Note: Descriptions are shown in the official language in which they were submitted.
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DENTAL FRAMEWORK AND PROSTHESIS
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Patent Application No.
14/272,566 filed May
8, 2014.
FIELD OF THE INVENTION
[0002] Dentists are continuously searching for methods in which they can
provide aesthetic
and durable prostheses for their patients. One of the greatest challenges they
face are providing a
restoration that will resist the occlusal forces in a reduced vertical
restorative dimension while
obtaining a high level of aesthetics. Dentists are also looking for a cost
effective and time efficient
manner in which to obtain this result. In application 14/272,566, the Inventor
demonstrated a novel
dental prosthesis with an implant framework supporting a series of
crowns/bridges to provide
improved aesthetics and functionality. In one of the embodiments of the
invention, the crowns were
united together into a bridge due to limitations of the case or for personal
preference by the dentist or
technician. This bridging provides significant advantages for cases where
there is limited restorative
space. This application will disclose a new dental prosthesis and design
method that provides
advantages over current systems and products in the market place and address
the challenges of
limited restorative space.
BACKGROUND OF THE INVENTION
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[0003] Traditional acrylic processed dental hybrid restorations utilize a
milled or cast
framework/bar where individual denture teeth are retained to the framework by
processed acrylic.
This process requires a high level of skill and significant time in the
laboratory. Many times due to
the limited restorative space, these traditional hybrids break and fracture
due to the occlusal forces of
the patient exceeding the strength of the acrylic. With the introduction of a
dental prosthesis
consisting of a dental implant framework supporting a series of individual
crowns/bridges, the
occlusal loads can be transferred through the crown and directly into the
supporting framework and
dental implants. This individual crown prosthesis has noted improved
performance and avoids
potential breakdown of the acrylic. However there are instances especially in
cases with limited
restorative space, where the individual crown prosthesis would not be an ideal
option due to the
space required for the underlying framework and appropriate wall thickness of
crowns. This
application will disclose an improved dental prosthesis and design process
that will provide
improved performance in these spatially limited cases while still achieving
the necessary aesthetics
for the Dentist and their patients. This application will also disclose a
unique CAD subtract body
that will be unique in the creation of the dental prosthesis.
[0004] In U.S. Patent Application 14/272,566 Schulter et al. teaches a dental
prosthesis
consisting of crowns and a dental implant framework intended to mate to a
series of
implants/abutments.
[0005] In U.S. Patent 8,100,692 Diagenlo, et al., teaches a dental framework
that is attached
to dental anchors, such as dental implants which are secured to the patient's
mandible or maxilla,
where the framework may be fabricated based on the dimensions and surface
contours of a stone cast
and diagnostic wax up created from an impression of the patient's mouth.
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[0006] In U.S. Patent Application 11/876,450 Karlsson teaches of the
utilization of a dental
scanning unit commonly found in the market place.
SUMMARY OF THE INVENTION
[0007] In accordance with the first embodiment of the invention, a dental
prosthesis is
disclosed consisting of a veneering overlay and dental implant framework
intended to mate to a
series of implants/abutments in a patient's mouth. The veneering overlay and
dental implant
framework are designed on the basis of digital data defining the appropriate
tooth contours, gingiva
contours, and implant locations. The dental implant framework consists of a
series of mating
cylinders, support posts. The veneering overlay duplicates the anatomy
provided in the digital data
defining the appropriate tooth position and gingiva contours of the final
prosthesis. The veneering
overlay and dental implant framework are designed simultaneously and with a
predefined mating
surface and clearance gaps to ensure the appropriate mating of the veneering
overlay to the dental
implant framework. The unique mating surface is created through a unique CAD
subtract body that
is dependent upon the design features of the dental implant framework. The
veneering overlay and
dental implant framework are permanently fixated to one another in providing
the completed dental
prosthesis.
[0008] In accordance with the second embodiment of the invention, a dental
implant
framework is disclosed which is intended to mate to a veneering overlay and a
series of
implants/abutments in a patient's mouth. The dental implant framework is
designed on the basis of
digital data defining the appropriate tooth contours, gingiva contours, and
implant locations. The
dental implant framework consists of a series of mating cylinders, support
posts. The dental implant
framework is designed with a predefined mating surface and clearance gaps to
ensure the appropriate
mating of the veneering overlay to the dental implant framework. The unique
mating surface is
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created through a unique CAD subtract body that is dependent upon the design
features of the dental
implant framework.
[0009] In accordance with the third embodiment of the invention, a unique CAD
subtract
body is disclosed to create the mating surface for a veneering overlay and a
dental implant
framework. The veneering overlay and dental implant framework are designed on
the basis of
digital data defining the appropriate tooth contours, gingiva contours, and
implant locations. The
dimension of the unique CAD subtract body are dependent upon the dimension of
the dental implant
framework. Some of the dimensions of the unique CAD subtract body are used in
creating the
mating surface for the veneering overlay to mate with the dental implant
framework, where other
dimensions are used in creating clearance gaps between the veneering overlay
and dental implant
framework. The unique CAD subtract body is fully parametric and can be updated
per the unique
requirements of the patient, dentist, or technician.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a fragmentary perspective view of a patient's open mouth with
the anchors
embedded in the patient's mandible;
[0011] FIG. 2 is a fragmentary perspective view of the patient's open mouth
with several
copings attached to the anchors and an impression tray with impression
material surrounding the
patient's mucosal tissue and submerging the copings;
[0012] FIG. 3 is a perspective view of the impression of FIG. 2 inverted and
removed from
the patient's mouth with two analogs attached to two of the copings;
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[0013] FIG. 4 is the same perspective view of FIG. 3, but with analogs
attached to all the
copings, and the impression filled with dental stone material and the analogs
submerged in the dental
stone material;
[0014] FIG. 5 is a perspective view of the stone cast formed by the dental
stone material
poured in the impression of FIG. 4 in its hardened state, inverted, and with
the impression removed
showing the analogs with the analog surfaces that mated with the copings (in
FIG. 4) now exposed;
[0015] FIG. 6 is a perspective view of the stone cast of FIG. 5 with the
dentist's fabricated
diagnostic wax-up built up on the stone cast and abutting the analogs;
[0016] FIG. 7 is a cross-sectional view of the stone cast of FIG. 6 taken at
section line 7-7 in
FIG. 6;
[0017] FIG. 8 is a perspective view of the stone cast of FIGS. 5-7, with a
putty index molded
to the facial aspect of the diagnostic wax-up;
[0018] FIG. 9A is a cross sectional view of the stone cast of FIGS. 5-8 taken
at section line
9-9 in FIG. 8;
[0019] FIG. 9B is a cross sectional view of the stone cast of FIGS. 5-8 with
the diagnostic
wax-up removed to show the inner surface of the putty index and the impression
of the facial aspect
of the diagnostic wax-up formed on the inner surface of the putty index;
[0020] FIG. 10A is a perspective view of the stone cast of FIGS. 5-9B with six
fittings, one
fitting attached to each of the six analogs;
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[0021] FIG. 10B is a perspective view of the bridging structures fixed to and
between each
of the six fittings to form a wax-up framework mounted on the six analogs;
[0022] FIG. 11A is a flow chart demonstrating the steps necessary for
fabricating a
framework to receive individual crowns through a "copymill" procedure;
[0023] FIG. 11B is a flow chart demonstrating the steps necessary for
fabricating a
framework through a "copymill" procedure for a traditional acrylic processed
hybrid utilizing
individual denture teeth;
[0024] FIG. 12A is a flow chart demonstrating the steps for the process in
designing and
fabricating a dental prosthesis composing of an implant framework and series
of crowns/bridges per
patent application 14/272,566;
[0025] FIG. 12B is a flow chart demonstrating the steps for the new invented
process and
invention;
[0026] FIG. 13 is a schematic diagram of the scanner and the wax-up framework
and
alignment posts that it is scanning;
[0027] FIG. 14A is a front view of the graphical representation of the surface
model scanned
from the denture tooth;
[0028] FIG. 14B is a side view of the graphical representation of the surface
model scanned
from the denture tooth;
[0029] FIG. 15A is a front view of the graphical representation of the crown
and support
post/prep tooth form models;
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[0030] FIG. 15B is a side view of the graphical representation of the crown
and support
post/prep tooth form models;
[0031] FIG. 15C is a cross sectional view of the crown and support post/prep
tooth form
models of FIG. 15B taken at section line C-C in FIG. 15A;
[0032] FIG. 15D is a cross sectional view of the crown and support post/prep
tooth form
models of FIG. 15A taken at section line D-D in FIG. 15B;
[0033] FIG. 15E is a perspective view of the crown and support post/prep tooth
form models
demonstrating their alignment separate from one another possessing independent
coordinate
systems;
[0034] FIG. 15F is a perspective view of the crown and support post/prep tooth
form models
aligned correctly relative to one another and showing their individual
coordinate systems aligned
correctly to one another;
[0035] FIG. 15G is a cross-sectional view of a crown and support post/prep
tooth form
model and demonstrates the feature dependency created between the crown and
support post/prep
tooth form models, where the cement gap and margin have been automatically
updated based upon
the support post/prep tooth form being positioned higher;
[0036] FIG. 15H is a cross-sectional view of a crown and support post/prep
tooth form
model and demonstrates the feature dependency created between the crown and
support post/prep
tooth form models, where the cement gap and margin have been automatically
updated based upon
the support post/prep tooth form being angulated to a new orientation;
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[0037] FIG. 16A is a graphical representation of diagnostic wax up surface
model with one
of the crown and support post/prep tooth form assemblies appropriately
aligned;
[0038] FIG. 16B is a graphical representation of diagnostic wax up surface
model with all of
the crown and support post/prep tooth form models appropriately aligned;
[0039] FIG. 17 is a graphical representation of the support posts/prep tooth
forms in their
appropriate alignment based upon the diagnostic was up surface model;
[0040] FIG. 18 is a graphical representation of the DPF's and support
posts/prep tooth forms
appropriately positioned relative to one another in creating the surface model
of the framework;
[0041] FIG 19A is a perspective view of the surface model of the framework
with the DPF's,
support posts/prep tooth forms, and bridging structures appropriately
positioned relative to one
another;
[0042] FIG. 19B is a top view of the surface model of the framework with the
DPF's,
support posts/prep tooth forms, and bridging structures appropriately
positioned relative to one
another;
[0043] FIG. 20A is a perspective view of the surface model of the framework
including
DPF's, support posts/prep tooth forms, and bridging structures with the crown
models appropriately
positioned;
[0044] FIG. 20B is a top view of the surface model of the framework including
DPF's,
support posts/prep tooth forms, and bridging structures with the crown models
appropriately
positioned;
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[0045] FIG. 21 is a side view of the bridge model;
[0046] FIG. 22 is a side view of the framework model with a PTF bridging
structure;
[0047] FIG. 23A is a side view of the framework model with the associated
bridge model
appropriately aligned together;
[0048] FIG. 23B is a top view of the framework model with the associated
bridge model
appropriately aligned together;
[0049] FIG. 24A is a perspective view of the framework designed to support the
veneering
overlay;
[0050] FIG. 24B is a side view of the framework designed to support the
veneering overlay;
[0051] FIG. 25A is a back side view of the framework and the veneering overlay
appropriately aligned and mating with one another;
[0052] FIG. 25B is a bottom side view of the framework and the veneering
overlay
appropriately aligned and mating with one another;
[0053] FIG. 25C is a perspective view of the framework and the veneering
overlay
appropriately aligned and mating with one another;
[0054] FIG. 25D is a cross-sectional view of the framework and the veneering
overlay
appropriately aligned and mating with one another;
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[0055] FIG. 25E is a second cross-sectional view of the framework and the
veneering
overlay appropriately aligned and mating with one another and demonstrating
the cement gap
pertaining to the protrusion on the top surface of the framework;
[0056] FIG. 26A is a perspective view of the framework, the veneering overlay,
and crown
appropriately aligned and mating with one another;
[0057] FIG. 26B is a perspective view of the framework and the veneering
overlay
appropriately aligned and mating with one another and with the PTF of the
framework extending
through the veneering overlay;
[0058] FIG. 26C is a cross-sectional view of the framework, the veneering
overlay, and
crown appropriately aligned and mating with one another, with the crown mating
to the PTF
associated with the framework;
[0059] FIG. 26D is a perspective view of the framework and the veneering
overlay
appropriately aligned and mating with one another and with the PTF as part of
the veneering
overlay; and
[0060] FIG. 26E is a cross-sectional view of the framework, the veneering
overlay, and
crown appropriately aligned and mating with one another, with the crown mating
to the PTF
associated with the veneering overlay.
