Abstract:
The present invention provides a device and method for facilitating the placement of dental implants by use of an implant placement locator and a sequentially sized drill orientation tube series. The implant placement locator disclosed herein comprises a visible radiolucent moldable grid, a set of radiopaque markers located at known intervals within the moldable grid, and a plastic sheeting encasing the visible radiolucent moldable grid and the radiopaque markers. The method of the present invention comprises obtaining a radiograph of a patient&#39;s mouth with the implant placement locator overlaying the patient&#39;s dental ridge and then transferring reference points as indicated by the location of the radiopaque markers relative to existing teeth and other oral structures to a dental stone model. In a preferred embodiment, drill bits are directed in the desired trajectory into the patient&#39;s available lower or upper jaw bone by use of drill orientation tubes in combination with the implant placement locator. A sequentially sized set of spacers is provided having sequentially sized inside diameters to direct varying diameter drills. Drill guide parallelism is thus provided by the invention.

Description:
FIELD OF THE INVENTION 
     The present embodiments relate to a device and method for indexing radiographic locations of dental structures to markers to facilitate implant surgery and placement of dental implants. The present embodiments further relate to a device and method for directing a drill bit to a specific drill site and angle for the placement of dental implants. 
     BACKGROUND OF THE INVENTION 
     Devices and methods for fabricating dental templates, utilizing radiopaque substances in connection with dental stents and manufacturing dental implant structures are disclosed in the following: U.S. Application No. 2004/0166462 A1 to Phan, U.S. Pat. No. 5,897,696 to Giordano, U.S. Pat. No. 5,415,546 to Cox, and U.S. Pat. No. 6,382,975 B1 to Poirier. Difficulties encountered in the placement of dental implants include maintaining the accuracy of placements and efficiently utilizing evidence of bone available for surgical drilling. 
     Surgical drills are typically used during dental implant surgery in order to achieve the placement of dental implants. Related patents include U.S. Pat. Nos. 5,409,493, 5,746,743, and 5,888,034 to Greenberg. Difficulty in maintaining a parallel orientation of the varying drill sizes throughout the implantation process is a common problem encountered during dental implant procedures. 
     The dental implant locator of the present invention is made for use in facilitating placement of implants relative to radiographic determinations of available bone structures relative to the oral tissues of the mouth. The dental implant placement locator disclosed overcomes the difficulty typically encountered in achieving an accurate placement of dental implants and in positioning drills during oral surgery. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the detailed description of the preferred embodiments presented below, reference is made to the accompanying drawings. 
         FIG. 1  is a perspective view of a preferred embodiment of an implant placement locator. 
         FIG. 2  is an isometric view depicting the moldable grid formed onto a dental stone model and radiopaque markers located at known intervals on the moldable grid. 
         FIG. 3  is a perspective view depicting the placement of radiopaque markers on a dental stone model of the upper jaw. 
         FIG. 4  is a perspective view depicting the implant placement locator on a dental stone model. 
         FIG. 5  is a perspective view depicting an alternate embodiment of the implant placement locator and drill guide. 
         FIG. 6  is a perspective view depicting an alternate embodiment of the implant placement locator and drill guide. 
         FIG. 7  is a panoramic radiograph of a patient&#39;s mouth without the implant placement locator in place, the radiograph showing the location of bone structures, including existing teeth. 
         FIG. 8  is panoramic radiograph of a patient&#39;s mouth showing the implant placement locator in place and providing reference points for identifying dental implant sites by relating radiopaque markers to various oral anatomical structures. 
         FIG. 9  is a perspective view depicting identified dental implant sites marked on a dental stone model, as determined by reference to the radiopaque markers on the implant placement locator. 
         FIG. 10  is a panoramic radiograph of a patient&#39;s mouth showing the final placement of dental implants with the implant placement locator in place. 
         FIG. 11  is an exploded view of the drill guide, drill bit spacer and drill bit. 
         FIG. 12  is an expanded view of an alternate embodiment of the drill guide. 
     
    
    
     The present embodiments are detailed below with reference to the listed Figures. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Before explaining the present embodiments in detail, it is to be understood that the embodiments are not limited to the particular descriptions and that the embodiments can be practiced or carried out in various ways. 
     The implant placement locator of the present invention is seen in  FIG. 1  and is generally referred to by reference number  10 . 
