Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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ORTHODONTIC SYSTEM WITH VARIABLY-SIZED ARCHWIRE SLOT
Technical Field
[0001] The field of the present disclosure relates generally to orthodontic
brackets
and, in particular, to such brackets used to correct misalignment of a
patient's teeth.
Such appliances, typically referred to as braces, are used to align and
straighten
teeth so as to both position them with regard to a person's bite, as well as
improve
the appearance of a patient's mouth. Such appliances may be used to correct
underbites, overbites, malocclusions, and various other misalignments of the
teeth.
Background
[0002] Dental braces are orthodontic devices commonly used to align and
straighten a patient's teeth and to correct various other flaws relating to
the teeth and
jaw. Typically, braces include a set of orthodontic brackets, each bracket
being
adhered to an individual tooth with a bonding material or other adhesive. Once
the
brackets are in position on the teeth, an archwire is inserted through a slot
formed on
each of the brackets. In this configuration, tightening of the archwire
applies
pressure on the brackets, which in turn urge movement of the teeth into a
desired
position and orientation. In conventional braces, an elastic ligature or 0-
ring may be
used to retain the archwire in position and ensure that the archwire does not
disengage from the bracket slot. In more recent designs, self-ligating braces
use a
sliding or hinged door mechanism, instead of an elastic ligature, to secure
the
archwire within the bracket slot.
[0003] Treatment of a patient's teeth using braces to correct dental issues
typically requires several appointments to monitor progress and make
adjustments to
the braces as treatment progresses. Accordingly, the present inventors have
identified a need for an improved system that streamlines the treatment
process to
reduce the length of treatment by more efficiently aligning a patient's teeth.
Additional aspects and advantages will be apparent from the following detailed
description of preferred embodiments, which proceeds with reference to the
accompanying drawings.
Brief Description of the Drawings
[0004] FIG. 1 is a view illustrating a row of teeth with dental appliances
attached
thereto using an archwire.
[0005] FIG. 2 is a sectional view of a dental appliance of FIG. 1.
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[0006] FIGS. 3A, 3B, and 3C collectively illustrate an example temporal
progression of a conventional treatment program that progressively applies
differently-shaped archwires to the dental appliances of FIG. 1 so as to
incrementally
move a patient's teeth towards a desired positon.
[0007] FIG. 4 is a view illustrating a row of teeth with dental appliances
attached
in accordance with disclosed embodiments.
[0008] FIGS. 4A and 4B illustrates a cross section along lines A-A and B-B,
respectively, of FIG. 4 using a novel orthodontic system disclosed in the
present
specification.
[0009] FIGS. 5A and 5B illustrate an example of improved torque control
using
the orthodontic system of FIGS. 4A and 4B.
[0010] FIG. 5C illustrates typical torque control expected using the
conventional
orthodontic system of FIGS. 3A, 3B, and 3C.
[0011] FIG. 6A illustrates an example of improved tip control using the
orthodontic
system of FIGS. 4A and 4B.
[0012] FIG. 6B illustrates typical tip control expected using the
conventional
orthodontic system of FIGS. 3A, 3B, and 3C.
[0013] FIGS. 7A and 7B illustrate an example of improved rotation control
using
the orthodontic system of FIGS. 4A and 4B.
[0014] FIG. 7C illustrates typical rotation control expected using the
conventional
orthodontic system of FIGS. 3A, 3B, and 3C.
Detailed Description of Example Embodiments
[0015] With reference to the drawings, this section describes particular
embodiments of various orthodontic brackets and their detailed construction
and
operation. Throughout the specification, reference to one embodiment," an
embodiment," or some embodiments" means that a particular described feature,
structure, or characteristic may be included in at least one embodiment of an
orthodontic bracket. Thus appearances of the phrases in one embodiment," in an
embodiment," or in some embodiments" in various places throughout this
specification are not necessarily all referring to the same embodiment.
Furthermore,
the described features, structures, and characteristics may be combined in any
suitable manner in one or more embodiments. In view of the disclosure herein,
those skilled in the art will recognize that the various embodiments can be
practiced
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without one or more of the specific details or with other methods, components,
materials, or the like.
[0016] In the following description, particular components of the
orthodontic
brackets may be described in detail. It should be understood that in some
instances,
well-known structures, materials, or operations are not shown and/or not
described
in detail to avoid obscuring more pertinent aspects of the embodiments. In
addition,
although the embodiments may illustrate and reference particular orthodontic
bracket
designs, other embodiments may include additional or fewer components than the
described embodiments.
