Patent Publication Number: US-2013252205-A1

Title: Dental implant system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a division of Ser. No. 12/461,954, filed on Aug. 28, 2009, now pending, which application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/111,941, filed on Nov. 6, 2008, and Ser. No. 61/215,954, filed on May 12, 2009. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to the field of dentistry, and particularly to a dental implant system for mini dental implants. 
     2. Description of the Related Art 
     Traditional removable partial dentures, i.e., the replacement of a relatively few missing teeth with prosthetic teeth, have been secured in the mouth by means of relatively rigid wire or other metal attachments extending from the dentures and removably attached to adjacent teeth. Removable full dentures, which replace all or nearly all of the mandibular or maxillary teeth, have traditionally been adhesively secured in the mouth. Single prosthetic teeth, i.e., crowns, traditionally require at least some portion of the natural tooth for fixed attachment thereto. 
     More recently, various implants have been developed that anchor directly into the mandibular or maxillary bone structure, with the prosthetic tooth or teeth being permanently or removably attached to the protruding abutment of the implant. Most such implants are relatively large and are not suitable for the medically, financially, or anatomically compromised patient. The installation of such larger implants is a multi-step procedure, with the patient initially receiving oral surgery to open the gingival tissue and expose the underlying bone structure, whereupon the bone is drilled and tapped for the implant and the implant is installed. The patient must then wait for the soft tissue to heal and for a considerable period of time for the bone to grow around the implant and anchor the implant firmly in place. A subsequent visit is required after healing for the dentist to make an impression of the area in which the dental prosthesis is to be installed. The impression is then sent out to a dental laboratory for the manufacture of the dental prosthesis. Finally, the completed prosthetic tooth or other dental prosthesis is fit into place during still another visit to the dentist. 
     Even more recently, so-called “mini-implants” or mini dental implants have been developed. These relatively small implants do not require specific lying open of the gingival tissue or the drilling of relatively large holes in the bone structure. Rather, the small hole for the miniature implant can be drilled directly through the gingival tissue and into the underlying bone. The mini-implant can be placed or installed in most all compromised patients. This is a minimally invasive approach and even the medically compromised patient, and particularly the edentulous patient, can withstand the placement procedure due to the stability of the mini-implant and prosthesis. In cases where the procedure is for the reinstallation of a retrofit denture or prosthesis, the mini-implant(s) can be installed and the prosthesis installed thereon in a single visit to the dentist. In the case of a new denture, the mini-implant(s) are placed during one visit, and the impression for the prosthetic tooth or teeth is made during the same visit. The patient returns in only a few days later for the final fitting of the new prosthesis after it has been manufactured in the dental laboratory. As can be seen, the use of mini-implants greatly reduces the time and effort, and thus the cost, of implant placement, as well as greatly reducing the trauma to the patient. 
     However, many if not most such implants are of multiple piece construction, with a threaded implant portion having an upper end fitting generally flush with the exposed gingival surface and an abutment portion that attaches to the implant in some manner. Moreover, it has been recognized that some cushioning is desired between the removable dental prosthesis and the underlying abutment, implant, and bone structure, thus relieving the stress otherwise imposed upon the implant. This has been accomplished in the past by means of a small O-ring installed between the dental prosthesis and the abutment, which has proven to be less than satisfactory. In practice, these systems tend to collect food residue between the retainer cap and the spherical head of the abutment, thus preventing the ball of the abutment from seating completely and resulting in an unstable and poorly fitting dental prosthesis. 
     Another problem that can occur in the placement of conventional miniature implants is that the impression material if not contained may flow into the crevice between the gum line and the overlying structure. This can result in some chance that the impression material (or prosthesis material, in the case of a retrofit installation) may be locked around the abutment and its retentive mechanism, within the overlying interface between the gingival surface and the overlying protruding abutment. 
     Thus, a dental implant system solving the aforementioned problems is desired. 
     SUMMARY OF THE INVENTION 
     The dental implant system comprises implants with integral abutments for use in securing both removable and fixed dental prostheses in the mouth. The system also includes components installed in the removable or fixed prostheses for securing the prostheses to the abutments of the implants. Various components are also provided for the formation of the prostheses and for their installation. Some or all of the various components of the present system may be combined as a kit, if so desired. A ratchet type instrument or tool having a drive socket may be provided for driving the implants, with the specific drive being configured as required for various abutment forms. Separate interfacing components having corresponding fittings for mating to the abutment of the implant and the socket of the instrument may also be provided. 
