Note: Descriptions are shown in the official language in which they were submitted.
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IMPLANT FOR USE IN AESTHETIC REGIONS OF THE MOUTH
SCOPE OF THE INVENTION
The present invention relates to a dental implant to be used in areas in
the mouth where aesthetics are of a high concern, and more preferably an
implant which has a bone engaging coated, textured and/or porous portion
which has a contour selected to approximately mirror a predetermined
surface contour of bone tissues at the site of implant placement.
BACKGROUND OF THE INVENTION
Conventional implant constructions are generally of a two-part design
and include a body portion which is adapted to be recessed into the patient's
jaw, and a prosthesis in the form of a ceramic tooth which is adapted for
coupling to a proximal end of the body. The implantable body which is
made from stainless steel, titanium or other suitable metals or alloys is
configured to be recessed into a suitable bore hole formed in the patient's
jaw bone at the site of a lost tooth. Typically, the body has a threaded
interior or is otherwise configured to mechanically receive thereto an
attachment post which serves as a support for the ceramic tooth.
United States Patent No. 5,344,457 to Pilliar et al., entitled "Porous
Surfaced Implant" , discloses a frustoconical shaped implant which is
characterized by a porous coated bone engaging lower portion and a smooth
non-porous upper bone attachment region or colT~r. The implant is press-
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fitted into a complementary sized bore formed in the patient's jaw bone at
the site of placement and over time, bone tissues grow into and engage the
porous coating on the lower portion of the implant to firmly anchor it in the
place of a natural tooth. The implant which is the subject of United States
Patent No. 5,344,457 has achieved a significant degree of success in the
market place, and is presently sold by Innova Corp. of Toronto, Canada,
under the name Endopore°°. Endopore° dental implants are
used in the
replacement of various teeth including, lost molars and bicuspid teeth in the
anterior and posterior regions of the mouth.
Other conventional implant constructions are characterized by the
implantable body being cylindrical in shape and provided with a roughened
lower exterior surface, texture, external thread configuration and/or coating,
to facilitate the engagement of the implant body with the patient's
surrounding bone tissues and its anchoring in place.
A difficultly exists with conventional implants in that todate, they
have achieved limited success in replacing incisors and teeth in the frontal-
most regions of the mouth where high aesthetic demands exist. The
abutment-implant interface, also termed "microgap", is believed to harbor
bacteria and bacterial products following exposure to the oral environment.
This in turn results in the establishment of a "biological width" around the
implant (i.e. the distance from the peri-implant bone crest to the microgap).
The biological width is relatively constant and seems to be approximately 2
mm, similar to the biological width present around natural teeth. It has
been found that following implantation, crestal bone remodeling occurs,
whereby supporting bone tissues and the overlying bone tissues tend to
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recede to the uppermost peripheral edge of the textured or porous coated
bone engaging portion of the implant body. A further variable that can play
a role in crestal bone remodeling is lack of mechanical coupling around any
smooth upper collar surface. For example, it has been demonstrated that
the crestal bone resorption around Endopore~ implants stops at the junction
of the smooth collar and the porous surface. It has been suggested that the
lack of mechanical coupling around the smooth collar surface results in
"disuse atrophy" of the crestal bone to the level of the junction with the
porous surface. This has been demonstrated also with other textured
implant surfaces.
The receding supporting tissues or crestal bone loss around dental
implants has led to an aesthetic challenge when attempting dental
restorations in that it may result in exposure of the metal implant body,
greatly detracting from the natural appearance of the prosthesis.
Conventional implants suffer the disadvantage in that the alveolar bone
which encases the tooth root tends to gradually disappear along the portion
of the implant where engagement of bone tissue with the implant body does
not occur. This leads to a corresponding recession of the sulcus and
overlying gum tissues which gradually results in the exposure of the
stainless steel body of the implant. In the more aesthetically important
regions of the mouth, the exposure of the stainless steel portion of the
implant body greatly detracts from the natural look of the prosthesis.
This problem is particularly pronounced in the anterior regions of the
mouth and when using two implants positioned adjacent to each other. Loss
of inter-implant bone height (as a result of the normal crestal bone
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remodeling that is associated with each of the implants) results in the
absence of a papilla between the two implants due to lack of bone support.
This creates an aesthetic deformity, often termed "black triangle", between
the two implant crowns. "Black triangles" are particularly visible when
present in the maxillary anterior region and the patient has a high lip line.
