Abstract:
An endosseous dental implant system has an externally threaded root-formed base ( 2 ) with self-tapping flutes ( 5 ) formed into apical threads of the root-formed base for easy insertion and immediate locking in an osteotomy. The coronal portion of the base has either a male or a female self-locking tapered friction held post that includes an apical anti-rotational polygon ( 7,23 ) to lock the coronal attachment to the base once attached. The implant incorporates an esthetic biological gingival profile ( 10,11,31,32 ) to enhance inter-proximal bone attachment to the root-formed implant, which supports the surrounding papilla.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    Priority is claimed under 35 U.S.C. Section 119 (e)(1) of Prov. Appl. No. 60/326,707, filed Oct. 4, 2001. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates generally to artificial orthopedic implant prostheses and more particularly, but not limited to, dental implants.  
         BACKGROUND OF THE INVENTION  
         [0003]    Over the last several decades many root-formed dental implants have been designed to replace natural dentition and provide for both esthetic and functional occlusion. Although these designs provided for the functional replacement of natural dentition that was either lost or missing, creating the natural inter-proximal tissue between adjacent implants has remained esthetically a restorative challenge. In fact, to maintain the soft tissue papilla between adjacent implants requires that the underlying inter-proximal bone area be two to three millimeters higher than in the buccal and lingual areas. Since most dental implants are not placed in a fresh tooth extraction site, where this physiological inter-proximal profile naturally occurs, grafting or countersinking the implant may be required to obtain this inter-proximal bone between the implants. Once the desired bone profile around the implant is surgically achieved, maintaining this inter-proximal bone for natural esthetics has remained a physiological challenge.  
         SUMMARY OF THE INVENTION  
         [0004]    It is an object of the present invention to overcome the limitations of the prior art noted above. Another object of the invention is to provide a root-formed dental implant which emulates the anatomical characteristics of natural dentition that can be easily manufactured and surgically placed. Another object of the invention is to provide such an implant with an anti-rotational interlocking mechanism to drive and secure the implant into the jaw and act as a receptor for securing a prosthetic attachment. A further object of the invention is the provision of a single or multiple unit implant that incorporates a defined inter-dental geometry to preserve and control inter-proximal bone and papilla.  
           [0005]    Briefly, according to a preferred embodiment of the invention, a dental implant comprises an elongated externally threaded base for receipt in an osteotomy, the base having a head portion formed with an esthetic profile extending around the outer periphery of the head and having opposed buccal and lingual sides and inter-proximal zones generally ninety degrees from the center of the buccal and lingual sides. The buccal side, and optionally the lingual side, is formed with a scalloped, smoothly curved recess simulating the corresponding areas of a natural tooth. Preferably, portions of the inter-proximal zones are formed with a roughened texture along a selected profile to enhance bone attachment thereto. According to a feature of the invention a male or female prosthetic receiving post having a self-locking taper extends from the head and an anti-rotational polygonal surface portion is disposed between the head and the post. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    Other objects, advantages and details of the invention appear in the following detailed description of the preferred embodiment, the detailed description referring to the drawings in which like reference characters refer to like components or structural features.  
         [0007]    [0007]FIG. 1 is an elevational view of a single stage endosseous dental implant with scalloped out buccal and lingual recessed portions made in accordance with a preferred embodiment of the invention and FIG. 1( a ) is a bottom view of the end face of the base of the FIG. 1 implant;  
         [0008]    [0008]FIG. 2 is an elevational view of a two stage endosseous dental implant with scalloped out buccal and lingual recessed portions made in accordance with a second preferred embodiment of the invention and FIG. 2( a ) is a bottom view of the base of the FIG. 2 implant;  
         [0009]    [0009]FIG. 3 is an elevational view of a modification of the FIG. 1 single stage endosseous dental implant having a scalloped out buccal recessed portion and FIG. 3( a ) is a top view thereof;  
         [0010]    [0010]FIG. 4 is an elevational view, partly in cross section, of a modification of the FIG. 3 two stage endosseous dental implant having a scalloped out buccal recessed portion;  
         [0011]    [0011]FIG. 5 is an elevational view of a single stage endosseous dental implant as shown in FIG. 3 with an assembled and attached prosthetic abutment shown separately in FIG. 5( a ); and  
         [0012]    [0012]FIG. 6 is an elevational view of a two stage endosseous dental implant as shown in FIG. 4 with an assembled and attached prosthetic abutment shown separately in FIG. 6( a ). 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0013]    With reference to FIGS. 1 and 1( a ), a single stage endosseous dental implant  1  made according to a first preferred embodiment of the invention comprises a root-formed externally threaded base  2  and a tapered interlocking coronal prosthetic attachment post  3 . Incorporated at the apex of the root-formed externally threaded base is a self-tapping thread  4  which will pull the implant downwardly during its initial placement. To assist in this process and to lock the implant into place, thread  4  utilizes specially designed cutting flutes  5  to cut, form and lock the implant into place. At the foot  6  of the tapered interlocking coronal prosthetic attachment post  3  is an anti-rotational polygonal surface  7  to lock the prosthetic attachment to root-formed implant  1 , once it is attached. To assure that the prosthesis remains attached to root-formed implant  1 , the male tapered post  3  uses a defined self-locking taper angle  8 , shown extending from demarcation line  6 , that friction locks with a female mate having a complimentary self-locking taper. Once the prosthesis is permanently attached to the tapered post, the now single unit implant and prosthesis is secured and cannot be rotated or removed.  
