[ 0046 ] fig1 illustrates an exploded implant construction 10 used in the replacement of a lost anterior or maxillary tooth , in accordance with a first preferred embodiment of the invention . the implant construction 10 consists of an implantable titanium or stainless steel body 12 , a stainless steel abutment assembly 14 , a stainless steel retaining screw 16 , and a ceramic tooth prosthesis 18 which has a profile and size selected to mimic the patient &# 39 ; s natural tooth which is to be replaced . as will be described , the implant construction 10 is adapted to be recessed at the site of a missing anterior or maxillary tooth within the lamellated and alveolar bone tissues 20 , 22 of the patient &# 39 ; s jaw 24 ( fig4 ) in the place of the lost natural tooth . the abutment assembly 14 serves as the base support for the prosthesis 18 and has an exterior shape selected for fitted engagement within a complementary sized recess 30 formed in the bottom of the prosthesis 18 . a central bore 32 is formed through the center of the abutment 14 which is sized to receive therein the screw 16 while preventing the screw head 34 from moving therethrough . it is to be appreciated that although fig1 illustrates a one - part abutment assembly 14 , its individual abutment components and configuration may vary having regard to the configuration of the prosthesis 18 . in the final assembly of the implant construction 10 , the prosthesis 18 is secured in place over the abutment assembly 14 by a suitable dental cement . as shown best in fig1 the implantable body 12 is formed with an internally threaded axial bore 36 which extends downwardly from a proximal surface 38 of the implant body to which the abutment assembly 14 is mounted approximately three - quarters along its longitudinal length . the internal threads of the bore 36 are selected for threaded engagement with the retaining screw 16 , to enable the mechanical coupling of the assembly 14 to the implant body by means of the retaining screw 16 . as will be described , following the positioning of the body 12 in a complementary sized bore formed in the patient &# 39 ; s jaw 24 , the abutment assembly 14 is coupled to the implant body 12 by inserting the screw through the bore 32 and into threaded engagement with the internal treads of the bore 36 . [ 0049 ] fig2 shows best the implant body 12 construction in accordance with the first embodiment of the invention where the implant body 12 is configured for use with a conventional abutment 14 and prosthesis 18 , as for example is shown in fig1 . although not essential , the implant body 12 most preferably has a tapered frustoconical shape . the body 12 has two principle portions or surfaces , namely a distalmost porous coated surface 40 for primary fixation of the implant ( i . e . bone - engagement ) with the patient &# 39 ; s bone tissues , as well as a non - porous smooth upper or coronal surface 42 . the coronal surface 42 is provided to prompt the maintenance of bone surrounding the surface of the implant 10 . as shown best in fig2 and 3 , a hexagonal mount 44 projects upwardly from the proximal end surface 38 of the implant body 12 . the hexagonal mount 44 is centered on the elongated central axis a - a 1 ( fig2 ) of the implant body . as seen best in fig3 the central bore 36 extends downwardly through the center of the hexagonal mount 44 in the axial direction . the hexagonal mount 44 more preferably has a size and shape selected for fitted placement within a complementary sized recess 46 ( fig1 ) which is formed in the bottom of the abutment assembly . fig2 further shows best the proximal end surface 38 as comprising a substantially flat surface extending radially generally normal to the axis a - a 1 . the implant body 12 is shown as frustoconically shaped along its entire length , however , the invention is not so limited and other implant configurations which taper only partially along their axial length are also possible . preferably , the implant body 12 tapers inwardly from the proximal end surface 38 to a distalmost apex 46 , which , as seen best in fig4 orients in a downwardmost position in a complementary bore 48 formed in the patient &# 39 ; s jaw 24 at the site of implant placement . the implant body 12 tapers toward the distalmost apex 46 at an angle of between about 1 and 20 degrees , preferably 2 and 10 degrees , and still more preferably at approximately 3 to 5 degrees . [ 0051 ] fig2 shows the distal side face 50 of the implant oriented in a forwardmost direction , with the mesial side face 51 ( fig3 ) having substantially the mirror construction , and the lingual and buccal implant side faces identified by reference numerals 52 and 54 , respectively . as seen best in fig2 the non - porous coronal surface 42 of the implant body 12 adjacent to the end surface 38 is provided with a smooth polished texture which minimizes the possibility that bacteria could be trapped thereabouts . preferably , the smooth coronal surface 42 extends in the axial direction