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BACKGROUND OF THE INVENTION
The present invention relates generally to dental implants and to the
replacement of removed or broken teeth with artificial dental prostheses,
and more particularly to the interconnection and adjustable alignment
between the artificial dental implant and a dental prosthesis.
Whenever a natural tooth is lost, it is often possible to surgically
implant an artificial replacement for the root of the lost tooth into the
jawbone. These devices are commonly called dental implants. The function
of these dental implants is to provide support for an artificial tooth or
dental prosthesis, the implant thus functioning as an artificial root.
Various devices are available to interconnect such implants with a dental
prosthesis or an artificial tooth. Such interconnecting devices are
commonly called dental implant inserts. These implant inserts are affixed
into and extend upwardly from the dental implant that would normally
protrude above the gum tissue into the oral cavity. Most modern dental
implants are first surgically placed into the jawbone and, after a period
of four to six months for healing, the implant insert is affixed to the
dental implant. This allows the dental practitioner to be confident that
the bony tissues have "osseointegrated" to the implant which is necessary
for the biological success of the implant. At this time, an implant insert
is attached to the dental implant by either threading engagement or
cementation.
However, where a portion of the tooth remains within the jawbone, a cavity
is prepared in the remaining tooth into which a suitable dental implant is
embedded and secured.
A number of such dental implants are known to applicant as follows:
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#4,252,525 Child
#4,671,768 Ton
#4,270,905 Mohammed
#4,195,409 Child
#3,797,113 Brainin
#3,717,932 Brainin
#3,629,943 Gindea
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Two additional unpatented dental implants, typically, are known to
applicant and distributed by Whaledent, International under their
trademarks TRIAX and PARA POST PLUS.
Additionally, artificial dentures or prostheses have been patented as
disclosed in U.S. Pat. No. 3,343,262 to Burg and in U.S. Pat. No.
4,318,696 to Casama.
Implant inserts presently available, however, do not adequately address
certain problems associated with fabrication of artificial teeth and/or a
dental prosthesis associated with dental implants. With regard to dental
prostheses, ideally, dental implants and their associated implants insert
should be positioned parallel with adjacent natural teeth and also
positioned parallel with other implants that may be required.
Unfortunately, such needed parallelism is often difficult to attain
because of anatomical considerations within the jawbone, loss of excess
bone, and a common presence of misaligned natural teeth. As a result of
these conditions, it is often desirable for the dental practitioner to be
able to vary the angle between the implant axis of the dental insert and
that of the dental insert, thus achieving needed parallelism. It is
therefore extremely useful that the dental practitioner have the ability
to easily vary this angular relationship between the implant and the
implant insert at the time that the implant insert is attached to the
previously permanently secured and positioned dental implant.
Two methods of attaching an implant insert to a permanently secured dental
implant are presently available. The first is by cementation of the
implant insert into the implant while the second method is by threadable
engagement of the implant insert within the implant. The only method known
to applicant, a practicing dentist (D.D.S.), for accommodating misaligned
installation of the implant insert dental prostheses is to individually
fabricate the interconnecting structure between dental implant and dental
prosthesis or to substantially deform presently available means for
interconnecting these two components prior to, or after, installation into
the dental implant.
A further difficulty with regard to threaded implant inserts is that, if
the dental practitioner must manually modify it to accommodate angular
misalignment, it is extremely difficult to determine the exact rotational
relationship between the implant and the implant insert when they are
secured tightly together unless the final rotational relationship is
established prior to deforming the implant insert or fabricating a custom
implant insert.
It is here emphasized that, throughout this disclosure, the term "dental
implant" or "implant" includes those devices which are securable within
the remaining root portion of a tooth, as well as those devices which are
intended to fully replace all tooth root material and to be
"osseointegranted" into the jawbone. Therefore, my invention is equally
applicable to both types of implants.