         [0014]    An esthetic coronal profile head  9  is disposed between root-formed externally threaded base  2  and tapered interlocking coronal prosthetic attachment post  3 . A unique scalloped out profile  10 ,  11  is formed in head  9  to replicate the buccal and lingual areas of a natural tooth. These scalloped out areas comprise generally smoothly curved recesses in an annular margin of a selected thickness machined within a one to two millimeter distance  12  to the beginning of the implant&#39;s first thread  13 . This one to two millimeter separation  12  allows for the clinically accepted bone resorption between the implant and prosthesis connection to end at the first thread  13  of the implant. Ninety degrees to [these] scalloped out profiles  10 ,  11  are enhanced profile areas for the inter-proximal zones  14 ,  15 , which are also designed to replicate the bone in between natural dentition. These areas preferably are further textured at  16 , by forming micro indentations or the like on the order of 30-50 microns, as by blasting with appropriate particulate material known in the art, to enhance bone attachment to the implant in these areas. Even with the standard one to two millimeter bone resorption in these areas  14 ,  15 , the additional textured surface  16  assures preservation and control of the inter-dental bone and papilla for the desired esthetics. The scalloped out recesses replicate the inter-dental geometry of a natural tooth and assist in the maintenance of the alveolar housing and gingival soft tissue.  
         [0015]    [0015]FIGS. 2 and 2( a ) show the endosseous dental implant  17  made in accordance with a second preferred embodiment of the invention for use with a two stage surgical process. Implant  17  comprises a root-formed externally threaded base  18  with an internally tapered, interlocking prosthetic attachment plug receiving bore  19 . As described with reference to FIG. 1, the apex of the root-formed externally threaded base  18  is a self-tapping thread  4  which pulls the implant downward during its initial placement. To assist in insertion and to lock the implant in place, threaded base  18  utilizes specially designed cutting flutes  5  to cut, form and lock the implant into place. An anti-rotational polygonal surface  23  is positioned at the apex  22  of the tapered prosthetic attachment plug receiving bore  19  of the implant to lock the prosthetic attachment to implant  17  once it is attached. To assure that the prosthesis remains attached to the root-formed implant the female tapered plug receiving bore  19  uses a defined self-locking taper angle  24  that friction locks with the plug of a male prosthetic mate such as post  42  of FIG. 6( a ) having a complimentary self-locking taper, to be discussed. Once the prosthesis is permanently attached in the tapered plug receiving bore  19  the now formed single unit implant and prosthesis is secured and cannot be rotated or removed without the assistance of a specially designed removal tool to be discussed.  
         [0016]    [0016]FIGS. 3 and 4, respectively, show the single and two stage esthetic implant embodiments  25 ,  26  modified to include only a single scalloped cut-out  10  formed on the buccal faces of the implants. In these embodiments, the lingual profile  29  are at the same height or level as the inter-proximal sides of the implants. Also lingual side surface texturing  31  extends above the threads to assist in tissue attachment on this side. Since the lingual side  29  has no esthetic concerns keeping the material in this area of the implant improves structural characteristics of the implant and simplifies the laboratory restorative challenges. In all the implant designs,  1 , 17 , 25 , 26 , alignment of the anti-rotational polygon prosthetic attachment  7 , 23  with the scalloped out profile  10  on the buccal side of the implant  1 , 25 , 26  assist for correct placement of the implant in its desired rotational location.  
         [0017]    [0017]FIGS. 5 and 6 show how the restorative attachments are made for either the single or the two-stage esthetic implant embodiments. The restorative prosthetic attachment  35 , shown in FIG. 5( a ) with an exemplary outer surface configuration having a generally tapered, grooved cylinder formed with a flat  35   a,  is used with the single stage implant embodiment. Prosthetic attachment  35  includes a female polygonal surface  36  and self-locking tapered plug receiving bore  37  that engages the male polygonal surface  7  and friction locks on the male plug or post  3 [ 9 ] of the implant. The restorative prosthetic attachment  40 , with an exemplary outer surface configuration including flat  40   a,  is used with the two stage implant embodiment. Prosthetic attachment  40  comprises a male polygonal portion  41  and tapered plug or post  42  that engages the female polygonal surface  23  and friction locks on the female post receiving bore  19  of the implant. In both cases once the prosthetic attachment is locked onto the implant, the restoration becomes one unit and cannot be rotated. However, in the FIG. 6 embodiment, prosthetic attachment  40  is provided with internal threads  40   b  which allow for the use of a specially designed jack screw removal tool to apply sufficient force for removal, if desired.  
         [0018]    Although the invention has been described with regard to specific preferred embodiments thereof, many variations and modifications will become apparent to those skilled in the art. It is, therefore, the intent that the appended claims be interpreted as broadly as possible in view of the prior art to include all such variations and modifications.