U.S. patent application number 10/375224 was filed with the patent office on 2004-08-26 for systems and methods for combination treatments of dental patients.
This patent application is currently assigned to ALIGN TECHNOLOGY, INC.. Invention is credited to Abolfathi, Amir, Kuo, Eric, Wen, Huafeng.
Application Number | 20040166463 10/375224 |
Document ID | / |
Family ID | 32869000 |
Filed Date | 2004-08-26 |
United States Patent
Application |
20040166463 |
Kind Code |
A1 |
Wen, Huafeng ; et
al. |
August 26, 2004 |
Systems and methods for combination treatments of dental
patients
Abstract
Systems and methods for fabricating a dental template to
position an object on a patient's tooth to move the tooth from an
initial position to a target position are disclosed. The system
digitizes a model of the patient's tooth at the initial position;
places an object on the tooth model at the target position;
determines the position of the object at the initial position; and
fabricates the dental template to locate the object on the
patient's tooth.
Inventors: |
Wen, Huafeng; (Redwood
Shores, CA) ; Kuo, Eric; (Foster City, CA) ;
Abolfathi, Amir; (Menlo Park, CA) |
Correspondence
Address: |
Bao Tran
Align Technology, Inc.
881 Martin Avenue
Santa Clara
CA
95050
US
|
Assignee: |
ALIGN TECHNOLOGY, INC.
Santa Clara
CA
|
Family ID: |
32869000 |
Appl. No.: |
10/375224 |
Filed: |
February 26, 2003 |
Current U.S.
Class: |
433/24 |
Current CPC
Class: |
A61C 7/146 20130101;
B33Y 80/00 20141201; A61C 7/002 20130101 |
Class at
Publication: |
433/024 |
International
Class: |
A61C 003/00 |
Claims
What is claimed is:
1. A method of fabricating a dental template to position an object
on a patient's tooth to move the tooth from an initial position to
a target position, comprising: digitizing a model of the patient's
tooth at the initial position; placing an object on the tooth model
at the target position; determining the position of the object at
the initial position; and fabricating the dental template to locate
the object on the patient's tooth.
2. The method of claim 1, wherein the object is a bracket
3. The method of claim 2, further comprising positioning the
bracket's slot to receive an orthodontic wire.
4. The method of claim 1, further comprising: a. positioning a
plurality of brackets on the patient's teeth at the target
position, each bracket having a slot adapted to receive an
orthodontic wire passing therethrough; and b. aligning the brackets
to minimize strain on the wire at the target position.
5. The method of claim 4, wherein the wire at the target position
is arch-shaped and wherein the wire at the initial position is
irregular.
6. The method of claim 1, further comprising interactively
adjusting the position of the object.
7. The method of claim 6, further comprising determining a
deviation of the object from an ideal placement and iteratively
adjusting the position of the object to minimize the deviation.
8. The method of claim 1, wherein fabricating comprises rendering a
physical dental template using a rapid prototyping method.
9. The method of claim 1, wherein the object is embedded in the
dental template.
10. The method of claim 1, wherein the object is inserted into an
opening on the dental template prior to being bonded on the
tooth.
11. A method to position a bracket on a patient's tooth,
comprising: digitizing the patient's tooth at an initial tooth
position; determining a final position for the tooth; placing the
bracket on the final tooth position; determining the position of
the bracket on the initial tooth position based on the bracket
position on the final tooth position; and fabricating a dental
appliance to mount the bracket on the patient's tooth.
12. The method of claim 11, wherein the wire at the target position
is arch-shaped.
13. The method of claim 11, wherein the wire at the initial
position is irregular.
14. The method of claim 11, wherein fabricating comprises rendering
a physical dental template using a rapid prototyping method.
15. The method of claim 11, wherein the template is articulable
with a plurality of flexibly linked cavities.
16. The method of claim 11, wherein the object is either embedded
in the dental template or inserted into an opening on the dental
template prior to mounting on the tooth.
17. The method of claim 11, further comprising rendering simulated
teeth movement over time.
18. The method of claim 11, further comprising treating teeth using
a combination of removable and fixed appliances.
19. The method of claim 18, wherein the fixed appliance covers two
or more teeth on an arch.
20. The method of claim 18, wherein the fixed appliance is
positioned on a lingual side of the patient's teeth.
21. An apparatus to fabricate a dental template to position an
object on a patient's tooth to move the tooth from an initial
position to a target position, comprising: a scanner to digitize a
model of the patient's tooth at the initial position; means for
placing an object on the tooth model at the target position; means
for determining the position of the object at the initial position;
and a machine to fabricate the dental template to locate the object
on the patient's tooth.
22. The apparatus of claim 21, wherein the machine comprises a
rapid prototyping machine.
23. The apparatus of claim 21, further comprising means for
determining a deviation of the object from an ideal placement and
iteratively adjusting the position of the object to minimize the
deviation
Description
BACKGROUND
[0001] The present invention relates generally to the field of
orthodontics.
[0002] One objective in orthodontics is to move a patient's teeth
to a position where the teeth function optimally and are also
aesthetically pleasing. Conventional appliances such as braces and
wires can be positioned on a patient's teeth by a treatment
provider such as an orthodontist or a suitably trained dentist.
Once mounted on the teeth, the hardware exerts continual forces on
the teeth and gradually urges the teeth toward their ideal
positions. Over a period of time, the treatment provider adjusts
the braces and the wires to move the teeth toward their final
destination.