     In one embodiment, the system comprises a threaded mini-implant having an integral abutment. A metal retentive housing includes a rubber retentive insert removably installed therein. The metal housing is permanently affixed in the dental prosthesis. The rubber insert installs removably over the abutment of the implant to permit the dental prosthesis to be removed and reinstalled as desired. A rubber gasket or ring is provided at the time of forming the impression or retrofitting an existing dental prosthesis. The gasket or ring is placed about the base of the abutment to prevent the flow of impression material into the gap between the gingival tissue and the overlying prosthetic retainer. 
     Another embodiment comprises a mini-implant with an asymmetric abutment that generally simulates the contours of a natural tooth. This implant is used for the installation of a fixed dental prosthesis, e.g., a single artificial tooth, or perhaps a plurality of implants for several teeth. 
     Yet another embodiment includes a transfer coping installed on the abutment at the time of forming the impression. The transfer coping is captured and becomes an integral component of the impression so that an analog may be placed for making a model of the structure. 
     Another embodiment includes a laboratory (lab) processing coping, with the lab processing coping serving two functions. First, the dentist can try the coping at the time of placement of the dental mini implant to assure that the finish line, i.e., the boundary between the base of the abutment structure and the overlying dental prosthesis, is sub-gingival in order to provide a seal between the prosthetic structure and the surrounding tissue to preclude the entry of food residue therein. Secondly, the laboratory technician can use the lab processing coping to fabricate the prosthetic material in the construction of the fixed prosthesis. An analog and sleeve assembly is also provided for handling the impression and for forming the dental prosthesis from the impression. 
     These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of a dental implant and prosthetic attachment assembly in a dental implant system according to the present invention, showing its various components. 
         FIG. 2  is an elevation view in section of the installed implant and prosthetic attachment assembly of  FIG. 1 , illustrating further details. 
         FIG. 3  is an exploded perspective view of a metal retentive housing and rubber retentive insert in a dental implant system according to the present invention, shown with an instrument used for their assembly. 
         FIG. 4  is an exploded perspective view of an implant adapted for the attachment of a fixed dental prosthesis thereon, and the transfer coping for forming the prosthesis on the abutment of the implant, in a dental implant system according to the present invention. 
         FIG. 5  is an exploded perspective view of an analog and pin and a sleeve used in the formation of a dental stone model and for receiving the lab processing coping in a dental implant system according to the present invention. 
         FIG. 6  is an elevation view in section of an installed implant and a lab processing coping used in the fabrication of a fixed dental prosthesis in a dental implant system according to the present invention. 
         FIG. 7  is an exploded perspective view of an alternative embodiment of an implant and abutment in a dental implant system according to the present invention, shown with a corresponding transfer coping. 
         FIG. 8  is an elevation view in section of an installed implant in a dental implant system according to the present invention, shown with its coping and dental prosthesis affixed thereto. 
     
    
    
     Similar reference characters denote corresponding features consistently throughout the attached drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention relates to a dental implant system incorporating mini dental implants having abutments formed integrally therewith. The system includes implant embodiments for installing both removable and fixed dental prostheses, as well as components for use with transfer and lab processing copings and an analog and pin with a locking feature for use during the manufacture of the prosthesis. The various components of each embodiment may be provided as a kit, if so desired. 
       FIGS. 1 through 3  of the drawings illustrate the components and exemplary installation of a first embodiment of the dental implant system, comprising an assembly wherein the dental prosthesis is removably secured within the mouth of the user.  FIG. 1  of the drawings provides a perspective view of a kit  10  for the installation of a removable prosthesis in the mouth, with  FIG. 2  providing an elevation view in section of the completed installation and  FIG. 3  illustrating the assembly of certain components of the system. 
     The assembly and installation shown in  FIGS. 1 through 3  uses a miniature dental implant  12 . The implant  12  is a so-called “mini” implant, i.e., having a total length, including the threaded base portion  14  and abutment portion  16 , of about 16 to 23 mm, more or less, with the base  14  and abutment  16  being formed as a single integral component. The base  14  includes helical threads  18  thereon, and tapers to a pointed distal tip  20 . The helically threaded base  14  further includes one or more axial grooves  22  therein, with the grooves  22  serving to accept bone growth during the healing process to prevent the implant  12  from rotating within the bone structure and to provide greater anchorage and security for the implant  12 . The threaded base portion  14  is narrow in width, having a diameter of about 2.4 mm, or between about 1.8 mm and 2.9 mm. 
