U.S. patent application number 12/772130 was filed with the patent office on 2011-11-03 for reinforced aligner hooks.
This patent application is currently assigned to Align Technology, Inc.. Invention is credited to Artem Borovinskih, Eric Kuo, Shiva Sambu.
Application Number | 20110269092 12/772130 |
Document ID | / |
Family ID | 44475187 |
Filed Date | 2011-11-03 |
United States Patent
Application |
20110269092 |
Kind Code |
A1 |
Kuo; Eric ; et al. |
November 3, 2011 |
REINFORCED ALIGNER HOOKS
Abstract
Orthodontic positioning devices, and related methods and
systems, are disclosed for use with one or more orthodontic elastic
members. The disclosed devices are configured to couple with an
orthodontic elastic member so as to react a force from the elastic
member into the appliance to, for example, generate traction forces
on the patient's teeth to produce a desired occlusion. A
positioning device includes a patient removable tooth positioning
appliance having teeth receiving cavities shaped to receive and
apply a resilient positioning force to a patient's teeth. The
appliance includes a hook configured to interface with an
orthodontic elastic member. The hook can be configured to be offset
from a surface of a tooth when the appliance is coupled with the
patient's teeth and no elastic member is coupled with the tooth.
The hook can be curved so that the hook is more retentive on the
aligner. The hook can be reinforced so that the reinforcement
resists deformation when the elastic is in place.
Inventors: |
Kuo; Eric; (San Jose,
CA) ; Borovinskih; Artem; (Union City, CA) ;
Sambu; Shiva; (Santa Clara, CA) |
Assignee: |
Align Technology, Inc.
Santa Clara
CA
|
Family ID: |
44475187 |
Appl. No.: |
12/772130 |
Filed: |
April 30, 2010 |
Current U.S.
Class: |
433/6 ; 433/215;
433/24 |
Current CPC
Class: |
A61C 9/0046 20130101;
A61C 7/002 20130101; A61C 7/08 20130101; G06F 30/20 20200101; B33Y
50/02 20141201 |
Class at
Publication: |
433/6 ; 433/24;
433/215 |
International
Class: |
A61C 13/00 20060101
A61C013/00; A61C 13/20 20060101 A61C013/20 |
Claims
1. An orthodontic positioning device for use with an orthodontic
elastic member, the device comprising: a patient removable
orthodontic tooth positioning appliance having teeth receiving
cavities shaped to receive and apply a resilient positioning force
to a patient's teeth, the appliance comprising a hook configured to
interface with an orthodontic elastic member so as to react a force
from the elastic member into the patient-worn appliance, the hook
configured to be laterally offset from a surface of a tooth when
the appliance is coupled with the patient's teeth and no
orthodontic elastic member is coupled with the hook.
2. The device of claim 1, wherein the appliance comprises a
reinforcement structure configured to stiffen the appliance against
lateral deflection induced by the force from the elastic
member.
3. The device of claim 2, wherein the reinforcement structure
comprises a corrugation in a portion of the appliance.
4. The device of claim 2, wherein the appliance further comprises a
locally reinforced area connected with the hook to stiffen the hook
against lateral deflection induced by the force from the elastic
member.
5. The device of claim 1, wherein the appliance further comprises a
locally reinforced area connected with the hook to stiffen the hook
against deflection induced by the force from the elastic
member.
6. The device of claim 1, wherein the hook is gingivally offset
from a gingival edge of the appliance.
7. The device of claim 1, wherein an orthodontic elastic member
contacts a surface of a tooth when the appliance is coupled with
the patient's teeth and the orthodontic elastic member is coupled
with the hook.
8. The device of claim 1, wherein an orthodontic elastic member
does not contact a surface of a tooth when the appliance is coupled
with the patient's teeth and the orthodontic elastic member is
coupled with the hook.
9. The device of claim 1, whereby the tip of the hook angles or
curves back toward a tooth surface such that a hook tip is pointed
closer to the tooth than a body portion of the hook so as to avoid
poking the patient's soft tissues.
10. The device of claim 1, whereby the hook is curved, angled, or
bent towards the gingival line so that the elastic can be secured
onto the aligner without it falling off when the aligner has not
yet been inserted.
11. A method for using one or more orthodontic positioning devices,
the method comprising: receiving a first orthodontic positioning
device in accordance with claim 1; coupling the first positioning
device with a first arch of a patient's teeth; and coupling an
orthodontic elastic member with the hook of the first positioning
device to transfer a force from the elastic member into the first
positioning device.
12. The method of claim 11, further comprising: receiving a second
orthodontic positioning device having teeth receiving cavities
shaped to receive and apply a resilient positioning force to a
patient's teeth, the second device comprising a hook configured to
interface with an orthodontic elastic member so as to react a force
from the elastic member into the patient-worn device, the hook
configured to be offset from a surface of a tooth when the second
device is coupled with the patient's teeth and no orthodontic
elastic member is coupled with the hook; coupling the second
orthodontic positioning device with a second arch of the patient's
teeth; and coupling the orthodontic elastic member that is coupled
with the hook of the first positioning device with the hook of the
second positioning device.
13. A computer-implemented method for designing an orthodontic
positioning device having teeth receiving cavities, the method
comprising: receiving a digital representation of a patient's teeth
in a selected arrangement; and modeling an appliance based on the
received representation, the appliance comprising teeth receiving
cavities shaped to receive and apply a resilient positioning force
to the patient's teeth, the appliance comprising a hook configured
to interface with an orthodontic elastic member so as to react a
force from the elastic member into the patient-worn appliance, the
hook configured to be offset from a surface of a tooth when the
appliance is coupled with the patient's teeth and no orthodontic
elastic member is coupled with the hook.
14. The method of claim 13, wherein modeling an appliance comprises
modeling a reinforcement structure configured to stiffen the
appliance against lateral deflection induced by the force from the
elastic member.
15. The method of claim 14, wherein modeling a reinforcement
structure comprises modeling a corrugation.
