Abstract:
A universal dental implant arrangement includes both internal attachment and external attachment possibilities. This is achieved by utilizing an anchor having an internal void or abutment receiving bore, adapted for internal attachment-type abutments, along with a platform that can be used for various purposes. The universality of the implant is in providing the alternative of leaving the platform in place, causing the implant to function as an external attachment implant, or removing the platform and thereby converting the implant into an internal attachment implant. The platform can support an external attachment abutment or be remove so that the implant can accommodate an internal attachment abutment.

Description:
FIELD AND BACKGROUND OF THE INVENTION 
     The present invention relates generally to the field of dentistry, and in particular, to a new and useful universal implant arrangement including a tapered and threaded anchor for implantation into the jaw bone of a mammal, means for rotating the anchor for seating it in the jaw bone, and means for mounting a replacement tooth or teeth to the anchor. 
     For the purpose of this disclosure and the claims forming a part thereof, relative terms and terms having functionally opposite but equivalent meanings such as, but not limited to, up, down, left, right, upwardly, downwardly, male and female, are used to include their opposite meaning. For, example, when referring to an implant anchor having a lower body portion with an upwardly facing opening, this is meant to also include an implant anchor having an upper body portion with a downwardly facing opening. 
     A wide variety of dental implant structures and systems is known. 
     U.S. Pat. No. 4,960,381 to Niznick, for example, discloses a screw-type dental implant anchor with an externally-threaded body portion joined to a top portion having an unthreaded exterior wall, and an internal, wrench-engaging surface. 
     U.S. Pat. No. 4,411,624 to Ogino, et al. discloses a dental implant with a dental root part having a substantial portion of the dental root surface to be placed in contact with the jaw bone, formed of a biologically active glass or glass-ceramic material that is contoured to have a selected taper. 
     U.S. Pat. No. 4,758,160 to Ismail discloses a dental implant having an alveolar surface and a hollow core therein, a prosthetic head having a shaft thereon, and a prosthesis. The shaft has a particular structure. 
     U.S. Pat. No. 4,863,383 to Grafelmann teaches a self-tapping screw implant. 
     U.S. Pat. No. 5,417,570 to Zuest, et al., U.S. Pat. No. 5,651,675 to Singer, U.S. Pat. No. 6,050,819 to Robinson and U.S. Pat. No. 6,126,662 to Carmichael et al., all disclose the use of the so called Morse taper in a dental implant. 
     U.S. Pat. No. 5,437,551 to Chalifoux teaches a dental system for insertion into a bore of a jaw bone of a patient which comprises an implant having a central bore extending from a top surface through a portion of the vertical height of the implant, one first extension extending from and directly attached to a first wall of the central bore, a dental post having a stem section shaped to fit into the central bore and having a second wall with at least one second extension attached directly to the post and positioned to frictionally fit with the first extension to retain the post within the central bore. 
     U.S. Pat. No. 5,199,873 discloses an implant with a stepped and threaded body for extending into the jaw bone. 
     Despite the effort of many practitioners in this field, a need remains for an effective universal dental implant arrangement. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a universal implant arrangement which includes an implant anchor, a platform or body that can be used, for example, for rotating the anchor to fix it in a jaw bone hole (and acts as an attachment surface for an external attachment abutment), and an abutment for mounting at least one tooth replacement, such as a crown or cap, to the anchor. 
     One of the main objects of the present invention is to provide a truly universal implant including both internal attachment and external attachment possibilities. This is achieved by utilizing an anchor having an internal void (also referred to here as a abutment receiving bore) adapted for internal attachment-type abutments, along with a (an attached) platform that can be used for various purposes. The universality of the implant is in providing the alternative of leaving the platform in place, causing the implant to function as an external attachment implant, or removing the platform and thereby converting the implant into an internal attachment implant. The platform can support an external attachment abutment or be remove so that the implant can accommodate an internal attachment abutment. For the purpose this disclosure the term “abutment” can mean any one or more of a wide variety of dental superstructures, such as a crown, a clip bar or spark erosion bar (that can be attached to more than one implant), a stud or post for helping support an over-denture, or the like. The external abutment can be attached to the platform, the platform thus providing any foundation needed for connecting the external abutment to the anchor. 
