U.S. patent application number 09/792782 was filed with the patent office on 2001-06-28 for self-ligating orthodontic bracket with enhanced rotation control.
This patent application is currently assigned to 3M Innovative Properties Company. Invention is credited to Georgakis, Evangelos G., Kelly, John S., Manemann, Robert C..
Application Number | 20010005574 09/792782 |
Document ID | / |
Family ID | 23054979 |
Filed Date | 2001-06-28 |
United States Patent
Application |
20010005574 |
Kind Code |
A1 |
Manemann, Robert C. ; et
al. |
June 28, 2001 |
Self-ligating orthodontic bracket with enhanced rotation
control
Abstract
An orthodontic bracket includes an archwire slot with mesial and
distal end sections that present archwire relief areas. The bracket
also includes a latch movable between a slot-open position in order
to enable insertion or removal of an archwire, and a slot-closed
position in order to retain an archwire in the archwire slot. The
bracket includes at least one flange that extends along at least a
portion of the mesial and distal archwire end sections and over a
portion of the latch in order to provide enhanced rotational
control over the underlying tooth without undue deformation of the
latch.
Inventors: |
Manemann, Robert C.;
(Corona, CA) ; Kelly, John S.; (Arcadia, CA)
; Georgakis, Evangelos G.; (Altaloma, CA) |
Correspondence
Address: |
Office of Intellectual Property Counsel
3M Innovative Properties Company
PO Box 33427
St. Paul
MN
55133-3427
US
|
Assignee: |
3M Innovative Properties
Company
|
Family ID: |
23054979 |
Appl. No.: |
09/792782 |
Filed: |
February 23, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09792782 |
Feb 23, 2001 |
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09276060 |
Mar 25, 1999 |
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6193508 |
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Current U.S.
Class: |
433/11 |
Current CPC
Class: |
A61C 7/287 20130101 |
Class at
Publication: |
433/11 |
International
Class: |
A61C 003/00 |
Claims
1. An orthodontic bracket comprising: a base; a body extending from
the base; an archwire slot extending along the body, the archwire
slot including a mesial end section, a distal end section and an
intermediate section between the mesial end section and the distal
end section, and wherein each of the mesial end section and the
distal end section includes an archwire relief area having a
greater occlusal-gingival width than the occlusal-gingival width of
the intermediate section; a latch movable relative to the body, the
latch being movable to a slot-open position to enable insertion or
removal of an archwire, the latch also being movable to a
slot-closed position in order to retain the archwire in the
archwire slot; and at least one flange connected to the body and
extending in a mesial-distal direction along at least a portion of
each of the mesial end section and the distal end section, wherein
the at least one flange extends over a portion of the latch in
buccolabial relation to the latch when the latch is in the
slot-closed position.
2. An orthodontic bracket according to claim 1 wherein the bracket
includes two flanges, one of which extends along at least a portion
of the mesial end section of the archwire slot and the other of
which extends along at least a portion of the distal end section of
the archwire slot.
3. An orthodontic bracket according to claim 2 and including a
third flange that extends along at least a portion of the
intermediate section.
4. An orthodontic bracket according to claim 3 wherein the third
flange is integrally connected to the first flange and to the
second flange.
5. An orthodontic bracket according to claim 1 wherein the at least
one flange has a length in a mesial-distal direction that is at
least as great as the length of adjacent portions of the latch when
the latch is in a slot-closed position.
6. An orthodontic bracket according to claim 1 wherein the latch
moves in a curved arc relative to the body.
7. An orthodontic bracket according to claim 1 wherein the latch
moves along a generally straight path relative to the body.
8. An orthodontic bracket according to claim 1 wherein the latch
comprises a section of wire.
9. An orthodontic bracket according to claim 8 wherein the wire has
a loop-shaped configuration.
10. An orthodontic bracket according to claim 9 wherein the latch
includes a gingival portion and occlusal portion, and wherein the
latch is disconnected from the body by shifting at least one of the
gingival portion and the occlusal portion toward the other.
11. An orthodontic bracket according to claim 1 wherein the bracket
body includes a mesial side and a distal side, and wherein the
latch extends past the mesial side in a mesial direction and also
extends past the distal side in a distal direction.