     The opposite end of the base portion  14  includes a sub-gingival collar  24  having a conical taper to the helical threads  18  of the base portion  14 , with the conical taper having a smooth and unthreaded upper portion with a plurality of very fine “micro-threads”  26  extending about the lower portion to the helical threads  18  of the base portion  14 . The relatively finely cut micro-threads  26  provide a better seal between the implant  12  and the surrounding bone or tissue structure once the implant has been installed. As the name implies, the conical sub-gingival collar  24  extends somewhat below the gingival tissue G and into the underlying bone structure B so that the micro-threads  26  engage the outermost cortical bone material, generally as shown in  FIG. 2  of the drawings. The top or widest diameter portion of this sub-gingival collar  24  is described as a “finish line,” and resides essentially level with the upper surface of the soft gingival tissue in the removable denture embodiment of  FIGS. 1 and 2 . 
     The abutment  16  has an essentially cylindrical shape and a circumferential groove  28  formed therearound. This groove  28  serves as a seating element and anchor for a resilient elastomeric (rubber, etc.) insert that is removably installed over the abutment  16 , as explained further below. The abutment  16  has a head  30  opposite the sub-gingival collar  24 . The head  30  has a somewhat larger diameter than that of the balance of the abutment  16 . The head  30  is of a non-circular configuration, e.g., it includes at least one flat  32  or other non-circular element (e.g., a notch, etc.) formed in the periphery thereof, as shown in  FIG. 1 . This provides for the placement of a torsion instrument or adapter over the head  30  of the abutment  16  for turning the implant  12  and advancing it into a hole previously formed in the bone structure. The relatively small diameter and length of the helically threaded base portion  14  of the implant  12  allows it to be screwed into a previously formed unthreaded hole without the need to perform the extra step of threading the hole. The self-tapping helical threads  18  enhance the physical security of the implant installation. 
     A prosthesis-retaining housing  34  is permanently affixed (i.e., cast or molded in place) within the dental prosthesis P. In the example of  FIG. 1 , the dental prosthesis P 1  is shown in broken lines as a section or portion of a removable partial or full denture or the like. The housing  34  is embedded in the lower portion or tissue side (internal surface) of the prosthesis P 1 . While a full or partial denture would be the most common installation for a removable prosthesis in the dental implant system, it will be seen that the same configuration may be applied to smaller, individual tooth prostheses, e.g., the single tooth prosthesis P 2  of  FIG. 2 , if so desired. 
     The housing  34  is preferably formed of thin metal, and has a generally cylindrical configuration with a closed top or cap defining a hollow interior  36  (shown in  FIGS. 2 and 3 ). The top or cap includes an outwardly extending circumferential flange  38 , serving to prevent the housing  34  from pulling out of the dental prosthesis P 1 . An outwardly protruding circumferential bead or band  40  extends about the housing  34 , the band  40  including at least one break or discontinuity  42  therein. This break or discontinuity  42  provides for the inclusion of material of the removable dental prosthesis P 1  to flow therein during manufacture of the prosthesis, thus precluding rotation of the otherwise circular or cylindrical retaining housing  34  within the prosthesis P 1 . 
     Further details of the retaining housing  34  are shown in  FIGS. 2 and 3 .  FIG. 3  particularly illustrates the means for retaining the elastomeric insert therein. The lower edge or base of the generally cylindrical housing  34  includes an inwardly extending base flange  44  defining a shallow conical shape. The flange  44  serves to retain the insert therein. The flange  44  includes a plurality of radially disposed slots  46  defined therein to permit the insertion of the insert into the housing  34 , with each slot  46  having a stop tab  48  formed from the upwardly bent end of the adjacent flange portion. 
     The resilient elastomeric insert  50  serves as a connecting element between the housing  34 , which is permanently affixed into the prosthesis P 1  or P 2 , and the abutment portion  16  of the implant  12 , which is permanently installed in the mandibular or maxillary bone structure of the patient. The insert  50  is of a generally cylindrical configuration. The diameter of the insert  50  closely matches the diameter of the passage defined by the base flange  44  of the retaining housing  34 . The insert  50  has a series of axial ribs  52  extending radially from the cylindrical core. The ribs  52  are aligned with and closely fit through the slots  46  of the base flange  44  of the housing  34  when the insert  50  is installed therein. The diameter defined by the outer reaches of the ribs  52  closely matches the internal diameter of the housing  34 , to provide a closer fit between the insert  50  and housing  34  when the insert  50  is installed therein. 
