U.S. patent application number 15/820132 was filed with the patent office on 2018-04-05 for dental retention systems.
This patent application is currently assigned to Rodo Medical, Inc.. The applicant listed for this patent is Rodo Medical, Inc.. Invention is credited to Young Seo.
Application Number | 20180092718 15/820132 |
Document ID | / |
Family ID | 43449694 |
Filed Date | 2018-04-05 |
United States Patent
Application |
20180092718 |
Kind Code |
A1 |
Seo; Young |
April 5, 2018 |
DENTAL RETENTION SYSTEMS
Abstract
Dental retention systems which facilitate the adjustment or
removal of an oral appliance, e.g., a crown or bridge, from a
reconfigurable abutment assembly are described. The adjustable
abutment assembly may be secured to an anchoring implant within the
mouth of a patient. The abutment assembly has a projecting abutment
portion with one or more shape memory elements extending along the
projecting abutment portion. Energy may be applied to the elements
such that the arcuate portion self-flattens to allow for the oral
appliance to be placed thereupon while removal of the energy allows
the elements to reconfigure into its curved configuration thereby
locking the oral appliance to the abutment. Removal of the oral
appliance may be effected by reapplication of energy to the
elements.
Inventors: |
Seo; Young; (Sunnyvale,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Rodo Medical, Inc. |
San Jose |
CA |
US |
|
|
Assignee: |
Rodo Medical, Inc.
San Jose
CA
|
Family ID: |
43449694 |
Appl. No.: |
15/820132 |
Filed: |
November 21, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14485430 |
Sep 12, 2014 |
9855120 |
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15820132 |
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14218629 |
Mar 18, 2014 |
8845329 |
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14485430 |
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13849336 |
Mar 22, 2013 |
8678822 |
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14218629 |
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13549110 |
Jul 13, 2012 |
8403668 |
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13849336 |
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13303764 |
Nov 23, 2011 |
8221118 |
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13549110 |
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13021579 |
Feb 4, 2011 |
8109764 |
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13303764 |
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12504561 |
Jul 16, 2009 |
8047844 |
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13021579 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61C 2201/007 20130101;
A61C 8/0065 20130101; A61C 8/0089 20130101; A61C 13/235 20130101;
A61C 8/005 20130101; A61C 8/0066 20130101; A61C 8/0048 20130101;
A61C 8/0075 20130101; A61C 8/0062 20130101 |
International
Class: |
A61C 8/00 20060101
A61C008/00 |
Claims
1. An oral prosthesis retention system, comprising: an abutment
assembly configured to couple to an implant secured within a mouth
of a patient, wherein the abutment assembly has a locking fixture
comprising a plurality of shape memory elements, wherein the
plurality of shape memory elements circumferentially surround an
upper abutment portion of the abutment assembly, wherein the shape
memory elements have a locking configuration and a portion of each
of the shape memory elements changes its shape by extending
radially relative to the abutment assembly when in the locking
configuration; an oral prosthesis configured to be positioned upon
the upper abutment portion such that the portions of the shape
memory elements extending radially are secured within a
corresponding receiving channel defined along a surface within the
oral prosthesis.
2. The system of claim 1, wherein the shape memory elements have a
low-profile configuration and the portions of the shape memory
elements extending radially are retracted from the receiving
channel when in the low-profile configuration.
3. The system of claim 2, wherein the oral prosthesis is adjustable
relative to the abutment assembly when the shape memory elements
are in the low-profile configuration.
4. The system of claim 1, wherein the oral prosthesis is at least
one of a crown, an overdenture, and a bridge.
5. The system of claim 1, wherein the surface within the oral
prosthesis is a coping surface.
6. The system of claim 1, wherein the locking fixture is a sleeve
configured to be positioned over the upper abutment portion.
7. The system of claim 6, wherein the sleeve is tapered.
8. The system of claim 1, wherein the upper abutment portion is
configured to extend beyond the gingiva of the patient.
9. The system of claim 1, wherein the plurality of shape memory
elements comprise a metal or metal alloy.
10. An oral prosthesis retention and removal system, comprising: an
abutment assembly configured to couple to an implant secured within
a mouth of a patient, wherein the abutment assembly has a locking
fixture comprising a plurality of shape memory elements, wherein
the plurality of shape memory elements circumferentially surround
an upper abutment portion of the abutment assembly, wherein the
shape memory elements have a locking configuration and a portion of
each of the shape memory elements changes its shape by extending
radially relative to the abutment assembly when in the locking
configuration; an oral prosthesis configured to be positioned upon
the upper abutment portion such that the portions of the shape
memory elements extending radially are secured within a
corresponding receiving channel defined along a surface within the
oral prosthesis, wherein the shape memory elements have a
low-profile configuration and the portions of the shape memory
elements extending radially are retracted from the receiving
channel when in the low-profile configuration; an energy applicator
configured to apply electromagnetic energy to the plurality of
shape memory elements to actuate at least one of the shape memory
elements from the locking configuration to the low-profile
configuration.
11. The system of claim 10, further comprising a controller coupled
to the energy applicator.
12. The system of claim 11, further comprising an energy source
coupled to the energy applicator.
13. The system of claim 10, wherein the oral prosthesis is
adjustable relative to the abutment assembly when the shape memory
elements are in the low-profile configuration.