     Accordingly, another object of the invention is to provide a dental implant arrangement for attaching a replacement tooth to the jaw bone of a mammal, which has an anchor for implantation into the jaw bone. The anchor has a lower outer tapered surface and a thread in a preferred embodiment, although anchors without a thread and even without a tapered surface, may also be used. The anchor also has an upper portion with an upper surface and an abutment receiving bore extending into the anchor. A platform is attached to the upper surface of the anchor also for rotating the anchor in the jaw bone, when rotation is needed to install the anchor. A non-circular projection projects from and is part of the top of the platform. This can be used for engagement by a wrench for rotating the platform. Orientation structures such as co-rotation keys and/or a Morse taper, can also transmit rotation of the platform to the anchor. The orientation structures can also be used to orient an abutment to the correct rotational position with respect to the anchor. The abutment for supporting the tooth replacement may have a foundation extending into and fixed to the abutment receiving bore in the anchor when the tooth replacement is to be supported on the anchor as an internal attachment. Platform  24  may serve as a permanent part of the implant arrangement in that it forms the attachment location for the crown, or for hardware that supports the crown. The platform also serves as part of the installation process, for example, to rotate a threaded anchor into the jaw bone, and ultimately may be removed and replaced with an internal attachment abutment or other internal attachment structures. 
    
    
     The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a side elevation of a first embodiment of the invention; 
     FIG. 2 is a sectional view taken along lines  2 — 2  of FIG. 1; 
     FIG. 3 is an exploded view of the embodiment of FIGS. 1 and 2; 
     FIG. 4 is an exploded view of another embodiment that is similar to that of FIGS. 1 and 2; 
     FIG. 5 is an exploded view of a still further embodiment of the invention; 
     FIG. 6 is an exploded view of another embodiment of the invention; 
     FIG. 7 is an exploded view of a still other embodiment of the invention; 
     FIG. 8 is an exploded view of another embodiment of the invention; 
     FIG. 9 is an elevation, partly in section of another embodiment; 
     FIG. 10 is a partial perspective and exploded view of the platform and top of the anchor of another embodiment of the invention; 
     FIG. 11 is a partial perspective view of another embodiment; 
     FIG. 12 is a view like FIG. 11 but of another embodiment of the invention; 
     FIG. 13 is an exploded view of the embodiment of FIG. 8 showing a crown or cap used as a tooth replacement; 
     FIG. 14 is a view similar to FIG. 13 of the embodiment of FIG. 6 with a tooth replacement; and 
     FIG. 15 is a view similar to FIG. 11 of another embodiment of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, in which like reference numerals are used to refer to the same or similar elements, FIG. 1 illustrates a dental implant arrangement for attaching at least one replacement tooth to the jaw bone of a mammal. 
     The arrangement comprising an anchor  10  for implantation into a hole in the jaw bone, the anchor having a lower portion  12  with an outer tapered surface  14  and a thread  16  on the outer tapered surface. Thread  16  may or may not be present on surface  14 . The anchor has an upper portion  18  with an upper or upwardly facing surface  20  and an abutment receiving bore  22  shown in FIG. 2, extending into the anchor and opening at the upper surface  20 . Texturing or roughening of the surface  14  and/or thread  16  is accomplished, for example, by acid etching, plasma spray of titanium or blasting. 
     A platform  24  is attached onto the upper surface  20  of the anchor  10  for rotating the anchor in the jaw bone hole. A non-circular projection  26  is fixed to and formed as one piece with a top surface  28  of the platform  24  and has at least one external wrench-engaging surface adapted for engagement by a wrench for rotating the platform and contiguous anchor thereby seating the anchor in the jaw bone. Projection  26 , is made as one piece with the rest of the platform  24 , e.g. of biocompatible metal. The wrench-engaging surface may be a hexagonal nut structure as shown, any other polygon or any other non-circular shape such as an oval so that a wrench can be used to turn the platform  24 . 