     The insert  50  has a cushioning flange  54  extending radially from and circumferentially about the base of the insert  50 . The cushioning flange  54  fits below the base flange  44  of the housing when the insert  50  is installed therein. The lower ends of the axial ribs  52  and the cushioning flange  54  define gaps  56  therebetween, to allow the base flange  44  of the housing  34  to fit between the ribs  52  and cushioning flange  54  of the insert  50 . The cushioning flange  54  serves as a cushion or shock absorber between the metal retentive housing  34  and the shoulder of the abutment  16  for the removable prosthesis P 1  of  FIG. 1  or the single tooth P 2  of  FIG. 2 , and the oral structure of the patient when the assembly is completed and installed in the mouth of the patient. 
     The resilient elastomeric insert  50  has an abutment receptacle  58  formed concentrically therein. The receptacle  58  provides for the removable installation of the insert  50  (and attached housing  34  and dental prosthesis P 1  or P 2 ) to the abutment  16  of the implant  12 . The receptacle  58  is configured to closely fit the contours of the abutment  16 , i.e., having an inwardly formed circumferential rib to fit the abutment groove  28 , a circumferential groove formed in the head of the receptacle  58  to fit the corresponding circumferential flange of the head  30  of the abutment  16 , and an inward conical taper at the mouth of the receptacle  58  to fit the conical collar  24  or shoulder of the abutment  16 . 
     The insert  50  is installed within the housing  34  by aligning the ribs  52  of the insert  50  with the slots  46  in the base flange  44  of the housing  34 , and inserting the insert  50  axially into the housing  34 . The insert  50  is then locked into the housing  34  by twisting or rotating the insert  50  within the housing  34  until the ribs  52  are stopped by the stop tabs  48  at one edge of each of the slots  46 . This captures the ribs  52  of the insert  50  above the base flange  44  of the housing  34  to prevent the insert  50  from pulling out of the housing  34 . The rotation of the insert  50  in the housing  34  also closes or covers the slots  46  of the housing  34 , thereby precluding entrance of foreign matter into the housing. 
     The abutment receptacle  58  of the insert  50  includes a non-circular instrument receptacle  60  in the upper end thereof, i.e., opposite the opening through the cushioning flange  54 . This instrument receptacle  60  allows the similarly shaped bit  62  of an insert installation instrument  64  to be inserted therein. Rotation of the instrument  64  produces corresponding rotation of the insert  50  within the housing  34 . Removal of the insert  50  from the housing  34  is accomplished by rotating the instrument  64 , and thus the insert  50 , in the opposite direction from that used to lock the insert  50  in place within the housing  34 , and withdrawing the insert  50  axially from the housing  34 . The process requires but a few minutes to remove and replace worn inserts  50  in a removable partial or full dental prosthesis P 1 , and is easily accomplished in the dental office, or even at home by the owner of the dental prosthesis. 
     Dental prostheses are conventionally formed by molding a pliable or semi-liquid material (plastic, etc.) in the mouth of the patient in order to provide a close and precise fit between the oral structure of the patient and the dental prosthesis. The insert  50  and housing  34  are installed on the previously installed implant  12 , and the material flows or is molded about the housing  34  to become an integral part of the removable prosthesis, or for a retrofit, an existing removable prosthesis. It will be seen that the semi-liquid characteristics of the material used to form the model will allow this material to flow beneath the conical cushioning flange  54  of the insert  50 . 
     Accordingly, an elastomeric ring  66  is provided to serve as a seal between the cushioning flange  54  of the insert  50  and the underlying oral structure of the patient during the process of making an impression for a new prosthesis or retrofitting an existing prosthesis. The elastomeric ring  66  includes a central passage therein to fit about the abutment  16  of the insert  12 , and a conically sloped intermediate portion  68  extending outwardly therefrom to a thin, flat outer sealing flange  70 . The intermediate portion  68  closely fits the conical shape of the bottom of the cushioning flange  54  of the insert  50 , and precludes the introduction of material between the flange  54  and the underlying soft tissue (gum) during the formation of the impression for the prosthesis. Once the impression has been formed and removed from the mouth of the patient (along with the housing  34  and insert  50  captured therein), the elastomeric ring  66  is removed from the abutment  16  and discarded. 