DETAILED DESCRIPTION OF THE INVENTION
[0061] The dental prosthesis is supported by a dental framework which
functions as a
structural support and point of attachment. The dental framework is attached
to dental anchors, such
as dental implants which are secured to the patient's mandible or maxilla, the
framework may be
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fabricated based on the dimensions and surface contours of a stone cast and
diagnostic wax up
created from an impression of the patient's mouth such as described in US
Patent No.: 8,100,692.
The stone cast replicates the soft tissue contours and implant positions in
the patient's mouth. The
diagnostic wax up represents the final prosthesis and ultimately the position
of the denture teeth to
be restored for the patient. In order to create the diagnostic wax up, the
dentist or technician will
position upon the stone cast the stock denture teeth and wax as required for
proper prosthetic
function and aesthetics. The commercially available stock teeth are generally
manufactured with
predetermined geometries of a typical given tooth in various sizes by a third-
party manufacturer.
[0062] Retention of the dental prosthetic requires anchors secured in the
patient's mouth. In
FIG. 1, the patient's jaw or mandible 100 can be seen overlaid with soft
mucosal tissue 102 (For the
purposes of this description, the inventor will be utilizing the term mucosal
tissue or soft tissue to
describe any of the soft tissue found in the oral cavity, which may include
but not limited to
mucosal, gingiva, or alveolar tissue.). An anchor 104, also known as an
"implant" or "fixture" is
shown embedded into the patient's mandible 100. This anchor is retained within
the bone of the
mandible by a screw thread. It is driven into the mandible 100 by coupling a
wrench or similar
device to the top of the anchor 104 and rotating the wrench to drive the
anchor into the jaw bone just
as one would drive a screw into a piece of wood. In an alternative embodiment,
the anchor 104 is
press fitted into a hole formed with a drill, reamer, broach, osteotome, or
similar device.
[0063] FIG. 1 illustrates the first step in the process, that of forming an
opening in the
mandible of the patient and fixing an anchor therein, while leaving a top
surface of the anchor
exposed above mucosal tissue 102 for mating (coupling) to and supporting a
dental prosthesis or
restorative component such as a denture, bridge, crown, framework, abutment,
healing cap, or
coping (hereinafter referred to as "denture"). Note that while the process
illustrated herein describes
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and illustrates a mandible for illustration purposes, the same process is
performed to embed anchors
104 into the patient's maxilla and create dental prostheses for the maxilla.
[0064] To attach anchors 104, the dentist first makes an incision in the
mucosal tissue 102
where a missing tooth or teeth would normally extend from the mandible where
it is embedded,
through the gum, and into the oral cavity. Once the incision is made, the
dentist makes a hole (which
may include such processes as drilling, broaching or reaming) in the mandible
100 in the same
general direction and location as the missing tooth. The dentist then fixes an
anchor 104 into the hole
thus created and sutures the incision, typically leaving mating surface 108 of
anchor 104 exposed
while the bone osseointegrates to the outer surface of anchor 104.
Alternatively, the dentist may
attach a healing cap to the anchor 104 and suture the gum around or over the
top of the anchor 104
and the healing cap, permitting the gum to heal around or over the top of the
anchor 104 as it
osseointegrates. In this alternative process, once the anchor has
osseointegrated, the dentist incises
the mucosal tissue 102 extending over the top of the now-integrated anchor 104
and retracts the
mucosal tissue to each side, exposing the mating surface 108 of anchor 104 and
permitting the
mucosal tissue to heal.
[0065] The anchor 104 has a central longitudinal aperture 107 in the top which
is configured
to receive an impression coping 110, as shown in FIG. 2, (or a fastener
configured to mount the
impression coping 110) that is affixed to the anchor 104. This coping
transfers the size, shape,
location or orientation of the mating surface 108 of the anchor (and
preferably all four) to the stone
cast (see below). It is the mating surface 108 that is oriented to the
finished denture, and hence the
mating surface 108 from which the structures of the denture that mount to the
anchors are derived. In
general, anywhere from one to twelve of these anchors are embedded in the jaw
and are provided as
mounting points for the denture. In an alternative configuration, anchor 104
may have a variety of
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configurations on its mating surface 108 including threaded or unthreaded
protrusions or recesses
that are configured to engage a denture. The use of an anchor 104 having a
central aperture and
internal threads for engaging a coping is a matter of convenience herein and
should not suggest that
the process is limited to an anchor having this configuration.
[0066] Mating surface 108 is typically the surface on which the denture will
be mounted or a
surface having a predetermined position with respect to that surface on which
the denture will
ultimately be mounted. The coping 110 is configured to engage surface 108 and
surrounding
structures of anchor 104 (if any) such as holes that extend into (or
protrusions that extend above) the
surface 108.
[0067] These inter engaging surfaces of coping 110 and anchor 104 serve to
align the coping
and the anchor in predetermined positions with respect to each other when
fixed together, such that
if one knows the position and orientation of surfaces on the coping one can
know the position and
orientation of corresponding structures on the anchor 104 and more preferably
when a scanner (see
below) determines the position and orientation of structures on copings 110 it
can mathematically
determine the position and orientation of corresponding structures on anchors
104. Anchor 104 is
preferably cylindrical and has a longitudinal axis 111, as does coping 110. In
a typical arrangement,
when the coping 110 is fixed in its predetermined position with respect to
anchor 104, a longitudinal
axis 111 of the coping is coaxial with the longitudinal axis of the anchor
104. The coping 110 and
the anchor 104 are preferably threadedly engaged to permit surfaces on the
coping to be drawn down
tightly against mating surface 108 for precise alignment of their inter
engaging surfaces.
Alternatively, the coping 110 and anchor 104 to which it is coupled may be
equipped with inter
engaging snap fastening connecting surfaces that hold the coping in the proper
orientation with
respect to anchor 104.
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[0068] In FIG.1, the edentulous mandible 100 has six anchors 104 affixed
therein in a
spaced-apart relation extending from the front of mandible 100 around each
side. The anchors 104
are disposed in a generally upright and parallel relation extending into the
top surface of mandible
100. The dentist attaches corresponding copings 110 to the top of each anchor
104 and extends
upward in a generally upright and parallel relation to the other copings 110.
The application
illustrated herein shows the use of six anchors configured to support a
denture. Other applications
with more or fewer anchors 104 are possible. Furthermore, the mandible need
not be edentulous
(shown here), but may have, and often does have, one or more natural teeth
remaining in the maxilla
or mandible between which the anchors 104 are embedded to support one or more
dentures (such as
fixed or removable partial dentures) to fill the gap or gaps between the
existing natural teeth. In this
case, the anchors would not be spaced evenly about the mandible, as shown
here, but would be
spaced irregularly in the gaps created by the absence of natural teeth.
[0069] FIG. 2 illustrates the next step in the process of creating a denture,
the step of creating
an impression of the patient's mandible. This figure shows an impression tray
120 filled with flexible
impression material 122. The tray is a semi flexible plastic structure that
holds the impression
material 122 in position around the patient's teeth (if any) and mucosal
tissue. FIG. 2 shows a tray
120 for the lower teeth surrounding teeth, mucosal tissue, and mandible of the
patient.
[0070] The copings 110 previously attached by the dentist to the anchors 104
are completely
submerged by the dentist in impression material 122 such that the entire outer
surfaces of the
copings 110 extending above the surface of the mucosal tissue on the patient's
mandible 100 are
completely covered. The impression material is left in this position to set.
Once set, the individual
copings 110 are fixed with respect to each other in the same position and
orientation that the anchors
104 are fixed with respect to each other. The curing process fixes the copings
in this position and
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thereby permits the copings to be collectively removed together with the
impression material while
preserving their orientation.
[0071] In the next step of the process, the dentist flexes the tray 120 and
the now set
impression material 122 and removes them from the patient's mouth. Enough
impression material
122 is placed in the tray and disposed around the patient's mandible 100 to
cover any still-existing
teeth of the mandible and the mucosal tissue 102 of the mandible as well as
the copings 110.
[0072] When the tray 120 and impression material 122 are removed, the copings
are
removed with them, embedded in the now-cured impression material 122. The
process of removal
disconnects the copings 110 from the anchors 104, permitting the copings to be
removed while still
embedded in the impression material 122. If the copings include a threaded
portion that holds them
to the anchors, this threaded portion is unthreaded from the anchors. If the
copings are fastened to
the anchors with a snap fastening portion, the snap fastening portions are
unsnapped from each
other. The now-cured impression material 122 that couples the copings 110 to
each other preserves
the relative positions and orientations of the mating surfaces of all the
copings 110 and hence
relative positions and orientations of the mating surfaces 108 of all the
anchors 104 with respect to
each other. This relationship is preserved in the relative positions and
orientations of the surfaces of
copings 110 that were connected to the mating surfaces 108 of anchors 104. To
even further ensure
the preservation of this relationship, some dentists will attach the copings
110 to one another by
applying a light cured acrylic material prior to submerging them in the
impression material 122. The
impression material 122 in which copings 110 are embedded also preserves the
surface contours of
the mucosal tissue and the remaining teeth (if any) in the mandible and their
relative positions with
respect to the mating surfaces of copings 110 and anchors 104. The surface of
the impression
material 122, once removed from the patient's mouth, is a negative replica of
the soft tissue and
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teeth. The surfaces of copings 110, now separated from anchors 104 and exposed
on the inside
surface of the impression material 122, are a negative replica of surfaces 108
of anchors 104 to
which they were coupled. The now-cured impression material 122 is therefore a
negative replica of
all the free surfaces, including teeth, mucosal tissue, and the surfaces of
the copings embedded in the
impression material are a negative replica of the mating surfaces 108 of
anchors 104. The cured
impression material with embedded copings is commonly called an "impression"
and identified in
the figures herein as item 123.