The patient's perception of a successful implant-supported prosthesis
depends not only on restoring function, but also on restoring normal
anatomy and aesthetics. The lack of a papilla and the presence of a "black
triangle" can lead to patients' dissatisfaction with the whole implant
treatment, even with patients having a low smile line. Heretofore, the dental
profession has been forced to come up with techniques to deal with "black
triangles" . Most commonly, pink acrylic or porcelain is added to the final
restoration to replace the missing papilla. This solution is far from ideal
since it is impossible to replicate the gingival tissue with acrylic or
porcelain
in terms of texture and colour. Several attempts have also been made in
establishing surgical procedures that will regenerate the missing papilla;
however, these procedures are very unpredictable and seldom result in
100 % regeneration.
Conventional implants are poorly suited to accommodate for the
crestal bone remodeling which occurs with implants. With conventional
implant designs, most often any bone engaging textured, porous or coated
surface extends downwardly from an uppermost radial edge surface which is
located a constant distance from the lower apex of the body. Conventional
implant designs suffer the disadvantage that they fail to account for the fact
that with natural incisor teeth, the surface contour of healthy supporting
bone tissues tends to be higher along the distal and medial surfaces of the
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tooth than along the lingual and buccal regions. Heretofore, the bone
engaging regions for conventional implants have either been limited by the
lowermost extent of expected bone recovery, weakening the integrity of the
dental implant attachment, or suffer the disadvantage that the lingual and
buccal portions of the implantable portion of the implant body may be
visible at the patient's gum line.
SUMMARY OF THE INVENTION
To at least partially overcome the disadvantages of the prior art, the
present invention seeks to provide an implant which includes an implantable
body portion adapted to be at least partially recessed within a patient's
alveolar bone, and which has a peripheral surface portion which is
configured to stimulate and/or facilitate the engagement of bone tissues with
the implant.
In a healthy jaw, the root of the tooth is supported by alveolar bone,
with lamellated bone surrounding the root of the tooth where periodontal
ligament fibres attach. The shape and crestal outline of interdental bone
will to a large extent depend upon the shape and size of the tooth roots, with
the distance from the crest of the alveolar bone to the cementoenamel
junction of the tooth in a healthy periodontium being about 2 mm and a
healthy sulcus extending about .5 mm. The present implant construction
preferably seeks to stimulate osteoblasts, namely the bone forming cells, so
as to promote bone ingrowth into and otherwise engage the implantable
portion of the implant, with the crestal surface of the regrown bone tissues
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substantially mirroring that of a healthy tooth, to firmly anchor the implant
in place.
Another object of the invention is to provide an improved dental
implant body for use in the anterior regions of the mouth, and which
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.
Another object of the invention is to provide an implant body
configuration which is configured to stimulate crestal bone tissue
remodeling to a normal pre-implant height.
Another object of the invention is to provide a dental implant body
which has a bone engaging porous, textured, threaded andlor coated exterior
surface, which is applied to the peripheral surface of the implant body in a
configuration which reflects the actual or a preselected optimum contour of
the crest of the alveolar bone and/or lamellated bone tissues at the site of
implant placement.
The implantable portion of the implant body could for example
include about all or only part of its periphery, a bone engaging surface
which, when the implant body is fully seated within the patient'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 take a number of possible forms including without
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restriction: 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. Suitable chemical
coatings for use with the bone engaging surface would typically 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.
The predetermined crestal outline could by way of non-limiting
example, be selected as a crestal outline of the patient's own alveolar and/or
lamellated bone tissues at the site of implant placement or at the site of one
or more of the patient's own teeth, or the crestal outline of alveolar and/or
lamellated bone tissues of a typical healthy jaw, and more preferably the
crestal outline at the site of or proximate to the intended site of implant
placement.
The bone engaging portion of the implant body could, for example,
consist of a narrow band between the proximal exposed end of the implant
body, and the distalmost end tip of the implant which is recessed into the
patient's jaw. The bone engaging portion may further extend partially or
completely about the circumference of the implant body. More preferably,
however, the bone engaging region extends from approximately adjacent to
the distalmost apex of the implant body to a proximal edge surface which,
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following placement of the implant body, approximately coincides with the
crest of the alveolar bone of either the patient's missing tooth or a healthy
tooth.
In one aspect, the "aesthetic implant" design features of the present
invention are therefore based on the principles governing peri-implant
crestal bone loss, and aim at maintaining the interproximal bone at a level
that is coronal to the buccal and lingual bone levels. In one simplified
construction, the implant is designed to be inserted in a single stage
surgery,
thereby ensuring, adequate biological width between the microgap and the
crest of the bone.