16. The method of claim 14, wherein modeling a reinforcement
structure comprises modeling a locally reinforced area connected
with the hook to stiffen the hook against deflection induced by the
force from the elastic member.
17. A system for orthodontic repositioning of a patient's teeth,
the system comprising: a plurality of orthodontic tooth positioning
appliances for a patient's teeth, at least two of the appliances
having different teeth receiving cavities shaped to receive and
resiliently reposition the patient's teeth in a first arch of the
patient's teeth from a first arrangement to a successive
arrangement, at least one of the appliances comprising a hook
configured to interface with an orthodontic elastic member so as to
react a force from the elastic member into the patient-worn
appliance, the hook configured to be offset from a surface of a
tooth when the appliance is coupled with the patient's teeth in the
first arch and no orthodontic elastic member is coupled with the
hook.
18. The system of claim 17, wherein the appliances comprise: a
plurality of appliances for repositioning an upper arch of the
patient's teeth; and a plurality of appliances for repositioning a
lower arch of the patient's teeth, wherein one of the upper arch
appliances and one of the lower arch appliances are configured to
be worn simultaneously and coupled with each other via an
orthodontic elastic member coupling the hook of the upper arch
appliance to the hook of the lower arch appliance.
19. The system of claim 17, wherein at least one of the appliances
comprises a corrugation to stiffen the appliance against lateral
deflection induced by the force from the elastic member.
20. The system of claim 17, wherein at least one of the appliances
comprises a locally reinforced area connected with the hook to
stiffen the hook against deflection induced by the force from the
elastic member.
21. The system of claim 17, wherein the hook is disposed gingivally
offset relative to a center of a tooth receiving cavity or a center
of a clinical crown of a tooth as received in a cavity proximate to
the hook.
22. The system of claim 17, wherein the hook gingivally offset from
a gingival line of the appliance.
23. A method for manufacturing an orthodontic positioning appliance
having teeth receiving cavities and an external hook for an
orthodontic elastic member, the method comprising: receiving a
digital representation of a patient's teeth in a selected
arrangement; defining a position and an orientation of an
orthodontic elastic member relative to the digital representation;
modifying the digital representation to add a witness object
adjacent to a tooth surface of the digital representation;
transmitting or storing the modified digital representation for
delivery to a fabrication system for fabricating a mold
corresponding to the modified digital representation and
fabricating from the mold an orthodontic appliance comprising a
hook configured to interface with an orthodontic elastic member so
as to react a force from the elastic member into the patient-worn
appliance.
24. The method of claim 23, wherein the hook is configured to be
laterally offset from a surface of a tooth or gingivally offset
from a gingival edge of the appliance when the appliance is coupled
with the patient's teeth and absent an orthodontic elastic member
coupled with the hook.
25. The method of claim 23, wherein fabricating the appliance
comprises molding a sheet of elastomeric material over the
mold.
26. The method of claim 23, further comprising adding or removing
material from the molded sheet.
27. A method for manufacturing an orthodontic positioning appliance
having teeth receiving cavities and an external hook for an
orthodontic elastic member, the method comprising: receiving a
digital representation of a patient's teeth in a selected
arrangement; defining a position and an orientation of an
orthodontic elastic member relative to the digital representation;
modifying the digital representation to add a hook representation
to the digital representation; directly fabricating an positioning
appliance from the modified digital representation, the appliance
comprising a hook configured to interface with an orthodontic
elastic member so as to react a force from the elastic member into
the patient-worn appliance.
28. The method of claim 27, wherein the device is fabricated using
a rapid prototyping method.
Description
BACKGROUND
[0001] The present invention relates generally to the field of
orthodontics, and more particularly to dental positioning
appliances configured to interface with an orthodontic elastic
member and react a force from the elastic member into the
appliance.
[0002] An objective of orthodontics is to move a patient's teeth to
positions where function and/or aesthetics are optimized.
Traditionally, appliances such as braces are applied to a patient's
teeth by a treating practitioner and the set of braces exerts
continual force on the teeth and gradually urges them toward their
intended positions. Over time and with a series of clinical visits
and adjustments to the braces, the practitioner adjusts the
appliances to move the teeth toward their final destination.
[0003] More recently, alternatives to conventional orthodontic
treatment with traditional affixed appliances (e.g., braces) have
become available. For example, systems including a series of
preformed appliances/aligners have become commercially available
from Align Technology, Inc., Santa Clara, Calif., under the
tradename Invisalign.RTM. System. The Invisalign.RTM. System is
described in numerous patents and patent applications assigned to
Align Technology, Inc. including, for example in U.S. Pat. Nos.
6,450,807, and 5,975,893, as well as on the company's website,
which is accessible on the World Wide Web (see, e.g., the url
"www.invisalign.com"). The Invisalign.RTM. System includes
designing and/or fabricating multiple, and sometimes all, of the
aligners to be worn by the patient before the aligners are
administered to the patient and used to reposition the teeth (e.g.,
at the outset of treatment). Often, designing and planning a
customized treatment for a patient makes use of computer-based
3-dimensional planning/design tools, such as Treat.TM. software
from Align Technology, Inc. The design of the aligners can rely on
computer modeling of a series of planned successive tooth
arrangements, and the individual aligners are designed to be worn
over the teeth and elastically reposition the teeth to each of the
planned tooth arrangements.
[0004] While recently developed orthodontic treatment technologies,
such as those described above, represent a considerable advancement
in the field of orthodontics, additional advancements remain of
interest. For example, in some instances it may be advantageous to
use an orthodontic elastic member to generate a tension force
between a patient's upper and lower teeth to bring the teeth into a
desired occlusion. In some traditional approaches, brackets are
bonded to the teeth and an orthodontic elastic member is used to
couple the brackets to generate the tension force. Generating such
a tension force in conjunction with recently developed orthodontic
approaches can be challenging. For example, shell aligners are
generally designed to match the geometry of a patient's teeth,
thereby leaving little room for bonding such brackets to a
patient's teeth. As such, there is a need for shell aligners that
can be used in conjunction with an orthodontic elastic member to,
for example, bring a patient's teeth into a desired occlusion.