[0003] Orthodontic brackets are often bonded directly to the
patient's teeth. Typically, a small quantity of adhesive is placed
on the base of each bracket and the bracket is then placed on a
selected tooth. Before the adhesive is set, the bracket is
maneuvered to a desired location on the tooth. Once the adhesive
has hardened, the bracket is bonded to the tooth with sufficient
strength to withstand subsequent orthodontic forces as treatment
progresses. One shortcoming with this technique is the difficulty
in accessing the optimal surface for bracket placement on severely
crowded teeth or in teeth where the bonding surface is obstructed
by teeth in the opposing arch during jaw closure. With posterior
teeth, the treatment provider may have difficulty seeing the
precise position of the bracket relative to the tooth surface. The
amount of time needed to carry out the bonding procedure may be a
nuisance both to the patient as well as to the treatment provider.
Also, the necessity of minimizing moisture contamination from the
patient's saliva can prolong the procedure and also unduly impair
the accuracy of placement of the brackets on the teeth. All of
these factors increase the chance that the ultimate adhesive bond
will not have sufficient strength to retain the brackets on the
teeth during treatment. One way to overcome some of the limitations
of direct bracket placement is with indirect bonding. Typically, an
impression of each of the patient's dental arches is taken and a
replica plaster or "stone" model is made from each impression and
sealed. Brackets are bonded to the sealed stone models using a
temporary cement. A transfer tray is then made by placing matrix
material over both the model and the brackets on the model. For
example, a heated plastic sheet matrix material may be placed over
the model and brackets and then under pressure. The plastic sheet
material then assumes a configuration that precisely matches the
shape of the replica teeth of the stone model with the brackets in
the desired position. The plastic material is then allowed to cool
and harden to form a tray. The temporary adhesive is removed, and
permanent adhesive is placed on the base of each bracket in the
tray, and the tray with the embedded brackets then placed over
matching portions of the patient's dental arches. Since the
configuration of the interior surface of the tray closely matches
the respective portions of the patient's dental arches, each
bracket is ultimately positioned on the patient's teeth at
precisely the same location that corresponds to the previous
location of the same bracket on the stone model. The adhesive is
hardened and the matrix material removed, leaving the brackets I
the desired positions. This method however, is labor intensive. An
additional problem with the indirect method is that brackets may
become dislodged during the removal of the matrix from the dental
arches. The problem of proper access to tooth surfaces for optimal
placement in the event of severely crooked teeth or teeth which
interfere with the opposing arch such that brackets cannot be
placed is also not addressed.
[0004] New methods such as those described in U.S. Pat. No.
5,975,893, commonly assigned to the assignee of the instant
invention, allow the treatment to be planned in advance and a
plurality of polymeric shell appliances are fabricated at the
outset of treatment. The use of polymeric shell appliances provides
treatments that are more comfortable; less visible, and removable
by the patient, greatly improves patient compliance, comfort, and
satisfaction.
[0005] Since each patient is unique and requires customized
treatment, on occasion, a patient may need to utilize a combination
of braces/wires and shell appliances. Ideally, a device would
enable precise placement of brackets on teeth with minimal risk of
displacing the brackets upon removal of the matrix and allow final
placement to be independent of adjacent geometries. In other words,
placement of obscured tooth surfaces may be accomplished at a later
time when the tooth surfaces have been exposed through initial
uncrowding of severely overlapped teeth.
SUMMARY
[0006] Systems and methods for fabricating a dental template to
position an object on a patient's tooth to move the tooth from an
initial position to a target position are disclosed. The system
digitizes a model of the patient's tooth at the initial position;
places an object on the tooth model at the target position;
determines the position of the object at the initial position; and
fabricates the dental template to locate the object on the
patient's tooth.
[0007] In another aspect, a method to position a bracket on a
patient's tooth includes digitizing the patient's tooth at an
initial tooth position; determining a final position for the tooth;
placing the bracket on the final tooth position; determining the
position of the bracket on the initial tooth position based on the
bracket position on the final tooth position; and fabricating a
dental appliance to mount the bracket on the patient's tooth.
[0008] Implementations of the above aspects may include one or more
of the following. The object can be a bracket and the bracket is
positioned in its slot to receive an orthodontic wire. The method
includes positioning a plurality of brackets on the patient's teeth
at the target position, each bracket having a slot adapted to
receive an orthodontic wire passing therethrough; and aligning the
brackets to minimize strain on the wire at the target position. The
wire at the target position is arch-shaped and wherein the wire at
the initial position is irregular. The method includes
interactively adjusting the position of the object. The method also
includes determining a deviation of the object from an ideal
placement and iteratively adjusting the position of the object to
minimize the deviation. The fabricating includes rendering a
physical dental template using a rapid prototyping method. The
object can be embedded in the dental template or can be inserted
into an opening on the dental template prior to being bonded on the
tooth. The wire at the target position is arch-shaped, while the
wire at the initial position is irregular. The template is
articulable with a plurality of flexibly linked cavities. The
template can be used for treating teeth using a combination of
removable and fixed appliances. The fixed appliance covers two or
more teeth on an arch (portion of arch) or the entire arch. The
fixed appliance can also be positioned on a lingual side of the
patient's teeth.