Although not essential, the implant body could be generally
frustoconical in shape and, for example, be provided with a porous coated
and/or textured bone engaging exterior surface which is designed to be
"press-fit" in a specific buccal/lingual and mesial/distal orientation. In
such
an embodiment, the invention is directed to an improved dental implant
which is suitable for use in aesthetic regions of the mouth, including as
replacement for upper incisor teeth, and may be developed as a modification
of the Endopore implant disclosed in United States Patent No. 5,344,457.
The implantable portion of the implant may optionally be provided with a
smooth upper collar portion which, for example, is provided to prevent or
minimize the accumulation of oral bacteria. The smooth collar portion
could, in a first embodiment, be provided as a smooth band which extends
from the proximal edge of the bone engaging surface to a proximal end of
the implant body which is provided with a substantially constant width,
extending from the bone engaging surface to a contoured implant end
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surface which also follows the general contour of the crestal surface of the
alveolar bone. In an alternate embodiment, the smooth collar of the implant
body could extend from the proximal-most edge of the lower bone engaging
portion to a generally flat proximal implant body surface.
In another construction, the present invention seeks to provide an
improved cylindrical implant body which is characterized by a bone
engaging portion which, by way of non-limiting example, could comprised
helical threads, ribs and/or a roughened implant surface formed by grit
blasting and/or acid etching. The bone engaging portion most preferably
extends from a lowermost distal end of the implant to a contoured upper
edge which at least generally follows the contour of the patient's crestal
bone or a pre-selected typical contour of healthy bone tissue at the site
where the implant is to be used.
A further construction of the invention provides an improved implant
coating which is selected to provide enhanced engagement between the bone
tissue and the implant body, and which for example could comprise a
hydroxyapatite or other dentally active coating used to facilitate the
anchoring of the implant ih situ in a patient's jaw. The dentally active
coating is applied about at least part of the circumference of the implant
body, and depending upon the intended site of implant placement, extends
from a distalmost end portion of the implant body to a proximal-most edge.
The coating is applied so as to be elongated along one or more of the
lingual, distal mesial and/or buccal sides of the implant body. More
preferably, the coating is applied such that its proximal edge of the coating
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generally mirrors the typical crestal surface contour of either the patient's
own or healthy bone tissues at the site at which the implant is to be used.
It is envisioned that the dental implant could also be placed in the
patient's alveolar bone in two stages. During the first stage surgery, the
implant body is submerged into a complementary size bone formed in the
bone to the level of a proximal end cap or platform used as a temporary
cover over the proximal end of the implant. Following initial placement, a
period of time is provided to allow bone tissue regrowth so as to grow into
and engage the bone engaging surface and firmly anchor the implant body in
place. As a next stage the proximal end platform is removed, and an
abutment and suitable prosthesis are then coupled to the proximal end of the
implant body in a mechanical and/or chemically bonded fit arrangement.
Accordingly, in one aspect the present invention resides in a dental
implant for use in replacing a missing tooth in a patient's jaw bone
comprising,
an implant body adapted to be at least partially recessed into a portion
of said patient's jaw bone, said implant body extending longitudinally along
an axis from a distalmost apex to a proximal end portion,
a bone engaging surface provided about at least a portion of a
peripheral surface of said implant body, said bone engaging surface selected
to promote bone tissue ingrowth or attachment thereto and extending
longitudinally along said periphery of said implant body to a proximal edge
spaced towards said proximal end portion, wherein at least a portion of said
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proximal edge having a contour selected to generally follow a crestal surface
contour of preselected bone tissues.
In another aspect, the present invention resides in a dental implant for
use in replacing a missing tooth in a patient's jaw bone comprising,
an implant body portion adapted to be recessed into a portion of said
patient's jaw bone, said implant body extending longitudinally along an axis
from a distalmost apex to a proximal end portion,
a bone engaging surface providing a peripheral surface of said
implant body, said bone engaging surface selected to promote bone tissue
ingrowth or attachment thereto and extending longitudinally along said
periphery of said implant body to a proximal edge spaced towards said
proximal end portion, wherein the proximal edge of the bone engaging
surface has a contour selected to generally follow a crestal surface contour
of a pre-selected jaw bone adjacent said missing tooth.