     Implant placement locator  10  is comprised of visible or visibly opaque moldable grid  14  having grid spacing  12 , radiopaque markers  20  located at indexed intervals on moldable grid  14 , and plastic sheeting  22  which encases moldable grid  14  and radiopaque markers  20 . 
     Implant placement locator  10  is designed to be placed in the patient&#39;s mouth in a variety of configurations, as required for a particular dental implant procedure. Referring to  FIG. 2 , in one embodiment, moldable grid  14  of implant placement locator  10  can cover the right or left dental ridge  18  on the upper or lower jaw, also respectively described as the maxilla or mandible, of a patient. In another embodiment, moldable grid  14  may cover both the right and left dental ridge  18  in addition to dental ridge  18  corresponding to the patient&#39;s front teeth on the upper or lower jaw. In yet another embodiment, moldable grid  14  may cover the entire dental palate of a patient. Referring to  FIG. 1  and  FIG. 4 , implant placement locator  10  is shown having dental implant sites at four locations on implant placement locator  10 . Each dental implant site is designated by drill hole  32  in moldable grid  14  and plastic sheeting  22  of implant placement locator  10 . 
     The moldable grid  14  can be radiotransparent or radiolucent and visibly opaque. When visibly opaque, the grid can be easily seen on the dental model or when in use in the oral cavity. When radiotransparent or radiolucent, no grid is seen in the radiograph. The grid shape of the preferred material for moldable grid  14  is square. The size of the open spaces of the grid (grid spacing) is between about 1 and about 5 millimeters with the preferred grid spacing being 2 millimeters. Other shapes and dimensions of the grid spacing can accommodate different applications. For instance, hexagonal or rectangular spacing may be used where applied angle of the grid relative to the radiograph is such that the square spacing would not be useful. In an alternate embodiment, moldable grid  14  can be formed from a plastic which is curable in ultraviolet light. 
     In an alternative embodiment, the moldable grid has molded within it a thin flexible radiopaque wire. In this embodiment the wire is visible as a white pattern in the radiograph allowing the grid to be used as a scale and index relative to bone structures and the markers. 
     Radiopaque markers  20  are located at indexed or known intervals within grid spacing  12  of moldable grid  14 , as can be clearly seen in  FIG. 1  and  FIG. 2 . The markers may be placed anywhere in the grid. For example, the markers are shown to be placed outside the dental ridge or the buccal side in  FIG. 2  and on top of the dental ridge in  FIG. 1 . Also shown in  FIG. 2-4  at  20   b , the markers may be placed on the buccal, lingual and palatal surfaces Radiopaque markers  20  provide reference points for radiographic determination of available bone (or other identifiable dental structure) relative to a particular oral tissue or marker location for surgical planning or at the time of dental implant surgery. Radiopaque markers  20  are preferably inert metallic spheres ranging in size from about 1 mm to about 5 mm. In a preferred embodiment, radiopaque markers  20  are formed from 3 mm stainless steel balls, which can be easily sterilized. Of course, other shapes such as cubes or tetrahedrons may be used as well, alone or in combination with other shapes. “Coding” or identifying dental structures through use of a combination of shapes of the radiopaque markers is also possible. Radiopaque markers  20  are held in place by a pressure fit in grid spacing  12  of moldable grid  14 , grid spacing  12  being locally deformed to accept the shape of radiopaque markers  20 . Plastic sheeting  22  is bonded to radiopaque markers  20  and moldable grid  14  by melting of plastic sheeting  22  around radiopaque markers  20  and moldable grid  14 . Plastic sheeting  22  therefore adheres to the radiopaque markers through a deformation that flows into moldable grid  14  upon heat treatment and vacuum formation of plastic sheeting  22 . 
     Alternatively, radiopaque markers  20  may be held in place by an adhesive which secures the markers in the interstices of grid spacing  12 . Epoxies and adhesives known for use in a dental environment can be used. 
     In the preferred embodiment, plastic sheeting  22  is approximately 1 millimeter thick and transparent. The thickness of plastic sheeting  22  can vary between about 1 millimeter and about 5 millimeters, depending on the rigidity of the final structure desired. Transparency of the plastic sheeting  22  allows for location of various bone structures  41  and tooth structures  42  during use. Location of various features of a stone model used during surgical planning is also enhanced by the transparency of plastic sheeting  27 . In an alternate embodiment, plastic sheeting  22  may be an optically shaded material. For example, clear colored and transparent colored plastic sheeting can be used to identify implant placements and placement locators with respect to a particular patient or surgical process. 