BRIEF SUMMARY
[0005] The present disclosure provides orthodontic positioning
appliances for use with an orthodontic elastic member, and related
systems and methods. The disclosed positioning appliances are
configured to couple with an orthodontic elastic member so as to
react a force from the elastic member into the appliance. Such
appliances can advantageously employ the force imparted by the
elastic member to apply desired repositioning forces to a patient's
teeth to, for example, generate a desired occlusion and/or
supplement repositioning forces generated by the appliance.
[0006] For a fuller understanding of the nature and advantages of
the present invention, reference should be made to the ensuing
detailed description and accompanying drawings. Other aspects,
objects and advantages of the invention will be apparent from the
drawings and detailed description that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 illustrates a jaw and an incremental positioning
appliance for the jaw, in accordance to an embodiment.
[0008] FIG. 2A illustrates upper and lower teeth received within
incremental tooth positioning appliances having gingivally disposed
hooks, in accordance to an embodiment.
[0009] FIG. 2B illustrates upper and lower teeth received within
incremental tooth positioning appliances having gingivally disposed
hooks, wherein the hooks are configured to angle or curve more
toward a tooth's surface, in accordance with an embodiment.
[0010] FIG. 3A illustrates teeth received within teeth receiving
cavities of an incremental tooth positioning appliance and an
orthodontic elastic member coupled with the positioning appliance.
The appliance includes notches or hooks cut or formed into a tooth
receiving cavity of the appliance.
[0011] FIG. 3B is a cross-sectional view of a tooth and the
positioning appliance of FIG. 3A illustrating hook displacement
induced by the orthodontic elastic member.
[0012] FIG. 4A is a cross-sectional view of an incremental tooth
positioning appliance having an offset hook, in accordance with an
embodiment of the present invention.
[0013] FIG. 4B illustrates a tooth received within a tooth
receiving cavity of the incremental tooth positioning appliance of
FIG. 4A and an orthodontic elastic member coupled with the offset
hook, in accordance with an embodiment of the present
invention.
[0014] FIG. 4C illustrates a reinforced version of the offset hook
of FIG. 4A, in accordance with an embodiment of the present
invention.
[0015] FIG. 5 illustrates a tooth received within a tooth receiving
cavity of an incremental tooth positioning appliance having a
gingivally disposed offset hook and an orthodontic elastic member
coupled with the gingivally disposed hook, in accordance with an
embodiment of the present invention.
[0016] FIG. 6 illustrates a reinforced version of the gingivally
disposed hook of FIG. 5, in accordance with an embodiment of the
present invention.
[0017] FIG. 7 illustrates a tooth received within a tooth receiving
cavity of an incremental tooth positioning appliance having a
gingivally disposed offset hook and an orthodontic elastic member
coupled with the gingivally disposed hook, in accordance with an
embodiment of the present invention.
[0018] FIG. 8A illustrates teeth received within teeth receiving
cavity of an incremental tooth positioning appliance having an
exterior hook and an orthodontic elastic member coupled with the
exterior hook, in accordance with an embodiment of the present
invention.
[0019] FIG. 8B is a cross-sectional view of a tooth and the
positioning appliance of FIG. 8A illustrating the orthodontic
elastic member coupled with the exterior hook, in accordance with
an embodiment of the present invention.
[0020] FIG. 9A illustrates teeth received within teeth receiving
cavities of an incremental tooth positioning appliance having a
gingivally disposed exterior hook and an orthodontic elastic member
coupled with the gingivally disposed exterior hook, in accordance
with an embodiment of the present invention.
[0021] FIG. 9B is a cross-sectional view of a tooth and the
positioning appliance of FIG. 9A illustrating the orthodontic
elastic member coupled with the gingivally disposed exterior hook,
in accordance with an embodiment of the present invention.
[0022] FIG. 10 illustrates an incremental tooth positioning
appliance having a reinforcing corrugation and an exterior hook
coupled with an orthodontic elastic member, in accordance with an
embodiment of the present invention.
[0023] FIG. 11 is a simplified block diagram illustrating a method
for fabricating an aligner having an exterior hook using a mold, in
accordance with an embodiment of the present invention.
[0024] FIGS. 12A and 12B illustrate the addition of a witness
object to mold geometry used to generate an appliance having an
offset hook, in accordance with an embodiment of the present
invention.
[0025] FIG. 13 is a simplified block diagram illustrating a method
for direct fabrication of an aligner having an exterior hook, in
accordance with an embodiment of the present invention.
[0026] FIG. 14 diagrammatically illustrates a fabrication system in
accordance with an embodiment of the present invention.
DETAILED DESCRIPTION
[0027] In the following description, various embodiments of the
present invention will be described. For purposes of explanation,
specific configurations and details are set forth in order to
provide a thorough understanding of the embodiments. However, it
will also be apparent to one skilled in the art that the present
invention may be practiced without the specific details.
Furthermore, well-known features may be omitted or simplified in
order not to obscure the embodiment being described.
[0028] Orthodontic positioning appliances are provided that can be
used in conjunction with one or more orthodontic elastic members,
as well as related methods and systems. During orthodontic
treatment, it may be necessary to apply forces to a tooth to
generate movement of the tooth to, for example, bring the patient's
teeth into a better occlusion. The presently disclosed appliances,
methods, and systems provide means by which such forces can be
applied during orthodontic treatment where appliances having teeth
receiving cavities are used, such as preformed appliances/aligners
available from Align Technology, Inc., Santa Clara, Calif., under
the tradename Invisalign.RTM. System.