[0009] In yet another aspect, an apparatus to fabricate a dental
template to position an object on a patient's tooth to move the
tooth from an initial position to a target position includes a
scanner to digitize a model of the patient's tooth at the initial
position; means for placing an object on the tooth model at the
target position; means for determining the position of the object
at the initial position; and a machine to fabricate the dental
template to locate the object on the patient's tooth.
[0010] Implementations of the above aspect may include one or more
of the following. The machine can be a rapid prototyping machine.
The apparatus can include means for determining a deviation of the
object from an ideal placement and iteratively adjusting the
position of the object to minimize the deviation.
[0011] Advantages of the template may include one or more of the
following. The template can be used for etching or for positioning
brackets on teeth. The treatment can be done virtually and the
placement of the brackets can be done using a template device that
is a removable guide. This device allows precise placement of the
bracket and enables bracket placement onto specific teeth
independent of overall arch geometry. The template makes it easier
for a less well-trained or an untrained person to bond a bracket.
The system minimizes variations in the perception of distance and
angles. The template provides a very precise control on the
placement of the bracket. Since bracket placement is one of the
critical variables to successful treatment, the template improves
treatment precision from patient to patient and from tooth to
tooth.
[0012] The device itself may not necessarily contain the bracket as
with traditional indirect bonding (IDB) templates, but rather,
directs the user as to the precise location where the bracket
should be placed based on geometric fit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 shows an exemplary method or process to fabricate a
dental template to position an object on a patient's tooth.
[0014] FIG. 2A shows an exemplary method or process for placing an
orthodontic object on a patient's tooth.
[0015] FIG. 2B shows a second method of placing the orthodontic
object on a patient's tooth.
[0016] FIG. 3A illustrates an exemplary process for fabricating the
dental template.
[0017] FIG. 3B shows a process for providing four possible
templates.
[0018] FIGS. 4A-4D show perspective views of various templates.
[0019] FIGS. 5A and 5B illustrate two embodiments of articulated
templates.
[0020] FIG. 6A illustrates a process of fabricating a dental
template to position an object on a patient's tooth to move the
tooth from an initial position to a target position.
[0021] FIG. 6B shows an example of brackets positioned on teeth at
their final positions.
[0022] FIG. 6C shows an exemplary user interface that allows a user
to visualize teeth at each treatment stage.
[0023] FIG. 6D shows the exemplary brackets when backtracked into
their initial positions.
[0024] FIG. 7 is a diagram of a process to attach an object on a
tooth.
[0025] FIG. 8 is a diagram of a process to fit wire on the
teeth.
[0026] FIG. 9 is a diagram illustrating the marking of a wire for
attachment placement.
[0027] FIG. 10 is a diagram illustrating bracket mounting using the
dental template.
DESCRIPTION
[0028] FIG. 1 shows an exemplary method or process to fabricate a
dental template to position an object on a patient's tooth. First,
the process digitizes the patient's tooth (10). Next, virtual
objects are added to pre-determined locations on the digitized
tooth (12). Finally, the process fabricates the dental template to
locate the object on the patient's tooth (14). One detailed
implementation of FIG. 1 is described in FIG. 3 below.
[0029] FIG. 2A shows an exemplary method or process for placing an
orthodontic object on a patient's tooth. The process uses the
template fabricated in the process of FIG. 1. The process includes
placing the template on the patient's teeth (20); mounting the
orthodontic object between the template and the tooth (22); and
bonding the orthodontic object to the tooth (24). In the bonding
operation, chemical curing or light curing adhesives can be used.
In chemical curing, separately supplied curing components are mixed
together and a small quantity of the mixture is placed on the back
of the bracket prior to placing the bracket on the tooth.
Light-curable adhesives include a photo-initiator that initiates
the curing reaction once the adhesive is exposed to a sufficient
amount of light. A common method of using light-curable adhesives
for direct bonding includes the steps of placing a small quantity
of the adhesive on the base of the bracket and then placing the
bracket on the patient's tooth. The practitioner then shifts the
bracket on the tooth as may be needed. Once the bracket is in its
precise, intended location, light from a dental curing unit is
directed toward the adhesive for a time period sufficient to
satisfactorily cure the adhesive.
[0030] FIG. 2B shows a second method of placing the orthodontic
object on a patient's tooth. In this process, the orthodontic
object is placed in the template (30). Next, the process includes
inserting the template containing the orthodontic object onto the
patient's teeth (32). Finally, the process includes bonding the
orthodontic object to the tooth (34).
[0031] FIG. 3A illustrates an exemplary process for fabricating the
dental template. First, a digital model of a patient's teeth of a
patient is obtained (102). The digital model can be obtained in a
variety of ways. For example, the patient's teeth may be scanned or
imaged using well known technology, such as X-rays,
three-dimensional x-rays, computer-aided tomographic images or data
sets, magnetic resonance images, etc. There are a variety of range
acquisition systems, generally categorized by whether the process
of acquisition requires contact with the three dimensional object.
A contact-type range acquisition system utilizes a probe, having
multiple degrees of translational and/or rotational freedom. By
recording the physical displacement of the probe as it is drawn
across the sample surface, a computer-readable representation of
the sample object is made. A non-contact-type range acquisition
device can be either a reflective-type or transmissive-type system.
