U.S. patent application number 11/737982 was filed with the patent office on 2007-08-16 for system for immediately placing a non-occlusive dental implant prosthesis.
This patent application is currently assigned to Zimmer Dental, Inc.. Invention is credited to Philip S. Lyren, Robert L. Riley.
Application Number | 20070190489 11/737982 |
Document ID | / |
Family ID | 33566942 |
Filed Date | 2007-08-16 |
United States Patent
Application |
20070190489 |
Kind Code |
A1 |
Riley; Robert L. ; et
al. |
August 16, 2007 |
System for Immediately Placing a Non-Occlusive Dental Implant
Prosthesis
Abstract
A system for immediately placing a non-occlusive and
non-functional temporary dental implant prosthesis in the jawbone
of a human patient with the prosthesis having a size and shape of a
natural human tooth.
Inventors: |
Riley; Robert L.; (Vista,
CA) ; Lyren; Philip S.; (Houston, TX) |
Correspondence
Address: |
FITCH EVEN TABIN AND FLANNERY
120 SOUTH LA SALLE STREET
SUITE 1600
CHICAGO
IL
60603-3406
US
|
Assignee: |
Zimmer Dental, Inc.
|
Family ID: |
33566942 |
Appl. No.: |
11/737982 |
Filed: |
April 20, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10861324 |
Jun 4, 2004 |
|
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|
11737982 |
Apr 20, 2007 |
|
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10050028 |
Oct 22, 2001 |
6746244 |
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10861324 |
Jun 4, 2004 |
|
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09755240 |
Jan 5, 2001 |
6368108 |
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10050028 |
Oct 22, 2001 |
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Current U.S.
Class: |
433/173 |
Current CPC
Class: |
A61C 13/0001 20130101;
A61C 8/005 20130101; A61C 5/70 20170201; A61C 8/0048 20130101 |
Class at
Publication: |
433/173 |
International
Class: |
A61C 8/00 20060101
A61C008/00 |
Claims
1. A dental system comprising: a dental implant; a non-occlusive
provisional prosthesis prefabricated to approximate the size and
shape of a human tooth; and an occlusive final prosthesis.
2. The system according to claim 1 wherein the final prosthesis
comprises the provisional prosthesis.
3. The system according to claim 1 wherein the implant includes an
integral abutment.
4. The system according to claim 1 wherein the implant is adapted
for use in a single-stage implantation procedure.
5. The system according to claim 1 wherein the provisional
prosthesis includes an abutment.
6. The system according to claim 1 wherein the abutment includes a
core.
7. The system according to claim 6 wherein the core comprises at
least two pieces.
8. The system according to claim 6 wherein the core includes an
anti-rotational surface.
9. The system according to claim 6 wherein the core includes a
coating.
10. The system according to claim 6 wherein the core is
cylindrical.
11. The system according to claim 6 wherein the core comprises a
cuff.
12. The system according to claim 6 wherein the core includes a
metal.
13. The system according to claim 12 wherein the metal is
titanium.
14. The system according to claim 1 wherein the provisional
prosthesis comprises at least two materials.
15. The system according to claim 14 wherein the at least two
materials include at least a ceramic and a polymer.
16. The system according to claim 1 wherein the provisional
prosthesis includes a bonding layer.
17. The system according to claim 1 wherein the provisional
prosthesis comprises material capable of coupling to porcelain.
18. The system according to claim 1 wherein an axial length of the
provisional prosthesis is about 0.5 mm to about 2 mm less than an
adjacent tooth in the jawbone.
19. A dental system comprising: a dental implant; an abutment
configured for being mounted on the dental implant; a non-occlusive
provisional prosthesis prefabricated to approximate the size and
shape of a human tooth and having a top, the provisional prosthesis
being removably mounted on the abutment and being configured for
positioning the top below a top of an adjacent tooth on a jawbone
when the provisional prosthesis is interconnected to the implant;
and an occlusive final prosthesis for replacing the provisional
prosthesis.