     Orientation or co-rotation means are defined between the anchor  10  and the platform  24  for transmitting rotation of the platform to the anchor when the platform is still attached to the anchor as shown in FIGS. 1 and 2 and the platform is rotated using a wrench. It is noted that in embodiments that do not include the thread  16  on the anchor  10  (and therefore need not be rotated to install), the projection  26  may still be retained on the platform as a mechanism for receiving an abutment or other crown supporting structure on the platform. Such an abutment has a mating recess for the projection so as to fix a relative rotational position between the abutment and the anchor and prevent rotation of the dental superstructures. The orientation means also remains useful as a mechanism for the provided plural rotational positions between the abutment and the anchor. 
     When used in its internal attachment implant application, platform  24  is removed and an abutment  30  shown in FIG. 6, adapted to support a tooth replacement such as a crown  100  in FIG. 14, is placed on the anchor. The abutment  30  includes a foundation  40  extending into and fixed to the abutment receiving bore  22  in the anchor  10 , when the tooth replacement is to be supported on the anchor in its internal attachment application in a patient&#39;s mouth. 
     The outer tapered surface  14 , e.g. in FIG. 1, and the thread  16 , are textured to improve bone integration to the anchor. This is done in a know fashion, e.g. by coating the surfaces with a titanium plasma spray. 
     The upper portion  18  of the anchor  10  has a non-threaded and substantially cylindrical neck  19 . The neck has an outer surface that is textured to improve bone integration to the anchor. A polished cylindrical collar  21  which is about 1 to 2 mm tall, is provided on the outer surface of the anchor, above the neck. 
     The platform has an upper, outer polished surface  27  that is contiguous with the cylindrical outer surfaces of the collar  21  and neck  19 . 
     The anchor  10  includes one or more circumferentially spaced toe recesses  42  at a lower end of the anchor, for improving threading of the anchor to the bone of the jaw. Recess or recesses  42  cause the anchor to be self-threading in the bone as the anchor is rotated. 
     The implant anchor, in the embodiments of FIGS. 1-8 has a abutment receiving bore  22  in the form of a female Morse taper surface. Such surfaces having a taper or inclination of about 8° or less, have been found to securely fix a mating male Morse taper member due to the inter-frictional effects between the tapered surfaces. 
     The fixation is so secure that the co-rotation means can simply comprise the platform having a male Morse taper member  23  for frictionally engaging the female Morse taper surface of the abutment receiving bore  22 . 
     The platform  24  also has a lower surface that closely engages and covers the upper surface  20  of the anchor  10 . A removal slot  44  either in the under surface of platform  24  as shown in FIG. 2, or on the upper surface  20  as shown in FIG. 4, but in any case between the lower surface of the platform and the upper surface of the anchor is provided for receiving a tool such as a small screw driver or like device, to overcome the frictional engagement of the Morse taper, and remove the platform  24  from the anchor  10 . 
     A more positive co-rotation means comprises one or more circumferentially spaced male keys  46  (FIG. 4) projecting from either the platform or the anchor, and a corresponding female key recess  48  in the other for receiving the male key projection (FIG.  4 ). This also provided orientation means between the abutment and the anchor that permits an equal number of rotational position for the abutment on the anchor. 
     A screw bore  50  extends into the platform  24  and a fixing screw  52  extending into the screw bore, in the embodiments of FIGS. 2-5 and  7 - 9 . The screw bore in the platform is at least partly threaded in the embodiment of FIG. 5, for holding an abutment such as abutment  60  in FIG. 7, to the platform  24 . As shown is FIG. 7, the bore  50  in the platform can be partially or entirely threaded in order to receive threads of the screw  52  to fix the abutment  60 . In this way, a shorter screw can be used which need not be threaded all the way into the anchor or the anchor may even be provided with no threaded bore. The same is true of FIG. 8 where part or all of the central bore through the abutment  62  may be threaded. 