[0073] FIG. 3 shows the impression 123 inverted and removed from the patient's
mouth. In
this embodiment, there are six copings 110 embedded in the impression 123. The
bulk of the copings
110 are embedded in the impression 123. Only the very ends of the copings 110
extend upward and
out of the impression 123 (in this inverted orientation).
[0074] In FIG. 3 the dentist has begun the next step of the process, that of
attaching analogs
124 to the exposed surfaces of all of the copings 110. Analogs 124 are
structures that replicate the
anchors 104. As in the case of the copings themselves, each analog 124
preferably comprises a
generally cylindrical body with a longitudinal axis 127 that is coaxial with
the longitudinal axis 111
when attached to coping 110.
[0075] The end surfaces of analogs 124 are configured to abut and mate with
the free
surfaces of the copings 110 that were previously coupled to anchors 104 and
normally attach in the
same manner as copings 110 to anchors 104. The surfaces of analogs 124
replicate the position and
orientation of mating surfaces 108 of anchors 104. In effect, the spacing and
orientation of anchors
104 was transferred to the copings 110, and transferred back again to analogs
124, which have the
same spacing and orientation as the anchors 104. Thus, each analog 124 is
coaxial with and is
disposed in the same position as anchor 104.
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[0076] In the next step of the process, illustrated in FIG. 4, the dentist
pours a mixed dental
stone material 126 into the cavity in impression 123 that was formed by the
patient's mandible,
submerging all of the analogs 124. Stone material 126 covers the exposed
portion of the analogs 124
as well as the surfaces of impression 123 formed by the patient's mucosal
tissues and teeth. Once
filled into impression 123, the stone material 126 is then permitted to harden
to a rock-like
consistency, creating a structure that is called a "stone cast" 125.
[0077] FIG. 5 represents the next step of the process which the dentist
performs once the
stone material 126 has hardened. The dentist removes impression 123 from the
stone cast 125,
leaving the stone cast 125 with the analogs embedded therein. The stone cast
125 positively
replicates the position and orientation of mating surfaces 108 of anchors 104,
which are represented
in the stone cast 125 by the mating surfaces 128 of the analogs 124 that were
fixed to the free ends
of copings 110 (FIG. 3). The portions of the stone cast 125 surrounding
analogs 124 positively
replicates the surface of the mucosal tissues of the mouth, which were
transferred from the mucosal
tissues of the mouth to the impression as a negative replica and then back to
the stone cast as a
positive replica of those tissues. The stone cast 125 also replicates the
surface of the patient's
existing teeth (not shown). When the patient has existing teeth, the position
and orientation of the
surfaces of the teeth are transferred first to the impression as a negative
replica and then to the stone
cast as a positive replica. In the present embodiment, the mandible 100 is
edentulous and therefore
there are no existing teeth.
[0078] As will be explained later, teeth that are replicated in impression 123
and stone cast
125 provide a precise reference to indicate the location of the jawbone. The
soft tissues that are
replicated in the impression 123 and stone cast 125 can change their position
due to swelling, edema,
injury, irritation, or damage to the mouth. Teeth, since they are much harder
and are embedded in the
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jawbone, provide a more stable reference, over time, of the position of the
jawbone and thus
indirectly, of the position and orientation of anchors 104.
[0079] The impression molding and stone casting processes described above
provide
accurate replicas of the position and orientation of the mating surfaces 108
of anchors 104, the
mucosal tissues, and the teeth.
[0080] In the preferred embodiment, the mating surfaces 108 of anchors 104 are
exactly
duplicated by the mating surfaces 128 of the analogs 124: they are in exactly
the same position and
at exactly the same orientation. In an alternative embodiment, the mating
surfaces 128 on the
analogs may be offset slightly or configured slightly differently than the
mating surfaces 108 of
anchors 104. In some cases, manufacturers choose to make analogs or other
connecting components
that have mating surfaces slightly different from the mating surfaces 108 of
the anchors 104 for
example to permit the copings 110 to be more easily attached to anchors 104 or
to permit analogs
124 to be more easily attached to copings 110. Any slight difference in
position such as this is
intentional, however, and is eliminated later in the process when the denture
is created so that the
mating surfaces of the denture are precisely oriented to mate properly with
surfaces 108 of anchors
104 in the patient's mouth.
[0081] Further, the anchors 104 in the patient's mouth may not be connected
directly to the
dental framework. Abutments may be mounted on the anchors 104 (i.e. the
anchors have surmounted
abutments). The dental framework may be mounted to these abutments, and thus
indirectly mounted
to anchors 104. When the dental framework being designed is intended to be
mounted on abutments
mounted on anchors 104, the analogs 124 may be provided with surmounted
abutments, i.e. the
analogs may include the abutment design incorporated into it, to replicate the
mating structure of the
abutment to the framework.
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[0082] While the mating surfaces 128 of the analogs 124 and the mating
surfaces 108 of
anchors 104 may be slightly differently configured, the longitudinal axes of
each of the anchors 104
and the analogs 124 are preferably identically oriented and spaced apart, each
pair of corresponding
analog and anchor sharing a common longitudinal axis (i.e. they are coaxial).
Considered differently,
if the surface of the stone cast representing the soft tissues and teeth of
the patient's mouth could be
superimposed on top of the patient's mucosal tissues 108 that formed the stone
cast 125, all the
longitudinal axes defined by the analogs would be superimposed on (i.e.
simultaneously coaxial
with) all the corresponding axes defined by the anchors. The longitudinal axes
127 of the analogs
124 and the surfaces of the stone cast 125 defined by the mucosal tissues 108
the patient are positive
replicas of the longitudinal axes 111 of anchors 104 and the surfaces of
mucosal tissues 108.
[0083] The replica of any teeth formed in the surface of the stone cast are
formed with
respect to one another and with respect to the analogs such that they
duplicate the position of any
existing real teeth in the patient's mouth with respect to one another and
with respect to mating
surfaces 108 and longitudinal axes of the anchors 104 in the patient's
mandible. The replica of the
mucosal tissues formed in the surface of the stone cast are in generally the
same position on the
stone cast as they are in the patient's mouth including the replication in the
stone cast 125 of the
junction between the mucosal tissue and any existing teeth and anchors 104, as
well as a replication
in the stone cast of all the mucosal tissue that will be covered by the
denture.
[0084] Once the dentist has created the stone cast 125, which is a positive
replica of the
patient's jaw, including replication of existing teeth, mucosal tissue, and
anchors, the dentist then
proceeds to the next step in the process: designing and creating the denture
that will be fitted to the
patient's mouth (in this case, the patient's jaw).
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[0085] The dentist or technician manually creates a diagnostic wax-up 130 of
the desired
denture teeth position and occlusal orientation, using flexible molding
materials such as wax, acrylic,
or other polymers and stock denture teeth commonly found in the market. These
stock denture teeth
are of a known dimension and have contours specific to the mold or catalog
number of the denture
teeth. These denture teeth are also made from a combination of materials such
as acrylic and
composite. The composite portion is typically used for the aesthetic upper
portion of the denture
tooth as the composite can provide the appearance of translucency. The lower
portion of the denture
tooth typically consists of acrylic which is ideal in bonding to the processed
acrylic for the denture
base or acrylic used in adhering the denture teeth to a milled or cast
framework/bar for a traditional
hybrid dental restoration. The dentist or technician may also modify these
denture teeth slightly in
order to provide the appropriate occlusal scheme to best fit any existing
teeth or dental prosthesis on
the opposing arch. These modifications may include but are not limited to the
addition of occlusal
contours by adding wax or the removal of occlusal contours by modifying the
surface with a bur and
hand piece.
[0086] The diagnostic wax-up 130 is created to verify the proper location of
the denture
mucosal tissue and denture teeth with respect to the patient's actual mouth to
ensure proper tooth
orientation, and to ensure that the location and placement of the denture
within the patient's mouth
restores form, fit and function. In short, the diagnostic wax-up 130 is a
model of and looks like the
denture that is ultimately produced, but is made of softer materials to permit
it to be adjusted and
adapted until the patient and dentist are pleased with its form, fit, function
and aesthetics.
[0087] The dentist creates the wax-up 130 on the stone cast 125, building it
up on the
patient's replica mucosal tissue. When the dentist is finished making the wax-
up 130, he removes the
wax-up 130 from the stone cast 125, and places it into the patient's mouth so
the patient can see,
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firsthand, what the denture or prosthesis will look like when it is finished.
If the wax-up 130 fits, the
patient can bite properly, and the patient is pleased with the appearance of
the wax-up 130, the
dentist then proceeds to manufacture the framework and resulting prosthesis.
[0088] FIGS. 6-7 illustrate the process of creating a wax-up, showing the
stone cast 125 as it
would appear with a wax-up 130 modeled on its outer surface. In FIG. 6, the
stone cast 125 is shown
covered with the wax-up 130 which comprises the denture teeth 132 embedded in
wax 134 which
the dentist has molded directly to the surface of the stone cast 125. FIG. 7
is a cross-sectional view
through the stone cast 125 plus wax-up 130 shown in FIG. 6. This cross-section
is taken at section
line 7-7 in FIG. 6. Once the dentist has created the wax-up 130 and has
verified the fitting of the
wax-up 130 in the patient's mouth, he can then begin the process of having the
framework fabricated
for the patient. Traditionally these frameworks have been cast, but more
recently it has become
common for these frameworks to be scanned and duplicated in an appropriate
dental material
(titanium, cobalt chrome, zirconia, plastic, PMMA, acrylic, etc...) by a
common manufacturing
method (milling, 3D printing, laser sintering, EDM, etc...)
[0089] The steps associated with the traditional "individual crown copymill"
process are
outline in flowchart 600 of FIG. 11A. As noted in STEP 604 of Flowchart 600,
the Dentist or
technician will begin to fabricate an acrylic model of the framework that will
be duplicated in a
material such as titanium, cobalt chrome, zirconia, or any other appropriate
dental material. The first
step in this process is creating a facial or putty index of the diagnostic wax-
up 130 while positioned
on stone cast 125, which captures the facial/buccal contours of the denture
teeth 132 including their
height and angulation and the soft tissue contours of the diagnostic wax up.
FIGS 8 and 9A-B
illustrate the process of creating the facial index. FIG 8 shows the facial
index 142 as created using
stone cast 125 and diagnostic wax up 130. This facial index 142 is created by
wrapping a silicone
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putty material 144 commonly used in the dental industry around the
facial/buccal aspect of the
diagnostic wax up 130 while it is properly positioned on stone cast 125. The
facial index will engage
a significant area of the stone cast 125 that is not covered by diagnostic wax
up 130. The facial
index 142 will have a unique stone mating area 145 that will allow for the
facial index to be properly
positioned back to stone cast 125 without the aid of diagnostic wax up 130.
FIG 9A is a cross-
sectional view through the facial index 142, stone cast 125, and diagnostic
wax up 130,
demonstrating the capturing of the buccal aspect of denture teeth 132. This
cross-section is taken at
section line 9-9 in FIG.8. Once the putty material 144 has set the facial
index 142 and diagnostic
wax-up 130 can be removed from the stone cast 125. FIG 9B shows the negative
impressions 147
left by the facial/buccal contours of denture teeth 132. The facial index 142
will be placed back onto
the stone cast 125 utilizing the unique stone mating areas 145. The dentist or
technician will utilize
facial index 142 as a guide to begin building the acrylic model of the
intended framework. As
demonstrated in FIG. 10A, wax copings or fittings 152A-F will be attached to
the mating surface of
the analogs 124 and begin stacking acrylic material 160 on top of them to
begin forming the design.
