Fixture and a fixture set

Abstract

A fixture for insertion into a bore hole arranged in bone tissue is provided. The fixture has a threaded leading portion provided with at least one cutting edge for creating a female thread in the bone tissue, and a threaded trailing portion following the leading portion in the created female thread. Compared to the geometry of a thread peak of said cutting edge of the leading portion, a thread peak of the trailing portion is displaced or overdimensioned in at least one of the coronal and apical directions of the fixture so that a strain is provided to the bone when said displaced or overdimensioned thread peak engages with the created female thread. A fixture set for creating a strain is also provided, the set comprising a fixture and a separate thread maker.

1 . A fixture for insertion into a bore hole arranged in bone tissue, the fixture having a geometrical central axis and comprising
 a leading portion provided with at least one cutting edge for creating a female thread in the bone tissue, and   a trailing portion following the leading portion in the created female thread,   wherein both of said portions comprise a respective outer surface being threaded for engagement with bone tissue, wherein thread tops and thread bottoms are provided alternatingly in the axial direction of the fixture, each thread top forming part of a thread peak arranged between two consecutive thread bottoms,   wherein a largest thread peak of said cutting edge of the leading portion forms part of a thread having a lead, wherein compared with an imaginary continuation into the trailing portion of said largest thread peak following said lead:
 a first area of a thread peak of the trailing portion is axially aligned with said imaginary continuation, and 
 a second area of said thread peak of the trailing portion is axially displaced compared with said imaginary continuation, thereby providing a strain to the bone when said thread peak of the trailing portion engages with the created female thread, the comparison of the thread peaks being made at a same first distance from a respective thread bottom measured perpendicularly to said central axis, and/or at a same second distance from a respective thread top measured perpendicularly to said central axis. 
   
     
     
         2 . The fixture as in  claim 1 , wherein said largest thread peak of said cutting edge of the leading portion forms part of a thread having a lead defining a first helical path in the leading portion, wherein said thread peak of the trailing portion forms part of a thread having a lead defining a second helical path which is partly axially displaced relative to an imaginary extension into the trailing portion of the first helical path. 
     
     
         3 . The fixture as in  claim 1 , wherein, compared to the geometry of the largest thread peak of said cutting edge of the leading portion, a thread peak of the trailing portion is overdimensioned in at least one of the coronal and apical directions of the fixture so that a strain is provided to the bone when said overdimensioned thread peak engages with the created female thread, the comparison being made at a same first distance from a respective thread bottom measured perpendicularly to said central axis, at a same second distance from a respective thread top measured perpendicularly to said central axis, or both. 
     
     
         4 . The fixture as in  claim 1 , wherein
 in the axial direction of the fixture a thread peak of the trailing portion has a longer extension than the largest thread peak of said cutting edge of the leading portion, the comparison being made at a same first distance from a respective thread bottom measured perpendicularly to said central axis,   in the axial direction of the fixture a thread peak of the trailing portion has a longer extension than the largest thread peak of said cutting edge of the leading portion, the comparison being made at a same second distance from a respective thread top measured perpendicularly to said central axis, or both.   
     
     
         5 . The fixture as in  claim 1 , wherein the axial extension of a thread top in the trailing portion is longer than the axial extension of a thread top of said largest thread peak of said cutting edge in the leading portion. 
     
     
         6 . The fixture as in  claim 1 , wherein a top radius of a thread peak in the trailing portion is larger than a top radius of said largest thread peak of said cutting edge in the leading portion. 
     
     
         7 . The fixture as in  claim 1 , wherein the axial extension of a thread bottom between two consecutive thread peaks in the trailing portion is shorter than the axial extension of a thread bottom between two consecutive thread peaks of said cutting edge in the leading portion. 
     
     
         8 . The fixture as in  claim 1 , wherein a bottom radius between two consecutive thread peaks in the trailing portion is smaller than a bottom radius between two consecutive thread peaks of said cutting edge in the leading portion. 
     
     
         9 . The fixture as in  claim 1 , wherein in the trailing portion and the leading portion each thread top interconnects a coronal and an apical flank, wherein at least one of a coronal and an apical flank of a thread peak in the trailing portion is axially displaced relative to a respective mating flank of the female thread cut in the bone tissue by the leading portion, wherein at least one of said coronal and apical flanks of the thread peak in the trailing portion provides a strain to the bone tissue when the fixture is installed in the bone. 
     
     
         10 . The fixture as in  claim 1 , wherein the trailing portion is included in a coronal fixture portion adapted to engage with cortical bone tissue, wherein the displacement of said second area of a thread peak of the trailing portion compared to said imaginary continuation into the trailing portion of said largest thread peak of said cutting edge following said lead, is such that the strain provided to the bone is in the range of 0.01-0.3. 
     
     
         11 . The fixture as in  claim 1 , wherein the trailing portion is included in a coronal fixture portion adapted to engage with cortical bone tissue, wherein the displacement of said second area of a thread peak of the trailing portion compared to said imaginary continuation into the trailing portion of said largest thread peak of said cutting edge following said lead, is such that the strain provided to the bone is in the range of 0.01-0.1. 
     
     
         12 . The fixture as in  claim 1 , wherein the trailing portion is included in a coronal fixture portion adapted to engage with cortical bone tissue, wherein the displacement of said second area of a thread peak of the trailing portion compared to said imaginary continuation into the trailing portion of said largest thread peak of said cutting edge following said lead, is such that the strain provided to the bone is in the range of 0.01-0.03. 
     
