U.S. patent application number 11/594219 was filed with the patent office on 2007-03-29 for method and system for assessing the outcome of an orthodontic treatment.
This patent application is currently assigned to Cadent Ltd.. Invention is credited to Avi Kopelman, Baruch Nissenbaum, Leonid Rasovsky.
Application Number | 20070072145 11/594219 |
Document ID | / |
Family ID | 46150323 |
Filed Date | 2007-03-29 |
United States Patent
Application |
20070072145 |
Kind Code |
A1 |
Kopelman; Avi ; et
al. |
March 29, 2007 |
Method and system for assessing the outcome of an orthodontic
treatment
Abstract
The present invention provides a virtual orthodontic treatment
method, comprising, providing a virtual diagnostic setup model of
teeth of at least one jaw of an individual, associating virtual
orthodontic appliances with all teeth in the model to obtain a
first composite model and repositioning teeth into an initial
treatment state according to pre-defined appliances-dependent
rules; in the initial treatment state, detaching one or more teeth
from their corresponding one or more orthodontic appliances,
repositioning one or more appliances, reassociating one or more
appliances with the teeth, permitting the teeth to reposition
according to the appliances-dependent rules to obtain an altered
treatment state, yielding a better grade, according to one or more
systems for grading an orthodontic model, as compared to the grade
of initial treatment state.
Inventors: |
Kopelman; Avi; (Ramat Chen,
IL) ; Nissenbaum; Baruch; (Ramat Gan, IL) ;
Rasovsky; Leonid; (Tel Aviv, IL) |
Correspondence
Address: |
Gary M. Nath;NATH & ASSOCIATES PLLC
112 South West Street
Alexandria
VA
22314
US
|
Assignee: |
Cadent Ltd.
|
Family ID: |
46150323 |
Appl. No.: |
11/594219 |
Filed: |
November 8, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10438267 |
May 15, 2003 |
7160107 |
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11594219 |
Nov 8, 2006 |
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10426975 |
May 1, 2003 |
7074039 |
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10438267 |
May 15, 2003 |
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60377325 |
May 2, 2002 |
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Current U.S.
Class: |
433/24 |
Current CPC
Class: |
A61C 7/002 20130101;
A61C 7/00 20130101; A61C 7/146 20130101 |
Class at
Publication: |
433/024 |
International
Class: |
A61C 3/00 20060101
A61C003/00 |
Claims
1. A virtual orthodontic treatment method, comprising: providing a
virtual diagnostic setup model of teeth of at least one jaw of an
individual, associating virtual orthodontic appliances with all
teeth in said model to obtain a first composite model and
repositioning teeth into an initial treatment state according to
pre-defined appliances-dependent rules; in said initial treatment
state, detaching one or more teeth from their corresponding one or
more orthodontic appliances, repositioning said one or more
appliances, reassociating said one or more appliances with the
teeth, permitting the teeth to reposition according to the
appliances-dependent rules to obtain an altered treatment state,
yielding a better grade, according to one or more systems for
grading an orthodontic model, as compared to the grade of said
initial treatment state.
2. A method according to claim 1, wherein the grading is based on
measuring one or more of alignment, marginal ridges, buccolingual
inclination, overjet, occlusal relationship, occlusal contacts and
interproximal contacts.
3. A method according to claim 2, wherein the grading is carried
out according to the grading system the American Board of
Orthodontics.
4. A method according to claim 1, wherein said orthodontic
appliances include brackets that are attached to teeth and a
straight arch wire received in a slot of said bracket.
5. A method according to claim 1, wherein a user selects a set of
orthodontic appliances for associating with the teeth.
6. A method according to claim 1, comprising any one of
automatically selecting a set of orthodontic appliances for
associating with the teeth; automatically defining one or more
additional orthodontic interventions.
7. A method for designing a real life orthodontic treatment,
comprising: (a) providing a virtual diagnostic setup model of an
initial state of teeth of at least one jaw of an individual,
associating virtual orthodontic appliances with all teeth in said
model in a first association arrangement to obtain a first
composite virtual model; (b) permitting the teeth to reposition
according to pre-defined appliances-dependent rules into an initial
treatment state with a second association arrangement of said teeth
and said appliances; (c) in said initial treatment state selecting
one or more teeth and virtually detaching at least the selected
teeth from said orthodontic appliances, repositioning said
appliances on the selected teeth and reassociating appliances to
the teeth and permitting the teeth to reposition according to
appliance-dependent rules into a second composite virtual model
with an altered treatment state, yielding a better grade, according
to one or more systems for grading an orthodontic model, as
compared to the grade of said initial treatment state. (d)
permitting the teeth to revert back from their state in said second
composite virtual model into said initial state with said
orthodontic appliance remaining associated with the teeth in a
manner as in said second composite virtual model to obtain a
treatment-design virtual model with orthodontic appliances
associated with the teeth in a manner of association to be applied
in a real life orthodontic treatment.
8. A method according to claim 7, wherein the grading is based on
measuring one or more of alignment, marginal ridges, buccolingual
inclination, overjet, occlusal relationship, occlusal contacts and
interproximal contacts.
9. A method according to claim 7, wherein the grading is carried
out according to the grading system the American Board of
Orthodontics.
10. A method according to claim 7, wherein said orthodontic
appliances include brackets that are attached to teeth and an arch
wire received in a slot of said bracket.
11. A method according to claim 7, wherein a user selects a set of
orthodontic appliances for associating with the teeth.