There are a variety of reflective systems in use. Some of these
reflective systems utilize non-optical incident energy sources such
as microwave radar or sonar. Others utilize optical energy. Those
non-contact-type systems working by reflected optical energy
further contain special instrumentation configured to permit
certain measuring techniques to be performed (e.g., imaging radar,
triangulation and interferometry).
[0032] Next, virtual brackets are selected (104). The virtual
brackets are 3D models of existing brackets. The 3D models may be a
computer aided design (CAD) model or may be scanned using scanners
described above. The brackets may be positioned on a digitized
tooth using a computer or workstation having a suitable graphical
user interface (GUI) and software appropriate for viewing and
modifying the images. The above-described component identification
and component manipulation software is designed to operate at
sophistication commensurate with the operator's training level. For
example, the component manipulation software can assist a computer
operator, lacking orthodontic training, by providing feedback
regarding permissible and forbidden manipulations of the teeth. On
the other hand, an orthodontist, having greater skill in intra-oral
physiology and teeth-moving dynamics, can simply use the component
identification and manipulation software as a tool and disable or
otherwise ignore the advice.
[0033] While the methods will rely on computer manipulation of
digital data, the dental templates or appliance may be produced by
non-computer-aided techniques. For example, plaster casts obtained
as described above may be cut using knives, saws, or other cutting
tools in order to permit repositioning of individual teeth within
the casting. The disconnected teeth may then be held in place by
soft wax or other malleable material, and a plurality of
intermediate tooth arrangements can then be prepared using such a
modified plaster casting of the patient's teeth. The different
arrangements can be used to prepare the template using pressure and
vacuum molding techniques. While such manual creation of the
appliance systems of the present invention will generally be much
less preferred, systems so produced will come within the scope of
the present invention.
[0034] Using the CAD workstation, a combined digital model of the
virtual brackets and the teeth is produced (106).
[0035] In one implementation, four template embodiments can be
selected: Direct-Articulated, Indirect-Articulated, Direct-Unified,
and Indirect-Unified, as discussed in more detail in FIG. 3B.
[0036] Once the template has been fabricated, in one embodiment,
the system sets the template over the model of the patient's arches
or otherwise positions the template in the approximate locations of
their respective teeth. A thermoformed, cast, or otherwise formed
layer of flexible material is deposited on the bodies. The layer
makes intimate and relatively durable contact with the bodies of
the templates. This may be accomplished, among other ways, by
adding or subtracting geometries to the bodies to engage well with
the material layer. This method could be performed either by a
factory or in the orthodontist's office.
[0037] The system produces both the template bodies and the
inter-tooth portion(s) at the same time and subsequently alter the
stiffness of the various parts. One way of achieving this would be
to produce the entire arch with a 3-D printer, mask the tooth
bodies from the inter-tooth portions, invest the tooth bodies with
a rigidifying agent and the inter-tooth portions with an agent to
create flexibility.
[0038] From 110, if a directly formed template is produced, the
process proceeds to 114 where each tooth is scaled; a cavity is
formed to enclose the tooth when the dental template or appliance
is inserted over the patient's teeth. Next, unnecessary structures
are removed from the digital model. The digital model is produced
as a physical model. A flexible pliable layer is formed and the
resulting combination is trimmed to allow proper fit and
function.
[0039] From 108, if a template of a whole arch is to be produced
the process. In the case of an indirectly-produced template the
process forms an Aligner and removes excess material (118). In the
case of a directly formed whole arch template, the process proceeds
to 120 where the entire arch is scaled; a cavity is formed to
enclose the arch when the dental template or appliance is inserted
over the patient's teeth. Next, unnecessary structures are removed
from the digital model. The digital model is produced as a physical
model. A flexible pliable layer is formed and the resulting
combination is trimmed to allow proper fit and function.
[0040] FIG. 3B shows a process for providing four possible
templates. First, the process acquires a digital model of
dentition, adds virtual brackets to teeth, and creates a combined
model (180). Next, one of four templates options can be selected.
The first option is unified (or single piece)--direct bonding
option where the process scales the arch (est. 105-150%), locates
original arch and scaled arch in same 3D space, creates cavity of
original inside scaled arch, removes gingival portions, substantial
part of lingual tooth surfaces, buccogingival surfaces covering
virtual brackets, and produces real arch model from digital model
(182).
[0041] In the second option (unified indirect bonding), the process
produces real arch model from digital model and forms a removable
appliance (aligner) template on real model of arch. The template is
removed from the real model, and the process then removes gingival
portions, substantial part of lingual tooth surfaces, buccogingival
surfaces covering virtual brackets (184)
[0042] In the third option (articulated direct bonding), the
process scales individual tooth (est. 105-150%), locates each
original tooth and its scaled version in same 3D space, creates a
cavity of each original inside its scaled version, removes gingival
portions, substantial part of lingual tooth surfaces, buccogingival
surfaces covering virtual brackets, produces real tooth models from
digital models, positions teeth in appropriate locations and
orientations, forms a flexible or pliable material over teeth, and
trims excess material from the template (186).
[0043] In the fourth option (articulated indirect bonding), the
process forms an aligner-like template on a mold of an arch. The
template is removed from the mold and gingival portions,
substantial part of lingual tooth surfaces, buccogingival surface
covering virtual brackets are trimmed. The process cuts an arch
template onto individual tooth. A flexible or pliable layer over
template is formed, and excess material is trimmed (188).