     FIGS. 5 and 6 also illustrate how the use of multiple, e.g. six, sets of male and female keys  46 , 48 , can be equally and circumferentially spaced around the implant (preferable with the female keys  48  in the top surface of the implant). In the case of off-axis abutments that are needed to accommodate implants that are at an angle to the axis of the crown to be installed (e.g. see FIGS. 6-8 of U.S. Pat. No. 5,417,570 to Zuest, et al.) this gives the practitioner an equal number of rotational positions to install the off-axis abutment. FIG. 15 shows four male keys  46  on the inner perimeter of the Morse taper surface  22  to provide the multiple position possibility for a platform and/or an abutment provided with four or more mating female key recesses. The inward placement of the keys also avoids the presence of an outer margin between the abutment and the anchor that is zig-zagged, since the keys are all spaced inwardly of the outer surface of the anchor. The line between these parts is a continuous circle which is thought to reduce the possibility of bacterial over growth. 
     In the embodiments of FIGS. 2-4 and  7 - 9 , the screw bore has a threaded portion  54  that extends into the anchor  10 , below the abutment receiving bore  22  for receiving the screw  52  for holding the platform to the anchor and/or for holding the abutment to the anchor, and/or for also holding a crown  102  to the abutment and anchor as in the embodiment of FIG.  13 . 
     The non-circular wrench-engaging projection  26  contains a counter sink  29  (see FIG. 2, for example). This accommodates the head of the screw  52  in the counter sink. Screw  52  can be turned using a Allen wrench in an internal hex or other engagement recess in the screw head (FIG.  2 ), or a socket wrench on an external hex or other engagement surface (FIG.  4 ). 
     In its external application, the abutment  60  is attached to the male Morse taper member  23  of the platform in the embodiment of FIG.  7 . In its internal attachment application, the abutment  62  with its foundation  61  having a male Morse taper member for frictionally engaging the female Morse taper surface of the abutment receiving bore, can be provided as shown in FIG.  8 . FIG. 6 illustrates a similar internal attachment embodiment but without screw bore or screw. 
     As shown in FIGS. 9,  11  and  12 , the abutment receiving bore  72  may be polygonal, e.g hexagonal. In these embodiments, the platform  24  includes a polygonal extension  74  extending from the platform, into the abutment receiving bore  72 . In the embodiment of FIG. 10, a screw bore is provided through the platform  25 , and the bore has a threaded portion  54  like that illustrated in FIG. 8, extending into the anchor  10 , below the abutment receiving bore  22 . The fixing screw  52  extends through the platform  25  and threads to the anchor  10  for holding the platform to the anchor. In this embodiment the platform is a cylindrical disk engaged onto the upper surface  20  of the anchor  10 , with no portion extending into the abutment receiving bore  22 . The same type of disk shaped platform  25  can be used with the polygonal bores of the anchors in FIGS. 11 and 12. In each male and mating female keys  46  and  48  act as the co-rotation or orientation means. 
     According to the invention a universal implant arrangement is provided in that the platform with external wrench-engaging projection can be used to seat the anchor, and if left in place acts as the top surface of the implant to which other dental superstructures can be externally attached. If, however, the platform is removed, other dental device superstructures may be internal attached to the anchor. An internal wrench-engaging device can be used either with the polygonal abutment receiving bore of FIG. 9, or even with a wrench outfitted with a Morse taper member. After this seating, a period of four to six months ensues during which time osseo-integration takes place on the external surface of the implant. After this period, the implant upon uncovering (stage two surgery) may be left as is and function as an external attachment implant. At that time it may also be converted to an internal attachment implant by removing the platform and using the internal bore as a receptacle for internal attachment structures. 
     After the period of integration, when the implant is uncovered (stage two surgery), a healing abutment is attached to the implant and soft tissue healing takes place. At this point the abutment of the invention is installed, either as the abutment  62  with its own foundation  61  (internal attachment application after platform  24  is removed), or the abutment  60  which uses the parts of the retained platform  24  extending into the abutment receiving bore  22  as the foundation (external attachment application). 
     The diameter at the top neck  19 , 21  of the anchor and contiguous platform surface  27 , is about 2-8 mm and preferably 3-7 mm. The length of the implant from top surface  28  of the platform to the bottom of anchor  10  is about 5-18 mm and preferably 6-15 mm. The platform  24  is attached to the anchor  10  in the usual case when a product embodying the invention is supplied to a practitioner for use. 
     While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.