20. A dental system comprising: a dental implant having a bore; a
core mounted on the dental implant and defining a through-hole
aligned with the bore; an anchor received by the bore and the
through-hole for securing the core to the dental implant; a
non-occlusive provisional prosthesis prefabricated to approximate
the size and shape of a human tooth and being attached to the core,
the provisional prosthesis having a top disposed below a top of an
adjacent tooth on a jawbone when the provisional prosthesis is
mounted on the core; and an occlusive final prosthesis for
replacing the provisional prosthesis.
21. A dental kit comprising: a dental implant; a plurality of
non-occlusive provisional prostheses prefabricated to approximate
the size and shape of a human tooth; and an occlusive final
prosthesis.
22. The dental kit of claim 21 wherein the plurality of
non-occlusive provisional prostheses includes prostheses of
different shapes.
23. The dental kit of claim 21 wherein the plurality of
non-occlusive provisional prostheses includes prostheses of
different sizes and having the same general shape.
24. The dental kit of claim 21 wherein the plurality of
non-occlusive provisional prostheses includes prostheses shaped as
at least one of: an incisor, a canine, a premolar, and a molar.
25. The dental kit of claim 21 wherein the plurality of
non-occlusive provisional prostheses includes prostheses shaped as
an incisor, a canine, a premolar, and a molar.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This is a divisional application of prior U.S. patent
application Ser. No. 10/861,324, filed Jun. 4, 2004, which is a
continuation of U.S. patent application Ser. No. 10/050,028, filed
Oct. 22, 2001, which issued into U.S. Pat. No. 6,746,244, and which
is a continuation-in-part of U.S. patent application Ser. No.
09/755,240, filed Jan. 5, 2001, which issued into U.S. Pat. No.
6,368,108, all of which are hereby incorporated herein by reference
in their entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to a method for
immediately placing a non-occlusive and non-functional temporary
dental implant prosthesis in the jawbone of a human patient wherein
the prosthesis has a size and shape of a natural human tooth.
BACKGROUND OF THE INVENTION
[0003] Numerous surgical techniques and methods currently exist to
install a dental implant and prosthesis into the jawbone of a human
patient. During a conventional surgical procedure, an incision is
made along the gingival tissue at the implant site of the patient,
a cylindrical bore is drilled into the alveolar bone, and the bore
of the bone is tapped. Once the bore is fully prepared, a dental
implant is positioned above the implant site and driven into the
bore. A healing screw or healing cap is then placed on the coronal
end of the implant, and the gingival tissue is sutured. The implant
and healing cap remain within the bone for several months as
osseointegration and healing 20 occur. After this healing period, a
second surgical procedure begins. During this procedure, the
gingival tissue is again cut, the implant is re-exposed, and the
healing cap is removed. Thereafter, an abutment is affixed onto the
top of the implant and a dental prosthesis is affixed to the
abutment.
[0004] This conventional surgical procedure has many disadvantages.
First, during the healing stage while the implant integrates into
the bone, a tooth or dental prosthesis will not be present at the
implantation site. The patient may have an unsightly gap or
otherwise unaesthetic appearance at this location. Further, in some
instances, a metallic healing cap or metallic gingival cuff may be
left attached to the implant while the tissue and bone heal. The
cap and cuff are often visibly exposed in the mouth of the patient
and present an unnatural appearance. Further yet in conventional
techniques, the patient has to undergo two separate surgical
procedures: an initial procedure to implant the implant and a
second procedure to remove the healing cap and attach the abutment
and prosthesis. Multiple surgical procedures are costly and not
desirable for the patient.
[0005] Some dental implant systems and surgical techniques attempt
to solve the disadvantages associated with conventional
implantation procedures. These systems place a prosthetic tooth in
occlusion immediately after the implant is driven and positioned in
the jawbone of the patient. In this scenario, the patient has a
tooth-like prosthesis immediately after the surgery, so aesthetic
appearance is no longer a concern. The prosthesis, however, is left
in occlusion and thus exposed to immediate loads.
[0006] This procedure has disadvantages too. Preferably, movement
and disturbance of the implant should be minimal immediately after
it is placed in the jawbone. If the prosthesis and attached implant
experience loading too soon, then the position of the implant may
rotate, loosen, or otherwise move. Such movement could adversely
effect the integration and alignment of the implant.