a distance of approximately 2 to 4 mm . the distalmost three - quarters of the implant body 12 which functions as a bone engaging surface is provided with the porous coated surface 40 formed by spray coating the implant with titanium beads . the porous surface 40 of the bone - engaging region of the implant body 12 may be in the form of a coating comprised of discrete titanium beads or particles adhered to a remainder of the implant body 12 into which the patient &# 39 ; s bone tissues 20 and / or 22 may grow . other porous coatings and / or constructs may also be used including porous coatings formed by mechanical abrasion , or a roughened portion of the implant . preferably , the porous surface 40 is formed having a porosity of from about 10 to 800 microns , with the porous coated surface having a porosity similar to that of the endopore implants . differing porosities are , however , also possible . as shown best in fig2 and 4 , the porous coated surface 40 is characterized by two axially elongated and proximally extending regions 60 a , 60 b which extend on each of the opposing distal and mesial sides 50 , 51 of the implant body 12 . in each of the regions 60 a , 60 b , the porous coated surface 40 extends an increased distance from the distal apex 46 of the implant body 12 towards its proximal end surface 38 relative to the portions of the porous coated surface 40 along the lingual and buccal implant sides 52 , 54 . more preferably , the regions 60 a , 60 b extend approximately 2 to 4 mm closer to the end surface 38 of the implant body 12 than the coated surface 40 at the buccal and lingual surfaces 52 , 54 . as seen best in fig2 in this manner the upper edge 62 of the porous coated surface 40 which is spaced closest to the implant body end 38 rides upwardly into the collar 42 along both the distal and mesial sides 50 , 51 of the implant 10 . most preferably , the proximal - most edge 62 of the porous surface 40 is formed so as to follow a predetermined profile , as for example the profile of the crestal ridge of typical healthy bone tissue 20 and / or alveolar tissues 22 at the site of intended implant use . it is to be appreciated that providing the proximal edge 62 of the porous coated portion 40 of the implant body 12 with a profile which generally follows the profile of healthy bone tissue advantageously stimulates bone tissues to engage the dental implant body 12 in the identical manner that occurs with natural teeth . as such , sites of higher bone tissue 20 , 22 engagement occur along the mesial and distal side portions 51 , 50 of the implant body 12 . it is to be appreciated that the sites of higher bone tissue 20 , 22 engagement in turn maintain the shape and crestal outline of interdental bone and overlying gum tissues 66 ( fig4 ) at the optimum spacing from the cementoenamel junction of the tooth , eliminating “ black triangles ” between implants 10 and adjacent natural teeth . in addition , the higher sites of bone tissue 20 , 22 attachment reduce the likelihood of alveolar bone tissue 22 loss which may otherwise result in the exposure of the collar 42 of the implant body 12 . to ensure proper orientation of the implant body 12 seated within the bore 48 , the proximal surface 38 of the body 12 may further include visual indicia 68 ( see stamped letters d and m ) or other striations , grooves , guides or posts used to assist in orienting the implant body 12 following its placement in the patient &# 39 ; s jaw 24 . in installation of the implant 10 , a frustoconical shaped bore 48 is formed in the patient &# 39 ; s jaw 24 at the site of intended tooth replacement , as for example is shown in fig5 . the bore 48 is formed to a depth selected so that the cementoenamel junction of the prosthesis 18 and collar 42 locates at a position corresponding to that of a natural healthy tooth . the implant body 12 is then inserted in the bore 48 in a press fit arrangement and the indicia 68 is used to facilitate in orienting the implant body 12 so that the distal and mesial sides 50 , 51 assume the desired orientation in the patient &# 39 ; s jaw bone . following placement of the implant , a temporary cap ( not shown ) is secured over the hexagonal mount 44 and proximal end 38 and the implant body 12 is sutured over and allowed to heal for several weeks . after a passage of time which is selected to permit the bone tissue 20 , 22 ingrowth into the bone engaging porous coated surface 40 , so as to sufficiently anchor the implant body , the temporary cap is removed . the abutment assembly 14 is then secured to the implant body 12 by means of the threaded engagement of the screw 16 within the bore 36 . the prosthesis 18 is thereafter positioned over and affixed over the abutment 14 by a suitable dental cement . the implant body 12 is constructed such that it may be placed in a press - fit manner with the raised regions 60 a , 60 b of the porous portions 40 oriented in a distal / mesial alignment , and the buccal and lingual sides 54 , 52 of the positioned implant body 10 characterized by the porous coated regions of a comparably shorter length . in an optimum construction , the implant body 12 is constructed such that : the proximal edge 62 of the porous coating 40 is curved or follows a contour whereby the buccal / lingual side portions 54 , 52 are more apical relative to the mesial / distal side portions 50 , 51 by 2 to 4 mm . the implant body 12 is adapted to be “ press fitted ” in the patient &# 39 ; s jaw . the smooth collar 42 of the body 12 is at least 1 . 