       FIG. 2 ,  FIG. 3 , and  FIG. 4 , depict fabrication steps of implant placement locator  10  on dental stone model  16 .  FIG. 2  shows dental stone model  16  with an implant placement locator in place. The material for moldable grid  14  is first cut to fit the areas of interest on the dental stone model. Moldable grid  14  is then placed on dental stone model  16 . For example,  FIG. 2  shows moldable grid  14  placed in a “saddle” type fashion over the left and right side of dental ridge  18 . The moldable grid  14  can also extend across the entire dental palate of a patient as in  FIG. 6 . 
     Application of heat to moldable grid  14  causes it to soften and become molded to the contours of dental stone model  16 . A heat gun may be used to supply the required temperature for softening. Radiant heat sources such as infrared lights may be used as well. Upon cooling, moldable grid  14  becomes rigid as it overlays dental stone model  16 . In an alternate embodiment, moldable grid  14  can be molded and then cured by ultraviolet light while on dental stone model  16 . 
     Once moldable grid  14  has become rigid, radiopaque markers  20  are placed at indexed intervals in grid spacing  12  of moldable grid  14  as moldable grid  14  overlays dental stone model  16  of a patient&#39;s mouth, as shown in  FIG. 2 . In another embodiment, radiopaque markers  20  can be placed at indexed intervals in grid spacing  12  of moldable grid  14  as moldable grid  14  overlays dental stone model  16  of the maxilla or upper jaw of a patient, as shown in  FIG. 3 . In an alternate embodiment, radiopaque markers  20  can be placed at a location on moldable grid  14  corresponding to a patient&#39;s tooth sockets. 
     Radiopaque markers  20  are stabilized within grid spacing  12  of moldable grid  14  by softening the moldable grid  14  through application of heat localized to placement of the radiopaque markers  20 . In the preferred embodiment, a 20 watt soldering iron is used to provide localized heat. Alternatively, an electric or propane torch can be used with a gas tip, as will other heat sources adapted to localized heat application. The radiopaque markers  20  are then pressed into the moldable grid  14  with sufficient force to spread the moldable grid  14  around the radiopaque markers  20  in conformance with the outer surface of the radiopaque markers  20 . Once allowed to cool, the radiopaque markers  20  are held in place by the moldable grid  14 , locally deformed to accept the shape of the radiopaque markers  20 . If an ultraviolet light curable plastic is used for moldable grid  14 , the markers are pressed into place before application of ultraviolet light and curing of the plastic to rigid form. 
     Plastic sheeting  22  is then molded to the contours of moldable grid  14  and other desired oral structures on the stone model not covered by moldable grid  14 . The plastic sheeting  22  in the preferred embodiment setting is a transparent thermoplastic capable of being deformed while heated. In this process, the plastic sheeting  22  is cut to overlap moldable grid  14 , radiopaque markers  20 , and the dental stone model  16 . The plastic sheeting  22  is heated and manually conformed to the dental stone model  16 , the moldable grid  14 , and the radiopaque markers  20 . The plastic sheeting  22  is then allowed to cool. After cooling, the conformance of the plastic sheeting  22  holds the moldable grid  14  and radiopaque markers  20  in place, forming a unitary and rigid yet pliable structure. 
     In an alternative embodiment, plastic sheeting  22  is heated and then drawn over moldable grid  14 , radiopaque markers  20 , and the dental stone model  16  through a vacuum forming process. In the vacuum forming process, a stone model is provided that is porous enough to allow the passage of the vacuum. A vacuum is then drawn on the stone model, allowing atmospheric pressure to compress the plastic sheeting  22  against the dental stone model  16 , moldable grid  14 , and radiopaque markers  20 . Upon cooling, the vacuum is released and the rigid structure of the implant placement locator  10  is achieved. 
     In a preferred embodiment, a small amount of acrylic powder and resin, is applied to radiopaque markers  20  upon placement of radiopaque makers  20  within grid spacing  12  of moldable grid  14  in order to prevent movement of radiopaque markers  20  from the desired location on moldable grid  14  upon heat treatment or vacuum forming of plastic sheeting  22 . In the preferred embodiment, the acrylic powder and resin mixture is well known in the art. A light cured composite as known in the art may also be used, as may a cyanoacrylate adhesive. 