12. A method according to claim 7, comprising any one of:
automatically selecting a set of orthodontic appliances for
associating with the teeth; automatically defining one or more
additional orthodontic interventions.
13. A system for virtual orthodontic treatment, comprising: (i) a
digital interface for receiving digital data representative of a
virtual diagnostic setup model of teeth; a processor including a
software for associating virtual orthodontic appliances with all
teeth in said model to obtain a first composite model,
repositioning teeth according to appliance-dependent rules into an
initial treatment state according to pre-defined
appliances-dependent rules, and for selecting teeth in said initial
treatment state and virtually detaching one or more teeth from
their corresponding orthodontic appliances, repositioning said one
or more appliances and reassociating said one or more appliances
with the teeth and permitting the positioning of the teeth
according to appliance-dependent rules, to obtain a second
composite virtual model with an altered treatment state, yielding a
better grade, according to one or more systems for grading an
orthodontic model, as compared to the grade of said initial
treatment position; and (iii) a user interface comprising at least
a display for displaying results of the virtual orthodontic
treatment.
14. A system according to claim 13, wherein the grading is based on
measuring one or more of alignment, marginal ridges, buccolingual
inclination, overjet, occlusal relationship, occlusal contacts and
interproximal contacts.
15. A system according to claim 14, wherein the grading is carried
out according to the grading system of the American Board of
Orthodontics.
16. A system according to claim 13, wherein said orthodontic
appliances include brackets that are attached to teeth and an arch
wire received in a slot of said bracket.
17. A system according to claim 13, wherein said reassociating can
be repeated a plurality of times with different positions of
brackets and the resulting improved treatment state is graded after
each time, for achieving best grade after said repositioning.
18. A system according to claim 13, wherein at least one of: the
set of orthodontic appliances is selected automatically by said
software; if applicable, said software defines one or more
additional orthodontic interventions; the user interface permits a
user to define one or more additional orthodontic
interventions.
19. A system for designing a real life orthodontic treatment,
comprising: a digital interface for inputting a virtual diagnostic
setup model of an initial state of teeth of an individual; a user
interface comprising at least an output for outputting results of
virtual orthodontic treatment and information on design of real
life orthodontic treatment; a processor including a software
running thereon for associating virtual orthodontic appliances with
all teeth in said model to obtain a first composite model,
repositioning teeth according to appliance-dependent rules into an
initial treatment state with a second association arrangement of
said teeth and said appliances, selecting teeth in said initial
treatment state and virtually detaching one or more teeth from
their corresponding orthodontic appliances, repositioning said one
or more appliances and reassociating said one or more appliances
with the teeth and permitting the positioning of the teeth
according to appliance-dependent rules, to obtain a second
composite virtual model with an altered treatment state, yielding a
better grade, according to one or more systems for grading an
orthodontic model, as compared to the grade of said initial
treatment position, permitting the teeth to revert back from their
state in said second composite virtual model into said initial
state with said orthodontic appliance remaining associated with the
teeth in a manner as in said second composite virtual model to
obtain treatment-design virtual model with orthodontic appliances
associated with the teeth in a manner of association to be applied
in a real life orthodontic treatment, and outputting data
representative of said treatment-design virtual model in a manner
suitable for use in the design of the real life orthodontic
treatment.
20. A system according to claim 19, wherein the grading is based on
measuring one or more of alignment, marginal ridges, buccolingual
inclination, overjet, occlusal relationship, occlusal contacts and
interproximal contacts.
21. A system according to claim 20, wherein the grading is carried
out according to the grading system of the American Board of
Orthodontics.
22. A system according to claim 19, wherein said orthodontic
appliances include brackets that are attached to teeth and an arch
wire received in a slot of said bracket.
Description
FIELD OF THE INVENTION
[0001] The present invention is generally in the field of
orthodontics. More specifically, the present invention relates to a
computerized method and system for virtual orthodontic treatment
which may assist an orthodontist in designing an orthodontic
treatment plan.
BACKGROUND OF THE INVENTION
[0002] Orthodontic therapy has the object of aligning and
repositioning teeth for both functional and aesthetic purposes.
This is achieved by the use of a variety of orthodontic appliances
including, brackets, wires (arch wires), coil springs and elastics.
In combination, these appliances are fixed to teeth in such manner
that orthodontic forces and moments cause the teeth to move in the
desired direction.
[0003] There are currently acceptable guidelines in orthodontics,
which define the optimal dental and skeletal relations which should
be the goal of the orthodontic treatment. A summary of such
guidelines can be found in Straight Wire, the Concept and
Appliances, by Laurence F. Andrews, L.A. Well, Co., San Diego,
Calif. USA, 1989. These guidelines are based on both functional and
aesthetic considerations.
[0004] A common problem in the orthodontic field is the lack of
space in the dental arch called dental crowding. In this clinical
situation the orthodontist should decide if his orthodontic
treatment plan will include the solution of tooth extractions
(which is an irreversible procedure), how teeth should be moved
against anchorage units during the treatment protocol and
accordingly what orthodontic appliances should be chosen and how to
apply them on the teeth to achieve a desired outcome. The procedure
of assessing the best treatment plan by the orthodontist is
typically based on patient clinical measurements, plaster cast and
radiographic analysis, the orthodontist's personal "look and feel",
and his prior experience and skills. In some cases it also required
to prepare wax-based diagnostic setup model which exhibits the
possible end result of the orthodontic case. This approach is time
consuming and also does not permit to easily visualize the outcome
of several treatment options at the same time.