5 - 2 mm wide . the implant can be offered in the same diameters and lengths as the endopore ® implants . although fig1 to 4 illustrates the implant body 12 as having a bone engaging porous coated surface 40 which includes elongated regions 60 a , 60 b extending towards the proximal end surface 38 and into the collar 42 along the distal and mesial sides 50 , 51 of the positioned implant 10 , the invention is not so limited . it is to be appreciated that in an alternate configuration , the proximal edge 62 of bone engaging porous surface 40 of the implant body 12 could include only one elongated porous coated region extending into the collar 42 along only one of the distal side 50 or mesial side 52 of the implant . in an alternate construction , the porous surface 40 could have elongated regions extending proximally along the lingual and / or buccal sides 52 , 54 of the implant body 12 . although fig1 to 4 illustrate the implant body 12 as having a generally flat proximal end surface 38 , the invention is not so limited . reference may be had to fig6 which shows an alternate implant body construction in which like reference numerals are used to identify like components . in fig6 the proximal end 38 of the implant body 12 is contoured so as to generally follow the same contour as the proximal edge 62 of the bone engaging porous surface 40 . it is to be appreciated that with the contoured proximal end surface 38 , a modified abutment assembly is provided which is adapted to substantially mate with the contoured end 38 in assembly of the implant 10 . in the construction shown , the non - porous coronal surface 42 follows the uppermost edge 62 of the porous coated surface 40 as a smooth band having a substantially constant width , which most preferably is selected at about 1 . 5 to 2 . 5 mm in width . it is to be appreciated , however , that a coronal surface 42 could also be provided which narrows in width at each raised region 60 a , 60 b of the porous surface 40 . although fig1 to 5 illustrate the implant 10 as having a tapered implant body 12 , the invention is not so limited . it is to be appreciated that the present invention is also operable with an implant body 12 which , for example , could be parallel sided or for that matter which could include a combination of parallel sided and tapered portions , without departing from the spirit and scope of the present invention . reference is made to fig7 which illustrates a further embodiment of the invention wherein like reference numerals are used to identify like components . in fig7 the dental implant body 12 is cylindrical in shape . the body 12 includes a distalmost bone engaging portion 140 which is provided with external helical threads 80 as the means by which bone engagement and anchorage of the implant body 12 is achieved . as with the porous coating 40 of the implant body 12 shown in fig1 the helical threads 80 of the implant body 12 of fig5 extend from a distalmost apex 40 upwardly to a proximal - most edge 62 . the external threads 80 extend axially in the proximal direction further along the distal side ( 50 ) and mesial side ( not shown ) of the implant body 12 than the regions of the external threads in the lingual and buccal 52 , 54 side portions . as with the raised porous region 60 a , 60 b , the elongated threaded region 60 a shown in fig5 thus extends closer to the proximal end surface 38 of the implant body and further proximally into the smooth collar 42 than the threads 80 of the implant body 12 along its lingual and buccal sides 52 , 54 . in fig7 the implant body 12 is similarly provided with a hexagonal or other polygonally shaped mount 44 . in addition to serving as a mount for the abutment assembly 14 , the mount 44 advantageously may be used to assist in theadedly inserting the implant body 12 into the patient &# 39 ; s jaw bone . if desired , the external hexagonal mount 50 on the implant body 12 could be provided with grooves , slots or other visual indicia which facilitate the positioning of the implant body 12 so that the elongated threaded regions 60 are in alignment with the mesial and distal surfaces of the patient &# 39 ; s immediately adjacent teeth . [ 0067 ] fig8 illustrates a further embodiment of the invention in which like reference numerals are used to identify like components . in fig8 the implant body 12 includes a conventional externally threaded bone engaging portion 140 . in the embodiment as shown , the implant body 12 further includes an enlarged flared non - porous