[0017] With general reference to the figures, the following disclosure
relates to an
orthodontic system designed for improving orthodontic treatments. The
orthodontic
system described in detail below uses the relationship between the dimension
of the
archwire relative to the dimension of the archwire slot in the dental brackets
to
increase precision and control of the forces applied to the teeth during the
treatment
process. Briefly, the orthodontic brackets are arranged against the patient's
teeth
such that the depth of the respective archwire slots of the brackets generally
increases moving from the anterior teeth toward the posterior teeth. In some
embodiments, the depth of the archwire slots may not necessarily increase for
each
subsequent bracket on each tooth beginning with the anterior teeth. For
example, in
some embodiments, the central, lateral and cuspid teeth may each have a first
bracket with a first archwire slot, the bicuspids may each have a second
bracket with
an archwire slot deeper than the first archwire slot of the first bracket, and
the molars
may each have a third bracket with an archwire slot deeper than the archwire
slot of
the second bracket.
[0018] In either embodiment, as the archwire progresses from a round cross-
section at the start of treatment and then through various round and square
cross-
sections over the course of treatment, the forces created by the archwire as
it
pushes against the brackets within the archwire slot urges all teeth to move.
Because the dimension of the archwire slot is smallest at the anterior teeth
and
largest at the posterior teeth, the treatment provides better control and
tighter
precision for the anterior teeth, while providing sufficient freedom of
movement to
allow all teeth to move and settle properly. As is described in further detail
below,
the gradual progression of archwire slot sizes from the anterior to posterior
teeth is
specifically designed to start the detailing and alignment process of the
teeth earlier
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in the process as compared to conventional treatments, thereby reducing
overall
treatment time. Additional details relating specifically to the orthodontic
treatment
system and related treatment methods are further described in detail below
with
reference to the figures.
[0019] Before turning to the written description, the following is a list
of terms that
are used in the disclosure. The terms are used in accordance with the meaning
understood by those having skill in the art, but are provided herein to ensure
consistency and to facilitate understanding of the specification by those
unskilled in
the art.
[0020] Anterior ¨ the direction towards the front of the head, or the lips;
opposite
of "posterior."
[0021] Anterior teeth ¨ the teeth on either one of the mandibular or
maxillary jaws
extending from one canine tooth to the other canine tooth.
[0022] Buccal ¨ the direction towards the cheek, typically used in
connection with
posterior teeth; opposite of "lingual."
[0023] Buccal-lingual direction ¨ a direction through or along any
particular
posterior tooth extending between a patient's cheek and the patient's tongue.
[0024] Distal ¨ the direction on the side of a particular tooth away from
the dental
midline; opposite of mesial.
[0025] Dental arch ¨ a row of teeth in either of the mandibular or
maxillary jaws.
[0026] Dental midline ¨ an imaginary line dividing a patient's mouth into
two
halves, extending through the patients two middle anterior teeth and towards
the
back of the mouth.
[0027] Gingival ¨ a direction towards the gums beneath a particular tooth.
[0028] Incisal ¨ a direction towards the biting surface of a particular
anterior tooth.
[0029] Incisal-gingival direction ¨ a direction through or along any
particular
anterior tooth extending from the biting surface to the gums beneath that
tooth.
[0030] Labial ¨ the direction towards the lips, typically used in
connection with
anterior teeth; opposite of lingual.
[0031] Labial-lingual direction ¨ a direction through or along any
particular
anterior tooth extending between the patient's lips to the patient's tongue.
[0032] Mandibular ¨ related to the lower jaw.
[0033] Maxillary ¨ related to the upper jaw.
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[0034] Mesial ¨ the direction on the side of a particular tooth toward the
dental
midline; opposite of distal.
[0035] Mesial-distal direction ¨ the direction through any particular tooth
extending from the mesial side of the tooth to the distal side of the tooth.
The mesial-
distal direction, relative to a tooth, is essentially along the curved line
through the
relevant upper or lower row of teeth.
[0036] Occlusal ¨ a direction towards the biting surface of a particular
posterior
tooth.
[0037] Occlusal-gingival direction ¨ a direction through or along any
particular
posterior tooth extending from the biting surface to the gums beneath that
tooth
[0038] Posterior ¨ the direction towards the back of the head; opposite of
anterior.
[0039] Posterior teeth ¨ the teeth on either one of the mandibular or
maxillary
jaws posterior of a canine tooth.