[0029] The disclosed orthodontic positioning appliances for use
with an orthodontic elastic member include, for example, a patient
removable tooth positioning appliance having teeth receiving
cavities shaped to receive and apply a resilient positioning force
to a patient's teeth. The positioning appliance can include a hook
configured to interface with an orthodontic elastic member so as to
react a force from the elastic member into the patient-worn
appliance, thereby applying (e.g., supplementing) forces other than
or in addition to the forces applied to the patient's teeth and
generated solely by the positioning appliance(s) in the absence of
the coupled elastic member. The appliance and/or hook thereof can
be configured to more optimally engage an elastic member when the
appliance is worn by the patient. In one embodiment, for example,
the hook can be configured to be laterally offset from another
portion of the appliance, such as a portion of the appliance that
engages the patients teeth when worn. For example, a hook can be
offset (e.g., laterally offset) from a portion of the appliance
that engages a buccal surface of a tooth when the appliance is
coupled with the patient's teeth. In such an embodiment, the hook
will be offset even when no orthodontic elastic member is coupled
with the tooth.
[0030] In another embodiment, an appliance can be configured such
that the hook is gingivally offset from a portion of the appliance.
For example, certain shell-type appliances will include a gingival
edge or edge of the appliance that, when worn by a patient, is
disposed substantially along the gingival line or margin where
gingival tissue meets the tooth crown at the base of the tooth. In
certain embodiments, a hook of an appliance will be gingivally
offset or offset in a gingival direction relative to the gingival
edge of the appliance. Such a configuration advantageously allows
incorporation of the hook into the appliance structure, but without
necessarily reducing tooth receiving/engaging surfaces of an
appliance cavity.
[0031] An appliance can include a reinforcement structure selected
and/or disposed on the appliance so as to stiffen the appliance
against lateral deflection induced by the force from the elastic
member. For example, a portion of the appliance can include a
corrugation to stiffen the appliance. In another embodiment, the
appliance can include a locally stiffened area (e.g., via an added
shape or contour) connected with the hook to stiffen the hook
against deflection (e.g., lateral deflection) induced by the force
from the elastic member.
[0032] Referring now to the drawings, in which like reference
numerals represent like parts throughout the several views, FIG. 1
provides an appropriate starting point in a discussion of the
present invention with respect to tooth repositioning appliances
designed to apply repositioning forces to teeth. A tooth
repositioning appliance 10 can be worn by a patient in order to
achieve an incremental repositioning of individual teeth in the jaw
11. The appliance can include a shell (e.g., polymeric shell)
having teeth-receiving cavities that receive and resiliently
reposition the teeth. In many embodiments, a polymeric appliance
can be formed from a thin sheet of suitable elastomeric polymeric
material, such a 0.03 inch thermal forming dental material by
Tru-Tain Plastics, Rochester, Minn. An appliance can fit over all
teeth present in an upper or lower jaw, or less than all of the
teeth. In some cases, only certain teeth received by an appliance
will be repositioned by the appliance while other teeth can provide
a base or anchor region for holding the appliance in place as it
applies force against the tooth or teeth targeted for
repositioning. In some cases, many or most, and even all, of the
teeth will be repositioned at some point during treatment. Teeth
that are moved can also serve as a base or anchor for holding the
appliance as it is worn by the patient. Typically, no wires or
other means will be provided for holding an appliance in place over
the teeth. In some cases, however, it may be desirable or necessary
to provide individual anchors on teeth with corresponding
receptacles or apertures in the appliance so that the appliance can
apply a selected force on the tooth. Exemplary appliances,
including those utilized in the Invisalign.RTM. System, are
described in numerous patents and patent applications assigned to
Align Technology, Inc. including, for example in U.S. Pat. Nos.
6,450,807, and 5,975,893, as well as on the company's website,
which is accessible on the World Wide Web (see, e.g., the url
"www.invisalign.com").
[0033] An appliance can be designed and/or provided as part of a
set or plurality of appliances. In such an embodiment, each
appliance may be configured so a tooth-receiving cavity has a
geometry corresponding to an intermediate or final tooth
arrangement intended for the appliance. The patient's teeth can be
progressively repositioned from an initial tooth arrangement to a
target tooth arrangement by placing a series of incremental
position adjustment appliances over the patient's teeth. A target
tooth arrangement can be a planned final tooth arrangement selected
for the patient's teeth at the end of all planned orthodontic
treatment. Alternatively, a target arrangement can be one of many
intermediate arrangements for the patient's teeth during the course
of orthodontic treatment, which may include where surgery is
recommended, where inter-proximal reduction (IPR) is appropriate,
where a progress check is scheduled, where anchor placement is
best, where palatal expansion is desirable, etc. As such, it is
understood that a target tooth arrangement can be any planned
resulting arrangement for the patient's teeth that follows one or
more incremental repositioning stages. Likewise, an initial tooth
arrangement can be any initial arrangement for the patient's teeth
that is followed by one or more incremental repositioning stages.
The adjustment appliances can be generated all at the same stage or
in sets or batches, e.g., at the beginning of a stage of the
treatment, and the patient wears each appliance until the pressure
of each appliance on the teeth can no longer be felt or has
resulted in the maximum amount of expressed tooth movement for that
given stage. A plurality of different appliances (e.g., set) can be
designed and even fabricated prior to the patient wearing any
appliance of the plurality. After wearing an appliance for an
appropriate period of time, the patient replaces the current
appliance with the next appliance in the series until no more
appliances remain. The appliances are generally not affixed to the
teeth and the patient may place and replace the appliances at any
time during the procedure (e.g., patient-removable appliances). The
final appliance or several appliances in the series may have a
geometry or geometries selected to overcorrect the tooth
arrangement, i.e., have a geometry which would (if fully achieved)
move individual teeth beyond the tooth arrangement which has been
selected as the "final." Such over-correction may be desirable in
order to offset potential relapse after the repositioning method
has been terminated, i.e., to permit movement of individual teeth
back toward their pre-corrected positions. Over-correction may also
be beneficial to speed the rate of correction, i.e., by having an
appliance with a geometry that is positioned beyond a desired
intermediate or final position, the individual teeth will be
shifted toward the position at a greater rate. In such cases, the
use of an appliance can be terminated before the teeth reach the
positions defined by the appliance.