upper portion 142 . a threaded bore ( not shown ) is formed in the proximal end surface 38 of the implant body 12 and is adapted for the mechanical coupling of an abutment assembly and prosthesis ( not shown ) thereto in a conventional manner . to provide an enhanced bone engaging surface , a bioreactive coating 144 is provided over the externally threaded portion 140 and part of upper portion 142 of the implant body 12 . the coating 144 extends further towards the proximal surface 38 along the lingual side 52 and buccal side 54 of the implant body as regions 160 a , 160 b . it is to be appreciated , however , that the coating 144 could equally extend further along the mesial and / or distal sides of the implant in the similar manner as the porous coated surface 40 shown in fig1 . the bioreactive coating 144 which is selected to facilitate the engagement of bone tissues with the implant and suitable coatings include without restriction , hydroxyapatite coatings and the like . as with the embodiments shown in fig1 to 5 , the proximal - most edge 162 of the bioreactive coating 144 has a contour which is selected to follow a predetermined contour , as for example , which follows the profile of the crestal surface of either a healthy jaw bone or the patient &# 39 ; s own jaw bone . [ 0068 ] fig9 illustrates another embodiment of the invention in which like reference numerals are used to identify like components . in fig9 the implant body 12 tapers from the distal apex end 46 of the implant body to the proximal end 38 . as with the implant construction shown in fig6 the proximal end 38 is provided with a contoured profile , which generally follows the same contour as the proximal edge 62 of the bone engaging porous coated surface 40 , and the crestal surface contour . as with the implant shown in fig1 to 4 , the porous surface 40 most preferably is formed by a coating of discreet titanium of ceramic beads or particles which are adhered to the remainder of the implant body . the porous coating is selected to form a porosity of from between about 10 to 800 microns . other manner of forming the porous coating including mechanical abrasion and / or roughening are however also envisioned as possible . the implant body 12 of fig9 includes a textured transition zone 104 which is provided between the porous coated portion 40 of the implant body 12 , and the smooth coronal surface 42 . the transition zone 102 is characterized by a roughened textured surface which , for example , is preferably formed by laser abradement , acid etching and / or other mechanical abradement . the transitional band 102 is provided as a contoured band extending in the direction of axis a - a 1 between about 0 . 25 to 3 mm , preferably between about 0 . 5 and 2 . 5 mm , and more preferably from about 0 . 75 to about 1 . 5 mm . in a simplified construction , the transitional band 102 has a substantially constant width and mimics the path of the crestal surface contour . it is to be appreciated , however , that the band 102 could be provided so as to narrow or increase in width at each of the raised and / or lower regions on the porous surface 40 without departing in scope from the present invention . the coronal surface 42 is formed as non - porous coloured substantially smooth coated or plated band 104 . the coloured coronal band 104 preferably extends from the proximal end 38 of the implant body 12 to a lower edge 108 spaced distally towards the apex end 46 . the coloured coronal band 104 has a width in the direction of axis a - a 1 of between about 0 . 5 and 2 . 5 mm , and more preferably about 0 . 75 to 1 . 25 mm . although not essential , the lower edge 108 of the band 104 preferably generally follows the contour of the proximal edge 62 surface of the porous surface 40 . it has been found that with conventional silver stainless steel and titanium implants , when a patient experiences partial recession of supporting gum tissue , the silver / grey colour of conventional titanium or stainless steel implants shows through the translucent gum tissues , tinting the gum tissues a grayish colour . the silver / grey colouring presents an unnatural and aesthetically displeasing appearance to the patient . to overcome these disadvantages , the coloured band 104 is provided with colour which is more complementary to the patient &# 39 ; s gum tissue colour , and which is selected so that when shown through translucent gum tissue , the band colour does not significantly tint the gum tissue from its natural colour . more preferably , the coloured band 104 is provided with a yellow gold or pink gold colouring . in such a construction , the coloured coronal band portion is formed by applying a gold coloured titanium nitride plating or coating , a , yellow gold or gold alloy coating or plating , or a pink gold or gold alloy plating or coating to the implant body 12 to form the smooth band 104 . other alloys used to create suitable coloured platings and coatings will also now become apparent . although fig9 