14. The system of claim 10, wherein the oral prosthesis is at least
one of a crown, an overdenture, and a bridge.
15. The system of claim 10, wherein the surface within the oral
prosthesis is a coping surface.
16. The system of claim 10, wherein the locking fixture is a sleeve
configured to be positioned over the upper abutment portion.
17. The system of claim 16, wherein the sleeve is tapered.
18. The system of claim 10, wherein the upper abutment portion is
configured to extend beyond the gingiva of the patient.
19. The system of claim 10, wherein the plurality of shape memory
elements comprise a metal or metal alloy.
20. The system of claim 10, wherein the energy applicator comprises
a handle.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/485,430 filed on Sep. 12, 2014, which is a
continuation of U.S. patent application Ser. No. 14/218,629 filed
on Mar. 18, 2014 (now U.S. Pat. No. 8,845,329), which is a
continuation of U.S. patent application Ser. No. 13/849,336 filed
on Mar. 22, 2013 (now U.S. Pat. No. 8,678,822), which is a
continuation of U.S. patent application Ser. No. 13/549,110 filed
on Jul. 13, 2012 (now U.S. Pat. No. 8,403,668), which is a
continuation of U.S. patent application Ser. No. 13/303,764 filed
on Nov. 23, 2011 (now U.S. Pat. No. 8,221,118), which is a
divisional of U.S. patent application Ser. No. 13/021,579 filed on
Feb. 4, 2011 (now U.S. Pat. No. 8,109,764), which is a continuation
of U.S. patent application Ser. No. 12/504,561 filed on Jul. 16,
2009 (now U.S. Pat. No. 8,047,844); all of which are incorporated
herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to methods and apparatus for
retaining one or more dental prostheses in a mouth of a user. More
particularly, the present invention relates to methods and
apparatus for retaining one or more dental prostheses in a manner
which facilitates placement and removal via an actuation
mechanism.
BACKGROUND OF THE INVENTION
[0003] The use of dental prostheses to replace missing or damaged
teeth is commonplace. Typically, artificial roots, or implants, are
implanted into the bone of the patient's jaw and are used to
provide structural support to an intermediate abutment. One or more
artificial replacement teeth or crowns are then fastened to the
abutment typically by cements or screws.
[0004] FIGS. 1A to 1D illustrate partial cross-sectional side views
of one example for implanting a typical crown within the mouth of a
patient. Depending upon the number of teeth to be replaced, one or
more holes may be bored within the bone of the jaw. As shown in
FIG. 1A, a portion of the gums or gingiva 14 may be cut open to
expose the underlying bone 10, e.g., maxilla or mandible, into
which a drill bit 16 may be used to bore open a hole 12. An
anchoring dental implant 18, optionally threaded, may be implanted
within hole 12 and covered by gingival 14 to allow for healing and
for the implant 18 to take hold within bone 10, as shown in FIG.
1B.
[0005] Once the implant 18 has been desirably positioned within
bone 10, an abutment assembly 20 may be securely attached to
implant 18, e.g., by a threaded pin 22 coupling to an implant
receiving well 26 defined within implant 18 such that abutment 24,
which defines a portion projecting through gingival 14 from implant
18 once coupled to implant 18, as shown in FIG. 1C. With abutment
24 secured to implant 18, crown 28 which defines crown opening 30
may be secured upon abutment 24 by utilizing a number of securement
mechanisms, such as cement or a fastener such as a screw. Other
securement mechanisms have also included interference fitting, such
as with a cross-bar or O-ring type attachment, magnets, etc.
[0006] Because the implants, abutments, and crowns are subjected to
high compressive and shear forces, initial positioning of the
crowns is important not only to provide adequate structural support
but also to ensure patient comfort. However, while utilizing cement
to attach the crown to the abutment initially allows for aligning
the crown more naturally with the dentition of the patient, the
tolerance for mistakes is low once the cement has set because of
the difficulty and expense in removing a cemented crown from the
abutment. Screw-type retention devices may also provide for good
securement of the crown to the abutment, but occlusal contact
within the patient dentition is often misaligned resulting in a
variety of complications. For instance, misaligned crowns result in
a compromised occlusal table which in turn may lead to chipping of
the crowns as well as poor aesthetic appearance of the patient's
dentition.
[0007] Previous devices have attempted to create removable denture
retention devices, such as that disclosed in U.S. Pat. No.
5,516,288, which is incorporated herein by reference in its
entirety. Such systems are described which implant a screw within
the jawbone of the patient while utilizing an abutment structure
coupled to the implant portion via a ball joint made of shape
memory materials. A restorative crown or dental replacement member
is then attached to the abutment via conventional retention
methods. However, such a device fails to disclose the use of shape
memory materials utilized in the interaction between the abutment
and the crown or bridge itself, as described in further detail
below, as such an interaction facilitates the retention and
retrieval of the crown or bridge from the abutment and/or
implant.
[0008] Accordingly, there exists a need for methods and devices
which are efficacious in facilitating not only the retention of
oral appliances or prostheses, such as crowns or bridges, along the
dentition of a patient but also the removal and/or repositioning of
the crown or bridge.