12. An orthodontic bracket according to claim 1 wherein the latch
is movable relative to the body in a generally mesial-distal
direction.
13. An orthodontic bracket according to claim 1 wherein the latch
has a generally U-shaped configuration and moves relative to the
body in a generally gingival-occlusal direction.
14. An orthodontic bracket according to claim 13 wherein the latch
is resilient.
15. An orthodontic bracket according to claim 13 wherein the body
includes a channel extending in a generally gingival-occlusal
direction, and wherein the latch has a lingual section that is
received in the channel.
16. An orthodontic bracket according to claim 1 wherein the bracket
includes two flanges, one of which extends along at least a portion
of the mesial end section and the other of which extends along a
portion of the distal end section, and wherein a space is presented
between the two flanges.
17. An orthodontic bracket comprising: a base; a body extending
from the base; an archwire slot extending along the body, the
archwire slot including a mesial end section, a distal end section
and an intermediate section between the mesial end section and the
distal end section, and wherein each of the mesial end section and
the distal end section includes an archwire relief area having a
greater labial-lingual depth than the labial-lingual depth of the
intermediate section; a latch movable relative to the body, the
latch being movable to a slot-open position to enable insertion or
removal of an archwire, the latch also being movable to a
slot-closed position in order to retain the archwire in the
archwire slot; and at least one flange connected to the body and
extending in a mesial-distal direction along at least a portion of
each of the mesial end section and the distal end section, wherein
the at least one flange extends over a portion of the latch in
buccolabial relation to the latch when the latch is in the
slot-closed position.
18. An orthodontic bracket according to claim 17 wherein the
bracket includes two flanges, one of which extends along at least a
portion of the mesial end section of the archwire slot and the
other of which extends along at least a portion of the distal end
section of the archwire slot.
19. An orthodontic bracket according to claim 18 and including a
third flange that extends along at least a portion of the
intermediate section.
20. An orthodontic bracket according to claim 19 wherein the third
flange is integrally connected to the first flange and to the
second flange.
21. An orthodontic bracket according to claim 17 wherein the at
least one flange has a length in a mesial-distal direction that is
at least as great as the length of adjacent portions of the latch
when the latch is in a slot-closed position.
22. An orthodontic bracket according to claim 17 wherein the latch
moves in a curved arc relative to the body.
23. An orthodontic bracket according to claim 17 wherein the latch
moves along a generally straight path relative to the body.
24. An orthodontic bracket according to claim 17 wherein the latch
comprises a section of wire.
25. An orthodontic bracket according to claim 24 wherein the wire
has a loop-shaped configuration.
26. An orthodontic bracket according to claim 25 wherein the latch
includes a gingival portion and occlusal portion, and wherein the
latch is disconnected from the body by shifting at least one of the
gingival portion and the occlusal portion toward the other.
27. An orthodontic bracket according to claim 17 wherein the
bracket body includes a mesial side and a distal side, and wherein
the latch extends past the mesial side in a mesial direction and
also extends past the distal side in a distal direction.
28. An orthodontic bracket according to claim 24 wherein the latch
is movable relative to the body in a generally mesial-distal
direction.
29. An orthodontic bracket according to claim 17 wherein the latch
has a generally U-shaped configuration and moves relative to the
body in a generally gingival-occlusal direction.
30. An orthodontic bracket according to claim 29 wherein the latch
is resilient.
31. An orthodontic bracket according to claim 29 wherein the body
includes a channel extending in a generally gingival-occlusal
direction, and wherein the latch has a lingual section that is
received in the channel.
32. An orthodontic bracket according to claim 17 wherein the
bracket includes two flanges, one of which extends along at least a
portion of the mesial end section and the other of which extends
along a portion of the distal end section, and wherein a space is
presented between the two flanges.
33. An orthodontic bracket comprising: a base; a body extending
from the base; an archwire slot extending along the body in a
generally mesial-distal direction; a pair of elongated cavities
extending along at least a portion of the archwire slot and located
buccolabially of the archwire slot, one of the cavities extending
along an occlusal side of the archwire slot and the other of the
cavities extending along a gingival side of the archwire slot; and
a latch received in the cavities for retaining an archwire in the
archwire slot.