The acrylic material 160 can be a light cured or cold cured resin commonly
used in dentistry. It can
also be appreciated that materials other than acrylic such as wax can be used
in creating the design of
the framework by the dentist or technician. Frequently the dentist of
technician will utilize a hand
piece and bur to reduce and refine the contour of the acrylic material 160 in
order to create the
necessary margins 162 and support posts 164 that the individual crowns will be
intended to mate to
on the framework. As shown in FIG. 10B, the support posts 164 will be attached
to one another by
bridging structure 154 that will run between fittings 152. The inventor is
using the term support
posts as a descriptive term in this application, but others may refer to this
framework feature as a
pontic, abutment, prep tooth form or framework abutment. The support posts 164
will be designed
in such a way as to support a crown that will be designed to mate to the
margin 162 as designed into
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the framework. Depending upon the tooth type, the design of the support post
164 will be adapted
per the dentist or technician to support the crown against the expected
occlusal forces of the patient.
[0090] Once the acrylic model 166 of the framework is deemed acceptable the
dentist or
technician will send the acrylic model 166 and stone cast 125 to a laboratory
or framework supplier
to have the acrylic model duplicated in the material of their choosing. These
STEPS 606, 608, and
660 are noted in Flowchart 600 shown in FIG. 11A. The laboratory or framework
supplier will scan
the stone cast 125 to determine the orientation and location of the mating
surfaces of analogs 124
and scan the acrylic model 166 to capture the contours designed by the dentist
or the technician.
Once an appropriate rendering of the acrylic model 166 has been generated, a
tool path will be
generated for fabricating the framework out of the appropriate material. The
laboratory or
framework supplier can use a number of manufacturing methods, such as milling,
3D printing, laser
sintering, ceramic pressing, EDM (electric discharge manufacturing), etc...,
in a multitude of
materials, such as titanium, zirconia, cobalt chrome, semi-precious metals,
etc... to fabricate the
resulting framework. It can also be appreciated that the dentist or technician
may also possess the
scanning and/or fabrication equipment necessary to perform these tasks or a
portion of these tasks
internally within their own facility.
[0091] Once the acrylic model 166 of the framework has been duplicated in the
appropriate
material the duplicate framework 168 and stone cast125 are returned to the
dentist or technician. As
noted in STEPS 662 and 664, the duplicate framework 168 is placed in the
patient's mouth onto
anchors 104 and reviewed for fit and to ensure the duplicate framework 168 has
the appropriate
contours necessary for the final prosthesis. The dentist and technician may
choose to alter some of
the contours of the framework to better accommodate the necessary function,
aesthetics and
phonetics of the patient. These alterations can vary from reducing the height
of the support posts
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164 or reducing a facial/buccal/lingual contour of bridging structure 154 to
reduce the potential of
the prosthesis from extending into the cheek or tongue. Some dentists and
technicians may elect to
skip these steps.
[0092] As noted in STEPS 666-630, the dentist or technician can begin
fabricating the
crowns. The process outlined here in is in utilization of dental scanning unit
commonly found in the
market place. More detailed information regarding this process can be found in
Patent Application
11/576,450. The following information will only briefly cover the necessary
steps associated with
this process to provide a general understanding and should not be considered a
detailed outline for
the different scan/design systems currently available in the dental market. It
can also be appreciated
that the crowns can be fabricated by alternative means such as a more
traditional waxing and casting
method. This enclosed process should only be considered as exemplary. In STEP
666, the dentist or
technician will refine the margins 162 of the framework where the crowns will
mate. Many times
the manufacturing process used in creating the duplicate framework can leave
tool marks or
additional material in these small areas due to limitations of tool size,
access, or limitations of the
manufacturing process itself. Using a hand piece and bur, the dentist or
technician will remove any
material left by the manufacturing process to create a clear and uniform
margin 162 around the
support post 164. Once the margins have been refined appropriately, the
framework while
positioned on stone cast 125 will be impressed utilizing an impression
material 122 and a second
framework stone will be created with dental stone material 126. These
processes are noted as
STEPS 668 and 620 in Flowchart 600. The dentist or technician will section the
stone support posts
from one another by splitting the framework stone into multiple individual
dies. The individual
support post dies will be separately scanned to accurately capture the margin
where the crown will
mate to the framework. The support post dies will be scanned together and a
stone cast of the
opposing arch will be scanned in an appropriate orientation relative to the
support post formations.
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These scan sets will be appropriately aligned relative to one another. A crown
for each support post
will be designed virtually. This process can take considerable time for the
dentist or technician in
creating the individual support post dies, scanning each one, and then in turn
designing an
appropriate crown. Once the virtual models of the crowns are complete, the
models are typically
loaded into a mill where the crowns are manufactured out of an appropriate
material such as
zirconia, titanium, semi-precious metal, lithium disilicate, plastic, PMMA,
acrylic, resin ceramic
(Lava-Ultimate, Vita-Enamic), etc... The crowns can also be manufactured by
means of additional
manufacturing processes, such as 3D printing, laser sintering, ceramic
pressing, EDM, etc...Once all
of the crowns 170 have been fabricated their fit is assessed against the
margin 162 and support posts
164 of duplicate framework 168, as noted in STEP 628. Many times the
technician or dentists have
to reduce or modify the contours of the framework or crown in order to achieve
the appropriate fit.
If the fit is deemed unacceptable, the dentist or technician may need to
attempt at refabricating the
crown, which may result in creating a new impression of the framework and
repeating the tasks
associated with fabricating the necessary crowns, STEPS 668-628. These errors
and reworks can be
costly, time consuming and prevent the final prosthesis from being completed
in a timely manner.
When all of the crowns have been deemed to fit appropriately to the duplicate
framework 168, the
dentist or technician will check the occlusal contacts of the crowns against
the opposing dentition
and modify utilizing a hand piece and bur to reduce the occlusal contours and
provide the
appropriate level of contact with the opposing arch. A gingival mask can be
applied to the
framework, which can be performed in several ways either by processing pink
acrylic, stacking
composite materials, or applying porcelain onto the duplicate framework 168.
These processes are
commonly known in the dental industry and will not be covered in great detail
here in this
application. Finally the dentist is ready to deliver the duplicate framework
with the gingival mask
and cement the crowns 170 onto the framework in the patient's mouth.
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[0093] If the framework design was indicated for a traditional hybrid design,
the technician
will not perform all the STEPS outlined in FIG. 11A. FIG. 11B provides a list
of reduced steps that
excludes the requirements for designing and fabricating the individual crowns.
Also the dentist or
technician will not be required to include or refine the margins or the
support posts as previously
discussed. Once the framework has been fabricated, the dentist or technician
will begin to set the
denture teeth to the framework as noted in STEP 714. Many times the underside
of the denture teeth
have to be reduced or modified in order to be correctly positioned relative to
the bar and the
opposing dentition and in order to create room for the acrylic that will be
processed. There may also
be times when the fabricated framework is reduced rather than the denture
tooth. The dentist and
technician have to be careful in performing these modifications. If the lower
acrylic portion of the
denture teeth are reduced significantly, the processed acrylic will not be
able to bond appropriately
to the denture teeth and the denture teeth can break free from the acrylic
when occlusal loads are
distributed onto the prosthesis. If the framework is reduced significantly,
the mechanical strength of
the framework can be compromised and the framework will begin to flex during
occlusal loading
potentially leading to the framework and/or acrylic breaking. Once the Denture
teeth have been
properly set, the dentist or technician will process the acrylic through a
commonly known method
(injection, packing, pour, VLC- visible light cured, heat cured, cold cure).
The dentist or technician
will refine and polish the processed acrylic and deliver the finished
restoration to the patient.
[0094] In addition to duplicating an acrylic model 166 of the framework, the
dentist or
technician can utilize a process as outlined in Patent 8,100,692, where the
framework is digitally
design on the basis on the soft tissue contours of stone cast 125 and position
of the denture teeth and
gingiva contours of diagnostic wax up 130. This process alleviates the need
for an acrylic model and
provides for an improved design in knowing the position of the buccal and
lingual boundaries of the
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prosthesis. However this process cannot guarantee that the denture teeth or
framework will not need
to be modified prior to processing the acrylic or prevent the potential
breakages noted above.
[0095] In creating a dental prosthesis consisting of an implant framework
supporting a series
of crowns/bridges as outlined in Application 14/272,566, the dentist and/or
technician will create a
stone cast 125 and diagnostic wax-up 130 as previously discussed. It is from
these elements, where
the invented process will allow for the simultaneous design and fabrication of
the crowns and
framework. First a digital scan of the stone cast 125 utilizing the alignment
posts 156 attached to the
analogs 124 as detailed in application serial number 11/875,826, is conducted.
This process will
determine the exact location of the critical mating geometries and their
correlation relative to one
another as well as relative to the soft tissue contours captured in the stone
cast. As demonstrated in
FIG 12A, in step 214 of the process, the dentist sends the stone cast 125 and
diagnostic wax up 130
to the laboratory. In step 216, the laboratory inserts alignment posts 156
into the analogs 124
embedded in the stone cast 125. These alignment posts 156 are configured to
engage the mating
surfaces of analogs 124 and hold the alignment posts coaxial with the
longitudinal axis of analogs
124. They may have differently shaped flat, frusto-conical and cylindrical
surfaces configured to
engage with the mating surfaces of analogs 124. The alignment posts 156 used
in this process have
two spherical surfaces comprising centers coaxial with analog 124. These
alignment posts need not
have spherical surface portions, but may have any predetermined geometric
shape as deemed suited
by the user. This process also encloses the use of a single gauge; however it
can be appreciated that
a series of gauges could be used instead of a single embodiment to achieve the
same result.
[0096] The mating surfaces on the alignment posts and the mating surfaces on
the analogs
124 inter engage to cause the alignment posts 156 to be aligned coaxial with
analogs 124. The
alignment posts 156 cover the free ends of the analogs 124 exposed in stone
cast 125.
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[0097] In step 218, once the alignment posts 156 have been attached to the
analogs 124, the
scanner 182 is configured to scan the alignment posts and the soft tissue
replica of the patient's
mouth formed in the surface of the stone cast 125, and the alignment posts
156. The surfaces of
stone cast 125 that are scanned by scanner 182 include the surfaces of the
stone cast that replicate the
mucosal tissue in the patient's mouth. Scanner 182 stores in the memory of
computer 186 a first
point cloud dataset of the stone cast 125 with alignment posts 156 attached.
In step 218, scanner 182
also scans the surface of diagnostic wax-up 130 and the surface of stone cast
125 (preferably when
they are assembled) and saves a second point cloud dataset collectively
representing the scanned
surface of the diagnostic wax-up 130 and stone cast 125. Alternatively, the
operator can scan the
diagnostic wax-up 130 separately from the stone cast and later register the
point cloud dataset of the
stone cast 125 and the diagnostic wax-up 130.