     In a preferred embodiment, the method of the present invention facilitates the placement of dental implants by following a series of steps. Implant placement locator  10 , is placed over a patient&#39;s dental ridge  18 . Implant placement locator  10  is held in place in the patient&#39;s mouth by fitting the implant placement locator  10  over existing teeth or other dental structures. A radiograph is then obtained of the patient&#39;s mouth with implant placement locator  10  in place.  FIG. 7  shows a radiograph taken of a patient&#39;s mouth without implant placement locator  10  in place. In contrast,  FIG. 8  shows a radiograph taken with implant placement locator  10  in place in the patient&#39;s mouth showing the location of radiopaque markers  20  relative to existing bone and tooth structures  42 . 
     Implant placement locator  10  is then transferred from the patient&#39;s mouth to dental stone model  16  as seen in  FIG. 4 . Once on dental stone model  16 , the implant placement locator allows surgical planning by correlating the location of bone structures  41  tooth structures  42  and tissue structures relative to moldable grid  14  and radiopaque markers  20 . For example, a certain tissue or marker might be 2 grid spacings in one direction and 2 to 3 grid spacings in another, as judged from a subsurface bone structure shown in the radiograph. The absolute location of the markers in the uniform grid spacing makes judging distances far more accurate than is possible without the use of the invention. 
     Returning to  FIG. 4 , reference to the dental stone model allows indexing of implant locations relative to the height of the dental ridge and other considerations visible from the dental stone model. In planning, dental stone model  16  can be marked as shown in  FIG. 9  with potential locations for implants shown as  33 . The potential implant locations are then transferred to the implant placement locator by drilling holes through the locator corresponding to the potential implant locations. As seen in  FIG. 4 , rigid implant locations marked  33  on  FIG. 9  correspond to drill holes  32 . 
     Implant placement locator  10  is then transferred back into the patient&#39;s mouth and the desired dental implant site is marked on the tissue surfaces of the patient as indicated by the location of drill hole  32  in implant placement locator  10 . In the preferred embodiment, the implant placement locator  10  is then removed from the patient&#39;s mouth and surgical holes are drilled based on the markings placed on the tissue surfaces of the patient. In an alternate embodiment, the implant placement locator may be left in place in the oral cavity during the surgical procedure to more accurately locate positions for the surgical holes. 
     During certain surgical procedures it is necessary to control the angle of or maintain parallelism between the holes drilled for the location of the dental implants. An alternate embodiment of the present invention includes a device for guiding the angle of the holes drilled pursuant to drill holes  32 . 
       FIG. 5  shows an alternative embodiment of the invention known as a surgical guide. Surgical guide  52  is a pliable plastic formed to match a patient&#39;s teeth and dental structures in either or both of the upper or lower jaw. Surgical guide  52  includes plastic sheeting  70 , block material  65 , a number of holes (an example is shown at  63 ) hole  63 , and drill guide  61 . Plastic sheeting  70  in the preferred embodiment is a transparent thermoplastic about 1 mm to about 5 mm thick. The plastic sheeting can be shaped to follow the dental ridge, a single side of the dental ridge or extended to cover the space between them, depending on the need in any particular surgical situation. Surgical guide  52  includes block material  65 . In the preferred embodiment, block material  65  can be visible light cured plastic or an acrylic powder and resin mixture. The block in the preferred embodiment is transparent. Transparency allows light to be directed toward and illuminate the surgical area through the block. The transparency also allows visible inspection of the area on which surgery is performed. In practice, block material  65  is shaped to fit within an interstitial gap created by missing teeth. In this preferred embodiment, block material  65  includes a hole  63  of appropriate diameter to match a drill bit or outer diameter of a drill bit spacer (which will be described further later). Drill guide  61  is concentrically fixed within hole  64  on surgical guide  52  at an angle dictated by surgical considerations. Drill guide  61  is secured within the hole by an adhesive such as epoxy, cyanoacrylate or acrylic powder and resin. The adhesive rigidly maintains drill guide  61  in a position relative to surgical guide  52 . 