34. An orthodontic bracket according to claim 33 wherein the
cavities extend in generally parallel relationship to each other
from one side of the bracket to another.
35. An orthodontic bracket according to claim 33 wherein the latch
comprises a section of wire.
36. An orthodontic bracket according to claim 35 wherein the wire
has a loop-shaped configuration.
37. An orthodontic bracket according to claim 33 wherein the latch
has a gingival portion and an occlusal portion, and wherein the
latch is disconnected from the body by shifting at least one of the
gingival portion and the occlusal portion toward the other.
38. An orthodontic bracket according to claim 33 wherein the
bracket body includes a mesial side and a distal side, and wherein
the latch extends past the mesial side in a mesial direction and
also extends past the distal side in a distal direction.
39. An orthodontic bracket according to claim 33 wherein the latch
is movable relative to the body in a generally mesial-distal
direction.
40. An orthodontic bracket according to claim 33 wherein the latch
is non-releasably retained in one of the cavities and is releasably
retained in the other cavity.
41. An orthodontic bracket according to claim 33 wherein the latch
is movable in a curved arc relative to the body to a slot-open
position to enable insertion or removal of an archwire from the
archwire slot.
42. An orthodontic bracket according to claim 33 wherein the latch
comprises a section of wire, and wherein the wire includes an
opposed pair of legs that are curved for reception of a hand
instrument.
43. An orthodontic bracket according to claim 33 wherein the latch
comprises a section of wire, and wherein the body includes a notch
extending from a buccolabial face of the body to one of the
cavities in order to facilitate manipulation of the wire by a hand
instrument.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention broadly relates to brackets used in
orthodontic treatment. More specifically, the present invention
concerns orthodontic brackets that have a latch for releasably
retaining an archwire in an archwire slot of the brackets.
[0003] 2. Description of the Related Art
[0004] Orthodontic therapy is a specialized type of treatment
within the field of dentistry, and involves movement of
malpositioned teeth to orthodontically correct locations.
Orthodontic treatment often improves the patient's occlusion and
typically enhances the aesthetic appearance of the teeth.
[0005] Many types of orthodontic treatment programs involve the use
of a set of tiny appliances and wires that are commonly known
collectively as "braces". During such treatment programs, small
appliances known as brackets are fixed to the patient's anterior,
cuspid and bicuspid teeth, and an archwire is inserted into a slot
of each bracket. The archwirc forms a track to guide movement of
the teeth to orthodontically correct locations. End sections of the
archwires are typically captured in tiny appliances known as buccal
tubes that are fixed to the patient's molar teeth.
[0006] Many types of orthodontic brackets have archwire slots that
are open on one side for insertion of the archwire, and bounded on
remaining sides by a central body of the bracket, by tiewings or by
other structure. Brackets that are intended to be bonded to the
patient's front tooth surfaces often have archwire slots that are
open either on a buccolabial side (i.e., a side facing the
patient's cheeks or lips) or an occlusal side (i.e., a side facing
the outer tips of the teeth) of the archwire slot. Some brackets,
however, are intended to be fixed to the lingual side of the
patient's teeth (i.e., the side of the teeth facing the patient's
tongue) and in that instance typically have an archwire slot that
is open on a lingual side or on an occlusal side.
[0007] Many orthodontists use ligatures to connect the archwire to
the brackets and to urge the archwire into an orientation of
seating engagement in the archwire slot. One type of commercially
available orthodontic ligature is a small, elastomeric O-ring.
Orthodontic O-rings are installed by stretching the O-ring around
small wings (known as "tiewings") that are connected to the bracket
body on the gingival side (i.e., the side facing the patient's
gingiva or gums) and on the occlusal side of the archwire slot.
Once installed, the O-ring ligature extends around the tiewings as
well as over the labial side of the archwire and urges the archwire
toward a lingual wall of the archwire slot.
[0008] Metal ligatures, such as ligatures made of stainless steel,
are also used to retain archwires in archwire slots of brackets.
Metal ligatures are typically made of a short section of initially
straight wire. During installation, the wire ligature is hooked
around the tiewings and extended over the labial side of the
archwire, and end sections of the ligature are then twisted
together to form a loop to retain the ligature in place.