[0040] Rotation ¨ angular rotation of a tooth during the course of
treatment
around a vertical axis oriented in the incisal-gingival direction.
[0041] Tip ¨ angular rotation of a tooth during the course of treatment
around a
horizontal axis oriented in the buccal-lingual direction.
[0042] Torque ¨ angular rotation of a tooth during the course of treatment
around
a horizontal axis oriented in the mesial-distal direction.
[0043] With general reference to FIGS. 1 and 2, the following briefly
describes a
treatment system 1 in accordance with a conventional process. With reference
to
the figures, the treatment system 1 comprises a plurality of brackets 2
applied to a
row of patient's teeth 3. The brackets 2 are connected together by an archwire
4
through appropriate means such as via an archwire slot 6, and a ligating
structure
such as a cover 5 for retaining the archwire 4 in the archwire slot 6. As
noted earlier,
treatment of a patient using braces typically requires repeated adjustment of
the
archwire 4 so that, over time, the tension in the archwire 4, applied to the
teeth 3
through the brackets 2, causes the teeth 3 to migrate to a desired final
position.
[0044] FIGS. 3A, 3B, and 3C collectively illustrate an example temporal
progression of a conventional treatment program that progressively applies
differently-shaped archwires to the dental appliances of FIG. 1 so as to
incrementally
move a patient's teeth towards a desired positon. Referring to FIG. 3A, an
archwire
slot 6 formed in each the respective brackets 2 may be formed as an elongated
rectangular aperture closed along a top end of the bracket 2 by a ligating
structure 5.
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The ligating structure 5 may be a sliding or hinged door that extends over the
archwire slot 6, or may be an elastic band, or any other appropriate
structure. When
a set of braces is first applied to each of a patient's teeth, an archwire 4A
of a
circular cross section may be used. Usually the circular archwire 4A is made
of a
nickel-titanium material that is relatively flexible so that, in combination
with the
circular cross-sectioned archwire 4A fitted in a rectangular slot 6, the
archwire 4A
applies relatively low forces to a patient's teeth 3, and the brackets 2 have
significant
play to move relative to each other as the teeth 3 move towards a more aligned
state. When the circular archwire 4A is used in the treatment process, there
is no
torque control of the teeth 3 since twisting the archwire 4A will not apply
any
rotational forces to the bracket 2.
[0045] Eventually, in a second stage of treatment shown in FIG. 3B, the
archwire
4A of a circular cross section is replaced by an archwire 4B of a rectangular
square
cross section. Depending on the degree of correction needed for the patient's
teeth,
the archwire 4B may be made of nickel-titanium (similar to the round archwire
4A) or
may be made of a stiffer material, such as a beta-titanium alloy, if a larger
degree of
correction is necessary. As illustrated in FIG. 3B, the archwire 4B has a
slightly
smaller overall dimension than the archwire slot 6, but has a larger overall
cross-
section than the round archwire 4A using in the first stage of treatment.
Accordingly,
the archwire 4B is capable of applying increased force and control to the
teeth 3, and
the brackets 2 have less play relative to the archwire 4A than existed in the
first
stage of treatment.
[0046] In a final stage of treatment, the archwire 4B is replaced with
another
rectangular archwire 4C of a larger cross section as illustrated in FIG. 3C.
The
archwire 4C is typically much stiffer than the archwire 4B it replaces, and
may be
made of stainless steel or other similarly stiff material. This third stage of
treatment
again increases the force and control applied to the teeth 3 through the
archwire 4C
and brackets 2 as compared to the previous stage of treatment. Due to the
tighter fit
of the archwire 4C in the archwire slot 6, the brackets 2 have very little
play relative
to each other than existed in either of the first and second stages of
treatment.
[0047] As mentioned previously, the present inventors have determined that
an
improved and more efficient treatment system and method could be applied than
the
conventional system described in FIGS. 3A-3C, based on the realization that
not all
teeth need to be simultaneously subjected to the same amount of force and/or
not all
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teeth require the same amount of play during treatment. In other words, a
uniform
force profile is not needed for all teeth. On the contrary, a force profile
that varies for
different teeth (e.g., anterior teeth vs. posterior teeth) as needed not only
reduces
overall treatment time, but also provides higher control for tooth movement
where
needed.