     Drill guide  61  is a rigid nylon or plastic tubing. Other rigid plastic tubing can be used, such as Teflon, polyethylene or polyvinyl chloride. In one embodiment, the tubing can be radiopaque by a coating of barium or incursion of powderized barium in the plastic of the tubing. Alternately, a metal tube can be used. The tubing is generally cylindrical having an inside diameter  64  ranging from about 1 millimeter to about 10 millimeters with a preferred range of 1.6 to 5.5 millimeters. The inside diameter  64  in the drill guide also matches the outside diameter of a drill bit to be used in the surgical procedure. The outer diameter of drill guide  61  in the preferred embodiment can range from 3 millimeters to 12 millimeters with a preferred range of between 5 millimeters to 7 millimeters. The length of drill guide  61  can range between about 2 millimeters and about 15 millimeters with a preferred range of between about 3 millimeters and about 5 millimeters. The drill guide may extend above the surface of block  65  if required for stability in a given surgical procedure. As will be appreciated by those skilled in the art, the precision of the angle which is maintained during drilling increases with the length of the drill guide. All dimensions are approximate and slight variations are acceptable. 
     Drill bit spacer  60  is used in association with drill guide  61  and a drill bit  62  and is shown in  FIG. 11 .  FIG. 11  illustrates a drill orientation guide  61 , drill bit spacer  60  and drill bit  62  in an exploded view. Drill bit  62  fits concentrically within drill bit spacer  60  which in turn fits concentrically within drill orientation guide  61  in the preferred embodiment. Drill bit spacer  60  is formed from a rigid nylon or plastic tubing. In an alternative embodiment the plastic tubing may include a radiopaque material or be made of a metal. The outer diameter of drill bit spacer  60  must be smaller than the inner diameter of drill guide  61  by sufficient clearance to allow drill bit spacer  60  to slide axially and rotate within drill guide  61 . However, the clearance cannot allow a significant variation between the axis of the drill guide  61  and the axis of the drill bit spacer  60  when the spacer is inserted in the drill guide. In the preferred embodiment, the clearance between the inner diameter of drill guide  61  and the outer diameter of drill bit spacer  60  is approximately 0.1 mm. 
     The length of drill bit spacer  60  in the preferred embodiment is generally the same as that of drill guide  61 . But the length of the spacer may be shorter or longer than the drill guide as required for the surgical procedure. 
     In the preferred embodiment, there is a series of drill bit spacers. The outer diameter of each drill bit spacer is designed to fit within the inside diameter of drill guide  61  within the clearance previously described. However, the inside diameter of the drill bit spacers is different. The inside diameter of each of the drill bit spacers in the series is sequentially larger. The inside diameters are sized to accommodate a series of drill bits having sequentially increasing diameters. In the preferred embodiment, the inside diameter of each drill bit spacer in the series can range between about 2 and about 5 mm with a preferred range between about 2.2 and 4.2 mm. The sequentially sized drill bits preferably range in diameter from about 2 millimeters to about 5 millimeters. 
     Any number of drill guides can be positioned in surgical guide  52  at any position or angle along or above the dental ridge. In the preferred embodiment, parallelism is maintained between each of the holes and drill guides in the surgical guide in order to maintain parallelism between the resulting holes in the patient&#39;s bone after the surgical procedure. For example, hole  63  along with drill guide  61  are fixed within surgical guide  52  such that their axes are generally parallel. Parallelism between the resulting holes allows dental fixtures, such as false teeth, to be easily attached to implants. In another embodiment, the drill guide  61  and hole  63  are fixed in surgical guide  52  such that their axes are directed toward a dental implant site but are not generally parallel. In this embodiment, the implant site is targeted at a supporting bone structure relatively distant from the hole entry point. 
     In  FIG. 5 , surgical guide  52  also includes alternate drill guides  69   a  and  69   b  with inside diameters  68   a  and  68   b , respectively and block material  67 . Alternate drill guide  68   b  is shown in detail in  FIG. 12 . Alternate drill guide  68   b  has a slot  79  which extends through the wall of block material  67 . The width of slot  79  corresponds generally to the diameter of inside diameter  69   b . The purpose of the slot is to allow horizontal insertion of the drill into the drill guide. Slot  79  allows operation in confined spaces such as those found in association with surgical procedures on back teeth at the back of the jaw. Alternate drill guides  68   a  and  68   b  are parallel to drill guides  61  and hole  63  in this embodiment. 