[0098] If the diagnostic wax up 130 is scanned on the stone cast 125, the scan
preferably
includes data points taken from all the exposed external surfaces of the
diagnostic wax-up 130 (i.e.
the outwardly facing surfaces that model the gum and the teeth) as well as
surfaces of the stone cast
125 adjacent to the diagnostic wax-up 130. The surfaces of the stone cast 125
adjacent to the
diagnostic wax-up that are scanned in the second point cloud dataset are also
preferably scanned in
the first point cloud dataset and thus there is some overlap in surface
contours in both the first and
the second point cloud datasets--both datasets include data points scanned
from the same surfaces of
stone cast 125. This permits later registration of the first and second point
cloud datasets.
[0099] If the diagnostic wax-up 130 is scanned when it is separate from the
stone cast 125, it
is preferably scanned so that the second point cloud dataset includes data
points taken from all the
exposed external surfaces of the diagnostic wax-up 130 (i.e. the outwardly
facing surfaces that
model the gum and the teeth) as well as surfaces of the diagnostic wax-up 130
that would abut stone
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cast 125 if the diagnostic wax-up 130 was mounted on the stone cast. Since the
diagnostic wax-up
130 was formed by molding a plastic (or wax or acrylic) material to the
surface of the stone cast 125,
the scanned surface contour of the diagnostic wax-up 130 that abut the stone
cast are a mirror image
of surface contours of the stone cast 125.
[0100] In the preferred embodiment these abutting stone cast 125 surfaces were
scanned
previously and are a part of the first point cloud dataset. Thus, the first
and second point cloud
datasets include a subset of data points taken from mirror image surface
contours--surface contours
common to both the first and second point cloud datasets¨common to the
diagnostic wax-up 130
and to the stone cast 125. This permits later registration of the first and
second point cloud datasets.
[0101] In step 220, computer 186 determines the location and orientation of
the alignment
posts as they are attached to analogs 124 in the stone cast 125. Computer 186
sequentially selects a
digital parameterized fitting 152" from its internal library and aligns the
mating surface (or surfaces)
and axis of the selected digital parameterized fitting 152" with the surface
(or surfaces) and axis of
one of the analogs based upon datums derived from the alignment posts 156.
Computer 186 repeats
this process for each additional analog 124 whose location and orientation
were determined in step
220, until it has built up an initial surface model of dental framework 324.
[0102] In step 222, a surface model of the unique contours of stone cast 125
is created which
is a representation of the soft tissue contours in the patient's mouth. The
stone cast surface model
320 will provide a lower limit to which the framework can be designed to.
[0103] In step 224, a surface model of the unique contours of diagnostic wax
up 130 is
created which is a representation of the proposed prosthesis for the patient.
The diagnostic wax-up
surface model 322 contains the unique buccal/facial and occlusal contours of
the denture teeth 132.
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The diagnostic wax-up surface model 322 will provide the necessary information
regarding the
orientation of the individual denture teeth 132 as they are positioned
relative to one another within
diagnostic wax-up 130. The diagnostic wax up surface model will also capture
any unique gingiva
contours as designed by the dentist or technician.
[0104] The surface models 320 and 322 can be the raw point clouds derived from
the scan
data of the stone cast 125 and diagnostic wax-up 130 or can be a sheet body,
where a surface has
been wrapped across the raw point clouds. These models can also be closed
surface models,
allowing for Boolean Unite and Subtract Operations to be performed utilizing
these models or other
CAD bodies.
[0105] The two sets of scan data and resulting surface models of the stone
cast 125 and
diagnostic wax-up 130 provide all of the necessary data for determining the
position of the denture
teeth 132 in diagnostic wax-up 130 relative to the implants/abutments and the
soft tissue contours of
stone cast 125 as well as defining the boundaries or limits in which the
framework should be
designed within. The scan data of the diagnostic wax up 130 will provide all
of the necessary
positional information for determining the correct orientation of the crowns
and related support posts
(The term prep tooth forms or PTF can be used in place of the term support
posts. Both prep tooth
forms (PTF) and support posts are descriptive of the portion of the framework
that will mate with
and support the crown.).
[0106] The framework is created through a novel concept in utilizing a library
of crown
models and prep tooth forms (support posts). The crown models are based upon
known dimensions
of standard tooth sizes. Many of the current dental design software systems,
such as Procera,
3Shape, or Dental Wings, have a library of digital crown or tooth files based
upon these standard
dimensions. Stock Denture Teeth are also constructed on the basis of the
standard tooth size and are
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commonly used in the construction of dentures, over-dentures, and fixed hybrid
restorations for
treatment of the edentulous patient. Also some of the previously mentioned
software systems
include models of the denture teeth in their library. As discussed previously,
these denture teeth 132
are commonly used in the dental market and consist of known dimensions that
have been
standardized for mass production. By utilizing a non-contact or touch probe
scanner similar to the
one described in FIG 13, an operator can capture the unique contours of the
commonly available
denture teeth 132 that are used by the dentist or technician in creating the
diagnostic wax up 130.
FIGS. 14A-B show a model of the reverse engineered denture tooth and shows the
unique occlusal
contours 300 and buccal/facial contours 302 captured during the scanning
process. The scanning
process will also capture the intaglio surface 304 or underside of the denture
tooth, which will enable
for the creation of a denture tooth model 306. On the basis of the denture
tooth model 306 and
occlusal contours 300 and buccal contours 302, a PTF 310 can be designed to
optimally support a
crown that has the same or similar contours as the denture tooth. The Prep
Tooth Form or PTF 310
can be designed to accommodate an appropriate wall thickness of the crown and
provide an ideal
margin 162 where the crown will mate with the framework. The crown model 312
consists mostly of
the contours of the reverse engineered denture tooth 132 captured in denture
tooth model 306, but
additional features or material can be added to the crown model in generating
an ideal mating
surface that will interface with the PTF or provide an ease in manufacturing.
The added lingual
crown material 308 as shown in FIGS. 15A and 15B has been included into the
design to create a
more planar mating surface or margin 162 between the crown model 312 and PTF
310. However it
can be appreciated that the mating surface or margin 162 can be non-planar and
provide a margin
162 that is more in line with one that the dentist or technician would find
for a prepped tooth or
custom abutment. The lingual crown material 308 can be designed to aid
during the gingival
masking process. In this example, straight parallel walls have been included
into the design to
improve the retention of the crowns after acrylic processing. An appropriate
cement gap 314 also
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has to be designed into the crown model 312 to provide the necessary space for
dental cement that
will allow for the crown to be fixated to the framework. The cement gap 314
will terminate at
margin 162, where the crown and framework will ultimately mate.
[0107] The crown model 312 can be designed in a parametric or non-parametric
CAD body.
In the non-parametric form, the crown model is a rigid duplicate of the
denture tooth model 306.
This non-parametric model does not provide the CAD Operator with an ability to
easily modify the
surface or contours of the crown model 312. For a non-parametric CAD body, the
operator will
have to use Boolean and Trim functions to add or subtract additional features
in order to change the
occlusal contours 300 and buccal contours 302 of the crown model 312. In
comparison the
parametric CAD body can be constructed of a series of splines and sheets,
possessing data points or
poles, allowing for the CAD Operator to modify or alter the surface of the
crown model 312. The
parametric CAD body allows for easy manipulation of the crown model surface to
accommodate any
design requirements required by the dentist. One example of manipulating the
crown model surface
would be modifying the occlusal contours of the crown. The dentist or
technician may choose to
lower or heighten all or portions of the occlusal surface to provide an ideal
occlusal relationship with
the opposing arch. Another example would be modifying the mesial/distal side
contours in order to
increase or decrease the mesial/distal contacts between the crowns.
[0108] FIGS. 15A-F depict an exemplary crown model and PTF. FIGS. 15A-F depict
a
molar crown model 312 and PTF 310. For demonstration purposes this application
will only show
the design of a crown model and PTF for a molar tooth. It can be appreciated
that the PTF can be
designed to properly accommodate any size tooth, such as an incisor, cuspid,
or premolar. It can
also be appreciated that any denture tooth system can be incorporated though
the disclosed process.
There are also available libraries of stock crown CAD files, in many of the
dental design systems
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that can be incorporated and utilized in addition to reverse engineering the
stock denture teeth. The
PTF 310 has been designed to properly support the cusp structure of the
reverse engineered denture
tooth and the designed crown model 312. The design of the PTF 310 can also be
modified in any
way deemed appropriate by the designer to meet the requests of the customer.
The height and width
of the PTF can be altered to better deal with the restorative space presented
with the case. The
enclosed PTF design has a much more flat and planar design associated with the
margin 162. Other
designs may utilize a much more natural root form margin that comes up higher
in the mesial/distal
aspects of the crown and lower in both the lingual/buccal aspects.
[0109] As demonstrated in FIGS. 15E-F the crown model and PTF can be combined
into
assembly 316 and share the exact coordinate system, allowing for them to be
aligned relative to one
another in an ideal fashion. Assembly 316 allows for the crown model 312 and
PTF 310 to be
readily imported and remain properly aligned relative to one another. However
it can also be
appreciated that the crown model 312 and PTF 310 can be imported separately
depending upon the
CAD system or processes being implemented by the Operator. One example of
importing PTF's
310 without the crown files would be if the dentist or technician is planning
on creating custom
crowns for the final restoration. In this instance the utilization of the
crown files may be completely
unnecessary and the operator can position PTF 310 in the ideal position to
support the crown. This
exemplary process would also allow the technician to utilize one of the other
dental design software
packages previously mentioned to design and fabricate the crowns, in a similar
fashion as through
the "copymill" process.
[0110] FIGS 15 A-D show in closer detail crown model 312 aligned appropriately
to PTF
310. As depicted in the figures the PTF 310 expands substantially to support
the crown model 312
in the mesial distal aspect FIG 15 A and the lingual facial aspect FIG 15 B.
FIGS. 15 C and D are
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cross-sectional views of the crown model 312 and PTF 310 showing the cement
gap 314 and margin
162 where the crown intimately mates with the PTF. The cement gap 314 and
margin 162 can be
adjusted by the designer to meet the customer requirements or to better suit
the preferred
manufacturing process. FIGS 15 A-F show the ideal orientation of the crown
model and PTF.
However there are instances when this orientation may not be ideal due a
design requirement for a
particular case. The crown model and PTF can have a series of dependent
features that when a
change in the feature of one body is performed, the second dependent body will
automatically update
based upon this change. One example would be repositioning the height of the
PTF. As
demonstrated in FIG 15 G, when the PTF is positioned higher relative to the
crown model 312, the
cement gap 314 and margin 162 will automatically update to accommodate for
this new position.
The crown model 312 and PTF 310 can also be allowed to be positioned in
different orientations
relative to one another and similarly update on these new positions. Another
example as
demonstrated in FIG. 15 H would be repositioning the angle of the PTF due to
an issue of path of
insertion or tool access for manufacturing. As shown in FIG 15 H, when the PTF
is aligned to the
new position not only does the cement gap 314 update, but also margin 162 will
update to this new
alignment. This dependency provides the ability for the designer to make
simple modifications in a
timely fashion when designing the framework in accommodating a design request
for a customer or
allowing for an ease in manufacturing.