     
         13 . The fixture as in  claim 1 , wherein the trailing portion is included in a coronal fixture portion adapted to engage with cortical bone tissue, wherein the displacement of said second area of a thread peak of the trailing portion compared to said imaginary continuation into the trailing portion of said largest thread peak of said cutting edge following said lead, is such that the strain provided to the bone is in the range of 0.01-0.02. 
     
     
         14 . The fixture as in  claim 1 , wherein the trailing portion is included in an intermediate fixture portion adapted to engage with cancellous bone tissue, wherein the displacement of said second area of a thread peak of the trailing portion compared to said imaginary continuation into the trailing portion of said largest thread peak of said cutting edge following said lead, is such that the strain provided to the bone is in the range of 0.01-0.3. 
     
     
         15 . The fixture as in  claim 1 , wherein the trailing portion is included in an intermediate fixture portion adapted to engage with cancellous bone tissue, wherein the displacement of said second area of a thread peak of the trailing portion compared to said imaginary continuation into the trailing portion of said largest thread peak of said cutting edge following said lead, is such that the strain provided to the bone is in the range of 0.06-0.3. 
     
     
         16 . The fixture as in  claim 1 , wherein the trailing portion is included in an intermediate fixture portion adapted to engage with cancellous bone tissue, wherein the displacement of said second area of a thread peak of the trailing portion compared to said imaginary continuation into the trailing portion of said largest thread peak of said cutting edge following said lead, is such that the strain provided to the bone is in the range of 0.06-0.1. 
     
     
         17 . The fixture as in  claim 1 , wherein threads in the trailing portion are microthreads. 
     
     
         18 . The fixture as in  claim 1 , wherein the trailing portion is cylindrical. 
     
     
         19 . The fixture as in  claim 1 , wherein said fixture is a dental fixture for arrangement in a jawbone. 
     
     
         20 . A fixture set, comprising
 a fixture comprising a condensation portion,   a thread maker provided with at least one cutting edge and adapted to be rotated into a bore hole arranged in bone tissue for making a female thread in the bone tissue prior to insertion of said fixture, the thread maker comprising a threaded outer surface, wherein thread tops and thread bottoms are provided alternatingly in the axial direction of the thread maker, each thread top forming part of a thread peak arranged between two consecutive thread bottoms, wherein   said condensation portion of the fixture comprises an outer surface being threaded for engagement with bone tissue, wherein thread tops and thread bottoms are provided alternatingly in the axial direction of the fixture, each thread top forming part of a thread peak arranged between two consecutive thread bottoms, wherein
 compared to the geometry of a thread peak of said cutting edge of the thread maker, a thread peak of said condensation portion of the fixture portion is overdimensioned in at least one of the coronal and apical directions of the fixture so that a strain is provided to the bone when said overdimensioned thread peak engages with the created female thread, 
 the comparison being made at a same first distance from a respective thread bottom measured perpendicularly to a respective central axis of the thread maker and the fixture, 
 the comparison being made at a same second distance from a respective thread top measured perpendicularly to a respective central axis of the thread maker and the fixture, or any combination thereof. 
   
     
     
         21 . A fixture for insertion into a bore hole arranged in bone tissue, the fixture being cylindrical and having a geometrical central axis and comprising
 a leading portion provided with at least one cutting edge for creating a female thread in the bone tissue, and   a trailing portion following the leading portion in the created female thread,   wherein both of said portions comprise a respective outer surface being threaded for engagement with bone tissue, wherein thread tops and thread bottoms are provided alternatingly in the axial direction of the fixture, each thread top forming part of a thread peak arranged between two consecutive thread bottoms, wherein
 compared to the geometry of the female thread created by a thread peak of said cutting edge of the leading portion, a thread peak of the trailing portion is overdimensioned in at least one of the coronal and apical directions of the fixture so that a strain is provided to the bone. 
   
     
     
         22 . A method of inserting a fixture, such as a dental fixture, into a bore hole arranged in bone tissue, comprising the steps of:
 creating a female thread in a surface of the bone tissue defining the bore hole,   inserting a condensation portion of a fixture having a male thread into the bore hole for mating with the female thread, wherein a first area of a thread peak of the male thread is aligned with a thread peak of the mating female thread and a second area of said thread peak of the male thread is axially displaced by comparison with said thread peak of the mating female thread, thereby providing a strain to the bone when said thread peak of the male thread engages with the created female thread, the comparison of the thread peaks being made at a same first distance from a respective thread bottom measured perpendicularly to a central axis of the bore hole, at a same second distance from a respective thread top measured perpendicularly to said central axis, or both.   
     
     
         23 . A fixture set, comprising
 a fixture comprising a leading portion and a trailing condensation portion, wherein both of said portions comprise a respective outer surface being threaded for engagement with bone tissue, wherein thread tops and thread bottoms are provided alternatingly in the axial direction of the fixture, each thread top forming part of a thread peak arranged between two consecutive thread bottoms,   a thread maker provided with at least one cutting edge and adapted to be rotated into a bore hole arranged in bone tissue for making a female thread in the bone tissue prior to insertion of said fixture,   wherein the thread of the leading portion is adapted to mate with the female bone thread and has the same lead as a thread of the thread maker,   wherein the lead of the thread in the leading portion defines a first helical path in the leading portion, wherein a thread peak of the trailing portion forms part of a thread having a lead defining a second helical path which is partly axially displaced relative to an imaginary extension into the trailing portion of the first helical path.