SUMMARY OF THE INVENTION
[0009] The assemblies described provide for mechanisms and methods
to facilitate the adjustment or removal of an oral appliance or
prosthesis, such as a crown or bridge, from a reconfigurable
abutment assembly. In utilizing the abutment assemblies described
herein, an anchoring implant may be bored into the bones within the
mouth of the patient to provide for the structural support of the
abutment assembly. Moreover, the implants and abutment assemblies
described herein may be utilized in any number of locations within
the mouth of the patient, for instance, along the maxilla or
mandible or other locations within the body which may benefit from
an adjustable abutment assembly as described herein. Additionally,
although some of the examples illustrate the placement and/or
removal of crowns, various other prostheses for placement within or
along the patient dentition may be utilized with the retention
devices described herein and are not intended to be limited to use
with crowns.
[0010] One example of an abutment retaining assembly may have a
projecting abutment portion which extends from a first or upper
abutment portion to a second or lower abutment portion. A threaded
pin may extend from the lower abutment portion for attachment to
the implant, which may be bored into the underlying bone to serve
as an anchor. Portions of the abutment retaining assembly may be
fabricated from any number of biocompatible materials, e.g., gold
alloys, stainless steel, nickel-titanium alloys, etc., and may be
sized for positioning along the patient's dentition.
[0011] With the projecting abutment portion extending from the
upper abutment portion, an upper retaining plate may be positioned
atop the projecting abutment portion to which one or more
compression plates or elements are attached. The compression plates
or elements may extend along the projection abutment portion while
secured between upper retaining plate and lower retaining portions
along the upper abutment portion. The upper retaining plate, as
well as the projecting abutment portion, may define an opening for
receiving an engagement instrument which may be inserted
temporarily within the opening and used to secure the abutment
assembly to the anchored implant.
[0012] The compression plates or elements may be sized to extend
longitudinally along the projecting abutment portion and may number
from one element to as many as practicable depending upon their
size, e.g., six elements, which are spaced circumferentially about
the portion in a uniform manner. Each of the plates has a length
with one or more straightened portions with at least one curved or
arcuate portion along the length of the element which projects
radially when each of the one or more elements are positioned
adjacent to one another over portion.
[0013] The one or more compression plates or elements may be
fabricated from various shape memory alloys, e.g., nickel-titanium
alloys such as Nitinol, such that the curved or arcuate portion may
be preformed along the element. A phase change may be initiated in
the element upon the application of energy, such as heat or
electrical energy, to transition the element between its
martensitic and austenitic phase such that the arcuate portion may
self-flatten with respect to the length of the element. A current
or energy, such as an electrical current may be applied to the one
or more elements via an input lead contact and return lead contact.
If more than a single element is utilized, each of the elements may
be electrically coupled to one another to allow for each of the
elements to be energized or heated. As the energy is applied to the
one or more elements, the phase change may be initiated such that
the arcuate portions of elements reconfigure from their curved
shape to a straightened shape.
[0014] The crown may define a crown opening which is slightly
larger in diameter than the abutment assembly in its straightened
configuration so that as the crown is lowered upon the abutment
assembly, the crown may be tightly fitted thereupon. A portion of
the crown opening may further define a widened diameter formed by,
e.g., an undercut, which is correspondingly sized to receive the
arcuate portions of the elements in their widened diameter.
Moreover, the crown may further define corresponding input lead
contact and corresponding return lead contact which are positioned
along the crown such that the corresponding contacts come into
electrical communication with their respective contacts to allow
for the transfer of energy directly through the crown and into the
elements when the crown is secured to the abutment.
[0015] Once the crown has been desirably positioned upon the
abutment assembly, the energy may be removed or ceased such that
straightened arcuate portions of the elements reconfigure into
their arcuate shape. As the arcuate portions reform, the elements
may shorten in length thus retracting the upper retaining plate and
radially expanding the arcuate portions into the widened diameter
of the crown. The reconfigured arcuate portions compress the
elements against the widened diameter thereby effectively
preventing relative movement between the crown and the elements and
locking the crown into position along the abutment.
[0016] In the event that the crown requires removal, replacement,
or repositioning upon the abutment, energy may again be applied to
the elements positioned within the crown through corresponding
contacts. As the arcuate portions are reconfigured back into their
straightened low-profile configurations, the compression against
the interior of the widened diameter may be released and the crown
may be adjusted or repositioned upon the abutment or simply pulled
entirely off the abutment assembly. A substitute crown may be
replaced upon the abutment, if so desired.
[0017] A power source may be electrically coupled to a controller,
e.g., resistance heating controller, to control the current flow to
the one or more elements either directly through the contacts or
through the corresponding contacts. As the controller is utilized
to control the amount of current, the one or more elements may rise
in temperature due to resistance heating. The power source may
comprise any number of power supplies, e.g., an AC outlet or
batteries, and the power source and controller may be configured
into various form factors. The power supplied may range from
between, e.g., about 10 to 150 Watts, while the heating time for
applying the power may range from, e.g., 0.1 to 2 seconds or
longer.
[0018] Yet another example for a power source for reconfiguring the
one or more elements may utilize inductive heating where the
elements may be heated without any direct contact between the power
source and the elements. An inductive heating assembly may be
regulated with a controller-like variable output oscillator circuit
which sends an alternating current through a conductor to one or
more coils which then generates an alternating magnetic field
between the coils which may be set apart in apposition and at a
distance from one another. The distance between the coils may
define a receiving channel which is sized to be positioned adjacent
to or in proximity to the crown and/or one or more elements.