[0044] In yet another embodiment, a process obtains tooth
geometries. Next, if direct bonding is to be used, the process
performs the following:
[0045] Scale the arch to a value likely within the range
105-150%.
[0046] Co-locate the original (100%) arch and the scaled arch in
the same 3D space
[0047] Place a virtual bracket or other appropriate geometry at a
specific location and in a specific orientation on each tooth to be
treated.
[0048] Cavity the original arch and the brackets in the scaled
arch.
[0049] Remove from the resulting template or body those aspects
that would be below the gingival line. Remove the portions of the
resultant body buccal and gingival to the brackets remove a
substantial portion or all of the lingual aspect of the resultant
body.
[0050] Convert this computer model to a real part, likely through
the use of a rapid prototyping method (e.g. Fused Deposition
Modeling, 3-D Printing, sterolithography).
[0051] If indirect bonding is to be done, the following operations
are done using an arch model:
[0052] Form an Aligner-like appliance or template over an arch
model that has brackets or other appropriate geometries properly
located on the teeth
[0053] Remove from the Aligner or template those aspects that would
be below the gingival line or in direct interproximal contact with
adjacent teeth. Remove the portions of the Aligner buccal and
gingival to the bracket. Remove a substantial portion or all of the
lingual aspect of the Aligner.
[0054] After completion, the process ships the templates, bodies or
the completed appliance to the orthodontist either at the onset of
treatment or when it is requested
[0055] FIG. 4A shows one embodiment of a dental template 220 or
appliance formed over a mold 210. The template looks like a
removable appliance; however, it has openings 222 or "port-holes"
approximating the footprint, key portions of the footprint, and/or
possibly other geometrical features of a bracket to guide the
precise placement of the bracket on its respective tooth. The
template 220 with the openings 222 or "port-holes" may also be a
guide for enamel etching or adhesive placement.
[0056] The mold 210 is a physical rendition of a digital model that
has been fabricated using rapid prototyping methods. A bump or
projection 212 rises from the mold 210 so when the dental template
or appliance is thermal-formed, an opening 222 is formed on the
template 220. The opening 222 is where the template is cut out
along the edge of the bump or projection 212. The opening 222 has a
brace support edge 226, whose operation is described in more detail
in FIG. 4B. In addition to the support edge 226, the template 220
may have features that will minimize the retention of it on the
dental anatomy. For example, the lingual side of the device may not
have maximum coverage.
[0057] Fabrication methods for the mold 210 employ a rapid
prototyping device such as a stereolithography machine or a fused
deposition modeling machine. A suitable rapid prototyping machine
is Model SLA-250/50 available from 3D System, Valencia, Calif. The
rapid prototyping machine selectively hardens a liquid or other
non-hardened resin into a three-dimensional structure, which can be
separated from the remaining non-hardened resin, washed, and used
either directly as the appliance or indirectly as a mold for
producing the appliance. The prototyping machine receives the
individual digital data sets and produces one structure
corresponding to each of the desired appliances. Generally, because
the stereolithography machine may utilize a resin having
non-optimum mechanical properties and which may not be generally
acceptable for patient use, the prototyping machine produces the
mold 210. After the positive model is prepared, a conventional
pressure or vacuum molding machine may be used to produce the
appliances from a more suitable material, such as 0.03 inch thermal
forming dental material, available from Tru-Tain Plastics,
Rochester, Minn. 55902. Suitable pressure molding equipment is
available under the trade name BIOSTAR from Great Lakes
Orthodontics, Ltd., Tonawanda, N.Y. 14150. The molding machine
produces each of the appliances directly from the positive tooth
model and the desired material. Suitable vacuum molding machines
are available from Raintree Essix, Inc.
[0058] In one embodiment, the template is made from a thick
material (for example 0.03 inches or more) to provide the user with
more guidance in the depth direction. Furthermore, the thick
template allows easier lining the bracket to the tooth.
[0059] More information on the fabrication of the dental template
or appliance is disclosed in U.S. Pat. No. 6,499,997 "Manipulable
dental model system for fabrication of a dental appliance"; U.S.
Pat. No. 6,497,574 "Modified tooth positioning appliances and
methods and systems for their manufacture"; U.S. Pat. No. 6,488,499
"Methods for correcting deviations in preplanned tooth
rearrangements"; U.S. Pat. No. 6,485,298 "System and method for
releasing tooth positioning appliances"; U.S. Pat. No. 6,471,511
"Defining tooth-moving appliances computationally"; U.S. Pat. No.
6,463,344 "Efficient data representation of teeth model"; U.S. Pat.
No. 6,457,972 "System for determining final position of teeth";
U.S. Pat. No. 6,454,565 "Systems and methods for varying elastic
modulus appliances"; U.S. Pat. No. 6,450,807 "System and method for
positioning teeth"; U.S. Pat. No. 6,409,504 "Manipulating a digital
dentition model to form models of individual dentition components";
U.S. Pat. No. 6,406,292 "System for determining final position of
teeth"; U.S. Pat. No. 6,398,548 "Method and system for
incrementally moving teeth"; U.S. Pat. No. 6,394,801 "Manipulable
dental model system for fabrication of dental appliances"; U.S.
Pat. No. 6,390,812 "System and method for releasing tooth
positioning appliances"; U.S. Pat. No. 6,386,878 "Systems and
methods for removing gingiva from teeth"; U.S. Pat. No. 6,386,864
"Stress indicators for tooth positioning appliances"; U.S. Pat. No.