[0034] During a course of orthodontic treatment, it may be
necessary to apply a force to a patient's teeth to generate
movement of the tooth to bring the patient's teeth into a better
occlusion. In many instances, it may not be possible to generate
desired levels of such a force solely through the use of a tooth
positioning appliance such as the tooth positioning appliance 10
described above. The forces generated by such a tooth positioning
appliance can, however, be supplemented by the use of an
orthodontic elastic member.
[0035] In accordance with an embodiment of the present invention,
an orthodontic appliance, such as those described above, can be
designed/configured for use in engagement with one or more elastic
members. Such an appliance, can be configured to include one or
more hooks for engagement with one or more elastic members. And a
set of appliances can include one or more appliances with
hooks.
[0036] FIG. 2A illustrates tooth positioning appliances 20, 22 for
receiving, respectively, upper and lower teeth of a patient.
Appliances 20, 22 include hooks 24, 26, respectively. Appliance 20
includes a gingival edge 25 of the appliance that substantially
follows along a gingival margin of the patient's dentition as the
appliance 20 is worn. Similarly, appliance 22 includes a gingival
edge 27. The hooks 24, 26 extend gingivally or in a gingival
direction relative to gingival edge 25, 27, respectively, and may
be pointed in a mesial, distal, or vertical direction In the
illustrated embodiment, hook 24 is pointed mesially and hook 26 is
pointed distally. As noted above, such a gingivally offset
configuration can maximize the surface area of the aligner material
engaging the tooth received in an adjacent tooth receiving cavity.
Hooks 24, 26 may further be offset laterally, e.g., to better
accommodate an elastic member engaging the hook, as described
further herein. In use, an orthodontic elastic member can be
coupled between the hooks 24, 26, thereby applying a reciprocal
force to each of the appliances 20, 22. One or more hooks can be
incorporated into each of the appliances 20, 22 to apply one or
more forces into the appliances. Such forces can be used to
supplement the teeth repositioning forces generated, e.g., by
engagement between the patient's teeth/tooth surfaces and surfaces
of corresponding receiving cavities of the appliances 20, 22.
[0037] FIG. 2B illustrates positioning appliances 20, 22. The
appliances 20, 22 include hooks 24, 26, respectively, wherein the
hooks 24, 26 angle or curve back more toward tooth's surfaces
compared to the embodiment illustrated in FIG. 2A. Hooks as in FIG.
2B may be selected, for example, to better avoid unwanted contact
or poking of the patient's soft tissue.
[0038] FIG. 3A illustrates teeth 28 received within teeth receiving
cavities of an incremental tooth positioning appliance 30. An
orthodontic elastic member 32 is coupled with the tooth positioning
appliance 30 via a hook 34 formed by creating a u-shaped aperture
36 located in the side of the appliance. The aperture 36 can be
formed into an existing appliance at a location selected for the
transfer of the force from the elastic member into the appliance.
The aperture 36 can have a slot width and a shape selected to
accommodate the elastic member. A hook 38 can also be positioned
along a gingival margin of the appliance 30. The hook 38 can be
formed, for example, via adjacent slots 40, 42 formed in the
gingival margin of the appliance 30. Hooks 34 and 38 may be formed
by simply cutting or trimming out material from a shell appliance.
However, hooks formed by such an approach reduce appliance material
or surfaces engaging a tooth received within an adjacent cavity and
require deflection of appliance material forming the hook in order
to accommodate a positioned elastic member (see, e.g., FIG.
3B).
[0039] FIG. 3B is a cross-sectional view of a tooth 28 and the
positioning appliance 30 of FIG. 2A. Because the hook 34 is formed
via the u-shaped aperture, when the elastic member 32 is coupled
with the hook 34, the hook is forced to deflect away from the
adjacent surface of the tooth 28 to accommodate the presence of the
elastic member 32 between the hook 34 and the tooth 28. Additional
deflection of the hook 34 may be induced by the force imparted into
the hook by the elastic member 32. Such additional deflections can
be controlled to some extent by shaping the overall width of the
u-shaped aperture to produce a wider hook.
[0040] FIG. 4A illustrates an incremental tooth positioning
appliance 40 having an offset hook 42. FIG. 4B illustrates a tooth
28 received within a tooth receiving cavity of the incremental
tooth positioning appliance 40 and an orthodontic elastic member 32
coupled with the offset hook 42. The offset hook 42 is offset from
an adjacent surface of the tooth 28 (e.g., buccal surface, lingual
surface) when the appliance 40 is coupled with the patient's teeth
and no orthodontic elastic member is coupled with the hook. The
offset can be configured to accommodate an elastic member with
reduced deflection, in contrast to the hook 34 or 38 of FIGS. 3A
and 3B. The hook 42 can be shaped to retain the elastic member in
the absence of the elastic member being coupled with an opposing
arch of the patient teeth. For example, the hook 42 can be shaped
to trap the elastic member in contact with the surface of the tooth
28 (e.g., via a hook shaped to engage a sufficient portion of the
perimeter of the elastic member), while still allowing installation
of the elastic member into the trapping engagement of the hook 42
via an opening 46. The lateral offset may be configured such that
the opening 46 is closer to the tooth than the maximum offset
distance, in order that the offset allows the elastic to be engaged
against the aligner without touching the tooth, but the hook does
not protrude towards the soft tissue, thereby making the hook
comfortable for the patient.
[0041] In one example, the tip of the hook may curve or angle away
from soft tissue or back toward the tooth surface. The tip of the
hook may also be curved, angled, or bent towards the gingival line
such that the elastic may be placed into the aligner first before
the aligner is worn, and the hook angle/curvature keeps the elastic
from falling off of the aligner.
[0042] The appliance 40 can optionally include a reinforcement
structure in the vicinity of the hook 42 to reduce deflection
induced by the force from the elastic member 32. For example, as
illustrated in FIG. 4C, the appliance 40 can include a locally
strengthened region 48 (e.g., via increased thickness in the area
of the hook). The appliance 40 can also be locally stiffened by
embedding a reinforcing structure (e.g., a stronger and stiffer
material such as stainless steel or plastic resin filler) into the
appliance to reinforce the appliance/hook against deflection
induced by the force from the elastic member.