[0019] With the abutment assembly and/or crown positioned within
the receiving channel, the alternating magnetic field may be
created between the coils to form eddy currents in the one or more
elements which causes the material to heat up due to electrical
resistance and thus activates the shape memory alloy to initiate
their shape change. The frequency of the alternating current and
the magnetic field can be set between, e.g., 1 kHz and 1 MHz,
depending on the size and configuration of the one or more elements
and the targeted activation time. Moreover, the power consumption
may range between about, e.g., 10 W to 5 kW.
[0020] In yet another variation of a dental retaining assembly, a
ferromagnetic shape memory alloy (FSMA) may be configured to have a
tapered circumferential edge but when exposed to a magnetic field,
the plate may become reconfigured such that the FSMA plate
maintains a straightened cylindrical shape from its tapered
configuration. As the magnetic field is maintained, the crown
defining a crown opening with a widened diameter formed by, e.g.,
an undercut, may be positioned upon the actuated FSMA plate such
that a position of the FSMA plate corresponds to the position of
widened diameter. With the crown desirably positioned upon the
abutment, the magnetic field may be removed or terminated such that
the plate reconfigures into its tapered configuration within the
widened diameter and compresses crown into securement upon the
abutment.
[0021] In yet another alternative, multiple implanted anchoring
assemblies may be secured to the patient to allow for the
securement of one or more partial bridges utilizing the mechanisms
and methods described herein. Accordingly, one or more anchoring
assemblies may be used to secure one or more partial bridges. In
another example, an overdenture may be secured to the patient
utilizing an implanted cross-bar configuration which incorporates
one or more anchoring assemblies. The anchoring assemblies may
similarly utilize the one or more elements to secure the
overdenture within the patient mouth.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIGS. 1A to 1D illustrate partial cross-sectional profiles
of an example of placing an implant within a jawbone of a patient
and attaching a crown thereto.
[0023] FIG. 2A illustrates a perspective view of attaching one
variation of an abutment retaining assembly to a conventional
implant.
[0024] FIG. 2B illustrates a perspective view where energy may be
applied to one or more shape memory compression plates or elements
positioned along the abutment retaining assembly to configure the
elements into a low-profile shape such that a crown may be received
upon the abutment.
[0025] FIG. 2C illustrates a perspective view where the shape
memory elements may be reconfigured into their expanded
configuration to secure the crown upon the abutment.
[0026] FIG. 2D illustrates a perspective view showing how energy
may be reapplied to the elements through the crown to yet again
configure the elements into a low-profile shape to allow for the
repositioning or removal of the crown from the abutment.
[0027] FIG. 3 illustrates an example of how energy may be applied
via a power source and controller to the one or more elements.
[0028] FIG. 4 illustrates schematically another example of how an
alternating magnetic field may be applied to the one or more
elements by inductively transferring energy to reconfigure the
shape of the elements.
[0029] FIG. 5 illustrates a housing configured into a mouthpiece
for applying energy to the compression elements.
[0030] FIG. 6A illustrates an example of another variation for
securing a crown where an abutment retaining assembly is secured to
an implant.
[0031] FIG. 6B illustrates a reconfigurable ferromagnetic shape
memory alloy (FSMA) plate which may be secured to the abutment.
[0032] FIG. 6C illustrates a magnetic field applied to the FSMA
plate to configure its shape into a low-profile to receive a
crown.
[0033] FIG. 6D illustrates the positioning of the crown upon the
FSMA plate and the reconfiguration of the FSMA plate into its
expanded profile to secure the crown thereto.
[0034] FIG. 7A illustrates the removal of the crown from the FSMA
plate by application of a magnetic field to reconfigure the shape
of the plate and allowing for the release of the crown.
[0035] FIG. 7B illustrates a partial cross-sectional side view
showing the reconfiguration of the FSMA plate and the release of
the crown.
[0036] FIG. 8 illustrates a representative partial side view of an
FSMA plate engaged against a widened diameter of the crown for
securing the crown in position.
[0037] FIG. 9 shows a perspective view of one or more crowns or
bridges which have been coupled to implants by utilizing the one or
more elements to show how the crowns or bridges may be positioned
along a patient's dentition to align the occlusal contact points
for patient comfort and safety.
[0038] FIG. 10 shows a perspective view of multiple implants and
abutment assemblies utilizing the reconfigurable plates or elements
herein to secure individual crowns or bridges to a patient's
bone.
[0039] FIG. 11 shows a perspective view of another example where an
implanted cross-bar may be utilized to secure an overdenture to the
patient's bone via the reconfigurable plates or elements.
[0040] FIG. 12 shows a perspective view of yet another example
where one or more anchoring assemblies may be used to secure a
dental prosthesis, such as an overdenture, to the patient's
mouth.
[0041] FIG. 13 shows yet another example of an anchoring assembly
utilizing compression plates comprised of biased spring elements
which are reconfigured by a shape memory wire.