6,371,761 "Flexible plane for separating teeth models"; U.S. Pat.
No. 6,318,994 "Tooth path treatment plan"; U.S. Pat. No. 6,309,215
"Attachment devices and method for a dental appliance"; U.S. Pat.
No. 6,299,440 "System and method for producing tooth movement";
U.S. Pat. No. 6,227,851 "Manipulable dental model system for
fabrication of a dental appliance"; U.S. Pat. No. 6,227,850 "Teeth
viewing system"; U.S. Pat. No. 6,217,325 "Method and system for
incrementally moving teeth"; U.S. Pat. No. 6,210,162 "Creating a
positive mold of a patient's dentition for use in forming an
orthodontic appliance"; and U.S. Pat. No. 5,975,893 "Method and
system for incrementally moving teeth," the contents of which are
hereby incorporated by reference.
[0060] Turning now to FIG. 4B, the template 220 is separated from
the mold 210. The opening 222 allows a bracket base to fit into the
opening 222. Brace support edge 226 is needed to securely position
the bracket in the template 220. In this embodiment, the brace
support edge 226 is curvaceous. If the edge 226 had been terminated
as a simple flat edge, the bracket can be located in X and Y
surfaces on the tooth, but the Z direction (buccal lingual
direction) would not be controlled. The edge 26 provides the needed
control of the bracket's degree of freedom in the Z direction to
allow orientation of the bracket about any given axis. Those
features allow the bracket to be secured in the proper position and
orientation on its respective tooth. The edge 26 can change,
depending on vendor-to-vendor or prescription-to-prescription.
[0061] Another embodiment of the template can be used for etching
bonding chemicals on the patient's teeth. The etching template
directs the user to predetermined locations on the teeth surfaces
that need to be bonded. The etching template can be either the
format of a windowed template or a concave surfaced template where
bonding gel is loaded or pre-loaded into the concavity.
[0062] FIG. 4C shows a template wherein each of the openings,
cut-outs, port-holes, or slots 222 in the template 220 are designed
to fit particular brackets 4A, 4B and a 4C, each of which fits into
its respective portion on the template.
[0063] FIG. 4D shows that the system is not limited to bracket
design or shape. In FIG. 4D, a molar tube bracket can be placed.
Hence, the template 220 is not limited to any specific bracket.
Rather, any form of fixed orthodontic appliances placed on a tooth
could be accommodated.
[0064] FIGS. 5A and 5B illustrate two exemplary embodiments of
articulated templates. FIG. 5A shows two segments joined at the
interproximal regions of two adjacent teeth. A number of alternate
methods to join the teeth can be used, including that the joining
methods could be alternate or vary from one interproximal region to
the next. Further, the joining method could also be a layer or
layers that cover additional or different surfaces of the teeth as
depicted in FIG. 5B.
[0065] In FIG. 5A, the template is made up of a number of movable
template components 250. Each of the template components 250 can be
mounted on a patient's tooth to facilitate bracket bonding. The
movable template components 250 are physically linked together by a
sheet of material 252 deposited above the components 250 so that
they do not break-up or otherwise become disassembled upon removal
from its mold or stereolithography apparatus (SLA) model. The
articulated templates are advantageous in that they provide greater
adjustment flexibility.
[0066] The template can additionally be used as an etching
template. An etching template allows the doctor to precisely etch
the areas of the teeth on which the brackets will be placed. The
small windows bound the regions that will be etched to minimize
teeth sensitivity to etching or unwanted enamel removal. In another
version of the etching template, the cut outs would not be formed.
Instead those areas would be concavities facing the tooth surfaces.
These concavities would contain an etching compound. The user would
expose or activate the etching compound prior to setting the
template on the teeth.
[0067] The template 220 may be made from materials that contain
physical property switches for ease of removal. These switches
might include temperature responsive, pH responsive, moisture
responsive or a multi-layer system wherein the layers have varying
physical properties. The section 500 represents a flexible or
pliable material. Additionally, the material could be fiber, cord,
fiber mesh, or a fiber-reinforced solid. The interproximal material
can be homogenous or heterogeneous.
[0068] FIGS. 5A and 5B illustrate two exemplary embodiments of
articulated templates. FIG. 5A shows two segments joined at the
interproximal regions of two adjacent teeth. A number of alternate
methods to join the teeth can be used, including alternating or
varying the joining of the segments from one interproximal region
to the next. Further, the joining method could also be a layer or
layers that cover additional or different surfaces of the teeth as
depicted in FIG. 5B.
[0069] In FIG. 5A, the template is made up of a number of movable
template components 250. Each of the template components 250 can be
mounted on a patient's tooth to facilitate bracket bonding. The
movable template components 250 are physically linked together by a
sheet of material 252 deposited above the components 250 so that
they do not break-up or otherwise become disassembled upon removal
from its mold or stereolithography apparatus (SLA) model.
[0070] The template can additionally be used as an etching
template. The etching template allows the doctor to precisely etch
selected portions or predetermined areas of the teeth on which the
brackets will be placed. The small windows bound the regions that
will be etched to minimize teeth sensitivity to etching or unwanted
enamel removal. In another version of the etching template, the cut
outs would not be formed. Instead those areas would be concavities
facing the tooth surfaces. These concavities would contain an
etching compound. The user would expose or activate the etching
compound prior to setting the template on the teeth.