[0043] As illustrated in FIG. 5, an offset hook 50 can also be
disposed gingivally offset relative to a center of a clinical crown
52 of a tooth 28 as received in a cavity proximate to the hook 50,
and may be gingivally offset relative to a gingival edge of the
appliance or a gingival margin or line 51 identifying or
approximating where gingival tissue meets the base of the tooth 28
crown. Such a gingival offset can be used to increase the surface
area of the positioning appliance that engages the tooth 28, as
well as to provide space for accommodating an elastic member 32
without necessarily requiring lateral deflection for elastic member
engagement. As illustrated in FIG. 6, an appliance having such a
gingivally offset hook 50 can include a locally reinforced area 54
(e.g., the appliance can be locally thickened in the vicinity of
the offset hook) to reduce deflection of the hook 50 induced by the
force from the elastic member. The appliance can also be locally
stiffened by embedding a reinforcing structure (e.g., a stronger
and stiffer material such as stainless steel or plastic resin) into
the appliance to reinforce the appliance/hook against deflection
induced by the force from the elastic member.
[0044] FIG. 7 illustrates an offset hook 56 that is disposed even
more gingivally offset relative to the center of a clinical crown
52 of a tooth 28 received in a cavity proximate to the hook 56 than
the hook 50 shown in FIGS. 5 and 6. In addition to being more
gingivally offset, the hook 56 is also offset further from the
adjacent surface of the tooth 28 in order to be disposed at or
below a gingival line 58 for the tooth 28. The appliance having
such a gingivally offset hook 56 can include a locally reinforced
area 60 (e.g., the appliance can be locally thickened in the
vicinity of the offset hook) to reduce deflection of the hook 56
induced by the force from the elastic member 32.
[0045] An appliance can be configured with an exterior offset hook
that couples with an elastic member such that the elastic member
does not contact a surface of the tooth. FIGS. 8A and 8B illustrate
an exterior offset hook 62 positioned similar to the offset hook 42
illustrated in FIGS. 4A through 4C. FIGS. 9A and 9B illustrate an
exterior offset hook 64 offset gingivally similar to the offset
hook illustrated in FIGS. 5 and 6. A positioning appliance can be
configured with such an exterior offset hook by incorporating
additional material on the exterior of a basic positioning
appliance such as the appliance 10 illustrated in FIG. 1. Exterior
hooks can also be locally reinforced, for example, via locally
thickened areas as illustrated in FIGS. 8B and 9B.
[0046] A tooth repositioning appliance can also include a
reinforcement structure to stiffen the appliance against deflection
induced by the force from an elastic member. For example, FIG. 10
illustrates a repositioning appliance 70 having a reinforcing
corrugation 72 formed along a gingival edge of the repositioning
appliance. The corrugation 72 can be formed by adding an elongated
protrusion to a male mold prior to forming the appliance over the
male mold. A corrugation can be used to stiffen the gingival edge
of the repositioning appliance against lateral deflection induced
by the force from the elastic member 32.
[0047] The present invention further provides methods for using one
or more orthodontic positioning devices having one or more hooks
configured to interface with an orthodontic elastic member so as to
react a force from the elastic member into the patient-worn device.
The above-described orthodontic positioning devices can be
configured for use in practicing orthodontic treatment or tooth
repositioning methods. For example, a first orthodontic positioning
device can be provided, the device having a hook configured to
interface with an orthodontic elastic member is received (e.g., by
a patient, by a dental professional, etc.), e.g., as described
above. The first positioning device is coupled with a first arch of
the patient's teeth. An orthodontic elastic member is coupled with
the hook of the first positioning device to transfer a force from
the elastic member into the first positioning device. A second
orthodontic positioning device having a hook configured to
interface with an orthodontic elastic member is received. The
second orthodontic positioning device is coupled with a second arch
of the patient's teeth, and the orthodontic elastic member that is
coupled with the hook of the first positioning device is coupled
with the hook of the second positioning device. Methods can include
use of a plurality of different (e.g., successive) positioning
devices or appliances.
[0048] The present invention further provides systems for
repositioning a patient's teeth. A system can include a plurality
of orthodontic tooth positioning appliances. Consistent with
discussion provided further herein, at least two of the appliances
can have different teeth receiving cavities shaped to receive and
resiliently reposition the patient's teeth in a first arch of the
patient's teeth from a first arrangement to a successive
arrangement. At least one of the appliances includes a hook
configured to interface with an orthodontic elastic member so as to
react a force from the elastic member into the patient-worn
appliance. The hook can be configured to be offset from a surface
of a tooth when the appliance is coupled with the patient's teeth
in the first arch and no orthodontic elastic member is coupled with
the hook.
[0049] A system can include a plurality appliances, or sets of
appliances, for repositioning a patient's upper and lower arch
teeth. For example, one of a plurality of upper arch appliances and
one of a plurality of lower arch appliances can be configured to be
worn simultaneously and coupled with each other via an orthodontic
elastic member coupling the hook of the upper arch appliance to the
hook of the lower arch appliance. The elastic member may also be
coupled within the same arch in order to connect the elastic to an
elastic hook that may be directly bonded to an exposed tooth
elsewhere in the arch, whereby the aligner has been cut around that
tooth-affixed elastic hook. The elastic member may also be coupled
from the aligner to an anchorage device attached somewhere in the
mouth such as a mini-implant or temporary anchorage device (TAD)
affixed to the patient's jaw structure.
[0050] The present invention further provides methods, such as a
computer-implemented methods, for designing an orthodontic
positioning device having teeth receiving cavities. Such a method
can be used to design the above-described orthodontic positioning
devices. A method can include providing and/or receiving a digital
representation of the patient's teeth in a selected arrangement.