     The preferred method for fabricating surgical guide  52  is as follows: Plastic sheeting  70  is cut to match the shape of dental ridge  18  or other dental structure on a dental stone model and heated. Sheeting  70  is then pressed into its desired shape around the features of the dental stone model. Sheeting  70  is then allowed to cool. Block material can be added underneath or on top of plastic sheeting  70  and is formed by using a moldable dental acrylic sized to fit within and interstitial space in the stone model. The block material is bonded to the plastic sheeting  70  with an epoxy, additional acrylic adhesive or acrylic power and resin. The required holes are then drilled through plastic sheeting  70  and into block material  65 . 
     In the case of hole  63 , the diameter is sized to be approximately the same as the drill bit which would be used during a surgical procedure. The outside diameter of hole  64  is sized to accommodate the outside diameter of drill guide  61 . In an alternative method of fabrication, the block material may be formed around a drill guide held in place by a paralleling jig. Drill guide  61  is then fixed within the hole using a suitable epoxy or acrylic adhesive. During drilling of the holes, parallelism can be maintained to a general degree by using a dental drill. If a higher degree of parallelism is required, a drill press, jig or device as known in the art can be used to maintain a near exacting parallelism between the axis of each of the holes. 
     In another preferred embodiment, the axis of the holes may be slanted with respect to each other or the dental ridge in order to accommodate location of bone or other dental structures required for dental implant placement. 
     In use, surgical guide  52  is placed in the oral cavity. If the drill guide is radiopaque, radiographics may be taken to locate the drill guide with respect to dental features. A series of holes is then drilled concentrically in the bone structure, starting with the smallest diameter and ending with the largest diameter required for the surgical procedure. In order to guide the holes, drill bit spacers of various inside diameters cooperate with the drill guide and a series of differently sized drill bits to place the holes where desired to achieve a correct hole diameter and angle (or parallelism) with respect to the dental ridge. In a preferred embodiment, a series of four drill bits is used with three corresponding drill bit spacers to drill an initial hole, two intermediate sized holes and a final sized hole. 
     In practice, the drill bit spacer with the smallest inside diameter is chosen to match the drill bit for the lead hole. A lead hole is then drilled by the smallest diameter drill bit. After the lead hole is drilled, the smallest drill bit is removed along with the smallest diameter drill bit spacer. The drill bit spacer with the next larger inside diameter is then placed on a drill bit with a larger inner diameter which corresponds to the desired larger hole. The next larger drill bit, along with the next larger drill bit spacer is then placed and centered within drill guide  61  to drill a larger lead hole. The drill bit spacers rotate within the drill guides. This process is then repeated for each drill guide and drill bit spacer until all desired holes are drilled at all desired diameters. In the preferred embodiment, the outer diameter of the largest and final drill bit corresponds with the inner diameter of the drill guide mounted in surgical guide  52  or the diameter of the holes (such as  63 ) in the block material. 
     In an embodiment where the drill guide is radiopaque, if swallowed by the patient, an X-ray of the patient may be taken to locate the drill guide. 
     In yet another embodiment, an implant placement locator and drill guide  200  is provided as per  FIG. 6 . In this embodiment, an implant placement locator such as shown in  FIG. 1  at  10  is constructed as previously described. Implant placement locator and drill guide  200  includes moldable grid  250 , radiopaque marker  260  and moldable sheet  270 . The implant placement locator also includes block material  230  affixed to the surface of moldable sheet  270 . Holes  205  and  206  are drilled in block  230  or the block is formed around the drill orientation guide as previously described. Drill orientation guide  210  is rigidly affixed within hole  206  by an epoxy or suitable dental acrylic adhesive. Block material  230  is formed with a suitable acrylic resin placed in the interstitial spaces between teeth or other gaps formed in dental structures. Block material  230  can include holes  235  and  205 . In a preferred embodiment all holes are maintained in a generally parallel orientation. In other preferred embodiments, parallelism is not required. 
     Radiopaque markers  260  are fixed within moldable grid  250 . In an alternative embodiment, the drill orientation guide can be a radiopaque material and serve as a radiopaque marker. The preferred embodiment of  FIG. 6  allows the advantages of surgical planning using the grid and radiopaque markers in conjunction with radiographs as well as the advantages of the surgical guide provided by the drill guides. 
       FIG. 10  illustrates a radiograph showing implant placement locator  10  in place on the patient&#39;s dental ridge  42  and further shows the final placement of dental implants  44  made pursuant to each drill hole  32  as identified by markers  20 . 
     The embodiments have been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the scope of the embodiments, especially to those skilled in the art.