[0007] U.S. Pat. No. 5,967,783 (entitled "Threaded Dental Implant
with a Core to Thread Ration Facilitating Immediate Loading and
Method of Installation") illustrates a dental implant system
designed to immediately place and then load a dental prosthesis. As
shown in FIG. 1, an implant 10 consists of an elongated unitary
body having a main implant portion 12 with external threads 14 and
an extended neck portion 16. One disadvantage to this system is
that the implant has an elongated implant and neck portions formed
from a single piece. A clinician may be required to perform
significant modifications to the extended neck portion so it has
the correct height or angle to receive the prosthesis. Further, the
neck portion could not easily accommodate a screw-retained
prosthesis, especially if the neck needed extensive modification.
Further yet, the implant is loaded immediately after it is placed;
and such loads, as discussed above, may move the implant or
otherwise interfere with its orientation or integration. The
external threads 14 on the implant further have a specific and
specialized thread pattern to help improve resistance of the
implant to chewing and compressive forces. This specialized thread
pattern may add additional cost to the implant.
[0008] The present invention solves the problems discussed with
prior methods and dental delivery systems and provides numerous
advantages over these prior systems and methods.
SUMMARY OF THE INVENTION
[0009] The present invention is directed toward a method for
placing a non-occlusive, non-functional temporary dental implant
prosthesis immediately after a dental implant is implanted into the
jawbone of a human patient. The implant is placed in a conventional
manner for edentulous or extraction dental implantation sites.
Thereafter, in one embodiment, a separate abutment is connected to
the implant; typically such a connection occurs with a screw or
cement. A temporary dental implant prosthesis is then attached to
the abutment. Most importantly, the temporary prosthesis is placed
to be non-occlusive and non-functional; that is to say loads and
compressive forces are not transmitted to the implant during
normal, mastication.
[0010] The present method has numerous advantages over prior
methods. First, a tooth-shaped temporary prosthesis is connected to
implant immediately after the implant is implanted into the jawbone
of the patient. As such, the patient does not have an unsightly gap
or otherwise unaesthetic appearance at the implantation site.
Further, a second, separate surgical procedure is not required
since the implant, abutment, and temporary prosthesis are all
placed during the first surgical procedure. Further yet, since the
prosthesis is left out of occlusion, it is not exposed to immediate
loads. Thus, movement and disturbance of the implant is minimized
during the integration period. Further yet, the implant and
abutment are made from two separate pieces, and the implant is not
required to have a special external thread design to help improve
resistance of the implant to chewing and compressive forces.
[0011] In another embodiment, the prosthesis is formed from an
internal metallic core and an external ceramic crown. The crown has
a shape that closely resembles the shape of a natural human tooth.
The prosthesis can be placed directly on the implant in one step,
leaving the patient with a temporary prosthesis that resembles a
natural human tooth.
[0012] This near net tooth shape of the crown will reduce the
amount of work, time, and expense required to create a final dental
prosthetic restoration. Further, the ceramic used to fabricate this
crown is compatible with commercially available porcelains so that
the gradients of shade and translucence of the natural tooth can be
replicated. Also, the crown may be manufactured to have a size that
is slightly smaller than the average natural tooth. This difference
in size enables the crown to receive an additional layer of
porcelain and then match the exact size of the natural tooth.
[0013] As another advantage, the prosthetic teeth of the present
invention may be manufactured and sold as a kit. Each kit would
include a plurality of prosthetic teeth having different sizes and
shapes emulating different sizes and shapes of natural human teeth.