The arrangement can be selected to define the shape of teeth
receiving cavities shaped to receive and apply a resilient
positioning force to a patient's teeth. An appliance can be modeled
based on the received representation. The received representation
can be used to define the teeth receiving cavities of the
appliance. The appliance is modeled to include a hook configured to
interface with an orthodontic elastic member so as to react a force
from the elastic member into the appliance, including hook designs
or configurations as indicated further herein. For example, the
modeled hook can be configured such that it is offset (e.g.,
laterally) from a surface of a tooth when the appliance is coupled
with the patient's teeth and no orthodontic elastic member is
coupled with the hook. The hook may alternatively or additionally
be gingivally offset, e.g., relative to a gingival edge of the
model appliance or a gingival line of the patient. A reinforcement
structure may further be designed or modeled so as to stiffen the
appliance against lateral deflection induced by the force from the
elastic member can optionally be modeled into the appliance. The
reinforcement structure can include, for example, a corrugation
(e.g., positioned along a gingival edge of the appliance to
increase the bending stiffness of the gingival edge). The
reinforcement structure can include a locally reinforced area
(e.g., locally thickened) connected with the hook to stiffen the
hook against deflection induced by the force from the elastic
member.
[0051] An aligner having an exterior hook can be created using
automated steps, manual steps, and/or a combination of automated
and manual steps. Such steps can include, for example, the removal
of material from an aligner assembly (e.g., using a physical cutter
such as an end mill, a drill, and a punch; using non-contact
removal techniques such as laser cutting, and electrical discharge
machining (EDM); using other media such as water jets, hot water,
and hot gases); the addition of material to an aligner assembly
(e.g., by bonding or attaching a pre-formed feature such as a
hook); and/or direct fabrication techniques (e.g., stereo
lithography).
[0052] FIG. 11 illustrates a method 100 for indirect fabrication of
an aligner having a hook by forming a sheet of material over a
mold. The geometry of the mold includes representations of a
patient's teeth in an arrangement suitable to generate desired
teeth receiving cavities. A witness object is added to the teeth
representations to generate an inner surface of an offset hook
portion of the aligner. While some of the steps of method 100 are
described as being computer-implemented, the alternate use of
non-computer implemented approaches may also be apparent to a
person of skill in the art. The method 100 can be used to generate
the appliances disclosed above.
[0053] In step 102, the position and orientation of an elastic
member relative to the aligner is defined. The defined position and
orientation of the elastic member can be generated, for example,
using computer-based 3-dimensional planning/design tools, such as
Treat.TM. from Align Technology, Inc. Computer modeling of one or
successive tooth arrangements for a patient's upper and lower teeth
can be used to position/orient an elastic member between an upper
jaw appliance hook (or a feature attached to an upper jaw tooth)
and a lower jaw appliance hook (or a feature attached to a lower
jaw tooth). While the elastics shown in the figures are oriented
generally vertically, other orientations are possible (e.g., to
couple non-occluding pairs of teeth). An elastic member can be
positioned so as to generate supplemental forces to treat certain
types of malocclusion (e.g., class II and III corrections, canine
rotation, extrusion, etc.).
[0054] In step 104, a hook edge is defined relative to the mold
geometry using the defined position/orientation of the elastic
member. The hook edge definition can be a spline on a tooth surface
in a 3-dimensional model. The hook edge can be used to position and
orient a witness object created in step 106. FIGS. 12A and 12B
illustrate a hook edge definition and a witness object positioned
and oriented using the hook edge definition and a corresponding
tooth surface. The witness object is shaped to generate a suitable
offset from the tooth surface to generate a corresponding offset in
the inner surface of the aligner. An area of the aligner that will
interface with the elastic member to hold the elastic member can be
determined. Based on the determined area, the witness object can be
created that corresponds to the determined area and merged into the
3-dimensional representation of the patient's teeth. The witness
object can be merged into a gingival surface included in the
3-dimensional representation of the patient's teeth, and
appropriate smoothing applied. The resulting 3-dimensional
representation (mold geometry) can be used to generate a positive
mold over which a sheet of material is formed to create an
aligner.
[0055] In step 108, one or more markers can optionally be
created/added to the mold geometry to generate a reference
feature(s) in an aligner that can be used to guide subsequent
removal of material from the aligner (e.g., see step 118 below)
and/or to guide subsequent addition of material to the aligner
(e.g., see step 116 below). Further, a production graphic(s) (e.g.,
a screenshot on a computer monitor or paper) can optionally be
generated from the mold geometry in step 110 to, for example, guide
subsequent removal of material from the aligner and/or to guide
subsequent addition of material to the aligner.
[0056] The mold geometry is then used to create a physical mold,
which is used to form a sheet of elastomeric material to form the
aligner. In step 112, a mold is created from the 3-dimensional mold
geometry. The mold can be created, for example, directly using
automated fabrication techniques (e.g., stereo lithography). In
step 114, the aligner is fabricated by molding a sheet of material
over the physical mold.
[0057] Once the basic aligner shell is fabricated, material can be
optionally added and/or removed from the aligner to finalize the
geometry of the hook. In step 116, material can be optionally added
to the aligner to, for example, form part or all of the hook
structure. For example, a preformed feature can be bonded or
otherwise attached to the aligner to serve as the hook. In step
118, material can be optionally removed from the aligner to
complete the formation of the offset hook. For example, localized
portions of the aligner can be removed to accommodate the elastic
member when installed on the hook.
[0058] FIG. 13 illustrates a method 200 for direct fabrication of
an aligner having a hook, for example, via direct fabrication from
a 3-dimensional representation of the aligner. Suitable direct
fabrication techniques (e.g., stereo lithography) can be used.
Because some of the steps of the method 200 are similar to
corresponding steps of the method 100 of FIG. 11, detailed
description of such steps is not repeated here. While some of the
steps of method 200 are described as being computer-implemented,
the alternate use of non-computer implemented approaches may also
be apparent to a person of skill in the art. The method 200 can be
used to generate the appliances disclosed above.
[0059] In step 202, the position and orientation of an elastic
member relative to the aligner is defined. The discussion above
regarding step 102 is applicable to step 202.
[0060] In step 204, an aligner shell is defined using a
3-dimensional representation of a patient's teeth. A computer
program can be used to define a 3-dimensional representation of the
aligner shell using representations of the patient's teeth to
define the teeth receiving cavities of the aligner shell. The outer
surfaces of the aligner shell can be defined, for example, using
suitable offsets from the surfaces of the teeth.