DETAILED DESCRIPTION OF THE INVENTION
[0042] In positioning and securing an oral appliance, such as a
crown or bridge, within the mouth of a patient, the retaining
assemblies described herein allow not only for secure attachment
but also for adjustment of the crown or bridge along the patient's
dentition. The assemblies described also provide for mechanisms and
methods to facilitate the entire removal of the crown or bridge
from the abutment. In utilizing the abutment assemblies described
herein, any number of typical anchoring implants may be bored into
the bones within the mouth of the patient to provide for the
structural support of the abutment assembly. Moreover, the implants
and abutment assemblies described herein may be utilized in any
number of locations within the mouth of the patient, for instance,
along the maxilla or mandible or other locations within the body
which may benefit from an adjustable abutment assembly as described
herein.
[0043] Turning now to FIG. 2A, one example of an abutment retaining
assembly 40 is illustrated as having a projecting abutment portion
42 which extends from a first or upper abutment portion 44, which
is optionally tapered, to a second or lower abutment portion 46. A
threaded pin 48 may extend from the lower abutment portion 46 for
attachment to implant 18, which may be bored into the underlying
bone 10 to serve as an anchor, and as previously described, which
may be adjacent to another crown or pre-existing tooth or teeth 68.
Portions of the abutment retaining assembly 40 may be fabricated
from any number of biocompatible materials, e.g., gold alloys,
stainless steel, nickel-titanium alloys, etc., and may be sized for
positioning along the patient's dentition. For instance, the
assembly 40 may have a diameter ranging from, e.g., 2 to 6 mm, with
a length ranging from, e.g., 5 to 15 mm. These dimensions are
exemplary and are not intended to be limiting.
[0044] With the projecting abutment portion 42 extending from the
upper abutment portion 44, an upper retaining plate 50 may be
positioned atop the projecting abutment portion 42 to which one or
more compression plates or elements 54 are attached. The
compression plates or elements 54 may extend along the projection
abutment portion 42 while secured between upper retaining plate 50
and lower retaining portions 52 along the upper abutment portion
44. The upper retaining plate 50, as well as projecting abutment
portion 42, may define an opening 64, which may be optionally
keyed, for receiving an engagement instrument 66 (as shown in FIG.
6A) which may be inserted temporarily within opening 64 and used to
secure abutment assembly 40 to the anchored implant 18, e.g., by
rotating abutment assembly 40 so as to screw threaded pin 48 into
implant 18.
[0045] The compression plates or elements 54 may be sized to extend
longitudinally along projecting abutment portion 42 and may number
from one element to as many as practicable depending upon their
size, e.g., six elements, which are spaced circumferentially about
portion 42 in a uniform manner. Each of the plates are illustrated
as having a length with one or more straightened portions 56 with
at least one curved or arcuate portion 58 along the length of the
element 54 which projects radially when each of the one or more
elements 54 are positioned adjacent to one another over portion 42,
as illustrated.
[0046] In one example, each of the elements 54 may range in length
from, e.g., about 5 to 10 mm, with a thickness of, e.g., about 0.5
to 1.5 mm. Moreover, the curved or arcuate portion 58 may have a
radius which defines a height of, e.g., about 1 to 2 mm, relative
to the thickness of the element 54 such that when element 54 is
reconfigured into a straightened configuration, element 54 may
extend an additional, e.g., 1.5 to 3 mm in length. These dimensions
are provided as exemplary values and are not intended to be
limiting. Variations in dimensions may be utilized as
practicable.
[0047] The one or more compression plates or elements 54 may be
fabricated from various shape memory alloys, e.g., Nitinol, such
that the curved or arcuate portion 58 may be preformed along the
element 54. A phase change may be initiated in the element 54 upon
the application of energy, such as heat or electrical energy, to
transition the element 54 between its martensitic and austenitic
phase such that the arcuate portion 58 may self-flatten with
respect to the length of the element 54. As illustrated in FIG. 2B,
current or energy 70, such as an electrical current i, may be
applied to the one or more elements 54 via an input lead contact 60
and return lead contact 62. If more than a single element 54 is
utilized, each of the elements 54 may be electrically coupled to
one another to allow for each of the elements 54 to be energized or
heated. The lead contacts 60, 62 may be positioned along a single
element or different elements so long the elements are in
electrical communication. As the energy is applied to the one or
more elements 54, the phase change may be initiated such that the
arcuate portions 58 of elements 54 reconfigure from their curved
shape to a straightened shape, as shown in the figure.
[0048] With the arcuate portions 58 reconfigured into straightened
portions 58', upper retaining plate 50 may be moved longitudinally
with respect to upper abutment portion 44 while the elements 54
remain attached to their lower retaining portions 52. The resulting
outer diameter of the elements 54 upon the abutment may be reduced
from, e.g., about 6 mm to about 4 mm, to thus allow for the
placement of a crown 72 upon the abutment assembly. Crown 72 may
define a crown opening 74 which is slightly larger in diameter than
the abutment assembly in its straightened configuration so that as
crown 72 is lowered upon the abutment assembly, crown 72 may be
tightly fitted thereupon. A portion of crown opening 74 may further
define a widened diameter 76 formed by, e.g., an undercut, which is
correspondingly sized to receive the arcuate portions 58 of
elements 54 in their widened diameter, as described below.