The present invention provides a universal dental prosthesis retention
system which conveniently allows the dental practitioner to universally
adjust the angular misalignment between the longitudinal axes of the
dental implant and the implant insert and, thereafter, to securely lock
this nonaligned arrangement for receipt of the dental prosthesis atop the
prosthesis insert portion of the invention.
BRIEF SUMMARY OF THE INVENTION
This invention is directed to a universal dental prosthesis retention
system adapted to interconnect a dental implant secured in a patient's jaw
bone to an artificial dental prosthesis. The retention system includes an
implant insert having a first longitudinal axis and securable into the
dental implant, a prosthesis insert having a second longitudinal axis and
securable within the dental prosthesis, and a universal connector adapted
to interconnect the implant insert and prosthesis insert. The universal
connector is also adapted to facilitate preselected or adjustable
universal angular alignment between the first and second axes, that
angular relationship then securably lockable to enable the dental
prosthesis to be thereafter securely mounted over the prosthesis insert.
Various locking means and universal connector means are provided.
It is therefore an object of this invention to provide a universal dental
prosthesis retention system for the interconnection of a dental implant
with a nonaligned dental prosthesis.
It is another object of this invention to provide a universally adjustable
dental prosthesis retention system for the adjustable axial alignment and
the secure connection of a dental prosthesis to a dental implant.
It is yet another object of the present invention to provide an
incrementally adjustable dental prosthesis retention system for the
adjustable axial alignment and the secure connection of a dental
prosthesis to a dental implant.
It is yet another object of the above invention to be adaptable to existing
dental implants and dental prostheses.
In accordance with these and other objects which will become apparent
hereinafter, the instant invention will now be described with reference to
the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation section view of one embodiment of the invention
in place between a dental implant in the tooth root and a dental
prosthesis.
FIG. 2 is an enlarged broken section view of the invention shown in FIG. 1.
FIG. 3 is a side elevation section view of another embodiment of the
invention.
FIG. 4 is a side elevation section view of yet another embodiment of the
invention.
FIG. 5 is an exploded partial section view of yet another embodiment of the
invention.
FIG. 6 is a partial broken section view depicting the boring of a cavity
into the ball of the embodiment shown in FIG. 5.
FIG. 7 is a side elevation section view of the embodiment of the invention
shown in FIG. 5 installed.
FIG. 8 is a side elevation section view of yet another embodiment of the
invention showing the jawbone, tooth root, and dental prosthesis in
phantom.
FIG. 9 is a perspective view of the array of angular spacers utilized in
the embodiment shown in FIG. 8.
FIG. 10 is a section view in the direction of arrows 10--10 in FIG. 3.
FIG. 11 is a side elevation section view of yet another embodiment of the
invention.
FIG. 12 is a view in the direction of arrows 12--12 in FIG. 11.
FIG. 13 is a view in the direction of arrows 13--13 in FIG. 12.
FIG. 14 is a side elevation section view of yet another embodiment of the
invention.
FIG. 15 is a side elevation section view of yet another embodiment of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings, and particularly to FIGS. 1 and 2, one
embodiment of the invention is shown generally at 10 and includes a
prosthesis insert 12, which is securely engageable within a dental
prosthesis DP, and an implant insert 16 which is rigidly securable within
a dental implant DI1. Interconnection of the prosthesis insert 12 within
the dental prosthesis DP may be by permanent cementation or threadable
engagement to facilitate later removal while the interconnection of the
implant insert 16 within the dental implant DI1 may be by bonding or by
mating threadable engagement.
The implant insert 16 includes an enlarged spherically shaped ball 18
disposed at its upper end which mateably and lockably engages into socket
14 disposed at the lower end of the prosthesis insert 12. Thus, prior to
locking, the longitudinal axis 22 of the prosthesis insert 12 may be
universally articulated about an imaginary point of articulation 20 formed
at the intersection with longitudinal axis 24 of implant insert 16.