A clinician could chose a prosthetic tooth to best match particular
needs of a patient.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The invention will hereafter be described with reference to
the accompanying drawings:
[0015] FIG. 1 is a side-view, partially in cross section, of a
prior art dental implant system;
[0016] FIG. 2 is a block diagram illustrating the method of the
present invention;
[0017] FIGS. 3A-3C show a dental implant, abutment, and temporary
prosthesis being implanted according to the method of the present
invention;
[0018] FIG. 4 is a cross-sectional side view illustrating an
embodiment of a dental prosthetic assembly according to one
embodiment of the invention;
[0019] FIG. 5 is an exploded cross-sectional side view illustrating
an embodiment of a dental prosthetic assembly;
[0020] FIG. 6 is a perspective view illustrating an embodiment of a
core member;
[0021] FIG. 7 is a perspective view illustrating another embodiment
of a core member;
[0022] FIG. 8 is a side-view illustrating an embodiment of a new
net tooth shaped crown;
[0023] FIGS. 9a-9e are views illustrating a plurality of tooth
shapes for the new net tooth shaped crown;
[0024] FIG. 10 is a cross-sectional side view illustrating an
embodiment of a threaded attachment of a near net tooth shaped
crown and a core member;
[0025] FIG. 11 is a cross-sectional side view illustrating another
embodiment of a dental prosthetic assembly; and
[0026] FIG. 12 is a cross-sectional view of an embodiment of a core
with a tapered outside diameter.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0027] Turning to FIG. 2 and FIGS. 3A-3C, the method of the present
invention is discussed in detail. Per block 20 of FIG. 2, the
invention may be utilized with both edentulous sites and extraction
sites. Further, such sites may be single or multiple restorations.
For illustrative purposes, the figures and accompanying description
teach application of the present invention to a single tooth
extraction implantation site.
[0028] As shown in block 22, initially the implantation site is
evaluated and prepared. Preferably, the site maintains a gentle
elevation of the tooth root to preserve the alveolar housing around
the extraction site. A periotome or other small elevators (not
shown) may be used to release the periodontal ligament or other
soft tissue attachment of the tooth to the surrounding bone. Once
the tooth is removed, the socket site should be debrided to remove
any soft tissue remnants and then irrigated with sterile saline. A
visual inspection of the site can aid in determining the
appropriate diameter implant.
[0029] As shown in block 24, the next step is to place the implant
into the implantation site 31 (shown in FIGS. 3A-3C). Various
implants may be placed using any one of numerous techniques known
to those skilled in the art. Preferably, the implant should be
dimensioned to sufficiently fill the entire cervical region of the
socket. Further, proper orientation and location of the receptor
site may be predicated on the initial step of scoring the apex of
the socket with a bur or similar instrument. Such scoring provides
a recess in the bone 32 to guide a pilot drill (not shown) to a
correct, predetermined location.
[0030] One example of an implant appropriate for the method of the
present invention is a Spline Twist MP-1 implant, manufactured by
Sulzer Calcitek Inc. of Carlsbad, Calif. In this instance, the
implant 34 can be delivered to the implantation site and inserted
via a handpiece and ratchet (not shown). The platform for this
implant preferably is placed approximately 1.5 mm below the
interproximal bone 36 and below the gingival tissue 38. Placement
in this location helps to ensure that the external threads on the
implant will be covered by bone and will be at or below the buccal
plate.
[0031] After the implant is placed, bone grafting may be required.
In this instance, a cover screw may be temporarily secured onto the
proximal end of the implant to prevent any particulate graft from
entering the internal chamber of the implant. Once grafting is
completed, the cover screw is removed.
[0032] As shown in block 26, the next step is to place an abutment
40 onto the implant. The abutment should be separate from the
implant and connectable to the implant using screws, cement, or
other techniques known to those skilled in the art. One advantage
of having a separate abutment is that various cuff heights and
angles may be selected to closely replicate the desired height,
angles, and profiles needed. In this manner, the amount of
alterations to the abutment is minimized. Of course, the abutment
can be modified to meet clinical needs, such as a modification to
the overall height or cuff contour.
[0033] As shown in block 28, the next step is to place a temporary,
non-functional prosthesis 42 on the abutment 40. One important
aspect of the present invention is that the prosthesis must be
placed in a non-functional or non-occlusive position. Preferably, a
top portion 44 of the prosthesis is placed between 0.5 mm and 2 mm
below a top 46 of adjacent teeth, as shown in FIG. 3C. In this
position, the prosthesis 42 will not be in occlusal loading during
the healing period. As such, the prosthesis should be taken
completely out of occlusion when the patient is in centric
relations and lateral excursions.
