application to the drilling of parallel holes in other bone structures.  
         [0024]    All components can be manufactured from metal, plastic, composite materials, or other compounds to provide the operating functions. Components can be disposable to meet sterility requirements or can be designed to be sterilized with conventional techniques applicable to the dental, medical and veterinary professions.  
         [0025]    Although the invention has been described in terms of certain preferred embodiments, it will become apparent to those of ordinary skill in the art that modifications and improvements can be made to the inventive concepts herein without departing from the scope of the invention. The embodiments shown herein are merely illustrative of the inventive concepts and should not be interpreted as limiting the scope of the invention.