In use, once the dental practitioner has determined the appropriate angular
orientation of longitudinal axis 22 such that prosthesis insert 12 is
generally centered within the mid-portion of dental prosthesis DP without
impinging too closely to one of the surfaces of dental prosthesis DP, set
screw 26 is provided when tightening to inhibit further movement between
socket 14 and ball 18. Virtually complete rigidity between the prosthesis
insert 12 and the implant insert 16 may be then established by use of a
drill bit D used to drill cavity 30 in alignment and registry with
aperture 28 previously formed in socket 14. Thereafter, locking pin 32 is
securely fixed by cementation, threadable engagement or interference fit
within aperture 28 and cavity 30, being additionally held in that position
by the dental prosthesis DP which is to be installed around and
encapsulating the prosthesis insert 12.
In this embodiment 10 as depicted in FIG. 1, the dental implant DI1 is
shown secured within the root R of the lower part of the patient's tooth
which remains normally embedded within the alveolar bone B and gingiva G.
However, other embodiments of the invention, including that depicted in
FIGS. 1 and 2, are equally well adapted to be interconnected within dental
implants which completely replace the root R of the tooth and have been
securely engaged by various methods within the alveolar bone B itself.
Referring now to FIGS. 3 and 10, another embodiment of the invention is
shown generally at 40 and comprises prosthesis insert 42 and implant
insert 50. In this embodiment, the implant insert 50 is threadably engaged
by its lower threaded portion into mateing female threads within dental
implant DI2 secured within the alveolar bone B. The outer surface 62 of
support 52 may include hexagonal flats to facilitate the secure tightening
of implant insert 50 within the mating threads of dental insert DI2.
The prosthesis insert 42 is comprised of mating inner and outer threaded
coaxial stems 46 and 66, respectively. Inner stem 46 includes spherically
shaped clamping shell 48 disposed at its lower end, while outer stem 66
includes spherically shaped clamping shell 44 disposed at its lower end.
Disposed at the upper end of implant insert 50 is an integral spherically
shaped generally hollow support 52 having an inner and an outer surface.
The inner surface of support 52 is adapted to mate against the outer
surface of clamping shell 48, while the outer surface of support 52 is
adapted to mate against the inner surface of clamping shell 44. By this
arrangement, then, the prosthesis insert 42 may be angularly articulated
with its longitudinal axis 56 about point of articulation 60 which is
defined by the intersection of longitudinal axis 58 of the implant insert
50 and axis 56.
Spherically shaped support 52 includes aperture 64 disposed through its
upper end to accommodate the universal articulation of the prosthesis
insert 66 about imaginary articulation point 60, providing clearance for
inner stem 46 passing therethrough. Once the dental practitioner has
determined the proper angular alignment of axis 56 so as to dispose the
prosthesis insert 66 at a mid point within dental prosthesis DP, inner and
outer stems 46 and 44 may be rotated one to another so as to forceably
urge clamping shells 48 and 44 together. By this means, then, sufficient
friction force is exerted against both inner and outer surfaces of support
52 so as to immobilize the prosthesis insert 42 with respect to the
implant insert 50 and dental prosthesis DP2.
Compression spring 54 is also provided to exert upwardly pressure against
inner clamping shell 48 to retain same in position against the inner
surface of support 52 during the preliminary adjusting and the universal
articulating of prosthesis insert 42 and its longitudinal axis 56 before
securing in place.
It should be noted that outer clamping shell 44, as best seen in FIG. 10,
is nonsymmetric so as to provide sufficient engagement against the outer
surface of support 52 when extreme angular adjustment of axis 56 is
required.
Referring now to FIG. 4, another embodiment of the invention shown
generally at 70 includes prosthesis insert 71 and implant insert 74. In
this embodiment 70, an intermediate spherically shaped member 84 is
provided which is lockably engaged for rotation into mating support 78
disposed at the upper end of implant insert 74. The lower end 80 of outer
stem 72 of prosthesis insert 71 includes a mating spherically outer shell
structure which engages around the outer surface of support 78. The
prosthesis insert 71 also includes inner stem 82 which is threadably
engageable within outer stem 72 so as to coaxially pass through and
threadably engage within a mating thread disposed centrally through
intermediate member 84. By this means, then, as previously described with
respect to FIG. 2, a drill bit may be passed longitudinally through outer
stem 72 and intermediate member 84 to prepare cavity 86 in implant insert
74 once the dental practitioner has determined the proper angular
alignment of the prosthesis insert 71. Thereafter, inner stem 72 is
threadably engaged into outer stem 72, through intermediate member 84 and
into cavity 86 so as to secure the entire arrangement at the predetermined
angular relationship required.