[0034] After a verification is made that no occlusal loading is
present, the prosthesis may be polished and seated with cement or a
screw, for example. The patient should be instructed to avoid
chewing in the implantation area of the prosthesis while the
implant is allowed to heal. Typically, the healing period will
occur from about one month to about nine months.
[0035] As one important advantage of the method of the present
invention, gingival tissue should be contoured around the temporary
prosthesis to maintain a natural shape and appearance. Gingival
tissue, for instance, can be sutured around a cervical portion 48
of the prosthesis (as shown in FIG. 3C) if the implantation site is
edentulous and an incision was made to expose the bone. Suturing
the tissue in this manner helps to maintain and develop soft tissue
contours around the prosthesis. Suturing, though, may not be
necessary if the implantation site is from an extraction and the
abutment and temporary prosthesis completely fill the hole left
from the natural tooth.
[0036] As yet another important advantage of this method, hard and
soft tissue contours adjacent to the implant and prosthesis should
be maintained to retain interdental papilla 50.
[0037] As shown in block 30, after the healing period has elapsed,
the temporary prosthesis is removed from the abutment and a
permanent prosthesis is connected. The permanent prosthesis is
functional and in occlusion in the jawbone of the patient. An
experimental trial was conducted on a small group of patients to
determine the feasibility of a method in accordance with the
present invention. The method was used on patients: 19 males and 36
females. The ages of the males ranged from 26-55 years and females
from 17-78 years. All implants were placed from the premolar
forward. In the male group, one implant was lost due to trauma. In
the female group, one implant was mobile after six weeks and
required removal. The male patient was removed from the combine
group resulting in a total of 54 patients. Survival rate was
approximately 98.15%.
[0038] Based on analysis of the patients in this trial, the method
of, the present invention appears to be a very efficacious for
replacing missing anterior teeth. Further evaluation is being
conducted in a larger population of patients but shows dramatic
promise for the effective replacement of lost anterior teeth. This
technique has not been employed to posterior teeth beyond the
second premolar. It may be effective in these regions as well;
however, the increased occlusal force and protection factors must
be considered. The following two cases are examples from the
experimental trial.
[0039] Case I
[0040] A 74-year old female had a fractured, non-salvageable first
premolar. The tooth was gently elevated, keeping the soft tissue
and hard tissue contours intact. There was no elevation of the soft
tissue. The socket site was checked to make sure the buccal plate
was intact. Direct visualization and palpation were used to
identify the inter-septal buccal plate rim. In this case, the site
was prepared via harvest instrumentation. The platform of the
implant was set approximately 1-1.5 mm below the level on the
inter-septal bone; such placement ensured the shoulder of a 2 mm
abutment to be approximately 1 mm below the level of gingival cuff
rim. This placement also ensured that the soft tissue would be
supported to maintain its position and would allow for maximum
emergence of the temporary prosthesis (or provisional). The
temporary prosthesis was seated with temporary cement and taken out
of occlusion. It was then allowed to heal for 16 weeks. After the
healing period, this patient was then sent to another doctor for
fabrication of the final restoration. The position of the papilla
was maintained as well as that of the buccal gingival contour,
allowing for maximum tissue esthetics and excellent emergence
profile.
[0041] Case II
[0042] A 47-year old man had tooth #9 that was super-erupted and
mobile. Due to his present occupation, aesthetics and a quick
remedy were necessary. The tooth was atraumatically removed and the
socket site debrided. The position and loss of the gingiva in
relation to the adjacent teeth was important here. The implantation
site was prepared in a sequential fashion, utilizing drills and
hand instrumentation. The implant was then seated in place,
positioning the platform approximately 1-1.5 mm below the level of
crestal bone. Here, the width of the socket determined the diameter
of the implant, and care was taken not to perforate the buccal
plate. The abutment was seated to place, the shoulder being
approximately 1 mm below the crest of the gingival collar. The
temporary prosthesis was placed and positioned to be out of centric
occlusion and excursive movement. The tissue and implant was
allowed to heal. After the normal healing time had transpired, the
implant was restored.