[0111] The crown/PTF assembly 316 can possess additional sub features in
addition to the
full contour crown surface. The crown model can have subtract features which
will provide the
technician and dentist with a standard coping or cutback coping that would be
ideal in stacking
porcelain. The standard coping or cutback coping can be included through the
use of a Boolean
Subtract Feature or as a separate CAD body within the Crown/PTF assembly 316.
The inclusion of
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these features provides a broad spectrum of restorative elements for the
dentist or technician to
choose from.
[0112] In step 226 of FIG 12, the Crown/PTF assembly 316 is imported and
aligned relative
to the diagnostic wax-up surface model 322. The crown /PTF assembly 316 will
have the same
surface contours as one of the denture teeth 132 that was incorporated into
diagnostic wax up 130.
Utilizing a best fit operation, the crown/PTF assembly 316 will be properly
positioned on the basis
of the facial/buccal and occlusal contours for the specific denture tooth 132.
FIGs 16 A-B
demonstrate this process. In FIG 16A, a molar crown/PTF assembly 316 is
aligned appropriately to
diagnostic wax-up surface model 322. In FIG 16B, the additional crown/PTF
assemblies are aligned
for the incisors, cuspids, premolars, and remaining molar. This alignment
process can be carried out
by computer 186 automatically or overseen and performed manually by the
operator.
[0113] In Step 228, the Operator will review and adjust the position of the
PTF's 310 to best
accommodate the aesthetic and functional demands for the case. As discussed
above, this process of
moving the PTF's 310 can also accommodate for improved tool access on the
basis of the
manufacturing method. Once appropriately positioned into the proper
orientation, the cement gap
314 and margin 162 will automatically update on the basis of this new
position. FIG 17 shows all of
the PTF's 310 in there appropriate position, while the crown models 312 and
diagnostic wax-up
surface model 322 are hidden. FIG 18 shows the PTF's 310 and DPF's 152"
properly positioned
relative to one another. In step 230, the computer 186 is configured to
generate a surface model of
bridging structure 154' (FIGS. 19 A-B) that will join PTF's 310 and the
digital parameterized fittings
152". This includes the computer 186 determining the cross-sectional shape,
length and location of
the bridging structures as described below. This surface model of this
bridging structure 154' extends
between and joins PTF's 310 and the digital parameterized fittings 152" and
thereby completes the
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surface model of the dental framework 324. Bridging structure 154' also
comprises the portions 155
that extend away from the end digital parameterized fittings 152" and are
supported only at one end.
One form of the bridging structure is shown in FIGS. 19A-B as a simple
elongated member having a
predetermined cross section.
[0114] To generate bridging structure 154', computer 186 determines the shape,
length, and
location of the individual portions of the bridging structure to attach PTF's
310 and digital
parameterized fittings 152". It is further configured to determine the shape
length and location such
that the individual portions will not intersect the stone cast surface model
320. Since the surface of
the stone cast 125 represents the exposed surfaces (including mucosal tissue)
in the patient's mouth,
this reduces the likelihood that the physical framework created from the
surface model will contact
and damage the patient's mucosal tissue. Computer 186 is configured to provide
a separation
distance between the surface model of the stone cast and the bridging
structures. In one arrangement
the computer 186 is configured to place the bridging structures a
predetermined minimum distance
from the surface model of the stone cast. In another arrangement the computer
is configured to
permit the operator to select a desired minimum distance between the bridging
structure and the
stone cast surface model 320. In another arrangement, the computer is
configured to offer to and/or
accept from the operator only a certain range or number of minimum separation
distances, such
minimum separation distances preferably ranging between 0.1 mm and 5 mm.
[0115] Computer 186 is configured to create the bridging structure by
providing a pre-
designed list of bridging structure forms (e.g., a cylinder, circle, ellipse,
square, polygon or other
geometric shape) that have been previously stored in the electronic memory of
the computer. In one
configuration, the computer is configured to automatically select the cross
sectional dimensions of
each form (diameter, radius, major and minor diameter, height, width, etc.).
In another configuration
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the computer is configured to present the user with a list of pre-set values
or defined by the user
among which the user can select preferred dimensions. In yet another
configuration, the computer is
configured to prompt the user to enter specific numeric values for these
dimensions. The form of the
bridging structures can also be defined by the user.
[0116] Computer 186 is configured to determine the proper location of the
bridging structure
154' extending between the PTF's 310 and the digital parameterized fittings
152" by locating the
beginning and end of each structure according to position information that is
derived from the
scanned point cloud dataset of the alignment posts. Position of the bridging
structure can also be
determined by the operator or from the point cloud data set of the stone cast
and/or diagnostic wax
up.
[0117] In another arrangement, the computer 186 is configured to determine the
location of
the bridging structure 154' extending from each of the PTF's 310 and digital
parameterized fittings
152" by locating the beginning and end of each structure according to
reference points and axes
assigned to the digital parameterized fittings 152" by the computer program
from a list of pre-set
values or defined by the user. For example, each PTF 310 and digital
parameterized fitting 152"
which is placed in the model may have only certain types of bridging
structures to which they can be
connected, and may only connect to those bridging structures at certain
locations on the PTF or
digital parameterized fitting. This information is stored in the electronic
memory of computer 186 in
association with each PTF or digital parameterized fitting. When a particular
PTF or fitting is
inserted into the model, computer 186 is configured to the type and location
information associated
with the inserted PTF or fitting and locate (or permit the operator to locate)
bridging structures of the
type and at the locations compatible with those PTF's or fittings. This
process can also ensure the
bridging structure does not extend into critical mating areas of PTF 310 and
digitally parameterized
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fitting 152" that would affect the potential fit of the crowns or
implant/abutments to the framework.
In the case of distal extensions 155, computer 186 is configured to cantilever
them off the digital
parameterized fittings 152" and extend them distally along the arch of the
patient's mouth. These
distal extensions 155 are preferably 20 mm in overall length or less. They are
also selected as
described above.
[0118] Computer 186 is configured to conduct a mechanical design analysis of
the distal
extensions 155 that validates shear and bending strength limits for those
geometries relative to their
chosen material and shapes. Computer 186 is configured to apply the
appropriate shear, tensile and
compressive stress analysis techniques to the chosen geometries automatically
or from a pre-
determined list of tests chosen by the user. Upon successful analysis of the
distal extension designs,
the extensions are verified or accepted by the user.
[0119] As part of the step of generating the bridging structure 154' computer
186 is
configured to determine a location for the bridging structure 154' that will
not intersect the
diagnostic wax-up surface model 322. This ensures that the bridging structure
154' of the final
denture framework will not stick through, but will be disposed within, the
body of the diagnostic
wax-up 130.
[0120] It can be appreciated that all of the disclosed steps being performed
by computer 186
can be performed manually by the Operator. The Operator can also determine the
use of any number
of custom geometries or series of geometries to be used for the bridging
structure 154' and distal
extensions 155.
[0121] Upon completion of the bridging structures 154' and distal extensions
155, the final
surface model of the framework 324 is complete. The final surface model of the
framework will
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consist of PTF's 310, DPF's 152", bridging structures 154' and distal
extensions 155. FIGS 19 A-B
show the final surface model of the framework 324. Computer 186 will also
determine any
interference between the crown models 312 and the surface model of the
framework 324 that may
have been generated during the design process.
[0122] In STEP 232, computer 186 will finalize the surface model of the
framework and
crowns by alleviating any interference between these surface models. This
process is performed
through a Boolean subtraction of the surface model of the framework 324 from
crown models 312.
FIGS 20A-B show the crown models 312 and surface model of the framework 324
appropriately
positioned relative to one another. At this time the Operator can also choose
to include screw access
holes into the crown models 312 at the request of the dentist or technician.
[0123] There also may be times when the dentist or technician may prefer the
crown models
312 be adjoined to one another into a bridge due to design limitations
associated with the case, such
as the position of a screw access hole or limited vertical space, or to meet a
personal preference of
the dentist. In FIG 21, crown models 312 have been adjoined to one another in
creating bridge
model 350. Through a Boolean Union or the addition of other CAD features
herein referred to as
bridge bodies 352, the crowns 312 can be adjoined to one another as best
determined by the Operator
and can include all of the crowns or as few as two. In FIG 21 five crown
models have been
combined into forming bridge model 350 by means of bridge bodies 352. Bridge
bodies 352 can
consist of a standardized profile (e.g., a cylinder, circle, ellipse, square,
polygon or other geometric
shape) or the Operator can custom design an appropriate structure to provide
the appropriate
mechanical strength to resist against the occlusal forces of the patient's
bite. If necessary the
Operator can add appropriate features or geometries to ensure the bridging
structure will properly
mate to the framework and function under the occlusal loads of the patient. At
times the creation of
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bridges or adjoining the crowns may be necessary due to the position of a
screw access hole that
would significantly reduce the size of a PTF 310 to a point where it would not
be able to properly
support a crown by itself. In this instance bridging the crown in this area to
one or both adjacent
crowns would prevent it from becoming damaged or dislodged when placed under
occlusal loads by
the patient.
[0124] The operator may also determine it be best for the PTF's 310 be linked
to one another
in creating a larger support post geometry to support the overlying bridge. In
the same manner that
the bridging structures 154' are extended between the PTF's 310 and digitally
parameterized fittings
152", a PTF bridging structure can be incorporated into the design either
automatically by computer
186 or manually by the operator. This PTF bridging structure can consist of a
standardized profile
(e.g., a cylinder, circle, ellipse, square, polygon or other geometric shape)
or the Operator can
custom design an appropriate structure based upon the patients clinical
conditions. The PTF
bridging structure can have a constant cross-section or allow for portions of
the PTF bridging
structure to taper in from the buccal/lingual aspects to provide additional
anti-rotation features when
the overlying crowns or bridges are positioned on them appropriately. FIG 22
shows a portion of
framework model 324 with a PTF Bridging Structure 354 that has been created to
support bridge
350. The PTF bridging structure extends across digitally parameterized fitting
152" in order to
provide the necessary support for bridge 350. Due to the position of digitally
parameterized fittings
152" and the resulting screw access holes, the standard PTF's were reduced
drastically requiring for
the creation of bridge 350 and the PTF bridging structure 354. FIG 23 A-B show
framework model
324 with bridge 350 properly positioned to one another.
[0125] It is also at this time that the Operator can choose to combine
portions or the majority
of the diagnostic wax-up surface model 322 to the crowns and/or bridge, to
ensure the gingiva
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contours are included in the design. This process may be advantageous where
there is limited
vertical space associated with the patient. In having the gingiva contours
incorporated into the
design, the operator can ensure the gingiva will have substantial strength
characteristics as it is
joined and fabricated from the same material as the crown or bridge. In the
case of a full Zirconia
restoration, the technician can apply coloring through stains and dyes in
order to create the aesthetics
for both the gingiva and crown portions. In addition to combining portions of
the diagnostic wax up
to the crowns in creating the gingival structures, the operator can choose to
design custom gingiva
features onto the crown utilizing the tools in the design software. This
process would allow the
operator to modify the contours to best meet the clinical demands of the case
or to provide the best
foundation for the finishing processes to be performed after the crown/bridge
with gingiva has been
fabricated. One example would be in the creation of gingival contours that
would be ideal for
porcelain stacking. Rather than having the exact contours of the diagnostic
wax-up surface model
322, the preferred geometry may be the creation of a small shelf with the
buccal aspect of the
gingiva contour reduced slightly to accommodate the added thickness of the
porcelain. The
Operator could determine the appropriate dimension for the necessary
porcelain, for example 1-2
mm, and create the appropriate trim or Boolean subtraction to reduce the
gingiva contour from the
diagnostic wax-up surface model 322 or custom design the appropriate gingiva
construct manually
using the CAD tools provided in the software.