       FIGS. 4 through 6  illustrate components used in the manufacture and installation of one embodiment of a fixed dental prosthesis. These components may be provided as a group in the form of a kit, if so desired. The implant  112  of  FIGS. 4 and 6  is similar to the implant  12  of  FIGS. 1 and 2 , and is in fact identical thereto from the finish line, i.e., the widest diameter or upper end of the sub-gingival collar  124  down, having a base  114  with helical threads  118  thereon and micro-threads  126  about the lower portion of the conical sub-gingival collar  124 , a sharply pointed distal tip  120 , and one or more axial grooves  122  formed along the base  114 . 
     The abutment portion  116  of the implant  112  has a significantly different configuration from the corresponding abutment  16  of the implant  12  of  FIGS. 1 and 2 , however. The abutment  116  is shaped or configured to conform to the interior shape and configuration of both the transfer coping  134  shown in  FIG. 4 , and the lab processing coping illustrated in  FIGS. 5 and 6 . The abutment  116  has a generally smoothly curved or rounded upper or distal portion, with a circumferential groove  128  formed therein at about one third of the distance from the base to the tip of the abutment  116 . A labial or forwardly oriented flat  132  is provided for abutments and implants configured for use with frontal (anterior) tooth prostheses. 
     The transfer coping  134  includes an abutment receptacle  136  defined therein that is configured to fit closely about the abutment  116 . The transfer coping  134  has a generally cylindrical external shape and an outwardly extending circumferential flange  138  at the top of the coping  134 , and an outwardly protruding circumferential band  140  extending about the coping  134 . The flange  138  and/or band  140  are preferably non-circular, i.e., having a flat or other non-circular discontinuity formed thereon or therein in the manner of the flat  32  formed along the side or edge of the head  30  of the abutment  16  of  FIG. 1 . A discontinuity or gap, respectively  138   a  and  140   a  for the flange  138  and band  140 , may be provided to serve this function. This prevents the impression I (shown in broken lines in  FIG. 4 ) from rotating thereon, or the uninstalled coping  134  from rotating within the impression I. An outwardly extending or flaring skirt or flange  144  extends circumferentially about the base of the transfer coping  134  from the “finish line,” i.e., the juncture between the base of the cylindrical body of the coping  134  and the skirt or flange  144 . This skirt or flange  144  serves to expand and hold back the gingival tissue during the fitting of the transfer coping  134 , in a manner similar to the use of packing cord about a natural tooth that has been prepared for a fixed prosthetic restoration. 
     The process of forming and installing a single, fixed prosthetic tooth, e.g., the prosthetic tooth P 3  of  FIGS. 5 and 6 , begins with the installation of the implant  112  into the jawbone structure of the patient, generally as described above for the removably installed dental prosthesis illustrated in  FIGS. 1 through 3 . A “stone model,” i.e., a casting formed of material that cures into a hard and rigid structure, is formed of the patient&#39;s mouth, or more precisely, the stone model is formed to provide an analog of that portion of the patient&#39;s mouth in which the dental prosthesis is to be installed. The transfer coping  134  is placed upon the abutment  116  of the implant  112 , and an impression I is formed over the transfer coping  134 . Once the impression I has been formed, the impression I and the transfer coping  134  are removed together from the implant abutment  116 . The transfer coping  134  and impression assembly is placed upon an implant analog pin in the stone model in order to send the impression I to a dental lab for manufacture of the fixed dental prosthesis, e.g., the prosthesis P 3  of  FIGS. 5 and 6 . 
     An implant analog and pin  212  and associated components are illustrated in  FIG. 5  of the drawings. The analog and pin  212  includes a base or pin portion  214  and an abutment or analog portion  216  extending upwardly therefrom. The pin or base  214  is devoid of threads, as it is not intended to be installed permanently in the stone model (or any other structure, as a permanent installation). However, it does have a non-circular cross section, e.g., longitudinal facets  218 , in order to prevent it from rotating within a fixture or sleeve previously installed in the stone model during the manufacture of the prosthetic tooth. The abutment or analog portion  216  is configured to match precisely the internal contour and shape of the transfer coping  134  and also the lab processing coping  150  shown in  FIGS. 5 and 6 , which internally match precisely the external contours of the abutment of the implant previously affixed in the patient&#39;s mouth. 