[0071] The template component 250 may be made from materials that
contain physical property switches for ease of removal. These
switches might include temperature responsive, pH responsive,
moisture responsive or a multi-layer system wherein the layers have
varying physical properties. The section 250 represents a flexible
or pliable material. Additionally, the material could be fiber,
cord, fiber mesh, or a fiber-reinforced solid. The interproximal
material can be homogenous or heterogeneous.
[0072] During one exemplary treatment using both a removable
appliance (such as those described in U.S. Pat. No. 6,309,215) and
a wire and bracket appliance, a doctor can view the patient's
arch(es) that require treatment during a consultation, and then
select a particular wire that he/she will use to perform a portion
of the treatment. Upon selection of the wire, the doctor submits
this information to a virtual setup system based on the doctor's
prescription. In another implementation, data mining can use
previously stored data to indicate the likelihood of success, and
failure rates, of tooth movement using the dental appliances. The
data is categorized into three areas to describe the likelihood of
successful treatment and movement: for example, a high likelihood
of success; a decreased likelihood of success in treatment outcome;
and little to no success. Based on the result of the data mining,
the system recommends an appropriate sequence of dental appliance
usage.
[0073] Sequencing is the determination of which aligner feasible
movements should be performed first, according to degree of ease or
needs for effective treatment outcome. One exemplary implementation
of combination treatment performs high-confidence movements earlier
in the treatment, followed by more challenging movements. This can
mean that removable appliances are used in the first phases of
treatment, followed by attachment and wire treatments.
Alternatively; attachment and wire treatments can be used first for
a case, with removable appliances used in the final phase of
treatment. Treatment methods can also be alternated (i.e. aligners,
attachments and wires, followed by aligners) and combination
treatments can be used simultaneously (i.e. aligners and
attachments and wires uses at the same time). Attachments and wires
can be placed on the buccal or lingual sides of the teeth. The
appliances can also be partial (such as a 3-3 anterior arch),
combined with partial attachments and wire treatments (i.e. placed
on molars or posterior teeth). In one example iteration, an IPR
(interproximal reduction) leads to the removal of the bicuspid on
the upper arch of a patient's jaw. Then, a wire is mounted to pull
the anterior teeth back to reduce the arch size and close the
interproximal space, followed by 3-3 movement that is achieved
using aligners.
[0074] FIG. 6A illustrates a process of fabricating a dental
template to position an object (such as a bracket) on a patient's
tooth to move the tooth from an initial position to a target
position. The process includes digitizing a model of the patient's
tooth at the initial position (602). Next, the target position is
determined (604). The target position can be a final position for
the teeth at the end of the treatment.
[0075] Next, the doctor positions a plurality of brackets on the
patient's teeth at the target position, each bracket having a slot
adapted to receive an orthodontic wire passing therethrough (606).
FIG. 6B illustrates the mounted brackets on the final position of
the patient's teeth. The process aligns the brackets to minimize
strain on the wire at the target position (608).
[0076] The process determines the position of the object at the
initial position by backtracking from the tooth's final position
one stage at a time until tooth reaches its the initial position
(610). The coordinate transformation for moving the tooth from its
final position to its initial position is applied to determine the
position of the object's initial position. FIG. 6B shows an example
of brackets positioned on teeth at their final positions. FIG. 6C
shows an exemplary user interface that allows a user to visualize
teeth at each treatment stage. In one example, the teeth can be
backtracked one stage at a time to arrive at the initial positions.
Since the brackets are secured to the teeth, the backtracked
position of the brackets can also be determined. FIG. 6D shows the
exemplary brackets when backtracked into their initial positions.
The process can also determine a deviation of the object from an
ideal placement and iteratively adjust the position of the object
to minimize the deviation.
[0077] Finally, the dental template is fabricated to allow the
doctor to precise locate the object on the patient's tooth (612).
The template can be fabricated using a rapid prototyping method.
One or more bracket objects can be embedded in the dental template
and the dental template can be inserted over the patient's teeth.
Alternatively, the bracket objects can be inserted into an opening
on the dental template prior to being bonded on the teeth.
[0078] FIG. 7 describes one exemplary implementation of Combination
Treatments. A stage of treatment is selected (step 702). The
process makes a prediction based on highest level of convenience
for the doctor, to use either a removable appliance for treatment
or to use attachments and wires (step 704).
[0079] Based on the final setup of the case, the proper attachments
are selected (step 706). Once the attachments are determined, a
predetermined fit value such as a FACC point is defined (step 708).
Factors included in the determination of the FACC point include
teeth, attachment, and wire collisions. Once the FACC point is
determined, the database provides the best-fit wire for use by the
doctor (step 710). Align practitioners use individual approaches
when selecting wires for patients. Some doctors use a single type
of wire, others choose from a number of different wires. Align
provides a third option, which is a standard wire. Once selected,
the wire is marked for proper placement of the attachments (step
712). Finally, the attachments and wire(s) are mounted on the
patient's teeth (step 714).
[0080] FIG. 8 describes Step 710. The best-fit wire is determined
using a series of simple least mean square mathematical formulas.
Given a particular patient case (step 722), a wire is selected.
Using the final position of the treatment (step 724), the shortest
distance from the bracket tip to the edge of the wire is calculated
(726).