Referring now to FIGS. 5 to 7, another embodiment of the invention is shown
generally at 90 and includes prosthesis insert assembly 91 and implant
insert 94. The implant insert includes enlarged spherically shaped ball 98
disposed at its upper end. The prosthesis insert assembly 91 includes
outer stem 92 having a socket 96 disposed at its lower end which is locked
and mateably engaged over ball 98 for universal articulation therebetween.
Prosthesis insert assembly 91 also includes inner stem 102 having external
threads which mateably engage within longitudinal female threads 100 in
outer stem 92. Once the dental practitioner, as previously described, has
established a proper angular orientation about point of articulation 108
between the longitudinal axis of the prosthesis insert assembly 91 and
that of the implant insert 94, inner stem 102 may be tightened and
forceably urged against the top surface of ball 98 within socket 96 to
establish and secure by friction force this angular relationship.
Thereafter, drill bit D may be used to prepare cavity 106 as best seen in
FIG. 7 into which locking pin 106 is inserted in alignment and registry
with longitudinal aperture 104 in inner stem 102. The entire prosthesis
insert assembly 91 is then embedded and encapsulated within a suitably
prepared cavity in the dental prosthesis DP, serving to additionally trap
locking pin 106 in secure position as shown.
Again, in this embodiment 90, insert implant 94 is shown secured by
cementation and/or forced interference fit within dental implant DI4
which, in this instance, is depicted cemented within the root R of a
natural tooth.
Referring now to FIGS. 8 and 9, yet another embodiment of the invention is
shown generally at 110 and includes prosthesis insert 116, interlocking
eye bolts 112, tapered spacer 124 and locking nut 120. Interlocking eye
bolts 112 have continuous rings 114 disposed from one end of each, the
rings 114 interlocking and contacting when tensioned apart about point of
articulation 128.
Lower eye bolt 112 is shown threadably engaged within dental implant DI5,
this lower eye bolt 112 thus being equivalent to an implant insert as
previously described.
Upper eye bolt 112 is disposed longitudinally within prosthesis insert 116
and held thusly for longitudinal adjustment and tensioning by internally
threaded nut 120 which mateably engages within cavity 118 as shown.
Disposed between the prosthesis insert 116 and the dental implant DI5 is
tapered spacer 124 having end surfaces 130 and 132 mating respectively
thereagainst at an acute angle one to another. Longitudinal aperture 126
is provided to facilitate positioning of the interlocking rings 114
therewithin. In this embodiment, as best seen in FIG. 9, a set of tapered
spacers typlified at 124, having diagonally disposed end surfaces
typically 130 and 132, are provided at various discrete angles so that the
dental practitioner may select the proper spacer 124 to establish the
desired angular relationship between the longitudinal axis of the
prosthesis insert 116 and implant insert/lower eye bolt 112 about point of
articulation 128. Again, this angular relationship is required and
dictated by the necessary angular alignment of the dental prosthesis DP in
relation to the other adjacent teeth in the patient's mouth.
Once the proper spacer 124 has been positioned around locking ring 114,
threaded nut 120, threadably engaged over eye bolt 112, may then be
tightenably secured within cavity 118 so as to rigidly compress and
stabilize the prosthesis insert 116 ready for installation of the dental
prosthesis DP thereover.
Referring now to FIGS. 11 to 13, yet another embodiment of the invention is
shown generally at 140. This embodiment 140, although generally providing
structure which functions in a similar fashion to the other embodiments of
the invention, provides incremental universal adjustment of the prosthesis
insert rather than infinite adjustment within a set range.