[0048] The present inventors understand that one of the primary objects of
dental
treatment with braces is the precise positioning of the anterior teeth so as
to achieve
a desired aesthetic look, and that positioning of the posterior teeth need not
be as
precise. Accordingly, an improved treatment system preferably uses a set of
brackets for placement along a dental arch, either mandibular or maxillary,
where the
cross section of the archwire slot varies in the distal direction of the arch
from the
dental midline (i.e., from the anterior brackets to the posterior brackets) to
effect
targeted force profiles on the anterior and posterior teeth as needed. This
system
provides for the following benefits compared to conventional systems: (1)
improved
quality of treatment due to increase control of the teeth in the anterior
segment of the
dental arch; (2) earlier control of tooth movement in treatment, resulting in
a reduced
treatment time when compared to current systems while providing appropriate
freedom of movement such that the teeth can efficiently move to the desired
position; and (3) an improved patient experience due to low and efficient
forces due
to appropriate sizing of the archwire dimensions. Additional details of the
improvement orthodontic treatment method and system are provided below.
[0049] With particular reference to FIGS. 4, 4A, and 4B, the following
description
provides an overview of the improved treatment method disclosed herein. The
remaining figures illustrate additional details relating to examples of how
the
disclosed treatment system and method provide better torque, rotation, and tip
control to urge the teeth into a desired alignment as compared to a
conventional
orthodontic treatment.
[0050] FIG. 4 illustrates an example row of a patient teeth 50 with a
plurality of
brackets 100, 102, 104 where a single bracket is attached to each of the
anterior
teeth 120 (e.g., central, lateral, and cuspid) through the posterior teeth 150
(bicuspids and molars). The brackets 100, 102, 104 each include an archwire
slot
105, 115, respectively, (cross-section of bracket 104 is not illustrated in
FIGS. 4A,
4B) sized and dimensioned for receiving an archwire 110 therethrough, the
archwire
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110 connecting all the brackets 100, 102, 104 together and providing force
against
each of the brackets 100, 102, 104 to urge the teeth into a desired alignment.
[0051] Preferably, the occlusal-gingival dimension of the archwire slots
105, 115
(i.e., the width of archwire slot) is the same or substantially the same
(e.g., within
manufacturing tolerances) for all brackets 100, 102, 104 in the set.
Maintaining the
width of the archwire slot equal (or substantially equal) across all brackets
enhances
the accuracy of the torque and tip positioning of all of the teeth in the
maxillary and
mandibular dental arches as further described in detail below. However, the
labial-
lingual dimension of the archwire slots 105, 115 (i.e., the depth of archwire
slot
measured from the top surface of the bracket body to the archwire floor) is
progressively increased from the bracket 100 positioned on the anterior teeth
120 to
the bracket 102 positioned on the posterior teeth 150.
[0052] In this configuration, the set of brackets 100 on the anterior teeth
120 are
all preferably identical, each having an archwire slot 105 of a minimum depth
(i.e.,
these brackets have an archwire slot with the smallest cross-sectional size),
and the
brackets 102 on the posterior teeth 150 (primarily the molars) have an
archwire slot
115 of a maximum depth (i.e., these brackets have an archwire slot with the
largest
cross-sectional size), with the archwire slots (not shown) on the posterior
brackets
104 of the bicuspids having a depth that is somewhere in between the
respective
depth of the archwire slots 105, 115 of the brackets 100, 102. In some
embodiments, the archwire slot 105 of the anterior bracket 100 may have a
generally
square-shaped cross-section, while the archwire slot (not shown) on the
bicuspid
brackets may have a generally rectangular-shaped cross-section, and the
archwire
slot 115 of the posterior brackets 102 has a more elongated rectangular-shaped
cross-section.
[0053] The arrangement of sets of brackets with progressively increasing
archwire slot depth provides sufficient precision and tighter control for the
anterior
teeth 120 to facilitate achieving a desired aesthetic look, while also
allowing
increased freedom of movement for the bicuspids and the molars to ensure all
teeth
are properly aligned when the treatment is complete. The following section
provides
additional details of these embodiments with reference to an example
arrangement
of the orthodontic brackets.
[0054] To provide a standard frame of reference that may be applied across
a
broad range of differently-sized brackets, the following example describes the
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relationship of the labial-lingual dimension of the archwire slot (e.g., the
depth) with
relation to the labial-lingual dimension of the archwire. It should be
understood that
the ratios described herein may apply to any size of the orthodontic brackets,
including standard bracket sizes now available and other bracket sizes that
may be
developed in the future.