In a further aspect, the present invention resides in a dental implant
for use in replacing a natural tooth in a patient's jaw bone comprising,
an implant body extending longitudinally along an axis from a
lowermost apex to an upper end portion and including,
a bone engaging surface providing a peripheral surface of said
implant body adapted to be recessed into said patient's jaw bone, said
bone engaging surface selected to promote bone tissue ingrowth or
attachment thereto and extending longitudinally along said periphery
of said implant body substantially from said apex to an upper edge
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spaced towards said upper end portion, wherein the upper edge of the
bone engaging surface has a contour selected to generally follow a
crestal surface contour of healthy bone tissues at a site of implant
placement, and
a smooth peripheral portion intermediate said bone engaging
surface and said upper end portion, and
an abutment for supporting a prosthesis thereon.
BRIEF DESCRIPTION OF THE DRAWING
Reference may be now had to the accompanying detailed description,
together with the accompanying drawing pages in which:
Figure 1 illustrates an exploded view of a dental implant construction
in accordance with a first embodiment of the invention;
Figure 2. shows an enlarged schematic side view of the distal surface
of the implant body used in the implant construction of Figure 1;
Figure 3 shows an enlarged plan view of the proximal end of the
implant body shown in Figure 2;
Figure 4 shows a schematic side view of the lingual surface of the
implant body of Figure 2 seated within a patient's jaw bone;
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Figure 5 shows a schematic view of the implant construction shown
in Figure 1 seated in place within a patient's jaw bone;
Figure 6 shows a schematic side view of a distal/mesial side of an
implant body in accordance with a second embodiment of the invention;
Figure 7 illustrates a schematic view of a distal/mesial side of an
implant body in accordance with a third embodiment of the invention; and
Figure 8 illustrates a schematic view of a distal/mesial side of an
implant body construction in accordance with a fourth embodiment of the
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Figure 1 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'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's jaw 24 (Figure 4) in the place of the lost natural
tooth.
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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 Figure 1
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 Figure 1, 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'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.
Figure 2 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
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example is shown in Figure 1. 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'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 Figures 2 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-A1 (Figure 2) of the implant body. As seen best in
Figure 3, 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 (Figure 1) which is formed in the bottom of
the abutment assembly. Figure 2 further shows best the proximal end
surface 38 as comprising a substantially flat surface extending radially
generally normal to the axis A-Al.
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
Figure 4, orients in a downwardmost position in a complementary bore 48
formed in the patient'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
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and 20 degrees, preferably 2 and 10 degrees, and still more preferably at
approximately 3 to 5 degrees.
Figure 2 shows the distal side face 50 of the implant oriented in a
forwardmost direction, with the mesial side face 51 (Figure 3) 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 Figure 2, 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'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
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 Figures 2 and 4, the porous coated surface 40 is
characterized by two axially elongated and proximally extending regions
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60a,60b which extend on each of the opposing distal and mesial sides 50,51
of the implant body 12. In each of the regions 60a,60b, 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 60a,60b 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 Figure
2, 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 (Figure 4) at the optimum
spacing from the cementoenamel junction of the tooth, eliminating "black
triangles" between implants 10 and adjacent natural teeth. In addition, the
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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's jaw 24.
In installation of the implant 10, a frustoconical shaped bore 48 is
formed in the patient's jaw 24 at the site of intended tooth replacement, as
for example is shown in Figure 5. 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'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
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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 60a,60b 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's
haw.
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 Figures 1 to 4 illustrates the implant body 12 as having a
bone engaging porous coated surface 40 which includes elongated regions
60a,60b 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
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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 Figures 1 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 Figure 6 which shows an alternate implant body
construction in which like reference numerals are used to identify like
components. In Figure 6, 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 60a,60b of the porous surface
40.
Although Figures 1 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
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combination of parallel sided and tapered portions, without departing from
the spirit and scope of the present invention.
Reference is made to Figure 7 which illustrates a further embodiment
of the invention wherein like reference numerals are used to identify like
components. In Figure 7, 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 Figure 1, the helical
threads 80 of the implant body 12 of Figure 5 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 60a,60b, the elongated threaded region 60a shown in Figure 5
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 Figure 7, 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'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
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threaded regions 60 are in alignment with the mesial and distal surfaces of
the patient's immediately adjacent teeth.
Figure 8 illustrates a further embodiment of the invention in which
like reference numerals are used to identify like components. In Figure 8,
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 160a,160b. 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 Figure 1. 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 Figures I to 5, the proximal-most edge
I62 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's own jaw bone,
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While it may be preferred that the implant body 12 include two
opposed elongated coated regions 160a,160b 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
160a 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 160a,160b could be provided for specific
orientation, where the loss of supporting bone height may otherwise occur.
Although Figures 1 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 Figure 1 illustrates the abutment assembly 14 as
comprising a single piece, the invention is not so limited. It is to be
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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'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.