[0061] In step 206, the definition of the aligner shell is modified
to incorporate a hook feature, for example, one of the above
disclosed hook features. To provide for efficient incorporation of
such a hook feature, pre-defined digital objects can be positioned,
oriented, and/or scaled relative to the aligner shell definition
and then merged into the aligner shell definition. Additional
material can be added and/or removed from the resulting aligner
definition using known methods.
[0062] In step 208, one or more markers can optionally be
created/added to the aligner definition as discussed above with
respect to step 108 of the method 100. Likewise, in step 210,
production graphics can be created and used as discussed above with
respect to step 110 of the method 100.
[0063] In step 212, the resulting 3-dimensional representation of
the aligner is used to directly fabricate the aligner. A suitable
direct fabrication method, such as known rapid prototyping
approaches (e.g., stereo lithography) can be used.
[0064] In step 214, material can be added to the resulting aligner
as discussed above with respect to step 116 of the method 100.
Likewise, in step 216, material can be removed from the resulting
aligner as discussed above with respect to step 118 of the method
100.
[0065] An alternative reinforcement technique provides marked
regions in the refractory model (the stereolithography model)
whereby protrusions or recessed areas are designed to hold wires
and/or plastic resin, which are inserted into the model, such that
when the aligner sheet material is formed over the model, the
reinforcements are "picked up" by the plastic formed over the
reinforcements. The aligner is trimmed according to specification,
leaving the reinforcement embedded into the hook region of the
aligner.
[0066] FIG. 14 is a simplified block diagram of a data processing
system 300 embodying the present invention. Data processing system
300 typically includes at least one processor 302 which
communicates with a number of peripheral devices via bus subsystem
304. These peripheral devices typically include a storage subsystem
306 (memory subsystem 308 and file storage subsystem 314), a set of
user interface input and output devices 318, and an interface to
outside networks 316, including the public switched telephone
network. This interface is shown schematically as "Modems and
Network Interface" block 316, and is coupled to corresponding
interface devices in other data processing systems via
communication network interface 324. Data processing system 300
could be a terminal or a low-end personal computer or a high-end
personal computer, workstation or mainframe.
[0067] The user interface input devices typically include a
keyboard and may further include a pointing device and a scanner.
The pointing device may be an indirect pointing device such as a
mouse, trackball, touchpad, or graphics tablet, or a direct
pointing device such as a touch screen incorporated into the
display. Other types of user interface input devices, such as voice
recognition systems, are also possible.
[0068] User interface output devices typically include a printer
and a display subsystem, which includes a display controller and a
display device coupled to the controller. The display device may be
a cathode ray tube (CRT), a flat-panel device such as a liquid
crystal display (LCD), or a projection device. The display
subsystem may also provide non-visual display such as audio
output.
[0069] Storage subsystem 306 maintains the basic programming and
data constructs that provide the functionality of the present
invention. The software modules discussed above are typically
stored in storage subsystem 306. Storage subsystem 306 typically
comprises memory subsystem 308 and file storage subsystem 314.
[0070] Memory subsystem 308 typically includes a number of memories
including a main random access memory (RAM) 310 for storage of
instructions and data during program execution and a read only
memory (ROM) 312 in which fixed instructions are stored. In the
case of Macintosh-compatible personal computers the ROM would
include portions of the operating system; in the case of
IBM-compatible personal computers, this would include the BIOS
(basic input/output system).
[0071] File storage subsystem 314 provides persistent
(non-volatile) storage for program and data files, and typically
includes at least one hard disk drive and at least one disk drive
(with associated removable media). There may also be other devices
such as a CD-ROM drive and optical drives (all with their
associated removable media). Additionally, the system may include
drives of the type with removable media cartridges. The removable
media cartridges may, for example be hard disk cartridges, such as
those marketed by Syquest and others, and flexible disk cartridges,
such as those marketed by Iomega. One or more of the drives may be
located at a remote location, such as in a server on a local area
network or at a site on the Internet's World Wide Web.
[0072] In this context, the term "bus subsystem" is used
generically so as to include any mechanism for letting the various
components and subsystems communicate with each other as intended.
With the exception of the input devices and the display, the other
components need not be at the same physical location. Thus, for
example, portions of the file storage system could be connected via
various local-area or wide-area network media, including telephone
lines. Similarly, the input devices and display need not be at the
same location as the processor, although it is anticipated that the
present invention will most often be implemented in the context of
PCs and workstations.
[0073] Bus subsystem 304 is shown schematically as a single bus,
but a typical system has a number of buses such as a local bus and
one or more expansion buses (e.g., ADB, SCSI, ISA, EISA, MCA,
NuBus, or PCI), as well as serial and parallel ports. Network
connections are usually established through a device such as a
network adapter on one of these expansion buses or a modem on a
serial port. The client computer may be a desktop system or a
portable system.
[0074] Scanner 320 is responsible for scanning casts of the
patient's teeth obtained either from the patient or from an
orthodontist and providing the scanned digital data set information
to data processing system 300 for further processing. In a
distributed environment, scanner 320 may be located at a remote
location and communicate scanned digital data set information to
data processing system 300 via network interface 324.
[0075] Fabrication machine 322 can encompass a range of fabrication
machines and methods used to fabricate positive molds for the
above-described repositioning appliances or directly fabricate the
above-described repositioning appliances based on data set
information received from data processing system 300. In a
distributed environment, fabrication machine 322 may be located at
a remote location and receive data set information from data
processing system 300 via network interface 324.
[0076] It is understood that the examples and embodiments described
herein are for illustrative purposes and that various modifications
or changes in light thereof will be suggested to persons skilled in
the art and are to be included within the spirit and purview of
this application and the scope of the appended claims. Numerous
different combinations or the illustrated or described embodiments
are possible, including combinations of any aspects of the
different described embodiments. Such combinations are considered
to be part of the present invention.
* * * * *