Moreover, crown 72 may further define corresponding input lead
contact 60' and corresponding return lead contact 62' which are
positioned along crown 72 such that the corresponding contacts 60',
62' come into electrical communication with their respective
contacts 60, 62 to allow for the transfer of energy directly
through the crown and into the elements 54 when the crown is
secured to the abutment. To guide the crown 72 upon the abutment
assembly, the opening 74 of crown 72 may be optionally keyed or
shaped in a predetermined manner which corresponds with a
configuration of the abutment such that advancement of the crown 72
upon the abutment may be achieved in a specified orientation, if so
desired.
[0049] Once crown 72 has been desirably positioned upon the
abutment assembly, the energy may be removed or ceased such that
straightened arcuate portions 58' of elements 54 reconfigure into
their arcuate shape. As the arcuate portions 58 reform, the
elements 54 may shorten in length thus retracting upper retaining
plate 50 and radially expanding the arcuate portions 58 into the
widened diameter 76 of crown 72, as shown in FIG. 2C. The
reconfigured arcuate portions 58 compress the elements 54 against
the widened diameter 76 thereby effectively preventing relative
movement between the crown 72 and the elements 54 and locking the
crown 72 into position along the abutment. The compressive force
which may be generated between the elements 54 and the crown
interior may range, e.g., between 10 N to 10 kN, to effectively
lock the crown 72 into position.
[0050] In the event that crown 72 requires removal, replacement, or
repositioning upon the abutment, energy may again be applied to the
elements 54 positioned within the crown 72 through corresponding
contacts 60', 62' which are in electrical communication with their
respective contacts 60, 62, as shown in FIG. 2D. As the arcuate
portions 58 are reconfigured back into their straightened
low-profile configurations 58', the compression against the
interior of widened diameter 76 may be released and crown 72 may be
adjusted or repositioned upon the abutment or simply pulled
entirely off the abutment assembly. A substitute crown may be
replaced upon the abutment, if so desired.
[0051] In delivering the energy to the one or more elements 54 for
initiating the phase change in the shape memory alloy, FIG. 3
illustrates one example which delivers a current to elements 54. A
power source 80 may be electrically coupled to a controller 82,
e.g., resistance heating controller, to control the current flow to
the one or more elements 54 either directly through contacts 60, 62
or through corresponding contacts 60', 62' if delivered through
crown 72. In either case, as the controller 82 is utilized to
control the amount of current, the one or more elements 54 may rise
in temperature due to resistance heating. The power source 80 may
comprise any number of power supplies, e.g., an AC outlet or
batteries, and the power source 80 and controller 82 may be
configured into various form factors. For example, the heating
assembly may be configured into a hand-held unit which is portable
by the user or it may be configured into a larger non-portable
unit. Because the size, configuration, and thermal conductivity of
the elements 54 may be varied, the amount of power applied and the
heating time may be varied accordingly. For instance, the power
supplied may range from between, e.g., about 10 to 150 Watts, while
the heating time for applying the power may range from, e.g., 0.1
to 2 seconds or longer.
[0052] Yet another example for a power source for reconfiguring the
one or more elements 54 is illustrated schematically in FIG. 4.
Because this particular variation may utilize inductive heating,
the elements 54 may be heated without any direct contact between
the power source and the elements 54. As shown, an inductive
heating assembly 90 may be regulated with a controller-like
variable output oscillator circuit 92 which sends an alternating
current i through conductor 94 to one or more coils 96, 98 which
then generates an alternating magnetic field 100 between the coils
96, 98, which may be set apart in apposition and at a distance from
one another. The distance between the coils 96, 98 may define a
receiving channel 104 which is sized to be positioned adjacent to
or in proximity to the crown 72 and/or one or more elements 54 such
that when the elements 54 are to be reconfigured, the heating
assembly 90 may be positioned upon the abutment assembly and/or
crown 72 within the user's mouth.
[0053] With the abutment assembly and/or crown 72 positioned within
receiving channel 104, the alternating magnetic field 100 may be
created between coils 96, 98 to form eddy currents 102 in the one
or more elements 54. These eddy currents 102, which may also be
described as the movement of electrons in the material, causes the
material to heat up due to electrical resistance and thus activates
the shape memory alloy to initiate their shape change. The
frequency of the alternating current i and the magnetic field can
be set between, e.g., 1 kHz and 1 MHz, depending on the size and
configuration of the one or more elements 54 and the targeted
activation time. Moreover, the power consumption may range between
about, e.g., 10 W to 5 kW. As described above, the heating assembly
90 may be configured, e.g., as a portable hand-held unit or as a
larger non-portable unit. Additional details and examples of an
inductive heating assembly are further shown in U.S. Pat. No.
6,710,314, which is incorporated herein by reference in its
entirety.
[0054] Additionally in this and other examples, a sealant 106, such
as a biodegradable silicone material, may be placed within the
crown cavity to at least partially encompass or encase the abutment
assembly to create a water-tight seal. This sealant 106 may
completely encase the abutment assembly or it may seal just around
a portion of the assembly, such as upper abutment portion 44.