[0005] There is accordingly a need in the art to provide the
orthodontist with a tool which enables him to design the treatment
procedure--which will yield an optimal outcome, and to analyze
possible outcome of different treatment methods.
[0006] PCT Application WO 99/34747 describes a method for virtual
orthodontic treatment, which utilizes a virtual set of orthodontic
components, in a virtual computerized environment. A set of rules,
which are mainly geometric rules, are applied to move the teeth by
the use of standard and non standard virtual orthodontic
components.
SUMMARY OF THE INVENTION
[0007] The present invention provides a method and system for
virtual orthodontic treatment. The virtual orthodontic treatment
may be used by an orthodontist to evaluate possible outcomes of the
orthodontic treatment. The present invention also provides, by one
preferred embodiment, a computerized method and system for
designing the real life orthodontic treatment scheme for a specific
individual.
[0008] The following are some terms which will be used herein and
their meanings:
[0009] The term "virtual orthodontic treatment" will be used to
denote a virtual set of operations that is carried out on a virtual
diagnostic setup model using a virtual set of orthodontic
appliances within the virtual computer environment. In the virtual
orthodontic treatment teeth are repositioned according to rules
that are dictated by the virtual orthodontic appliances. For
example, where the orthodontic appliances include a straight arch
wire set comprising a straight arch wire and brackets attached to
the teeth with the arch wire received in a slot within the bracket,
the rules may dictate that the outcome of the treatment should be
that all grooves of all brackets be in a plane defined by the arch
wire with the teeth aligned along an arch defined by said arch
wire.
[0010] The term "virtual diagnostic setup model" refers to a
virtual teeth model with the teeth separated such that each tooth
can be repositioned.
[0011] The term "reposition" will be used to denote, collectively,
a change in the position of a tooth in the anteroposterior
direction, in a vertical direction from a more attracted to a more
extracted state or vice versa, an angular change in the
buccullingual inclination, an angular axial change in orientation
of a tooth, and in general any change in position and/or
orientation of a tooth.
[0012] The term "associated" or "association" will be used to
denote the formation of a virtual physical relationship between the
teeth of the virtual diagnostic setup model and the virtual
orthodontic appliances. Where associated the teeth will be
repositioned according to appliances-dependent rules, similar to
the manner in which such appliances cause repositioning of teeth in
real life orthodontic treatment. For example, the association of
brackets with teeth involve attachment of brackets to the teeth's
crown, or fixing an orthodontic band with integral bracket over a
tooth. Association of arch wire involves snapping of the arch wire
into a groove defined on the external face of the bracket.
[0013] The term "appliance-dependent rules" refers to rules that
govern the manner in which teeth will be repositioned in the
virtual orthodontic treatment according to the invention, which are
dictated by the properties of the appliances. For example, an
appliance dependent rule in a combination of treatment appliances
that include brackets attached to teeth and an arch wire may be a
rule that calls for the arch wire to assume its normal or native
curvature and the brackets to have a position with their slots
fitted into the wire. In an initial state of the teeth, once
virtual brackets are attached to the teeth surface in the virtual
teeth image and an arch wire is associated therewith, many brackets
will deviate from their position dictated by such a rule and will
thus be repositioned until the rule is fulfilled. Other examples
are for example longitudinal movement of brackets along the arch
wire with its slot engaging the arch wire with such path of
relocation being dictated by the arch wire's orientation. As is no
doubt clear, these are only examples of appliances-dependent rules.
It is also no doubt clear, since the virtual brackets are
associated with the virtual teeth in the teeth image, any movements
of the brackets will bring to repositioning of the tooth associated
therewith.
[0014] Some other terms are used herein, which generally have a
meaning similar to that ascribed to these terms in a real life
orthodontic treatment, or have meaning that become clear from the
context in which they are used. It should be understood that use of
physical terms such as "repositioning", "extraction", etc., refers
to such manipulations performed within the virtual computer
environment, unless it otherwise becomes clear from the
context.
[0015] The present invention is based on a novel concept for
virtual orthodontic treatment. In accordance with the invention, a
virtual set of orthodontic appliances is associated with teeth of a
virtual diagnostic setup model to obtain a first composite model,
and the teeth are permitted to reposition into an initial treatment
state according to pre-defined appliances-dependent rules. Typical
rules in the case of use of brackets and a straight arch wire set
that comprise brackets and a straight arch wire include alignment
of all horizontal slots on the face of the bracket that receive the
arch wire on a plane defined by the wire and alignment of the teeth
along the arch defined by the arch wire. Upon achieving said
initial treatment state, one or more teeth are virtually detached
from the appliances and thus the virtual appliance is reassociated
in a different location on the tooth surface, to obtain an improved
treatment state that yields a better grade, according to one or
more systems for grading orthodontic models, as compared to the
grade of said initial treatment state. The detachment and
reassociating procedure may be repeated a plurality of times, with
different types of teeth repositioning, to achieve the highest
possible grade.
[0016] For the purpose of designing an orthodontic treatment plan,
following repositioning and reassociation of the orthodontic
appliances with the teeth, the teeth are reverted back to their
initial position in the virtual diagnostic setup model with the
orthodontic appliances remaining attached thereon. The association
of the orthodontic appliances set with the teeth in the resulting
composite model will thus be different than that in the first
composite model. This resulting composite model may be thus used by
an orthodont to design the manner of association of the orthodontic
appliances with teeth within the framework of the real life
orthodontic treatment. Such association will give rise to result in
the real life treatment similar to those of the virtual orthodontic
treatment carried out in accordance with the invention.