This embodiment 140 includes an implant insert 142 which is threadably
engaged within the dental implant DI6. The upper end of implant insert 142
includes a transverse annular groove 146 positioned adjacent the upper end
of the implant insert 142. The prosthesis insert 144 of this embodiment is
generally formed of two mating halves 150 and 152 which, when moved
together as shown in the figures, mateably engage at 164 and 166 into
groove 146 to securely orient the prosthesis insert 144 atop and connected
to the implant insert 142. The prosthesis insert halves 150 and 152 are
structured so as to provide gap 154 therebetween and securely held in this
position and from rotation by threaded cross pin 160 which is disposed
transversely within smooth aperture 156 and threaded aperture 158. After
securing prosthesis insert 144 atop implant insert 142, as in the previous
embodiments, the dental prosthesis (not shown) is connected atop the
prosthesis insert 144.
To achieve the incremental universal alignment feature between longitudinal
axis 172 of the prosthesis insert 144 and the longitudinal axis 171 of the
implant insert 142, the dental practitioner is provided with an array of
prosthesis insert halves 150' and 152' as best seen in FIGS. 12 and 13
which collectively provide an incremental array of acute angle axes 172'
alignments to axis 171 about the point of articulation 170.
Referring now to FIG. 14, a variation of the embodiment of the invention
shown in FIGS. 1 and 2 previously described is there shown. This
embodiment 180 includes implant insert 182 having its main elongated body
externally threaded to mateably engage within female threads provided in
dental implant DI7. Integrally disposed at the upper end of implant insert
182 is enlarged ball 184 which mateably engages within the socket formed
by the mating socket halves 190 and 192 of the prosthesis insert halves
186 and 188.
As with respect to FIGS. 11 through 13, the prosthesis halves 186 and 188
are held in mateing alignment tightly and securely together by threaded
fasteners 196, gap 194 provided between prosthesis insert halves 186 and
188 to insure tightenability of socket halves 190 and 192 against ball
184.
After proper alignment of longitudinal axis 214 in relation to implant
insert longitudinal axis 212 about point of articulation 216, threaded
fasteners 196 are then tightened and, thereafter to insure immobility of
this arrangement, locking pin 206 is forceably urged into cavity 210 in
alignment and registry with aperture 208 in socket half 192 as previously
described with respect to FIG. 2.
Referring lastly to FIG. 15, a variation of the embodiment of the invention
shown in FIGS. 11 through 13 is there shown. This embodiment 220 includes
a prosthesis insert 222 held in place atop dental implant DI8 by threaded
fastener 224 which is threadably engageable into the dental implant DI8.
This threaded fastener 224 serves as an implant insert. Aperture 226 is
provided in prosthesis insert 222 to securely receive and conceal the
enlarged head of threaded fastener 224 as shown.
As with respect to FIGS. 11 to 13, to achieve the incremental universal
alignment feature between the longitudinal axis 232 of the prosthesis
insert 222 and the longitudinal axis 230 of the implant DI8, the dental
practitioner is provided with an array of prosthesis inserts which
collectively provide an incremental array of acute angle axes' 232'
alignments to axis 230 about the point of articulation 238.
To prevent rotation of prosthesis insert 222 about axis 230, locking pin
234 is provided to be inserted into aperture 236 and the cavity drilled
into dental insert DI8 in alignment and registry therewith as previously
described.
Threaded aperture 228 is provided in the distal end of prosthesis insert
222 to receive a threaded fastener for assisting in the retention of the
dental prosthesis to be applied surrounding the prosthesis insert 222
after it is secured in place.
While the instant invention has been shown and described herein in what is
conceived to be the most practical and preferred embodiment, it is
recognized that departures may be made therefrom within the scope of the
invention, which is therefore not to be limited to the details disclosed
herein, but is to be accorded the full scope of the claims so as to
entrance any and all equivalent apparatus and articles.
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