[0055] In applying the energy (either resistive or inductive
heating) to the one or more compression elements, one variation of
a housing 101 configured into the form of a mouthpiece which may be
inserted temporarily into the mouth of a patient is shown in the
perspective assembly view of FIG. 5. Housing 101 may generally
comprise two biteplates 103 which extend from a handle 111 and
which define a receiving cavity 105 for receiving within or
placement against a dental prosthesis such as an overdenture,
crown, etc. Other variations may comprise a single biteplate or a
partial biteplate depending upon the dental prosthesis to be
secured. Moreover, handle 111, which generally extends from the
mouth of the patient, may be removed or omitted entirely.
[0056] In either variation, one or more contacts 109 may be defined
along the receiving cavity 105 and are in electrical communication
with a power supply 107 through electrical conductor 113, which may
be routed through the housing 101 to each of the respective
contacts 109. In use, with one or more anchoring assemblies 119
secured within the patient's mouth, the dental prosthesis 115 (or
prostheses) may either be positioned directly upon the respective
anchoring assembly 119 or the dental prosthesis 115 may be
positioned within receiving cavity 105 of housing 101. The housing
101 may then be positioned within the patient's mouth such that the
respective dental prosthesis 115 is either placed upon a
corresponding anchoring assembly 119 and/or such that the one or
more contacts 109 positioned within housing 101 is aligned with a
corresponding contact 117 positioned along the dental prosthesis.
In either case, once the respective contacts 109, 117 are aligned,
power supply 107 may be activated to actuate the compression plates
to reconfigure and secure the dental prosthesis 115 to the one or
more anchoring assemblies 119. Once the dental prosthesis 115 is
fully secured, housing 101 may be removed from the patient's mouth.
Housing 101 may be reinserted into the patient's mouth to reverse
the securement process for readjusting or entirely removing the
prostheses from the anchoring assemblies 119, if so desired.
Moreover, housing 101 may be optionally used by the patient for
inserting and/or removing prostheses such as overdentures on a
daily basis or it may also be used by a practitioner for securing
and/or removing any number of dental prostheses.
[0057] In yet another variation of a dental retaining assembly,
FIG. 6A illustrates an example of an assembly which may utilize a
ferromagnetic shape memory alloy (FSMA), which are ferromagnetic
materials which generally exhibit relatively large changes in shape
and size when exposed to a magnetic field. In this variation, an
abutment assembly having a projecting abutment portion 110
extending from an upper abutment portion 44 may be connected to an
implant 18 via a threaded pin 26, as previously described. With the
abutment secured to implant 18, a circular FSMA plate 114 having a
tapered circumferential edge may be attached to the abutment
opening 112 via a threaded retaining pin 116, which may be
optionally keyed with respect to opening 112, as shown in FIG. 6B.
Although illustrated as a circular element, FSMA plate 114 may be
configured into various shapes or sizes depending upon the coupling
mechanism to the crown.
[0058] The FSMA plate 114 may be configured to have a tapered
circumferential edge but when exposed to a magnetic field 124, as
shown in FIG. 6C, the plate 114 may become reconfigured such that
the FSMA plate 114' maintains a straightened cylindrical shape from
its tapered configuration. As the magnetic field 124 is maintained,
crown 118 defining a crown opening 120 with a widened diameter 122
formed by, e.g., an undercut, may be positioned upon the actuated
FSMA plate 114' such that a position of FSMA plate 114' corresponds
to the position of widened diameter 122. With the crown 118
desirably positioned upon the abutment, the magnetic field 124 may
be removed or terminated such that the plate 114 reconfigures into
its tapered configuration within the widened diameter 122 and
compresses crown 118 into securement upon the abutment, as shown in
FIG. 6D. Also as described above, crown 118 may be configured to be
positioned upon the abutment in a predetermined orientation, if so
desired.
[0059] As shown in FIG. 7A, in the event that the crown 118 needs
to be repositioned upon the abutment, readjusted, or removed
entirely, the magnetic field 124 may be reapplied upon the crown
118 such that FSMA plate 114 reconfigures again from its tapered
configuration to its straightened cylindrical configuration. FIG.
7B illustrates a partial cross-sectional side view of the FSMA
plate 114 reconfigurable between its tapered configuration and its
straightened configuration 114'. Also shown is another variation of
the widened diameter utilizing a locking ring 126, which may be
alternatively configured to define an undercut through which FSMA
plate 114 may freely slide when straightened yet which interlocks
against when the FSMA plate 114 is in its tapered
configuration.
[0060] FIG. 8 illustrates a detail view of the locking interaction
between the FSMA plate and the ring 126. With the FSMA plate 114'
in its straightened configuration while under the magnetic field
124, plate 114' may freely slide into position through the ring
126. However, upon removal of the magnetic field 124, the FSMA
plate 114' may reconfigure into its tapered configuration 114 such
that the FSMA plate 114 is secured against the ring 126 to prevent
movement of the crown relative to the plate 114. The plate 114 may
be keyed relative to the ring 126 such that the crown is fitted
upon the abutment in a predetermined orientation, if so
desired.
[0061] In determining the amount of retention force retention force
before yield F.sub.r between the plate 114 and the ring 126, the
effective stress .sigma..sub.0 may be initially calculated
utilizing the following equation (1) while assuming that the FSMA
is isotopic in nature.