[0043] The experimental trial demonstrates numerous advantages to
the method of the present invention. First, the patient does not
need to wear a removable prosthesis during the healing period.
Second, the patient leaves the implantation procedure with a fixed
provisional prosthesis or tooth. This fact alleviates any
apprehension that the patient may have about the loss of anterior
teeth and provides an esthetically pleasing option. Third,
preservation of the implantation site's soft and hard tissue
contours are maintained, improving the esthetics of the temporary
and permanent prostheses. This preservation also allows for the
final restoration of soft tissue such that no sutures are required
at the surgical site. Further, the patient receives a temporary
prosthetic tooth the same day as surgery, and no unsightly gaps or
unnatural appearances occur in the mouth of the patient at the
implantation site.
[0044] Blocks 24 and 26 in FIG. 2 discuss an abutment and
prosthesis placed on the implant in two separate steps. In an
alternate embodiment of the present invention, these steps may be
combined. The abutment and prosthesis may be pre-connected and
placed on the implant in one step. Further, regardless whether the
abutment and prosthesis are pre-connected or separate, the
prosthesis may be manufactured to have a tooth shape. These
alternate embodiments are discussed below.
[0045] FIGS. 4 and 5 show a tooth-like prosthesis 110 having a new
net tooth shaped crown 112 and a metallic core 116. The crown 112
has an internal bore 114 to receive the core and is manufactured to
have a size and shape of a natural human tooth.
[0046] As shown, a threaded fastener or screw 120 connects the core
116 to the anchor 118. The fastener includes a first end 120a
having threads 122 and a second end 120b having a polygonal socket
124. A tool (not shown) can be inserted into socket 124 to turn
fastener 120 into threaded engagement with a threaded bore 119 in
anchor 118. Core 116 includes a screw bore 126 and a screw seat
128.
[0047] Screw bore 126 includes an is C that extends substantially
co-axially with an is A of anchor 118. Fastener 120 is inserted
through core 116 and threaded into anchor 118. When fully seated, a
shoulder 117 of second end 120b of threaded fastener 120 is seated
on screw seat 128 within core 116. Further, an is B passes through
the new net crown 112 from an incisal edge 112i to a cervix
112k.
[0048] In FIG. 5, all axes (A, B, and C) are longitudinal and
co-axial. In another embodiment of the invention, the crown,
however, may be angled to provide proper alignment or angular
correction of the prosthesis in the jawbone of the patient. Axis B,
for example, could be canted or angled to provide angular offset
for the crown.
[0049] The core 116 is preferably formed of a material selected for
fatigue strength suitability such as a metal, like titanium or
titanium alloy. The metal core can be fabricated with various
shapes, such as a cylindrical geometry (shown in FIG. 6) or a
frusto-conical geometry (shown in FIG. 7). Further, the core may be
formed from one piece (as shown in FIG. 4, for example) or formed
from two or more pieces. FIG. 4 shows a core formed from two
pieces: a core body 116a and a core cuff 116b.
[0050] Preferably, the core anti-rotationally engages the implant.
The anti-rotational engagement between the core and implant may
occur with numerous techniques known to those skilled in the art.
Some examples of these techniques include male and female polygonal
projections or locking tapers. FIGS. 4 and 5 show a spline
connection between the core and implant. In this connection, a
plurality of splines 116c on the core engage a plurality of mating
splines 118a on anchor 118.
[0051] The outer surface of the core may have various textures,
coatings, and configurations. FIG. 6, for example, shows core 116
with a textured coating 116e on the outer surface. FIG. 7 shows
core 116 having a plurality of grooves 116d. The various textures
and coatings can enhance the strength of connection between the
core and crown.
[0052] While ceramics can be strong, they are often brittle. The
addition of a metallic core adds strength to the overall assembly.
This added strength is especially important at the implant
interface where forces are transferred from the restoration to the
anchoring implant.