illustrates the coloured coronal band of the implant body 12 as extending to a contoured lower edge 108 , the invention is not so limited . it is to be appreciated that the coloured band could be provided along the non - contoured proximal edge 38 of each of the implant bodies shown in fig1 , 7 or 8 and which extends the lower edge which is either parallel to the contoured edge 38 or the proximal edge 62 of the bone engaging portion . while it may be preferred that the implant body 12 include two opposed elongated coated regions 160 a , 160 b on both the distal / mesial sides 50 , 51 of the implant body 12 , the invention is not so limited . if desired , the body 12 could be modified to include only a single elongated coated region 160 a where for example , the implant 10 is to be placed in a position interposed between a natural tooth and a second implant . in this construction , any proximally extending or elongated portion of the coating 144 would be located adjacent to the second implant alone . alternately , it is envisioned that the implant having two or more non - opposed discrete elongated coated regions 160 a , 160 b could be provided for specific orientation , where the loss of supporting bone height may otherwise occur . although fig1 to 4 illustrate the implant body 12 as including a hexagonal mount or projection 44 sized for complementary insertion within the bore 46 of the abutment assembly 14 , the invention is not so limited . other forms and configurations of mounts may also be used and will now become apparent . in a less preferred embodiment , the mount may be omitted in its entirety or alternately , a complementary form recess could be provided within the implant body 12 . the hexagonal projection 44 , however , is believed to represent a preferred construction in that it acts to correctly seat the abutment 14 , preventing any rotational movement thereof once secured against the implant body surface 38 . the hexagonal projection 44 most preferably is of a standard size so as to provide compatibility with a variety of prosthetic systems from a variety of different manufacturers . although fig1 illustrates the abutment assembly 14 as comprising a single piece , the invention is not so limited . it is to be appreciated that the present invention is suitable for use with a variety of abutment configurations including , without restriction , other single , two - piece and multiple - piece abutments . although the preferred embodiments of the invention disclose and describe the bone engaging regions of the implant body 12 as comprising a porous coated surface , an externally threaded surface or a biochemically coated surface , the invention is not so limited . it is to be appreciated that other bone engaging surfaces could also be used with the present invention , including , without restriction , the use of other textured or roughened surfaces which are provided with a contoured profile selected to follow the crestal surface of a patient &# 39 ; s or other preselected jaw bone tissues . although the preferred embodiment of the invention describes and illustrates various preferred aspects of the invention , the invention is not so limited . many modifications and variations will now occur to persons skilled in the art . for a definition of the invention , reference may be had to the appended claims .
an implant includes an implantable body portion adapted to be at least partially recessed within a patient &# 39 ; s alveolar bone , and which has a peripheral surface portion which is configured to stimulate and / or facilitate the engagement of osteoblasts and other bone tissues with the implant . the implant body provides bone engaging regions along one or more of the distal and / or mesial implant surfaces which are elongated relative to bone engaging regions on the lingual and / or buccal surfaces of the implant body . in particular , the implantable portion of the implant body includes a bone engaging surface which , when the implant body is fully seated within the patient &# 39 ; s jaw bone , extends from a distal portion of the implant body to a remote proximal - most edge . the proximal - most edge has a contour selected to generally follow a predetermined crestal outline of the supporting bone tissue . the bone engaging surface could include an externally threaded portion in which the proximal - most thread patterns are configured to generally follow the surface contour of alveolar and / or lamellated bone , an acid etched , physically abraded or other roughened or textured peripheral surface of the implant body , a porous coated surface which , for example , could consist of titanium , metal or ceramic beads and / or a chemically coated portion . chemical coatings for use with the bone engaging surface could comprise bioreactive coatings , including coatings formed from hydroxyapatite and other compounds suitable for stimulating bone tissue growth , and which facilitate the anchoring of the implant body by bone tissues following its placement .