.sigma. 0 = 1 2 .sigma. n 2 + 6 .sigma. t 2 ( 1 ) ##EQU00001##
where .sigma..sub.n represents the normal stress and .sigma..sub.t
represents the tangential stress values. Expanding the formula (1)
in terms of .sigma..sub.0 and .THETA. which represents the undercut
angle, the force may be calculated utilizing the following equation
(2).
F R = 2 2 A ( 5 cos 2 2 .theta. + 12 cos 2 .theta. + 7 ) .sigma. 0
( 2 ) ##EQU00002##
where A represents the nominal cross-sectional area of the plate
114 against the ring 126, .THETA. represents the undercut angle,
and .sigma..sub.0 represents the effective stress. Thus assuming
cos 2.theta..apprxeq.1, the equation (2) for calculating the
retention force may be simply reduced to the following equation
(3).
F.sub.R=0.577A.sigma..sub.0 (3)
[0062] Because of the adjustable nature of the retention assemblies
described herein, the crowns or bridges secured to the abutment
assemblies may be adjusted in vivo to ensure that the dentition,
once secured, aligns properly. As indicated in the perspective view
of FIG. 9, multiple anchored crowns 130 as shown which have been
secured to the patient. The resulting occlusal contact points 132,
which are those areas along the occlusal surface which contact the
opposed tooth or teeth as the jaw is articulated, may thus be
adjusted utilizing the mechanisms and methods described to ensure
proper alignment for patient comfort, safety, and reliability of
the crowns.
[0063] Although the previous examples have illustrated a single
crown placed upon a single corresponding abutment assembly,
alternative variations may be utilized. For instance, FIG. 10
illustrates an example where multiple implanted anchoring
assemblies 144 may be secured to the patient to allow for the
securement of one or more partial bridges 140, 142 utilizing the
mechanisms and methods described herein. Accordingly, one or more
anchoring assemblies 144 may be used to secure one or more partial
bridges. In another example, FIG. 11 shows another variation where
an overdenture 150 may be secured to the patient utilizing a
cross-bar 152 configuration implanted into the patient's bone. The
overdenture 150 itself may incorporate one or more anchoring
assemblies 154 which extend away from the overdenture 150 for
coupling to the cross-bar 152. The anchoring assemblies 154 may
similarly utilize the one or more elements for securing the
overdenture 150 within the patient mouth as they may be configured
to operate in a similar manner as those previously described. For
instance, rather than transitioning from an extended to a
compressed configuration for compression against the interior of
the dental prosthesis, anchoring assemblies 154 may transition from
to an extended configuration to a compressed configuration which
compresses over and/or upon the cross-bar 152 to secure the
overdenture 150 thereto.
[0064] In yet another example, as shown in the perspective view of
FIG. 12, one or more anchoring assemblies 144 may be secured to the
patient's mouth for coupling to a dental prosthesis such as an
overdenture 150. In this example, the overdenture 150 may define
one or more receiving channels corresponding to the one or more
anchoring assemblies 144 such that reconfiguration of the
compression plates along anchoring assemblies 144 may compress and
secure against an interior surface of each respective receiving
channel in a manner as described above to secure the overdenture
150 within the patient's mouth. Removal of overdenture 150 may be
effected utilizing any of the variations described herein to allow
for daily removal of overdenture 150, if so desired.
[0065] Another variation of the anchoring assembly is illustrated
in the side view of FIG. 13, which shows an anchoring assembly 160
utilizing compression plates which are comprised of biased elements
162, e.g., leaf springs, which are prefabricated to be biased in an
outwardly radial direction relative to the abutment assembly 164 to
which they are mounted. The biased elements 162 may be fabricated
into individual plates from a material such as spring stainless
steel which are formed to have a curved or arcuate portion rather
than from a shape memory alloy, as previously described. Thus, when
the elements 162 are positioned within or along the abutment
assembly 164, the curved or arcuate portions may extend radially
and function as a biased spring element.
[0066] Each of the elements 162 may define a channel or opening
through which a separate shape memory wire 166, such as a wire made
from a nickel-titanium alloy, may pass through. Shape memory wire
166 may be stretched relatively taut through elements 162 such that
when wire 166 is energized, as previously described, the wire 166
may shorten in length to compress the curved or arcuate portions of
elements 162 into a flattened configuration against abutment
assembly 164 to allow for the placement or positioning of a dental
prosthesis, such as a crown 170, over abutment assembly 164. Once
crown 170 has been desirably positioned, energy may be removed from
wire 166 to allow for its re-lengthening which in turn may allow
for elements 162 to relax back into its curved or arcuate shape
such that elements 162 compress against the interior surface of
crown 170 thus locking or securing crown 170 into position upon the
anchoring assembly 160. As previously described, a sealant 168 may
also be optionally positioned upon the crown interior for forming a
water-tight seal against the anchoring assembly 160 to prevent the
entry of food and liquids into the crown interior.
[0067] The applications of the devices and methods discussed above
are not limited to the securement of crowns or bridges but may
include any number of further treatment applications where the
securement and adjustability of devices within a patient may be
utilized. Moreover, such devices and methods may be applied to
other treatment sites within the body. Modification of the
above-described assemblies and methods for carrying out the
invention, combinations between different variations as
practicable, and variations of aspects of the invention that are
obvious to those of skill in the art are intended to be within the
scope of the claims.
* * * * *