the principles of the present invention are particularly useful when incorporated into an implant , for example , an orthopedic implant , such as a dental implant , of an embodiment of the implant body generally indicated at 10 in fig1 which acts with a spacer generally indicated at 32 in fig2 . the implant body 10 is of a type with external thread ( s ). the implant body 10 , which is closed at its one end or cervical end which is at the bottom of fig1 has towards a coronal end at the top an open blind bore 11 . near the closed end , the blind bore 11 is provided with internal threads 12 with a relatively small diameter in which can be screwed an spacer screw which is not shown in fig1 and which will be discussed hereinafter . the implant body 10 , exhibits an outer substantially cylindrical portion 16 between the coronal front edge 22 and the external thread 18 . to the internal threads 12 of the implant body 10 is connected in the coronal direction a guidance and centering area 20 which is a cylindrical larger diameter portion than the internal threads 12 and has a smooth , hollow cylindrical inner wall 21 . from the guidance and center area 20 to the coronal front edge 22 of the implant body 10 is a positive connection area 24 of the bore 11 in which there are several positive connecting elements in the form of axially extending grooves 26 in an inner wall 27 forming ridges 14 . from the front edge 22 to the positive connecting area 24 of the bore 11 has a bevel or chamfer 28 tapering conically in the direction of the cervical or closed end and extending into the vicinity of the positive connecting grooves 26 . between the guidance and centering area 20 and the positive connecting elements or groove 26 there is an annular undercut 30 of minimal height which facilitates a chip deposition - free production of the positive connecting elements or grooves 26 . the spacer 32 as shown in fig2 serves or is incorporated in a tightly fitting prosthesis and is provided with an all around attachment shoulder 34 for the prosthesis which may be a crown of a tooth . the spacer 32 has an annular shoulder 36 which connects the fastening end to a stub or plug portion which is received in the blind bore 11 of the implant body 10 . the stub or plug portion has immediately adjacent the shoulder 36 a positive connection portion 38 followed by a guidance and centering portion 40 which will be received in the blind bore with the shoulder 36 engaging the front edge 22 . the positive connection area 38 has a plurality of axially directed positive connection noses 46 whose shape and arrangement but not necessarily the number corresponds to the positive connection grooves 26 of the implant body 10 . the positive connection area 38 of the spacer 32 is provided with an annular undercut 48 between the shoulder 36 and the positive connecting noses 46 and this facilitates the chip deposition during manufacture of the positive connecting noses 46 . when inserting the spacer 32 , which is provided with the axial longitudinal bore 33 whose internal diameter corresponds to the external diameter of a not shown spacer screw , is inserted in the implant body 10 , the guidance and centering portion 40 which is formed by a cylindrical guidance and centering collar 44 , will be engaged in the guidance and centering area 20 so that a smooth cylindrical circumferential surface of the guidance and centering portion 40 comes to rest on the inner cylindrical surface 21 of the guidance and centering area 20 of the implant body 10 . at the same time positive connection portion 38 engage in the positive connection grooves 26 while the shoulder 36 comes to rest on the front edge 22 . therefore , the spacer 32 is connected to the implant body 10 in a twist preventing manner . by means of the spacer screw traversing the spacer 32 and being screwed into the internal threads 12 of the implant body 10 , the spacer 32 can be firmly connected to the implant body 10 . as shown in fig3 a , the positive connecting area of the implant body 10 has six equally spaced , axial positive connecting grooves 26 which in the represented embodiment have a cross sectional shape of a rectangle with a substantially tangential directed but also curved longitudinal edges and have an annular spacing of 60 ° between centres of adjacent grooves . in fig3 b , the spacer 32 in the embodiment of fig1 and 2 is provided with six equally spaced , axial positive connecting noses 46 . in the embodiments of fig4 a and 4 b , the implant body 10 ′ in fig4 a has twelve positive connecting grooves 26 ′ with an equal annular spacing of 30 ° and in fig4 b the spacer 32 ′ is only provided with four positive connecting noses 46 ′. the positive connecting grooves 26 ′ and the positive connecting noses 46 ′ have in this case a triangular cross section in a plane perpendicular to the longitudinal axes of the implant body and of the spacer . it is pointed out that the spacer 32 ′ has only four positive connecting noses 46 which have a 90 degree annular spacing therebetween . in the embodiment of fig5 a and 5 b , the implant body 10 ″ of fig5 a has twelve positive connecting grooves 26 ″ with a 30 degree spacing and the grooves 26 ″ have a circular segmental cross section in a plane perpendicular to the longitudinal axis of the implant body 10 ″. according to fig5 b , the spacer 32 ″ is provided with six positive connecting noses 46 ″ each having a corresponding cross section to the cross section of the grooves 26 ″. as a function of the spacing or the spacing ratio of the implant body 10 ′ and 10 ″ relative to the spacers 32 ′ and 32 ″, the spacers 32 ′ and 32 ″ can be inserted in different rotational positions within their respective basic bodies 10 ′ and 10 ″. thus , the treating surgeon has a number of desired positions available to him as far as orienting the spacer such as 32 ′ relative to the implant body 10 . the axial grooves 26 apart from being twisting preventing means for the spacer also arranged to be used as a connection for a tool which is described below . fig6 shows a tool part 49 which can be coupled to an electrically operated or otherwise operated ( pneumatically , hydraulically , etc .) motor ( not shown ) or hand driven handle via its upper part 50 which has an attachment for the drive motor or handle . at its other end , the tool is provided with recesses ( grooves ) 51 for forming wing shaped elements 50 . a cone angle . alpha . is chosen a about 4 - 6 °. fig7 shows the cooperation between the tool 49 and the positive connection area 24 of the implant body . by means of a cone shape on the front part 52 of the tool , a bearing function of the implant body 10 is obtained via axial grooves . the number of recesses and wings in this embodiment is six each but other embodiments can have a number of recesses less than the axial grooves . the wings correspond in terms of shape with grooves 26 in the positive connection area 24 of the implant body . another embodiment is when the inner tool surface 53 has conical shape and the bearing function is conducted though interaction with the most coronal part of the ridges 14 and the inner surface 27 . although modifications and changes may be suggested by those versed in the art , it should be understood that we wish to embody within the scope of the patent granted herein all such modifications that reasonably and properly come within the scope of our contribution to the art . referring to fig8 , the connecting area of the implant body ( 810 ) has six equally spaced , axial positive connecting noses ( 850 ) which in the represented embodiment have a cross sectional shape of a deformable rectangle and an annular spacing of 60 ° between centres of adjacent noses . referring to fig9 , the connecting noses ( 950 ) comprise a flange ( 928 ) on the side of ridges ( 926 ) between each of the grooves ( 927 ). referring to fig1 , a corner ( 1051 ) of the nose ( 1050 ) is deformable from an acute ( internal ) angle .
the present invention is directed to a threaded implant intended to be screwed into bone , preferably into jawbone , and for tightly fitting a prosthesis , including a spacer portion in the screwed - in position . the implant body has an internal connection arrangement for rotationally locking said spacer , said arrangement also cooperating during positioning and insertion of the implant body with a tool and said arrangement having a low vertical height .