[0055] As noted above, the labial-lingual dimension of the archwire slot in
the
brackets is progressively increased from the anterior brackets to the
posterior
brackets, such that the anterior teeth, bicuspids, and molars are subjected to
different force profiles specifically targeted for best controlling movement
for the
respective teeth. Table 1 below illustrates an example configuration in
accordance
with one embodiment, with the depth of the archwire slot presented as a
percentage
of the labial-lingual dimension of the archwire from the central teeth to the
molars in
both the maxillary and mandibular dental arches.
Table 1:
LABIAL-LINGUAL DIMENSION OF SLOT
AS (%) OF ARCHWIRE LABIAL-LINGUAL DIMENSION
Tooth Example Range
Position Embodiment Minimum Maximum
(%) (%) (%)
Central 105 102 110
Lateral 105 102 110
Cuspid 105 102 110
1st Bicuspid 115 110 125
2nd Bicuspid 115 110 125
1st Molar 130 120 140
2nd Molar 130 120 140
[0056] With collective reference to FIG. 4 and Table 1, during an example
orthodontic treatment method, the brackets 100 are attached to the anterior
teeth
120 (central, lateral, and cuspid teeth) of the patient. As noted previously
and
illustrated in table 1, all brackets 100 are preferably identical such that
all anterior
teeth 120 each have a bracket with identical dimensions relative to one
another. As
noted in Table 1, the labial-lingual dimension of the archwire slot 105 ranges
from
102% - 110% of the corresponding dimension of the archwire 110. Next, brackets
104 are attached to the first and second bicuspids of the patient, with the
labial-
lingual dimension of the archwire slot for those brackets ranging from 110% -
125%.
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Finally, the brackets 102 are attached to the posterior teeth 150 (e.g., first
and
second molars, may include a third molar if present) of the patient. As noted
in
Table 1, the labial-lingual dimension of the archwire slot 115 for the
brackets 102
ranges from 120% - 140% of the corresponding dimension of the archwire 110. As
noted previously, the occlusal-gingival dimension of the archwire slot remains
constant for all brackets. Accordingly, in one embodiment, the occlusal-
gingival
dimension of the archwire slot as a percentage of the occlusal-gingival
dimension of
the archwire may range from 102% to 110%.
[0057] Table 2 below provides example of dimension ranges for the archwire
slots of the brackets using a square archwire that measures .020" x .020." In
such
embodiments, the occlusal-gingival dimension of the archwire slots in the
brackets of
a system using a final archwire that is .020" x .020" square is 0.021" in such
an
embodiment, with a range of 0.0204" to 0.022".
Table 2:
LABIAL-LINGUAL DIMENSION OF SLOT
USING SQUARE ARCHWIRE OF .020" x .020."
Tooth Example Range
Position Embodiment Minimum Maximum
(inches) (inches) (inches)
Central 0.021 0.0204 0.022
Lateral 0.021 0.0204 0.022
Cuspid 0.021 0.0204 0.022
1st Bicuspid 0.023 0.022 0.025
2nd Bicuspid 0.023 0.022 0.025
1st Molar 0.026 0.024 0.028
2' Molar 0.026 0.024 0.028
[0058] While Table 2 illustrates example dimensional ranges for a square
archwire measuring .020" x .020," in other embodiments, the labial-lingual and
occlusal-gingival dimensions of the final archwire can range from 0.017" x
0.017"
square to 0.021" x 0.021" square. In still other embodiments, the dimensions
of the
archwire may be larger or smaller than the ranges provided.
[0059] In the embodiment described above, the bracket sizes are essentially
grouped based on the specific teeth to which they are attached. For example,
all the
anterior teeth 120 have respective brackets with the same dimensions for the
archwire slot, and all the posterior teeth 150 have respective brackets with
the same
dimensions for the archwire slot. It should be understood that in other
embodiments,
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the bracket sizes and dimensions may be grouped differently, or the labial-
lingual
dimension of the slot may simply become progressively deeper for each
successive
bracket beginning from the central tooth and ending with the second (or third)
molar.
Preferably, however, the brackets are arranged in groups to ensure that the
various
groups of teeth are controlled as needed (i.e., the anterior teeth are more
finely
controlled) to reduce treatment time while also providing a positive outcome
for the
patient. FIGS. 4A and 4B below illustrate an example embodiment of the
improved
orthodontic treatment method and system, illustrating how the archwire sits
within
the respective archwire slots of the anterior brackets 100 and the posterior
brackets
102 during an example stage of treatment.