[0017] The invention thus provides a virtual orthodontic treatment
method, that comprises:
[0018] providing a virtual diagnostic setup model of teeth of at
least one jaw of an individual, associating virtual orthodontic
appliances with all teeth in said model to obtain a first composite
model and repositioning teeth into an initial treatment state
according to pre-defined appliances-dependent rules;
[0019] in said initial treatment state, detaching one or more teeth
from their corresponding one or more orthodontic appliances,
repositioning said one or more appliances, reassociating said one
or more appliances with the teeth, permitting the teeth to
reposition according to the appliances-dependent rules to obtain an
altered treatment state, yielding a better grade, according to one
or more systems for grading an orthodontic model, as compared to
the grade of said initial treatment state.
[0020] The present invention also provides a system for virtual
orthodontic treatment, that comprises [0021] (i) a digital
interface for receiving digital data representative of a virtual
diagnostic setup model of teeth; [0022] (ii) a processor including
a software for [0023] associating virtual orthodontic appliances
with all teeth in said model to obtain a first composite model,
[0024] repositioning teeth according to appliance-dependent rules
into an initial treatment state according to pre-defined
appliances-dependent rules, and for [0025] selecting teeth in said
initial treatment state and virtually detaching one or more teeth
from their corresponding orthodontic appliances, repositioning said
one or more appliances and reassociating said one or more
appliances with the teeth and permitting the positioning of the
teeth according to appliance-dependent rules, to obtain a second
composite virtual model with an altered treatment state, yielding a
better grade, according to one or more systems for grading an
orthodontic model, as compared to the grade of said initial
treatment position; and [0026] (iii) a user interface comprising at
least a display for displaying results of the virtual orthodontic
treatment.
[0027] Also provided by the present invention in accordance with a
preferred embodiment, is a method for designing a real life
orthodontic treatment, comprising: [0028] (a) providing a virtual
diagnostic setup model of an initial state of teeth of at least one
jaw of an individual, associating virtual orthodontic appliances
with all teeth in said model in a first association arrangement to
obtain a first composite virtual model; [0029] (b) permitting the
teeth to reposition according to pre-defined appliances-dependent
rules into an initial treatment state with a second association
arrangement of said teeth and said appliances; [0030] (c) in said
initial treatment state [0031] selecting one or more teeth and
virtually detaching at least the selected teeth from said
orthodontic appliances, [0032] repositioning said appliances on the
selected teeth and reassociating appliances to the teeth and
permitting the teeth to reposition according to appliance-dependent
rules into a second composite virtual model with an altered
treatment state, yielding a better grade, according to one or more
systems for grading an orthodontic model, as compared to the grade
of said initial treatment state. [0033] (d) permitting the teeth to
revert back from their state in said second composite virtual model
into said initial state with said orthodontic appliance remaining
associated with the teeth in a manner as in said second composite
virtual model to obtain a treatment-design virtual model with
orthodontic appliances associated with the teeth in a manner of
association to be applied in a real life orthodontic treatment.
[0034] Still further provided in accordance with this preferred
embodiment is a system for designing a real life orthodontic
treatment, comprising: [0035] (i) a digital interface for inputting
a virtual diagnostic setup model of an initial state of teeth of an
individual; [0036] (ii) a user interface comprising at least an
output for outputting results of virtual orthodontic treatment and
information on design of real life orthodontic treatment; [0037]
(iii) a processor including a software running thereon for [0038]
associating virtual orthodontic appliances with all teeth in said
model to obtain a first composite model, [0039] repositioning teeth
according to appliance-dependent rules into an initial treatment
state according to pre-defined appliances-dependent rules, and for
[0040] selecting teeth in said initial treatment state and
virtually detaching one or more teeth from their corresponding
orthodontic appliances, repositioning said one or more appliances
and reassociating said one or more appliances with the teeth and
permitting the positioning of the teeth according to
appliance-dependent rules, to obtain a second composite virtual
model with an altered treatment state, yielding a better grade,
according to one or more systems for grading an orthodontic model,
as compared to the grade of said initial treatment position; and
[0041] permitting the teeth to revert back from their state in said
second composite virtual model into said initial state with said
orthodontic appliance remaining associated with the teeth in a
manner as in said second composite virtual model to obtain
treatment-design virtual model with orthodontic appliances
associated with the teeth in a manner of association to be applied
in a real life orthodontic treatment, and [0042] outputting data
representative of said treatment-design virtual model in a manner
suitable for use in the design of the real life orthodontic
treatment.
[0043] The grading system, according to one embodiment, is based on
measuring one or more of the following parameters: alignment,
marginal ridges, buccollingual inclination, overjet, occlusal
relationship, occlusal contacts and interproximal contacts. Each of
these parameters has a defined standard and the grading may be
based on the extent of deviation of the measured parameter from
said standard.
[0044] Alignment is usually a fundamental objective of an
orthodontic treatment plan. In the maxillary and mandibular
interior regions, proper alignment is typically characterized by
coordination of alignment of the incisor edges and the lingual
incisor surfaces of the maxillary incisors and canines, and the
incisor edges and labial incisor surfaces of the mandibular
incisors and canines. In the mandibular posterior region, for
proper alignment, the mesiobuccal and distobuccal cusps of the
molars and premolars should be in the same mesiodistal alignment.
In the maxillary arch, for proper alignment, the central grooves
should all be in the same plane or alignment. Preferably, the
deviation should be within 0.5 mm of proper alignment.