[0126] In STEP 234, tool paths are generated for the surface model of the
framework 324,
crown models 312 and/or bridges 350. Since the orientation and position of the
framework and
crowns has been determined along with the orientation and position of the
DPF's 152" and margins
162 (where the crowns mate to the framework), both the framework and crowns
can be
manufactured simultaneously in the chosen material (titanium, cobalt chrome,
zirconia, wax, plastic,
composites, acrylic, lithium disilicate, plastic, PMNIA, resin ceramic (Lava-
Ultimate, Vita-Enamic)
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etc...) and through the preferred manufacturing process (milling, laser
sintering, 3D printing, EDM,
etc...).
[0127] Once the framework and crowns have been manufactured, they are
delivered to the
dentist and/or technician for the creation of the gingiva contours. The
gingiva contours can be
created by applying acrylic, composites, porcelain, or any other preferable
dental material to the
framework. If the gingiva contours were included in the design of the crowns,
the technician will
perform the necessary processing (i.e. staining, coloring, stacking porcelain,
adding acrylic or
composite...) to complete the gingiva aesthetics.
[0128] The above disclosed invented process utilizes a traditional diagnostic
wax-up 130,
which provided the position of denture teeth 132 and ultimately PTF's 310 and
crown models 312.
In the first alternate embodiment of the process outlined in Application
14/272,566, the use of a
virtual set up is used in place of the diagnostic wax-up 130. There are
currently multiple dental
systems and software (such as 3Shape, Dental Wings, Avadent and Procera) which
have the ability
to lay in CAD models of denture teeth or stock teeth relative to scans of a
stone cast and an opposing
dentition. For this first alternate process, the stone cast and opposing cast
would be scanned
separately and then scanned in their proper orientation relative to one
another. Utilizing the scan
capturing the orientation of the stone cast and opposing cast, the scan data
of the stone cast and
opposing cast will be properly aligned to one another. Once properly aligned,
the Operator will
position the CAD models of the denture teeth or stock teeth relative to the
occlusion of the opposing
cast. Once the position of the CAD models of the denture teeth or stock teeth
have been finalized,
this information can be used in aligning the crown and PTF assemblies 316 and
begin designing the
crowns and framework. In addition to utilizing the CAD models of the denture
teeth or stock teeth,
the operator can immediately begin utilizing the library of crown and PTF
assemblies 316 and align
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the assemblies relative to the opposing cast for the proper orientation. This
process may be
advantageous over the previous described process as it alleviates the dentist
and/or technician from
having to create the diagnostic wax up. Also if the crown models are truly
parametric, the operator
can modify the design of the occlusal contours and buccal contours of the
desired crown to meet any
unique design requirements for the dentist.
[0129] In the second alternate process outlined in Application 14/272,566, the
scanning
process for capturing the implant and abutment positions is altered by the use
of an intra-oral scanner
that would directly capture the implant and/or abutment locations in the
patient's mouth along with
the gingiva contours. The intra-oral scanner can also capture the contours of
a diagnostic wax up
that has been placed in the patient's mouth or the position and orientation of
the opposing arch
during the scanning process. From this digital data, the dentist or technician
can identify the
appropriate location of the crown/PTF assemblies 316 and digitally
parameterized fittings 152".
This process would alleviate the dentist or technician from being required to
create an impression or
stone cast.
[0130] In a third alternate process outlined in Application 14/272,566, the
dentist or
technician can utilize a CT scan or series of CT scans for the basis of
determining the appropriate
position of the crown/PTF assemblies 316 and the digitally parameterized
fittings 152". The dentist
or technician can use the CT scan data for determining or planning the
position of the implant
locations and ultimately the position of the digitally parameterized fittings
152". The use of a
radiographic stent demonstrating the ideal tooth position for the restoration
can also be included in
this process and provide the dentist and technician with an ability to align
the crown/PTF assemblies
316 relative to the contours of the radiographic stent or relative to the
position of the opposing arch.
The dentist or technician could also utilize a CT scan of the patient's
previous existing dentition,
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which could be aligned utilizing anatomical markers, in order to determine the
ideal position of the
crown/PTF assemblies 316.
[0131] These alternate embodiments only demonstrate some of the potential
options in
combining different digital data acquisition protocols into the invented
process. As can be
appreciated, these are only a handful of potential embodiments of the invented
process, but should
provide insight as to the adaptation of future technologies.
[0132] The above descriptions, alternate embodiments and processes described
and outlined
in Application 14/272,566 can be appreciated for its ability in providing an
improved functional and
aesthetic restoration for cases with large vertical dimensions. For patients
exhibiting a much smaller
vertical dimension (less than 10 mm), the functional or aesthetic
characteristics of the resulting
restoration may not be ideal. We have already discussed the issues surrounding
traditional hybrid
designed prosthesis utilizing denture teeth and processed acrylic in reduced
vertical dimensions
where acrylic breakage is a common problem. For Individual crown type
restorations, the issue of
reduced vertical dimensions provides a unique challenge where the designer
does not have the
appropriate space for the fabrication of the individual support post or PTF's
and providing crowns
with an appropriate wall thickness to prevent breakage. An additional concern
in reducing the wall
thickness of the crowns is the potential show through of the underlying
support post, which may
affect the shade of the prosthesis. The proposed invention is to provide an
improved prosthesis and
process over any of the previously described in dealing with reduced vertical
dimensions.
[0133] The preferred embodiment of the invention consists of a framework
fabricated form a
dental material (titanium, cobalt chrome, semi-precious metals, precious
metals, zirconia, lithium
disilicate, ceramic, PMMA, composite, plastic, acrylic, wax, etc...) that
supports a veneering overlay
consisting of a second dental material (titanium, cobalt chrome, semi-precious
metals, precious
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metals, zirconia, lithium disilicate, ceramic, PMNIA, composite, plastic,
acrylic, wax, etc ...). FIG
12B outlines the steps for designing and fabricating the preferred embodiment
of the invention.
Similar to the process outlined in Application 14/272,566, alignment posts 156
are attached to the
analogs 124 of stone cast 125 and scanned where computer 186 determines the
location and
orientation of the alignment posts and sequentially selects and aligns digital
parameterized fitting
152" based upon datums derived from the alignment posts 156. Diagnostic wax-up
130 is also
scanned either properly positioned on stone cast 125 or separately and then
aligned to stone cast 125
utilizing the surface contour of the diagnostic wax-up 130 that abut the stone
cast as they are a
mirror image of surface contours of the stone cast 125. When the diagnostic
wax-up is scanned it is
critical to capture the contours of the denture teeth and gingiva as these
contours will be replicated in
the veneering overlay. Surface models of the stone cast (320) and diagnostic
wax-up (322) are
generated on the basis of the scan data. These surface models are constructed
in such a way as to
allow for Boolean Unite, Subtract, and Trim Operations to be performed
utilizing these models or
other CAD bodies. The above listed processes are outlined in Steps 814-824 of
FIG 12B.
[0134] Once all of the scan data, surface models (320 and 322) and digital
parameterized
fittings 152" have been aligned properly to one another, computer 186 imports
and appropriately
aligns framework bridging structure 400 relative to the digital parameterized
fittings 152", stone cast
surface model 320 and diagnostic wax-up surface model 322 as noted in STEP
826. This step can
also be performed manually by the operator. The framework bridging structure
400 consists of a
predefined cross-section and possesses parametric attributes allowing for
portion of the framework
bridging structure to be adaptable to the unique contours of the diagnostic
wax-up and stone cast
surface models. In the preferred embodiment the framework bridging
structure consists of a
rectangular cross-section and can vary in height and length depending upon the
contours of the
surface models 320 and 322. In some areas the bar may be taller than others
due to the changes in
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the patient's soft tissue that are captured in the stone cast surface model
320. In other areas the bar
may be wider than others due to the varying contours of the diagnostic wax-up
surface model 322.
Frequently the width of the diagnostic wax-up 130 is greater in the posterior
regions, where the
molar teeth reside in comparison to the anterior where you will find the
incisors. Ideally the top
surface of the framework will remain on a single plane, but this top surface
can be offset in certain
areas due to fluctuations of the vertical dimension in the patient's mouth.
This top surface 402 will
support and engage the resulting veneering overlay 404. The position and
angulation of this top
surface 402 can be adjusted automatically by computer 186 or by the operator
to meet either the
clinical demands for the dentist and technician or for ease in manufacturing.
The position of this top
surface 402 can be positioned substantially into the area where the denture
teeth reside in the
diagnostic wax-up 130. This design feature is possible as the veneering
overlay 404 will be
fabricated from a single monolithic piece. The buccal wall 410 of framework
bridging structure 400
will be positioned ideally 1-4 mm from the buccal aspect of the diagnostic wax-
up surface model
322. This required clearance allows for an appropriate amount of material to
prevent any potential
show through of the framework through the veneering overlay 404. The operator
or computer will
also adjust the bottom surface 403 of the bridging structure to have the
appropriate clearance or
contact with the gingiva contours as captured in the stone cast surface model
320. The stone cast
surface model 320 can also be used as a Boolean CAD Tool to contour the bottom
of the bar to
match gingiva contours in the patient's mouth by means of a Boolean Subtract
operation. In the
preferred embodiment of the invention, the buccal wall 410 is typically flat
and held at a 90 degree
angle relative to the top surface 402. This design aspect provides an ease in
milling and fabrication.
Obviously this wall angle could be adjusted to meet the technical demands of
the dentist or
technician or due to a limitation associated with the case. In the preferred
embodiment, the lingual
wall 412 of the framework bridging structure 400 will be adjusted to terminate
at the lingual
boundary of the diagnostic wax-up surface model 322 and can be flush with this
boundary. The
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lingual wall 412 can be flat similar to the buccal wall 410 or even rounded if
preferred by the dentist
and/or technician. However using Boolean Unite, Subtract, and Trim Operations
in the CAD
software the lingual wall 412 can be shaped to exactly replicate the boundary
of the diagnostic wax-
up surface model 322 and follow the exact lingual contours as created in
diagnostic wax-up 130 by
the dentist. FIG 24A and 24B depict an embodiment of the framework 408. As
demonstrated by
these figures, digital parameterized fittings 152" has been united through a
Boolean Unite Operation
to framework bridging structure 400, as noted in Step 828. In this embodiment,
the digital
parameterized fittings 152" are substantially within the body of the framework
bridging structure
400. In some embodiments these digital parameterized fittings 152" may extend
through or slightly
out of the framework bridging structure 400.