[0053] Crown 112, FIG. 8, is formed of an aesthetic suitable
material, such as a ceramic material, an unfired ceramic material,
a polymer material, or a combination of ceramic and polymer
materials. Preferably, the crown is made from a ceramic, such as
aluminum oxide, zirconium oxide, or a composite thereof. These
materials can be made to have mechanical strength sufficient to
support occlusal forces and are relatively inert when exposed to
body fluid and tissues. These materials also allow for the addition
of porcelain to their surface to provide shading to the unique
color of the adjacent natural dentition. A clinician, laboratory,
or the like may add a layer of porcelain to the outer surface of
the crown to match the aesthetics of adjacent natural teeth. The
crown can also be manufactured and sold with a thin layer of
porcelain 112b already applied to its surface. This latter
application facilitates minor modifications to the final prosthetic
restoration.
[0054] In one embodiment, the crown may be manufactured to have a
size that is slightly smaller than the average natural tooth. For
example, the crown can be manufactured to have an outside surface
or outside diameter that is 0.5 mm to 1.5 mm smaller than the
natural tooth to be replaced. This difference in size enables the
crown to receive an additional layer of porcelain and then match
the exact size of the natural tooth.
[0055] One important advantage of the present invention is that the
crown is manufactured to have shapes approximately equal to the
natural shapes of human dentition. The crowns, manufactured in
these shapes are thus prefabricated and sold to clinicians,
laboratories, and the like in the shape of human teeth. Since
ceramic materials are typically difficult to shape using machining
techniques, the present invention significantly reduces or
completely eliminates the amount of machining required to create
the shape and size of the final prosthetic restoration.
[0056] Crown 112 may be provided in a kit to have a plurality of
different sizes and shapes that mimic the sizes and shapes of
natural human teeth. These shapes, for example, could include tooth
shapes such as an incisor 112c, FIGS. 9a, 9b, a canine 112d, FIG.
9c, a premolar 112e, FIG. 9d and a molar 112f, FIG. 9e.
[0057] Crown 112 may be attached to core 16 by various means known
to those skilled in the art. In FIG. 4, the bore 114 in the ceramic
crown 112 is made slightly larger that the outside diameter of the
core 116. This difference in size creates a cement gap 117. The
cement gap is a space for dental cement that holds the crown to the
core. In FIG. 10, an alternative connecting method is shown, a
threaded fastener 130, such as a set screw, is used to attach crown
112 to core 116.
[0058] FIGS. 11 and 12 show another embodiment of the present
invention and in particular illustrate an alternative way to attach
crown 112 to core 116. A layer of material 129 is provided between
the crown and the core. This material is suitable for bonding the
two components when the components are heated. This layer of
material may be a heat activated adhesive or may be formed from
precious metals, such as gold, silver, platinum, palladium, or
alloys formed from these metals.
[0059] In the preferred embodiment, the core is fabricated from
gold (or a gold alloy) and then gold (or a gold alloy) is used to
bond the core and the crown. Gold is
[0060] 30 advantageous since it is both strong and biocompatible.
Further, dental gold alloys are capable of withstanding higher
temperatures than titanium.
[0061] Preferably, the gold is applied to the inner bore in the
crown. The gold core and crown are then connected together, and
heat is applied to bond them permanently together. The bonding may
occur after an outer layer of porcelain is applied to the crown and
subsequently heated or baked to bond the porcelain to the ceramic
crown. This latter step often occurs since dental laboratories bake
shades of porcelain onto the ceramic crown to match color of
natural teeth. The heat during this operation melts or activates
the layer of material 129. After the prosthesis is heated, the
porcelain baked, and the crown and core bonded, the prosthesis is
ready to be implanted into the jawbone of the patient. As shown in
FIGS. 11 and 12, a hole 121 may be left in the crown to provide
access to the screw 120.
[0062] Gold soldering or a brazing process can be used to join the
core to the crown. A dental laboratory, for example, can add the
soldering or brazing gold, or the gold can be supplied as a preform
coating installed during the manufacturing stage. The preform
coating can also be added using an electroplating process that
metallizes the surface of the internal bore and bonds the crown and
core.
* * * * *