[0045] Marginal ridges are used to assess proper vertical
positioning of the posterior teeth. In both maxillary and
mandibular arches, marginal ridges of adjacent posterior teeth
should be the same level, or preferably within 0.5 mm of the same
level.
[0046] Buccolingual inclination is used to assess the buccolingual
angulation of the posterior teeth. The buccolingual inclination of
the maxillary and mandibular posterior teeth is assessed by
measuring the distance between the lingual cusps and the straight
line that connects buccal cusps of contra lateral teeth. Such a
vertical distance preferably below 1 mm is typically permitted.
[0047] Occlusal relationship is used to assess the relative
anteroposterior position of the maxillary and mandibular posterior
teeth. For a proper relationship, the buccal cusps of the maxillary
molars, premolars and canines should preferably align within 1 mm
of the interproximal embrasures of the mandibular posterior teeth.
The mesiobuccal cusps of the maxillary first molar should
prefereably align within 1 mm of the buccal groove of the
mandibular first molar.
[0048] Occlusal contacts is a measure that assesses the adequacy of
the posterior occlusion. For proper occlusal contacts, the buccal
cusps of the mandibular premolars and molars and the lingual cusps
of the maxillary premolars and molars should be contacting the
occlusal surfaces of the opposing teeth.
[0049] Overjet is a measure used to assess the relative transverse
relationships of the posterior teeth and the anteroposterior
relationship of the anterior teeth, typically, in the posterior
region, the mandibular buccal cusps and maxillary lingual cusps are
used to determine proper position within the fossae of the opposing
arch. In the anterior region, the mandibular incisor edges should
be in contact with the lingual surfaces of the maxillary anterior
teeth. In case of a proper overjet, the buccal cusps of the
mandibular molars and premolars will contact in the center of the
occlusal surfaces, buccolingually, of the maxillary premolars and
molars. In the anterior region, the mandibular canines and incisors
will contact the lingual surfaces of the maxillary canines and
incisors.
[0050] Interproximal contacts is used to determine if all spaces
within the dental arch have been closed.
[0051] For grading, the virtual teeth mode, whether in said initial
treatment state or in the altered treatment state, may be graded by
one of these parameters by determining the extent of deviation from
established or conventional standards. It should, however, be
appreciated that the invention is not limited to the use of the
above parameters for grading of the virtual teeth model and also
not to any specific standard applied for grading. On the contrary,
any parameter or any standard acceptable or that will become
acceptable may be employed within the framework of the present
invention, for grading of the virtual teeth model.
[0052] The grading system that can be used may be that established
by the American Board of Orthodontics (ABO) for grading dental
cusps for Phase III clinical examination for candidates requested
to become members of ABO (John S. Casko, et al., The American Board
of Orthodontics, Grading System for Dental Casts and Panoramic
Rodeographs, November 1998).
[0053] The virtual set of orthodontic appliances used in the method
and system of the invention, typically, but not exclusively,
comprise brackets and arch wires. In accordance with a preferred
embodiment of the invention, the orthodontic appliances comprise
straight-wire appliances. In addition to wires and brackets, the
virtual set of orthodontic appliances may also include a variety of
other appliances such hooks, springs, expansion screws, wire locks
such as Gurin locks, hooks, orthodontic bands, orthodontic elastics
such as rubber bands or springs, etc. In accordance with some
embodiments of the invention, rather than a single straight wire,
virtual loops, bands or twists or bands may be introduced into the
wire.
[0054] In the case of the use of a virtual set of straight wire
appliances, the brackets are typically fixed initially at the
center of the crown of the teeth and the teeth are then permitted
to reposition so that the slots of all brackets align in the plane
defined by the arch wire and the teeth are aligned along an arch
defined by said arch wire.
[0055] In said initial treatment stage, appliances may be detached
from their associated teeth and then repositioned in a manner to
give a higher grade, following which the bracket and/or other
orthodontic appliances may be reassociated to the tooth. This step
may be repeated a plurality of times so as to yield an optimal
result yielding the best grade.
[0056] In accordance with some embodiments of the invention, the
user may be permitted to select a set of orthodontic appliances
that will be associated with the teeth. In other embodiments of the
invention, this is automatic.
[0057] Similarly as in real life orthodontic treatment, also in the
virtual treatment in accordance with the invention, additional
virtual orthodontic interventions may be carried out. These
additional interventions may include, for example, a tooth
extraction or tooth stripping. Here again, in some embodiments of
the invention, the need for an additional orthodontic intervention
is automatically established and the type of additional orthodontic
intervention is automatically selected. In other embodiments of the
invention, the need and nature of initial orthodontic intervention
is defined by the user.
[0058] Such additional orthodontic interventions may, for example,
be a tooth extraction or interproximal stripping of a tooth.
[0059] In some embodiments the grading system used is automatically
selected by the system. In other embodiments, the user may be
permitted to manually select a certain grading system. A preferred
grading system for grading the above parameters is said ABO grading
system. The grading may be automatic or may be carried manually
through the user interface.
[0060] Where the virtual treatment method or system serves for a
design of an orthodontic treatment, data representative of
association of orthodontic appliances with the teeth to achieve
orthodontic treatment targets as determined through the virtual
treatment method or system is obtained. Data of such association
may be output to a display or a suitable treatment guidance
system.