[0135] As part of the framework bridging structure, one or more support posts
406 can be
positioned on top surface 402. Support posts 406 provide macro retention and
resistance against
lateral forces between the framework bridging structure 400 and the veneering
overlay 404. The
support posts 406 can be imported as part of framework bridging structure 400
or imported
separately. The preferred design of the support posts 406 is a design
consistent with a cylinder,
which can be easily milled or fabricated by a known method (laser sintering,
wire EDM, etc...), but
can consist of any number of different cross-sections as desired by the
operator, e.g., a cylinder,
circle, ellipse, square, polygon or other geometric shape. In addition to the
support posts, the design
can consist of slots or recesses on the buccal wall 410 or lingual wall 412.
The combination of
framework bridging structure 400, digital parameterized fittings 152" and the
associative retention
features (support posts 406 or other retention features) creates the complete
embodiment of the
dental implant framework 408.
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[0136] As the framework bridging structure 400 is being designed, the
veneering overlay 404
is being designed simultaneously. The veneering overlay 404 is created
directly from diagnostic
surface model 322, by the use of a Boolean subtract operation and a unique
subtract body related to
the framework bridging structure 400. As discussed in Application 14/272,566
where the crowns,
margins, and cement gaps are updated by the repositioning of the PTF or
support post, the unique
mating surface of the veneering overlay 404 is updated/refined by a unique
subtract body that is
dependent upon the design features of framework bridging structure 400 and
digital parametrized
fittings 152" (top surface 402, support posts 406, buccal wall 410, lingual
wall 412, slots, recesses
etc.). The subtract body creates the necessary overlay mating surface 402' and
the appropriate
clearance gaps 414 that provide the necessary space and clearance between
buccal wall 410,
parameterized fittings 152", and protrusions 406. Clearance around the buccal
wall 410,
parameterized fittings 152", and protrusions 406 allows for an intimate mating
of the overlay mating
surface 402' to the top surface 402 of the framework bridging structure 400.
This design aspect
allows for an appropriate transfer of occlusal forces from the veneering
overlay 404 to the top
surface 402 of framework bridging structure 400 and ultimately to the dental
implants in the
patient's mouth. This clearance gap 414 also provides a space where a bonding
agent such as
cement, acrylic, heat cured bonding agent, chemical bonding agent (epoxy) can
be used to
permanently retain the veneering overlay 404 to framework 408. The subtract
body for veneering
overlay 404 can also include bodies for the parameterized fittings 152" and
screw access holes 418
to be subtracted from the veneering overlay 404. This design feature allows
for the dentist to access
the screws retaining the framework to the implants without having to remove
the cemented
veneering overlay 404. However at times the dentist may choose to bond the
veneering overlay 404
in the patient's mouth either due to aesthetic demand or issue with a screw
access hole coming
through a buccal aspect of the prosthesis. The previous description describes
a design where the
veneering overlay 404 is retained to framework 408 by means of a bonding
agent, which is the
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preferred method. Bonding agents, such as cement, allow for the restoration to
work in the smallest
restorative spaces possible and permanently fixates the veneering overlay to
the framework, which
allows for the most optimal performance of the restoration in the patient's
mouth. It is obvious that
other means of retention such as the use of screws, mechanical clamps, or
memory alloy clamps
(Patent 8,678,822) could also be used in retaining the overlay to the
framework if space allows, but
these mechanical retention means can deteriorate over time and be costly in
replacing. If a
mechanical retention means is used, the dentist or technician would still want
to apply a material
(silicone) that would seal the clearance gap between the veneering overlay 404
and framework 408.
[0137] FIG 25A, B, C, D and E depict the preferred embodiment of the invention
as
described above and demonstrates the framework bridging structure 400,
veneering overlay 404, the
mating surface 402', top surface 402, support posts 406, buccal wall 410,
lingual wall 412 and
clearance gap 414. FIG 25D and E are cross-sectional views of the framework
408 and veneering
overlay 404 and demonstrate the areas where clearance gap 414 are positioned
relative to the two
parts. In the preferred embodiment depict in these figures, the lingual wall
of the framework is
exposed. This feature is aimed in simplifying the operations associated with
fabricating the
framework and veneering overlay. The lingual wall 412 and the bottom surface
403 of the
framework 408 may be polished and left exposed or the technician may choose to
apply a dental
material such as composite or acrylic to wrap and seal these surfaces. Some
doctors prefer this type
of design as it allows them to adjust or add to this surface as the patient's
gingiva contours may
change over time. This additional work can be done at the same time that any
other required
finishing steps are performed prior to delivering the restoration to the
patient's mouth. The design of
the veneering overlay 404 can also be altered by covering the lingual wall
412. The unique subtract
body would need to be slightly altered to accommodate this design feature in
creating the
appropriate clearance between the lingual wall 412 and veneering overlay 404.
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[0138] In addition to cementing the veneering overlay 404 in the patient's
mouth to avoid the
poor aesthetics, a "prep tooth form" or "PTF" can be designed into the
framework bridging structure
or into the veneering overlay to support a single crown, veneer or bridge to
cover the screw access
hole. FIG' s 26A, B, and C depict a crown 420 being placed onto a PTF 422 that
is part of the
framework bridge structure 400. In FIG's 26D and E demonstrates a crown being
supported by a
PTF 422 that is part of the veneering overlay 404. One benefit in designing
PTF 422 as part of
veneering overlay 404 is crown 420 and veneering overlay 404 can be fabricated
from similar
materials, such as Zirconia and allow for an improved shade match. In a
similar fashion as discussed
in Patent Application 14/272,566, the crown/PTF Assembly can be aligned
relative to the contours
of the diagnostic wax-up surface model 322. Once properly positioned, the PTF
422 and
spacing/cement gap for the crown, veneer, or bridge in the veneering overlay
404 can be created by
using Boolean Unite, Subtract, and Trim Operations in the CAD software. This
process does not
have to be limited to just areas where there is an issue with the screw access
hole. This operation or
design can be conducted throughout the entire prosthesis and allow for the
utilization of different
dental materials on the basis of the patient's clinical demands or doctor's
preferences.
[0139] As previously mentioned, the veneering overlay 404 is created from the
diagnostic
wax up surface model 322 which captured all of the surface characteristics of
the teeth and gingiva
contours of diagnostic wax up 130. These contours can be left intact and the
operator or technician
can use a series of stains to color these contours to the appropriate shade
per the material that the
veneering overlay is fabricated from. However the veneering overlay 404 can be
further refined to
allow for additional laboratory processing such as the application of
porcelain, composite, acrylics,
or other dental materials to aid in the aesthetics of the final prosthesis.
Additional Boolean or offset
operations can be performed to the surface contours of the teeth or gingiva in
the veneering overlay
404 to create a cutback 416 allowing for the appropriate support structure and
space for these
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materials to be applied post fabrication. This process allows the laboratory
technician to have a
higher level of control on the look, shade and aesthetics of the final
prosthesis. This process can also
be performed on the tooth aspect of the overlay, again allowing for the
technician to apply
porcelains, composites, acrylics, or other dental materials to aid or improve
the aesthetics of the final
prosthesis. FIGs 25A-E and 26A-E demonstrate a cutback for the gingiva only.
It is obvious to one
trained in the art, that a similar cutback could be performed to the tooth
portions of the veneering
overlay 404.
[0140] Once the surface models for both the Framework 408 and veneering
overlay 404 have
been finalized as noted in Step 832 the appropriate tool paths can be
generated (Step 834) for the
simultaneous manufacturing (Step 836) of both items. For fabrication purposes,
one can choose
from a number of different methodologies such as but not limited to milling,
laser sintering, 3D
printing, ceramic pressing, EDM, etc... The framework and veneering overlay
can also be
manufactured from a number of materials such as but not limited to titanium,
cobalt chrome, semi-
precious metals, precious metals, zirconia, wax, plastic, composites, acrylic,
PMMA, resin ceramic
(Lava-Ultimate, Vita-Enamic) etc... Once the framework 408 and veneering
overlay 404 have been
manufactured, the operator can perform any of the necessary finishing
activities and attach the
veneering overlay to the framework by means of a bonding agent or other means
of retention. In
addition, the veneering overlay 404 may be manufactured directly to framework
408. In one
example the Veneering Overlay can be printed directly onto the framework in
the appropriately
selected materials. A second example would be first milling the Veneering
overlay in a wax
material and then through the use of a lost wax technique, the veneering
overlay portion can be cast
directly to the framework. Obviously these processes would involve additional
work to refine the
aesthetics before delivering to the patient's mouth.
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[0141] In the first alternate embodiment of the invented process, the use of a
virtual set up in
place of the diagnostic wax-up 130. There are currently multiple dental
systems and software (such
as 3Shape, Dental Wings, Avadent, Ivoclar and Procera) which have the ability
to lay in CAD
models of denture teeth or stock teeth relative to scans of a stone cast and
an opposing dentition. For
this first alternate process, the stone cast and opposing cast would be
scanned separately and then
scanned in their proper orientation relative to one another. Utilizing the
scan capturing the
orientation of the stone cast and opposing cast, the scan data of the stone
cast and opposing cast will
be properly aligned to one another. Once properly aligned, the Operator will
position the CAD
models of the denture teeth or stock teeth relative to the occlusion of the
opposing cast or anatomical
markers found on the casts. The operator can also adjust the occlusion by
tools provided in the
software. Once these CAD models have been properly positioned, the gingiva
contours of the
prosthesis can be constructed. This resulting model can be used in the same
fashion as the
diagnostic wax-up surface model 322 in the above described process and provide
the tooth and
gingiva contours for the veneering overlay 404. The software programs also
have tools that would
allow for the appropriate design or construction of a gingiva or tooth cutback
design allowing for the
application of acrylic, composites, porcelain or other dental material to
improve the aesthetics of the
case.
[0142] In the second alternate process, the scanning process for capturing the
implant and
abutment positions is altered by the use of an intra-oral scanner that would
directly capture the
implant and/or abutment locations in the patient's mouth along with the
gingiva contours. The intra-
oral scanner can also capture the contours of a diagnostic wax up that has
been placed in the
patient's mouth or the position and orientation of the opposing arch during
the scanning process.
From this digital data, the dentist or technician can identify the appropriate
location of the digitally
parameterized fittings 152" and generate the stone cast surface model 320 and
the diagnostic wax-up
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surface model 322. This process would alleviate the dentist or technician from
being required to
create an impression or stone cast.
[0143] In a third alternate process, the dentist or technician can utilize a
CT scan or series of
CT scans for the basis of determining the appropriate position of the
digitally parameterized fittings
152". The dentist or technician can use the CT scan data for determining or
planning the position of
the implant locations and ultimately the position of the digitally
parameterized fittings 152". The
use of a radiographic stent demonstrating the ideal tooth position for the
restoration can also be
included in this process and provide the dentist and technician with an
ability to create the diagnostic
wax-up surface model 322 relative to the contours of the radiographic stent or
create a virtual set up
relative to the position of the opposing arch. The dentist or technician could
also utilize a CT scan of
the patient's previous existing dentition, which could be aligned utilizing
anatomical markers, in
order to create the diagnostic wax-up surface model 322.
[0144] These alternate embodiments only demonstrate some of the potential
options in
combining different digital data acquisition protocols into the invented
process. As can be
appreciated, these are only a handful of potential embodiments of the invented
process, but should
provide insight as to the adaptation of future technologies.
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