[0060] FIG. 4A illustrates the improved dental bracket 100 attached to one
of the
anterior teeth 120. The bracket 100 includes a square archwire slot 105 with a
depth
measured from the top surface in a labial-lingual direction to the first floor
substantially equal to its width extending across in an occlusal-gingival
direction such
that the archwire 110 closely fits within the archwire slot 105 during a final
stage of
treatment. The square archwire slot 105 in these anterior brackets 100 has a
minimum depth as compared to the brackets on the posterior teeth, such that
the fit
of the archwire 110 within the slot 105 provides for the most accuracy in
positioning
the anterior teeth 120, as is further described in detail below with reference
to FIGS.
5A-7C. As noted previously, the brackets used on the central, lateral, and
cuspid
teeth in both the mandibular and maxillary dental arch have an archwire slot
identical
to the square archwire slot 105 of FIG. 4A.
[0061] FIG. 4B illustrates the improved dental bracket 102 attached to one
of the
posterior teeth 150. With reference to FIG. 4B, the dental bracket 102 has an
archwire slot 115 that extends to a depth that is greater than the
corresponding
depth of the archwire slot 105. In some embodiments, the archwire slot 115 may
have a generally rectangular shape, as compared to the generally square shape
of
the bracket 100 on the anterior teeth 120. Accordingly, the archwire 110 fits
relatively loosely within the archwire slot 115 and provides more freedom of
movement to the posterior teeth 150 as compared to the anterior teeth 120.
While
the posterior teeth 150 have more freedom to move, the relatively loose fit of
the
archwire 110 in the archwire slot 115 also results in a smaller degree of fine
control
of the tooth movement for the posterior teeth 150 as compared to the anterior
teeth
120. However, the orthodontic treatment is designed such that all teeth in the
dental
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arch as a whole have sufficient freedom of movement and the archwire and
brackets
provide sufficient control to move the teeth into a desired alignment.
[0062] It should be understood that FIGS. 4A and 4B are meant to illustrate
an
example configuration for a final stage of treatment. Those having skill in
the art
understand that initial and intermediate stages of treatment may use different
sizes
and shapes for the archwire as needed. For example, in some embodiments, the
archwire cross section may progress from a round archwire at the start of
treatment,
then through various round and square cross sections over the course of
treatment
to a final archwire with a square cross section as shown in FIGS. 4A and 4B.
The
final square cross section archwire creates forces that are patient friendly
and
effective for tooth movement. In addition the square cross section of the
final
archwire provides excellent control of the tooth position.
[0063] Those of ordinary skill in the art will also appreciate that other
embodiments of the disclosed systems and methods may use other cross sectional
shapes than those just described. For example, in some embodiments the dental
bracket 100 may have an archwire slot of a rectangular cross section, but
smaller
than that of the dental bracket 102. Similarly, in some embodiments the dental
bracket 102 may have an archwire slot of a square cross section larger than
that of
the dental bracket 100.
[0064] The combination of archwire slot dimensions of the anterior and
posterior
brackets coupled with a square final archwire, according to the dimensions
shown in
Tables 1 and 2, provides an improved orthodontic treatment system and method
that
results in accurate positioning of the anterior and posterior teeth while
maintaining
efficient control of all teeth for reduced treatment time. With collective
reference to
FIGS. 5A-7C, the following paragraphs describe additional details relating to
how the
improved treatment method provides for more efficient control of tooth
movement as
compared to conventional treatment methods.
[0065] With collective reference to FIGS. 5A, 5B, and 5C, the following
illustrates
how the varied dimensions of the archwire slots 105, 115 provide for much
finer
control of tooth positioning, earlier in treatment, than do existing systems.
FIGS. 5A
and 5B illustrate the control over torque (e.g., the angular rotation of a
tooth during
the course of treatment around a horizontal axis oriented in the mesial-distal
direction) provided in the anterior teeth (FIG. 5A) and the posterior teeth
(FIG. 5B)
using the brackets as shown in FIGS. 4A and 4B during the finishing stages of
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treatment. As the archwire 110 connecting the brackets 100, 102 is twisted in
the
archwire slots 105, 115, respectively, the corners of the square archwire 110
the
sides of the archwire slots at angles of rotation 160 (FIG. 5A) and 165 (FIG.
5B),
thereby transmitting forces on the teeth to which the brackets are attached,
and
consequently inducing the teeth to rotate about an axis oriented in the mesial-
distal
direction.
