Patent Publication Number: US-2009239196-A1

Title: Dental implant system

Description:
FIELD OF THE INVENTION  
     The present invention relates generally to the field of dental prosthetics and more particularly, to a dental implant system. 
     BACKGROUND OF THE INVENTION  
     The prior art related to dental implant systems includes the following U.S. patents. 
     U.S. Pat. No. 7,090,495 B1, for a “Dental Implant Screw and Post System” to Rosen shows an assembly which includes a first part which may be attached to a prosthetic tooth and an implant. The implant is configured for receiving a threaded fastener. The threaded fastener includes a head portion and a threaded portion. The head portion has a taper configuration. The head portion descends into the implant for the purpose of shielding the threaded portion of the screw from masticating forces during use. 
     U.S. Pat. No. 7,264,469 B2 to Albarno for a “Split-Implant and Abutment System for Dental Reconstruction” includes an apical insert which is secured to the jawbone and another component such as a coronal base. The apical insert and the coronal base are mutually secured via a tapered Morse fit. The device uses a straight fastener which passes through an abutment and which also passes through the coronal base to secure the abutment and the coronal base to the apical insert. 
     U.S. Pat. No. 7,137,817 B2 to Mena shows an Implant Fixation Device which includes a portion which is implantable into tissue and which has an external thread. The device also has a straight internal thread. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a dental implant system which includes an abutment, a dental implant and a fastening screw, and in which the abutment and the fastening screw each have a complementary Morse taper. 
     Another object of the present invention is to provide a dental implant system in which the fastening screw and the abutment are in locking engagement. 
     Another object of the present invention is to provide a dental implant system which may be easily and conveniently attached to a patient&#39;s jawbone thereby minimizing patient discomfort. 
     Yet another object of the present invention is to provide a dental implant system which may be manufactured efficiently in volume. 
     Despite the developments of the prior art, there remains a need for a dental implant system in which the fastening screw and the abutment each have a Morse or locking taper. 
     In accordance with the present invention, there is provided a dental implant system which includes an abutment, a dental implant and a fastening screw. 
     The dental implant is an elongated, generally cylindrical member which includes a first end and a second end, a first intermediate portion and a second intermediate portion. The first intermediate portion is slightly convex and is tapered. The first intermediate portion includes a self-tapping thread which is adapted for threading into a patient&#39;s jawbone. The dental implant has a bore which includes a tapered portion, a straight cylindrical portion, and a threaded portion. 
     The abutment is generally cylindrical and includes a first end and a second end. The outer surface of the abutment includes a cylindrical portion which leads to a first tapered portion which generally matches the taper of the dental implant and which leads to a cylindrical portion and a second tapered portion. The second tapered portion leads to a third tapered portion which leads to a wrench engaging surface which is disposed on the second end of the abutment. The abutment includes a bore within which a first cylindrical portion leads to a tapered portion which, in turn, leads to a second cylindrical portion. 
     The fastening screw has a threaded portion which engages the internally threaded portion of the abutment, a cylindrical portion and a head which includes a tapered portion. The tapered portion of the head matches the tapered portion in the bore of the abutment. The head also includes a wrench engaging surface. 
     The engaging tapered portions on the fastening screw and the abutment create a locking relationship between the fastening screw, the abutment and the dental implant. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
       Other important objects and advantages will be made clear with reference to the following description and drawings in which: 
         FIG. 1  is a cross-sectional view of a dental implant system made in accordance with the present invention; 
         FIG. 2  is a cross-sectional view of a fixation screw shown removed from the dental implant system of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of an abutment shown removed from the dental implant system of  FIG. 1 ; 
         FIG. 4  is a cross-sectional view of a dental implant shown removed from the dental implant system of  FIG. 1 ; 
         FIG. 5  is a top plan view of the fixation screw of  FIG. 2 ; 
         FIG. 6  is a top plan view of the fixation screw of  FIG. 2  similar to  FIG. 6  showing an alternative configuration of the wrench engaging surface; and 
         FIG. 7  is a cross-sectional view similar to  FIG. 1  showing the use of an alternate abutment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     With reference to  FIGS. 1-7 , there is shown a dental implant system  10  which includes an abutment  50 , a dental implant  14  and a fastening screw  100  made in accordance with the present invention. 
     The dental implant  14  is an elongated, generally cylindrical member which includes a first end  18 , a second end  20 , a first intermediate portion  22  and a second intermediate portion  26 . The first intermediate portion  22  is slightly convex and is tapered. The first intermediate portion  22  includes a self-tapping thread  24  which is adapted for threading into a patient&#39;s jawbone. The second intermediate portion  26  includes a plurality of relatively fine grooves  28 . The dental implant  14  has a bore  30  which includes a tapered portion  32 , a straight cylindrical portion  34 , and a threaded portion  36 . The second end  20  includes a flat upper surface  40 . 