     When the lab receives the assembly that includes the impression I and transfer coping  134  ( FIG. 4 ) temporarily installed on the analog and pin  212  ( FIG. 5 ), the base portion  214  of the analog pin is installed in a holder or sheath  312  ( FIG. 5 ) in the stone model. The sheath  312  also has a non-circular cross section, both internally and externally. The internal cross section is configured to fit closely about the exterior of the base or pin portion  214  of the analog and pin  212  in order to prevent the analog and pin  212  from rotating within the sheath  312 , while the non-circular exterior of the sheath  312  prevents it from rotating when installed in the stone model (analog of the oral structure of the patient) for the manufacture of the dental prosthesis. Additional anti-rotation means may be provided by one or more circumferentially discontinuous bands or rings  340  disposed about the sheath  312 . The bands  340  may have breaks or discontinuities  342  therein to preclude rotation of the sheath  312  within the stone die or model. 
     The analog and pin  212  is retained within the sheath  312  by a distal protruding tab  220  that extends from the tip of the pin portion  214  and through a hole  320  in the tip of the sheath  312 . The base or pin portion  214  of the analog and pin  212  is installed in the sheath  312  with the tab  220  protruding through the hole  320  in the base of the sheath, and a washer  366  is placed over the tab  220 . The tab  220  includes a passage  222  therethrough, through which a retaining pin  322  is placed to secure the analog pin  212  within the sheath  312  for the duration of manufacture of the dental prosthesis, e.g., single tooth prosthesis P 3 ; multiple units would be required for a denture having multiple teeth. 
     A lab processing coping  150  is provided for the manufacture and permanent installation of the dental prosthesis P 3  thereon. The lab processing coping  150  is formed as a thin shell and includes an internal cavity or recess  158   a  closely matching and mating with the contours and shape of the abutment  216  of the analog pin  212 . The internal cavity or recess  158   a  is devoid of any rings or other retaining structure, as it must be removable from the abutment analog  216  of the analog and pin  212 . The external shape and contour  158   b  closely matches the internal shape and contour of the receptacle  136  of the transfer coping  134 . This permits the dental prosthesis P 3  to be manufactured on the lab processing (fixed) coping  150  with the coping  150  installed securely on the abutment analog portion  216  of the analog and pin  212 . 
     The prosthesis manufacturing process initially involves the installation of the lab processing coping  150  on the abutment analog portion  216  of the analog and pin  212 , once the transfer coping  134  and its impression I ( FIG. 4 ) have been removed. A handling tab  152  extends from the tip of the lab processing coping  150 , allowing the dentist to handle the coping during intraoral procedures. The dental prosthesis P 3 , e.g., a single prosthetic tooth, is then constructed on the lab processing coping  150 . When this has been accomplished, the stone model with the analog and pin  212 , coping  150 , and completed dental prosthesis P 3  are returned to the dentist for installation on the abutment  116  of the insert  112  ( FIG. 4 ) previously installed in the mouth of the patient. 
       FIG. 6  of the drawings provides an illustration of the completed placement of the fixed dental prosthesis P 3 . The implant  112  was previously installed in the mouth of the patient, with the abutment portion  116  extending above the gingival layer G. It will be noted that the sub-gingival flange  124 , i.e., the “finish line” of the implant  112 , is slightly below the surface of the gingival layer. This results in the lower, outer flange of the permanent coping  150  residing slightly below the gingival surface, with the lowermost edge of the prosthesis P 3  also residing slightly below the gingival surface due to its congruency with the lower and outer flange of the coping  150 . The result is much like a natural tooth; there is no gap between the gingival tissue and the structure of the prosthetic tooth P 3 . 
       FIG. 7  illustrates an implant  412  and transfer coping  434  for use therewith, with  FIG. 8  illustrating the installed implant  412 , and a lab processing coping  450  and dental prosthesis P 4  cemented or otherwise fixed thereon. The implant  412  of  FIGS. 7 and 8  is similar to the implant  112  of  FIGS. 4 and 6 , and is in fact identical thereto from the sub-gingival collar finish line  424  down, having a base  414  with helical threads  418  thereon and micro-threads  426  about the lower portion of the conical sub-gingival collar  424 , a sharply pointed distal tip  420 , and one or more axial grooves  422  formed along the base  414 . 