[0066] As illustrated in FIG. 5A, a portion of the archwire 110 in the
anterior
bracket 100 is seated against and contacts the floor of the archwire slot 105,
and
another portion of the archwire 110 contacts the ligating structure extending
over the
archwire slot 105. As the archwire 110 is twisted in the archwire slot 105,
the
contact against the sidewalls and floor of the archwire slot 105, and against
the
ligating structure urge the tooth to rotate as desired. In FIG. 5B, the
archwire 110 in
the posterior bracket 102 similarly contacts the sidewalls and floor of the
archwire
slot 115, but the archwire 110 is spaced apart from the ligating structure
because of
the greater depth of the archwire slot 115 as compared to the archwire slot
105. In
other embodiments (not shown), the archwire 110 may instead contact the
ligating
structure and be spaced apart from the floor of the archwire slot.
[0067] In FIG. 5A, because the archwire slot 105 is only slightly larger in
overall
dimension than the archwire 110, the angle of rotation 160 is relatively
small. In FIG.
5B, the archwire slot 115 has a larger, rectangular shape as compared to the
archwire slot 105, but because the occlusal-gingival dimension (i.e., width)
is the
same in both brackets, the angle of rotation 165 is also relatively small and
may be
equal (or substantially equal) to the angle of rotation 160. In some
embodiments, the
angles of rotation 160, 165 may range from 30 to 6 when using a square .020"
x
.020" archwire, such as may be common during the final stages of treatment.
When
using a smaller square .018" x .018" archwire, such as may be common during
the
initial stages of treatment, the angles of rotation 160, 165 may range from 13
to 16 .
[0068] FIG. 5C illustrates a conventional treatment method in accordance
with
one embodiment using a rectangular .018" x .025" archwire 4 in conjunction
with a
bracket 2 having a rectangular archwire slot 6. In this configuration, it is
readily
apparent that the angle of rotation 170 is substantially larger than the
respective
angles of rotation 160, 165 of the improved system due to the looser fit of
the
archwire 4 in the archwire slot 2. In some embodiments, the angle of rotation
170
may range from 10 to 15 during the final stages of treatment. When using a
smaller
13
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WO 2018/217353 PCT/US2018/028680
rectangular .014" x .025" archwire that is more common during the initial
stages of
treatment, the angle of rotation 170 may range from 25 to 30 . Notably, the
angles
of rotation 160, 165 for both the initial and final stages of treatment are
substantially
smaller than the corresponding angles of rotation 170 in the conventional
system,
meaning that the system of FIGS. 5A and 5B offers more precise torque control
than
the conventional system of FIG. 5C.
[0069] With reference to FIGS. 6A and 6B, the following illustrates the
same
phenomenon with respect to tip control, which is the angular rotation of a
tooth
during the course of treatment around a horizontal axis oriented in the buccal-
lingual
direction. FIG. 6A illustrates the anterior bracket 100 with an archwire slot
105
through which an archwire 110 is used to position a tooth attached to the
bracket.
As illustrated in FIG. 6A, the relative fit of the archwire 110 within the
archwire slot
105 provides a tighter control over the angle of rotation 175. When using a
square
.020" x .020" archwire, the angle of rotation 175 is less than 1 , and may
range
between 0.4 and 0.6 . Those of ordinary skill in the art will appreciate that
the
diagram of FIG. 6A also represents the tip control provided by the posterior
bracket
105.
[0070] FIG. 6B illustrates a conventional bracket 2 with an archwire slot 6
through
which an archwire 4 is used to position a tooth attached to the bracket 2. As
illustrated in FIG. 6B, the relatively looseness of the archwire 4 within the
slot 6
results in a large angle of rotation 180. In some embodiments, using a
rectangular
archwire .018" x .025" archwire, the angle 180 may range from 1.5 to 2.0 .
Again,
the angle 175 is noticeably less than the angle 180 achieved by the prior art
system
of FIG. 6B, thereby illustrating that the improved treatment method and system
provides for finer tip control.
[0071] With reference to FIGS. 7A, 7B and 7C, the following illustrates the
same
phenomenon with respect to rotation control, which is the angular rotation of
a tooth
during the course of treatment around a vertical axis oriented in the incisal-
gingival
direction. FIG. 7A illustrates the anterior bracket 100 with an archwire slot
105
through which an archwire 110 is used to position a tooth attached to the
bracket.