     As is best shown in  FIG. 3 , the abutment  50  is generally cylindrical and includes a first end  52  and a second end  54 . The outer surface  56  of the abutment  50  includes a first cylindrical portion  58  which leads to a first tapered portion  60  which matches the tapered portion  32  of the dental implant  14  and which leads in turn to a second cylindrical portion  62  and a second tapered portion  64 . The second tapered portion  64  leads in turn to a third cylindrical portion  66 , a curved portion  68  and a third tapered portion  70 . A wrench engaging surface  72  is disposed on the second end  54  of the abutment  50 . The abutment  50  includes a bore  80  which has a first cylindrical portion  82  which leads to a tapered portion  84  which, in turn, leads to a second cylindrical portion  86 . 
     The fastening screw  100  has a threaded portion  102  which engages the internally threaded portion  36  of the dental implant  14 , a cylindrical portion  104  and a head portion  106  which includes a tapered portion  108 . The tapered portion  108  of the head  106  matches the tapered portion  84  in the bore  80  of the abutment  50  as will be presently described. The head portion  106  also includes a wrench engaging surface  110 . 
     The tapered surface  84  on the abutment  50  and the tapered portion  108  on the head portion  106  form a key feature of the present invention  10 . 
     The angle of taper of the tapered portion  108  on the head portion  106  of the fastening screw  100  is slightly greater than the angle of taper of the tapered surface  84  of the abutment  50 . 
     The angle of taper of the tapered surface  108  on the fastening screw  100  and the tapered surface  84  on the abutment  50  is less than 15 degrees and is in the preferred range of 0.5 to 1.5 degrees. This preferred range of the angle of taper of the surfaces  84 ,  108  results in a secure locking relationship between the fastening screw  100  and the abutment  50  and the dental implant  14 . 
     The wrench engaging surface  72  of the abutment  50  may preferably include a plurality of flat surfaces forming a hexagonal surface. 
     The wrench engaging surface may also include a plurality of concave surfaces, a plurality of convex surfaces, and a plurality of flat surfaces. 
     The wrench engaging surface  110  on the fastening screw  100  may include a plurality of flat surfaces  140  forming a hexagonal cavity  142  as is shown in  FIG. 6 . 
     Alternatively, the wrench engaging surface  110  of the fastening screw  100  may include a plurality of curved surfaces  150  which form a multi-lobed cavity  152  as is shown in  FIG. 5 . 
     As is shown in  FIG. 1 , tightening the fastening screw  100  causes the tapered portion  60  of the abutment  50  to bear against the tapered portion  32  of the dental implant  14 . The tapered portion  108  of the head  106  forms a locking relationship with the tapered surface  84  of the abutment  50  resulting in a secure and reliable connection between the fastening screw  100 , the abutment  50  and the dental implant  14 . 
     In an alternative embodiment of the invention  200  which is shown in  FIG. 7  the dental implant  14  and the fastening screw  100  are the same as has been described in connection with  FIG. 1 . The abutment  202  shown in  FIG. 7  is generally cylindrical and includes a first end  204  and a second end  206 . The outer surface  208  of the abutment  202  includes a first cylindrical surface  208 , a second cylindrical surface  210  which is slightly larger in diameter than the surface  208 , and a step surface  212 . The step surface  212  leads to an outwardly tapered surface  214  which leads to a curved surface  216 . The curved surface  216  leads to a tapered surface  218 . The tapered surface  218  leads to a wrench engaging surface  220  which is generally similar to the wrench engaging surface  72  which has been previously described. 
     The abutment  202  has a bore  224  and has a first cylindrical portion  226  which leads to a tapered portion  228  which in turn leads to a second cylindrical portion  230 . 
     The angle of taper of the tapered portion  228  is the same as previously described in connection with the abutment  50 . 
     Tightening the fastening screw  100  causes the step portion  212  of the abutment  202  to bear against the surface  40  of the dental implant  14  with the tapered portion  108  of the head  106  forming a locking relationship with the tapered portion  228 . The dental implant  14 , the fastening screw  100  and the abutment  202  form a secure and reliable connection. 
     The foregoing specific embodiment of the present invention as set forth in the specification herein is for illustrative purposes only. Various deviations and modifications may be made within the spirit and scope of the invention without departing from the main theme thereof.