[0081] Let d=distance between the attachment and the wire,
[0082] For any i=1-16 or 17-32, depending on which tooth/jaw,
[0083] di>0
[0084] di<D
[0085] where D is a number defined by Align between 0.1 mm and 50
mm. This wire is set as the best-fit wire, with the minimum
distance between the attachments and wire (728). All subsequent
wires are measured using the same calculations (730-734).
[0086] FIG. 9 describes more detail step 712, marking the wire for
attachment placement by the doctor. Measurements are retrieved from
the placement of the attachments on the jaw at the initial
position. Distance and direction are measured between the points
(742). Two additional areas can be measured: 1) the physical
property of the wire, i.e. how much wire can bend (step 744), and
2) the curve distance from one bracket tip to the next (step 746).
Finally, points are placed on the wire to show the place where the
first attachment stops (step 748). The same iteration is repeated
with each subsequent attachment.
[0087] FIG. 10 describes in more detail step 714. To mount the wire
and attachments, transition geometry is determined from the base of
the tooth to the wire (752). Attachment object is placed inside the
pocket area of the aligner (754). The filler material, most likely
cement, is placed in the aligner behind the attachment and in the
remaining aligner area (756 and 758). This increases ease of
removal of the aligner at the later stages when the attachments are
placed on the teeth. The doctor snaps the aligner with the
attachment and cement on the teeth (760). Ultraviolet light is used
to secure the cement filler material to the teeth (762). Hot water
is sprayed on the aligner (step 764) because the Tesla material
responds to the heat by becoming more pliable. Once the aligner has
cooled (766), the doctor can remove it from the patient's mouth
with relative ease (768). The attachment(s) are now fastened to the
teeth, which follows standard orthodontics principles of placing
brackets. Finally, the doctor connects the wire to each attachment
using the designations that were marked on the wire in step 712 as
a reference.
[0088] Exemplary pseudo-code to perform a combination treatment is
as follows:
[0089] Select a stage of treatment.
[0090] Make a prediction to use attachments and wires treatment
based on highest degree of convenience for Align doctor.
[0091] Select the proper attachments based on the final setup of
the case.
[0092] Define the FACC point.
[0093] Use least mean square formulas to determine the best-fit
wire.
[0094] Choose a wire.
[0095] Go to the final position of treatment.
[0096] Calculate the shortest distance from the bracket tip to the
edge of the wire.
[0097] Set this value as (set-minimum distance) and best-fit
wire.
[0098] Choose next wire.
[0099] Calculate the shortest distance from the bracket tip to the
edge of the wire.
[0100] If value of distance (in mm) is smaller than the minimum
distance of the first wire, this wire is reset as best-fit
wire.
[0101] If value of distance (in mm) is larger, the first wire is
selected as the best-fit.
[0102] Mark the wire for proper placement of the attachments.
[0103] Measure the distance and direction between the attachment
points.
[0104] Measure the physical property of the wire.
[0105] Calculate curve distance from one tip to the next.
[0106] Mark attachment points at final position.
[0107] If points are acceptable, repeat this iteration for each
subsequent attachment.
[0108] Mount the wire and attachments on the patient's teeth.
[0109] Determine transition geometry from the base of the tooth to
the wire.
[0110] Position attachment in designated aligner `pockets`.
[0111] Fill cement/filler in aligner behind and around each
attachment.
[0112] Place additional cement filler into aligner to increase ease
of removal of aligner.
[0113] Snap aligner on teeth.
[0114] Use UV light to set attachment to tooth.
[0115] Spray hot water on Testa-based aligner.
[0116] Allow aligner to cool.
[0117] Remove aligner.
[0118] Thus, the above process determines an optimum treatment
sequence based on historical data; and fabricating one or more
dental devices to move teeth, the devices being selected from
either a computer-synthesized retainer or a combination of
attachments and wire. The determining of an optimum treatment
sequence can include capturing a digital model of a patient's
teeth; and comparing the digital model to a library of historical
treatment cases. The treatment can include moving teeth using the
retainers and at the end of treatment with aligners, fabricate a
retainer with the attachments embedded therein.
[0119] Various alternatives, modifications, and equivalents may be
used in lieu of the above components. Additionally, the techniques
described here may be implemented in hardware or software, or a
combination of the two. The techniques may be implemented in
computer programs executing on programmable computers that each
includes a processor, a storage medium readable by the processor
(including volatile and nonvolatile memory and/or storage
elements), and suitable input and output devices. Program code is
applied to data entered using an input device to perform the
functions described and to generate output information. The output
information is applied to one or more output devices. Each program
can be implemented in a high level procedural or object-oriented
programming language to operate in conjunction with a computer
system. However, the programs can be implemented in assembly or
machine language, if desired. In any case, the language may be a
compiled or interpreted language. Each such computer program can be
stored on a storage medium or device (e.g., CD-ROM, hard disk or
magnetic diskette) that is readable by a general or special purpose
programmable computer for configuring and operating the computer
when the storage medium or device is read by the computer to
perform the procedures described. The system also may be
implemented as a computer-readable storage medium, configured with
a computer program, where the storage medium so configured causes a
computer to operate in a specific and predefined manner. Further,
while the invention has been shown and described with reference to
an embodiment thereof, those skilled in the art will understand
that the above and other changes in form and detail may be made
without departing from the spirit and scope of the following
claims.
* * * * *