As illustrated in FIG. 7A, the relative fit of the archwire 110 within the
archwire slot
105 provides a tighter control over the angle of rotation 185 imparted by the
bracket
100 on the anterior teeth 120. When using a square .020" x .020" archwire, the
angle of rotation 185 is less than 1 , and may range between 0.4 and 0.7 .
When
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WO 2018/217353 PCT/US2018/028680
using a smaller square .018" x .018" archwire, such as may be common during
the
initial stages of treatment, the angle of rotation 185 may range between 1.5
and
2.2 .
[0072] Similarly, FIG. 7B illustrates the posterior bracket 102 with an
archwire slot
115 through which an archwire 110 is used to position a tooth attached to the
bracket. When using a square .020" x .020" archwire, the angle of rotation 190
may
range between 1.7 and 2.2 . When using a smaller square .018" x .018"
archwire,
such as may be common during the initial stages of treatment, the angle of
rotation
190 may range between 3.0 and 3.30
.
[0073] FIG. 7C illustrates a conventional bracket 2 with an archwire slot 6
through
which an archwire 4 is used to position a tooth attached to the bracket 2. As
illustrated in FIG. 7C, the conventional system results in a rotational
control angle
195 that may range between 1.5 and 2.0 using a rectangular archwire .018" x
.025"
archwire. While the rotational control angle 195 may be similar to the angle
of
rotation 190, it is significantly larger than the angle of rotation 185.
Accordingly, the
improved treatment method and system provides for finer rotation control of
the
anterior teeth and slightly improved control for the posterior teeth as
compared to the
conventional treatment system.
[0074] While FIGS. 5A-7C focus primarily on the finishing stages of
treatment to
illustrate the improvement over torque, tip, and rotation over conventional
treatment
methods, the following tables and written description illustrate how the
improved
treatment system provides significant advantages during all stages of
treatment.
Using an initial phase of treatment as an illustrative example, where the
improved
system herein described uses an archwire of 0.014 diameter in an archwire slot
having measurements shown in Table 2, the following Tables 3 and 4 together
delineate the improvement in control over torque, tip, and rotation over
conventional
systems.
[0075] In an initial stage of treatment, a round archwire is preferably
used, which
provides no torque control since the round archwire has no edges to catch on
the
archwire slot when twisted, but achieves 4.46 degrees of rotation control and
3.83
degrees of tip control. The prior art system in the initial treatment phase,
however,
though similarly providing no control over torque, can only provide 8.47
degrees of
rotation control and 4.29 degrees of tip control. As with control over torque,
Table 3
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WO 2018/217353 PCT/US2018/028680
shows that the disclosed system provides greater control over tooth movement
at
every stage of treatment.
Table 3: Improved Orthodontic System
Phase Initial Working Finishing &
Detailing
X-Section .014 Rd. .018 x .018 .020 x .020 .020 x .020
Material NiTI NiTi NiTi TMA or SS
Torque Lock-up None 14.20 deg. 4.18 deg. 4.18 deg.
Control Rotation Lock-up 4.46 deg. 1.92 deg. 0.64 deg. 0.64 deg.
Tip Lock-up 3.83 deg. 1.92 deg. 0.55 deg. 0.55 deg.
Table 4: Conventional Orthodontic System
Phase Initial Working Finishing &
Detailing
X-Section .014 Rd. .018 Rd .014 x .025 .018 x .025 .019 x .025
Material NiTI NiTi NiTi NiTi SS
Torque Lock-up None None 28.77 deg.
13.78 deg. 10.88 deg.
Control Rotation Lock-up 8.47 deg. 6.09 deg. 1.85 deg. 1.85 deg. 1.85
deg.
Tip Lock-up 4.29 deg. 2.15 deg. 4.29 deg. 2.15 deg. 1.62 deg.
[0076] It should be understood that while the figures and associated
written
description illustrate example embodiments of brackets with specified
dimensions,
other configurations may be possible without departing from the principles of
the
disclosed subject matter. In addition, although the description above contains
much
specificity, these details should not be construed as limiting the scope of
the
invention, but as merely providing illustrations of some embodiments of the
invention. It should be understood that subject matter disclosed in one
portion
herein can be combined with the subject matter of one or more of other
portions
herein as long as such combinations are not mutually exclusive or inoperable.
[0077] The terms and descriptions used above are set forth by way of
illustration
only and are not meant as limitations. It will be obvious to those having
skill in the
art that many changes may be made to the details of the above-described
embodiments without departing from the underlying principles of the invention.
16