     The abutment portion  416  of the implant  412  has a somewhat different configuration from the corresponding abutment  116  of the implant  112  of  FIGS. 4 and 6 , however. The abutment  116  is shaped for use with a forwardly positioned or anterior prosthetic tooth, e.g., an incisor, with such teeth having a somewhat thinner section in the fore-aft orientation. Thus, the non-circular, flattened shape of the abutment  116  also provides for the placement of a corresponding instrument thereon to rotate and thread the insert base  114  into the bone structure. However, the abutment  416  is intended for a more distal or posterior, i.e., rearward installation in the mouth to support a molar-type tooth having a more uniform width or thickness in both longitudinal and lateral orientations. Accordingly, the abutment  416  has a more conical shape with a truncated top, with the circumferential groove  428  being located closer to the midpoint of the conical portion. A flat  432  is formed in the conical surface of the abutment  416 , providing a non-circular cross section at that point for an instrument to grip the abutment  416  (and thus the base portion  414  of the implant  412 , formed integrally therewith), for applying torque to advance the implant  412  through the soft tissue and into the underlying bone. Alternatively, a tool or instrument bit receptacle  430  having a non-circular cross section may be provided in the upper end of the abutment  416  (or the abutments of other implants disclosed herein), if so desired. 
     The transfer coping  434  of  FIG. 7  includes an abutment receptacle  436  defined therein that is configured to fit closely about the abutment  416  and thus the analog of the abutment. The transfer coping  434  has an external shape essentially identical to that of the transfer coping  134  of  FIG. 4 , i.e., a generally cylindrical external shape, with an outwardly extending circumferential flange  438  about the head or upper end thereof and an outwardly protruding circumferential band  440  extending about the coping  434 . The flange  438  and/or band  440  are preferably non-circular, i.e., having a flat or other non-circular discontinuity formed thereon or therein in the manner of the flat  32  formed along the side or edge of the head  30  of the abutment  16  of  FIG. 1 . This prevents the impression (e.g., similar to the impression I shown in broken lines in  FIG. 4 ) from rotating thereon. A discontinuity or gap, respectively  438   a  and  440   a  for the flange  438  and band  440 , may be provided to serve this function. An outwardly extending or flaring skirt or flange  444  extends circumferentially about the base of the transfer coping  434  from the “finish line,” i.e., the juncture between the base of the cylindrical body of the coping  434  and the skirt or flange  444 . This skirt or flange  444  serves to expand and hold back the gingival tissue during the fitting of the transfer coping  434  during the making of the impression, in a manner similar to the use of packing cord about a natural tooth that has been prepared for a fixed prosthetic restoration. 
     The process of forming and installing a single, fixed prosthetic tooth, e.g., the prosthetic tooth P 4  of  FIG. 8 , is essentially the same as that described further above for the components illustrated in  FIGS. 4 through 6 . The end result is generally as illustrated in  FIG. 8  of the drawings. The lab processing or fixed coping  450  is installed upon the abutment  416 , and the dental prosthesis P 4  is affixed upon the coping  450 , and thus upon the abutment  416  of the previously installed implant  412 . The lab processing coping  450  is formed in a manner similar to the coping  150  of  FIGS. 5 and 6 , i.e., as a thin shell including an internal cavity or recess  458   a  closely matching and mating with the contours and shape of the abutment  416  of the implant  412 . The external shape and contour  458   b  has a similar shape and configuration, with the prosthetic tooth P 4  being formed thereover. As in the case of the installation illustrated in  FIG. 6 , the sub-gingival collar  424  is slightly below the surface of the gingival layer. This results in the finish line of the fixed coping  450  residing slightly below the gingival surface, the lowermost edge of the prosthesis P 4  also residing slightly below the gingival surface due to its congruency with the lower and outer flange of the coping  450 . The result is much like a natural tooth, with no gap between the gingival tissue and the structure of the prosthetic tooth P 4 . 
     In the case of the removable prostheses shown in  FIGS. 1 and 2 , the dental implant system allows the prostheses to be installed and removed quickly and easily by the user thereof, while still providing secure retention in the mouth. The resilient components used in the system may be quickly and easily replaced as needed. In the case of the fixed prostheses of  FIGS. 6 and 8 , the durability and security of the installation should provide years of use for the user, and could last for the life of the user. In either case, the relative simplicity of installation provides many benefits both to the dental practitioner and to the patient, with those benefits providing more rapid and thus less costly installation. 
     It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.