[0061] By the method and system of the invention the orthodontist
can visualize, e.g. on a screen, how the final outcome of the
treatment will be when using a specific set of orthodontic
appliances. In addition, the orthodontist may also assess the
effect of a variety of additional manipulations that in real-life
orthodontic treatment are irreversible, such as extraction and/or
stripping of one or more teeth. This procedure may also be
automatic according to some embodiments of the invention. Based on
the outcome of the procedure, which, as aforesaid may be visualized
on a screen, the orthodontist may decide whether to use the
selected orthodontic appliances and the additional intervention for
the treatment of the specific individual or change one or more of
the procedure parameters such as the type of wire, type of
brackets, type of tooth to be extracted, etc., and test the outcome
with the newly selected parameters. Eventually, the orthodontist
will obtain, in accordance with the invention, a three-dimensional
digital model which yields a desired outcome; and a set of virtual
appliances, their positioning and other manipulations which yielded
this desired result, that can then be applied in the real life
orthodontic treatment plan.
[0062] The virtual diagnostic setup model of the teeth may be
prepared on the basis of a teeth impression. Teeth impressions are
used in the art to prepare plaster models, and the digital
three-dimensional model will typically have an overall
representation resembling that of a plaster model. The preparation
of plaster models and the like are known in the art of orthodontry.
Methods for obtaining a three-dimensional digital model of teeth of
an individual are generally known and one such method is described
in U.S. Pat. No. 6,099,314 that is incorporated herein by
reference.
[0063] The virtual diagnostic setup model is inputted to the system
as a digital representation of data that can be processed by a
computer, and when presented, for example, on the computer's
screen, resembles the three-dimensional structure of a real life
physical model. A virtual diagnostic setup model of teeth includes
at least a representation of the external contours of the teeth and
the separation if teeth from their adjacent teeth, but preferably
also includes a representation of portions of the gums. The virtual
setup model may be visualized on a screen in a manner resembling a
plaster setup model used in orthodontry.
[0064] The invention will now be further illustrated by the
following embodiments with occasional reference to the annexed
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0065] In order to understand the invention and to see how it may
be carried out in practice, a preferred embodiment will now be
described, by way of non-limiting example only, with reference to
the accompanying drawings, in which:
[0066] FIG. 1 shows an overall flow chart of a virtual orthodontic
treatment in accordance with an embodiment of the invention.
[0067] FIG. 2 shows a flow diagram of the manner of utilizing the
results of the virtual orthodontic treatment for obtaining data to
be used in design of a real-life orthodontic treatment.
[0068] FIGS. 3 and 4 are screen displays showing, respectively, a
side and a front view of a jaw of an individual before applying any
virtual orthodontic procedure in accordance with the present
invention.
[0069] FIGS. 5 and 6 are screen displays showing the same jaws as
in FIGS. 4 and 5 after performing a virtual orthodontic treatment
in accordance with the invention in respective side and front
view.
[0070] FIG. 7 shows a screen display of the same jaws as in FIGS. 4
and 5 in which the lower center A-P point selected was different
than in the previous results shown in FIGS. 5-6.
[0071] FIG. 8 shows a side view of an outcome of a virtual
treatment in which the inter arch relationship is determined
according to the fixed maxillary jaw.
[0072] FIG. 9 shows a side view of an outcome of a virtual
treatment with the same parameters as in FIG. 8, however, with a
fixed mandibular jaw.
[0073] FIG. 10 shows a screen display for selecting a tooth for
extraction.
[0074] FIG. 11 shows a screen display showing the outcome of a
virtual treatment after extracting a tooth.
DETAILED DESCRIPTION OF THE INVENTION
[0075] Reference is first being made to FIG. 1 that shows a general
flow chart of an embodiment of the virtual treatment method in
accordance with the invention. Upon initiation 20, a virtual
diagnostic setup model is inputted. This model may be obtained by a
number of different ways. The basis is a virtual teeth model
obtained through a variety of teeth scanning or direct teeth
imaging techniques, or through scanning or otherwise capturing a
negative teeth impression or a positive teeth model. An example of
a method for obtaining three-dimensional digital model of teeth is
disclosed in U.S. Pat. No. 6,099,314. From such a model a virtual
setup model may be obtained through an automatic or manual
procedure in which the setup model the teeth are separated from one
another in a manner that permits separate manipulation of the
position of each of the teeth.
[0076] At the next step 24 a set of orthodontic appliances is
selected for subsequent association with the teeth. As will be
appreciated, the invention is not limited to a specific set of
orthodontic appliances and the general principle described herein
applies to any selected set. However, in accordance with a
preferred embodiment of the invention, the set of orthodontic
appliances which is to be used is a straight wire set that
comprises a straight wire and brackets. As known, each bracket has
a horizontal slot for receiving the wire. In addition, similarly as
in real life orthodontic treatment, other orthodontic appliances
such as hooks, elastic components, and others may be included in
the set. The selection of the set may be automatic by the system or
may be manual. For selection of a set of orthodontic appliances,
different options may be presented to the user, for example, sets
of different manufacturers, and the orthodont may then choose the
one most familiar to him or the set which he prefers to use.
Alternatively, rather than selecting a complete set, optionally the
user may select individual components that together will comprise
the set.
[0077] At a next step 26 the appliances are attached to or made to
associate with the teeth. In one embodiment of the invention this
is an automatic operation. In such an embodiment, after selection
of the set for orthodontic appliances, the brackets are
automatically attached to teeth. In such an automatic attachment,
the brackets are typically attached to the center point of the
teeth crown (namely at the center of the exposed surface of the
teeth). In accordance with another embodiment the user may be
permitted to select the position of all or of only some of the
brackets.
