Fixture

Abstract

The present invention relates to a fixture for insertion into a bore hole arranged in bone tissue, comprising a threaded leading portion and a threaded trailing portion located coronally of the leading portion.

1 . A fixture for insertion into a bore hole arranged in bone tissue, comprising a threaded leading portion and a threaded trailing portion located coronally of the leading portion,
 wherein the threading of the leading portion has at least one first thread spiral,   wherein the threading of the trailing portion has at least one more thread spirals than the threading in the leading portion,   wherein the threading of the trailing portion and the threading of the leading portion have the same or substantially the same lead,   wherein the profile of at least one of the thread spirals in the trailing portion is, at least along a portion of its extension, substantially the same as the profile of the outermost part of said first thread spiral in the leading portion, and   wherein the at least one thread spiral in the trailing portion having substantially the same profile as the outermost part of said first thread spiral in the leading portion is arranged to follow the spiral path of said first thread spiral.   
     
     
         2 . A fixture according to  claim 1 , wherein the thread spiral in the trailing portion that follows the path of said first thread spiral in the leading portion has the same radius of curvature at the top of the peaks as said first thread spiral. 
     
     
         3 . A fixture according to  claim 1 , wherein the thread spiral in the trailing portion that follows the path of said first thread spiral in the leading portion has the same flank angles, respectively, as said first thread spiral. 
     
     
         4 . A fixture according to  claim 1 , wherein all thread spirals in the trailing portion have substantially the same profile as the outermost part of said first thread spiral in the leading portion. 
     
     
         5 . A fixture according to  claim 1 , wherein the profile of one of the thread spirals in the trailing portion, that does not follow the path of said first thread spiral in the leading portion, alters along the thread. 
     
     
         6 . A fixture according to  claim 1 , wherein the smallest spacing between adjacent peaks of the threading in the trailing portion is smaller than the smallest spacing between adjacent peaks of the threading in the leading portion. 
     
     
         7 . A fixture according to  claim 1 , wherein the number of thread spirals in the threaded trailing portion is a multiple integer of the number of thread spirals in the leading portion. 
     
     
         8 . A fixture according to  claim 1 , wherein the threading in the leading portion has at least a first and a second thread spiral, and wherein one of the thread spirals in the trailing portion follows the path of said first thread spiral in the leading portion. 
     
     
         9 . A fixture according to  claim 1 , wherein the fixture is self-tapping. 
     
     
         10 . A fixture according to  claim 1 , wherein the fixture is provided with separate cutting means adapted for cutting a female thread in the bone that corresponds to the profile of at least one of the thread spirals at the trailing portion. 
     
     
         11 . A fixture according to  claim 1 , wherein the depth of the threads in the leading portion is larger than the depth of the threads in the trailing portion. 
     
     
         12 . A fixture according to  claim 1 , wherein the major diameter of the fixture is similar in both the leading portion and the trailing portion. 
     
     
         13 . A fixture according to  claim 1 , wherein the major diameter of the fixture is greater in the trailing portion than in the leading portion. 
     
     
         14 . A fixture according to  claim 1 , wherein the major diameter of the fixture is increasing in the trailing portion, as seen in apical to coronal direction.