[0078] Once all brackets have been selected, a wire, typically a
straight wire as pointed out above, is added, and the first
sequence of orthodontic treatment follows. In this first sequence,
teeth are repositioned in a manner so that all the wire-receiving
slots on the brackets snap onto the wire. This causes all slots to
align in the plane defined by the wire and the teeth to align in an
overall arch is also defined by the wire. This step may be carried
out, for example, in a manner as described in PCT Publication WO
99/34747. Thereby, a first treatment state of the virtual model is
obtained. A more detailed description of the step appears further
below.
[0079] In a next step 30, this initial treatment state is analyzed
and graded by a variety of criteria C1, C2, . . . CN. These grading
criteria include, in accordance with a preferred embodiment of the
invention, the following: alignment, marginal ridges, buccolingual
inclination, overjet, occlusal relationship, occlusal contact and
interproximal contacts. Reference is made to the explanation above
of these criteria. The grading, as pointed out above, is based on
the deviation of the teeth arrangement from a standard or ideal
arrangement, in accordance with one or more of established
standards. An example of a standard which may be applied is that
set by the American Board of Orthdontics, referenced above. It
should, however, be noted that in some embodiments only part of the
above criteria or at times even one, e.g. only the criteria of
alignment, may be used to grade the teeth arrangement. In a typical
embodiment of the invention, the grading is carried out
automatically, although optionally, the grading may be manually
done by the user.
[0080] Following the grading according to one or more of the above
criteria, at a next step 32 an overall model analysis is carried
out. In this analysis the different grading scores are combined,
which combination may be a simple combination, may be a weighted
combination (ascribing a different way to a different criteria) or
any other acceptable analysis of the system. Here again, the
overall model analysis is typically automatic, although it is
possible also to permit the user to do it manually.
[0081] Following this overall analysis, at a distant point 34 an
assessment is made whether the model meets orthodontic standards or
whether an improvement is required. If no improvement is required,
the virtual treatment ends 36. If a decision is made and an
improvement is required, which decision may be automatic or may be
a decision made by the user, a next step 38 teeth for repositioning
are selected, then at 40 the orthodontic appliances are virtually
detached from at least the selected teeth, the detached appliances
are then repositioned at 42, to yield repositioning of the teeth.
For example, where a bracket is repositioned to a different lateral
portion of the tooth, it causes axial rotation of the tooth. Where,
by another example the bracket is repositioned to a different
vertical position of the tooth crown, it causes extraction or
retraction of the tooth. Where, by a further example, the
attachment of the bracket to the wire is the different
anteoposterior point on the wire, it causes the tooth to move in
the anterior or posterior direction.
[0082] It should be noted that optionally in steps 40 and 42,
orthodontic appliances are at least temporary removed or hidden for
easier visualization of the manipulation outcome.
[0083] Then, at 44, the detached orthodontic appliances are
reassociated to the teeth and a resulting altered treatment state
is obtained.
[0084] The appliances repositioning may be done using an
optimization algorithm employing one of many optimization or
goal-seeking algorithms where the variable set is the set of
appliances positions and the goal is best grade. Possible
algorithms include Deepest descent, Newton-Raphson method and
others. In addition, the goal may also include additional
restrictions such as having minimal angle between teeth to avoid
results that may give a goal grade but are less aesthetically
appealing.
[0085] The resulting altered treatment state so obtained is
analyzed and graded in the same manner as described above.
[0086] Typically in the orthodontic treatment, each tooth is
assembled with its corresponding bracket such that the base point
of the bracket falls initially on the facial axis point of the
tooth, as typically done in orthodontry. The assembled teeth may
then translocate along the wire's curve according to the following
criteria: [0087] (i) The two central incisors are translocated
along the wire curve (along the curve falling on the Andrews plane)
until they are brought into at least one point of contact,
preferably such that their contact point falls on the mid-platal
plane. [0088] (ii) The lateral incisors on each side of the
mid-platal (the left and right lateral incisors) may be
translocated towards their respective central incisors (i.e. the
left and right incisors, respectively), followed by translocating
the canine, premolar (first premolar, then premolar) and molar (for
the first molar, then second molar and optionally then the third
molar) teeth such that each flanking teeth have at least one point
of contact therebetween. It should be clear that the same procedure
is applied whenever a tooth is extracted or stripped, taking into
consideration which tooth exactly was extracted.
[0089] The outcome of the above procedure is an arch wire set with
brackets which are fixed with the respective tooth, the teeth being
optimally arranged according to orthodontic criteria. At times,
movement of the first molar teeth by the system of the invention
may result in a distilization of the mandibular molar teeth in an
amount greater than that allowed in a real life treatment according
to real life treatment considerations. Accordingly, after
translocation of teeth as described above, the system verifies
whether the mandibular distilization performed would be allowed in
real life considerations and if in the negative, the result
displayed on the display screen, will show the user that the
procedure performed would not be feasible in the real life
orthodontic treatment. The user will then know that the orthodontic
treatment plan he selected should be changed, e.g. by selecting a
different wire, different brackets, performing other, if any
manipulations on the teeth, etc.
[0090] The resulting arrangement of the teeth may further be
processed by applying a vertical repositioning of the teeth, and if
necessary, move in a manner similar to that in step (ii) above. The
result obtained for one arch, i.e. the maxillary arch or the
mandibular arch, is then used for determination of the inter arch
relationship.
[0091] The algorithm employed may also use some optimization
criteria for obtaining the initial treatment stage. For example,
the mandibular arch may be first aligned with the mandibular jaw by
their central point (an average distance between the central
incisors) to fall onto the mid palatal plane. The maxillary arch
fixed onto the maxillary jaw may then be vertically aligned onto
the mandibular jaw in the manner as described in PCT Publication
No. WO 98/52493. The alignment between the two jaws may be
according to a fixed mandibular jaw or alternatively according to a
fixed maxillary jaw.
[0092] The following description refers to alignment of the maxilla
according to the fixed mandibular jaw. However, it should be
understood that the same steps apply in flow diagram, for alignment
of the mandible according to the fixed maxilla jaw (muatis
mutandis).
[0093] For determining the inter arch relationship, first the
parameters of the mandibular jaw are provided, with which the
mandibular arch is aligned by determining their center
antheroposterior point (lower center point A-P56). Then occlusion
of the mandibular first molar with the maxillary first molar is
dictated by the features of Class (I) type of occlusion. If
necessary, i.e. when the outcome obtained and displayed on the
display screen is not the desired outcome or when the user decides
it is required to change the Class type, he may change the class by
which the mandibular first molar and the maxillary first molar
interlock until reaching the desired outcome.
[0094] At times, the horizontal alignment performed will result in
a mandibular distilization which is greater than that acceptable in
real life orthodontic treatment. As a result, the procedure
according to the invention may be carried out while each arch is
positioned onto their respective jaw by defining their center
antheroposterior point, the steps of interlocking the molar teeth
according to standard orthodontic guidelines is not performed.
[0095] The definition of the different classes which can be
selected by the user in a manner as shown herein in FIG. 3, which
shows an example of a screen display showing a virtual model 100
with an upper jaw 102 and a lower jaw 103. Shown in this view is
also a view control window 105 which permits control of position of
orientation as well as view angles in a manner as described in PCT
Application, Publication No. WO 98/53428. The treatment parameters
may be controlled through user interface window 106.
[0096] A front view of the same jaw is seen in FIG. 4.
[0097] FIGS. 3 and 4 also show a virtual diagnostic setup model of
an individual's jaws, in its original, untreated form. Once an
orthodontic treatment is executed, a second three dimensional
digital model is obtained. The second three dimensional digital
model includes the jaw carrying teeth assembled with brackets and a
wire. The teeth in the second model are arranged in an optimal
dental and skeletal arrangement as obtained by the system of the
invention. The teeth are automatically associated with brackets,
the later set on a wire. The outcome of virtual treatment of the
original model (shown in FIGS. 3 and 4) is seen in FIGS. 5 and 6.
In this case the parameters of the system were automatically
selected, including the arch wire (RothoFormIII-Ovoid), the
brackets (Clarity.TM.), and class (Class I) and yielded one optimal
outcome.
[0098] There are different classes which may be applied. Class 1,
which is a default Class in the system and is that applied in FIGS.
5 and 6. Change in the Class may be achieved by ticking off box 120
in user interface window 106 and moving scroll bar 122 to either
side.
[0099] Another parameter which may be selected is a lower center
point, which may be automatically selected (the automatic selection
is dictated by the original center point in the individual's jaw
before treatment), as in FIGS. 3-6 or, it may be moved between the
interior posterior direction by ticking off box 124 and moving
scroll bar 126 to either the left, as seen in FIG. 7 or the right
directions.
[0100] In addition, the arch wire selection may be automatic, as in
FIGS. 6 and 7, which in this case is the default arch wire known as
Ortho Form11-Ovoid, but may also be manually selected within
selection window 130.
[0101] The user may also control the parameters of which jaw will
be fixed during the procedure. This is achieved by ticking in the
set up design user interface 140 between the mandible 142 selection
point or the maxilla 144 selection point. In the case of FIG. 8,
the parameters of maxillary jaw are fixed during the procedure and
after aligning therewith the maxillary arch, the inter arch
arrangement is performed. By the default of the system, the
mandible parameters are fixed and the maxilla is moved accordingly.
The reverse selection is shown in FIG. 9 (145). Thus, as can be
seen, in view of the initial structure of the teeth, the two jaws
are more forwardly oriented in FIG. 9 as compared to FIG. 8.
[0102] Another manner of control is a virtual extraction of teeth.
In FIG. 10, the treatment is preceded normally without extraction.
By ticking Alleviation box 138 and marking in the user interface
window 106 the tooth or teeth to be extracted, the marked tooth, in
this particular case, the second molar 148 is virtually extracted
and the void 150 which is left is at least partially filled by
lateral movement of the flanking teeth, as seen in FIG. 11. This
feature of the system of the invention enables the user to decide
whether extraction of a tooth in a real life treatment will be
effective in achieving a desired orthodontic outcome before
performing such an irreversible manipulation in the real life
treatment.
[0103] Reference is made now to FIG. 2 which shows the manner of
using the results of the virtual orthodontic treatment for guidance
for the real-life orthodontic treatment. Following start 50, the
virtual model with the altered treatment state obtained through the
virtual orthodontic treatment (36 in FIG. 1) is inputted at 52. The
teeth are then, at 54, permitted to reposition to their original
position in the original diagnostic setup model with the
orthodontic appliances remaining attached thereon. The association
of the orthodontic appliances with the teeth is then recorded as 56
and this is served as an input for guidance of the real-life
orthodontic treatment for the purpose of achieving results similar
to those obtained in the virtual treatment in accordance with the
invention. The manner of association of the orthodontic appliances
may be displayed on the screen or may be outputted to a guidance
system for proper placing of an orthodontic element on a tooth's
surface, such as that described in U.S. Pat. No. 6,334,772.
* * * * *