[0009] Unfortunately, some orthodontists are not entirely satisfied
with elastomeric and metal ligatures. Such ligatures are somewhat
time-consuming to install, both during initial installation and
also during reinstallation whenever replacement of the archwire or
ligatures is desired. As can be appreciated, a savings in the
amount of time needed for ligation can help to reduce the total
time that the practitioner must spend with the patient and
consequently aid in reducing the overall costs of orthodontic
treatment.
[0010] Other disadvantages are also associated with elastomeric and
metal ligatures. For example, there have been reports that certain
polyurethane elastomeric ligatures have exhibited deformation and
force decay during the course of treatment. In some instances,
elastomeric ligatures are stained by food and beverages consumed by
the patient and become somewhat unsightly. Metal ligatures often
have sharp ends that may retain plaque and food debris and also may
increase the risk of infection.
[0011] In an effort to overcome the problems associated with
conventional ligatures, a variety of orthodontic brackets have been
proposed having various types of latches for coupling the archwire
to the bracket. Such brackets are also known as self-ligating
brackets. The latch comprises a clip, spring member, cover,
shutter, bail or other structure that is connected to the bracket
body for retaining an archwire in the archwire slot.
[0012] Examples of self-ligating orthodontic brackets having
generally U-shaped ligating latch clips are described in U.S. Pat.
Nos. 3,772,787, 4,248,588 and 4,492,573. In general, the clip of
such brackets is slidably mounted on the bracket body, and a dental
explorer or other small-tipped dental tool is used to move the clip
relative to the body when needed in order to open or close the
archwire slot. A self-ligating bracket known as the "Speed" brand
bracket also has a movable, generally U-shaped clip for ligating
the archwire to the bracket.
[0013] Other types of self-ligating brackets have latches that
resemble swinging shutters or closures that pivotally move between
a slot-open and a slot-closed position. For example, U.S. Pat. No.
4,712,999 has a rotatable cover plate that is pivotally connected
at one end to a tiewing of the bracket along one side of the slot,
and is releasably engagable at the other end with a tiewing that is
located along the opposite side of the archwire slot. Other
orthodontic brackets with swinging latches are described in U.S.
Pat. Nos. 4,103,423, 5,516,284 and 5,685,711.
[0014] U.S. Pat. Nos. 4,371,337 and 4,559,012 describe
self-ligating orthodontic brackets having latches that rotate about
the longitudinal axis of the archwire slot. The latch of these
references has a somewhat cylindrical shape and is rotatably
received in a mating, cylindrical channel, and an outwardly
extending arm is provided to assist in rotatably moving the latch
between a slot-open and a slot-closed position.
[0015] A self-ligating orthodontic bracket that is described in
U.S. Pat. No. 5,711,666 has a ligating latch that comprises a
flexible flat spring member. One end of the spring member is fixed
to the bracket body on one side of the archwire slot, and the
opposite end of the spring member has notches that releasably
engage latch sears or catches when the spring member is moved to a
slot-closed position. To open the slot, the notches are disengaged
from the catches and the spring member is bent to an orientation
sufficient to enable the archwire to be removed from the archwire
slot.
[0016] Other types of self-ligating orthodontic brackets have
latches that comprise essentially flat plates that are slidable
between a slot-open and a slot-closed position. Examples of such
construction are shown in U.S. Pat. Nos. 5,094,614, 5,322,435 and
5,613,850. In general, the sliding latches described in those
references move in upright channels that are located buccolabially
of the archwire slot.
[0017] Another type of self-ligating bracket that has been proposed
in the past has a latch that is made of a section of wire material
that functions similar to a bail. The orthodontic brackets
described in U.S. Pat. Nos. 4,149,314, 4,725,229 and 5,269,681 have
wire-like latches that swing between a slot-closed position and a
slot-open position. The orthodontic bracket described in U.S. Pat.
No. 4,260,375 has a wire latch that is slidable between a slot-open
and a slot-closed position.
[0018] Many of the self-ligating brackets described above as well
as commercially-available self-ligating brackets have structure
that is intended to prevent unintentional movement of the latch. It
is undesirable, for example, for the latch to accidentally move to
a slot-open position during the course of treatment since the
archwire may disengage the bracket once the slot has been opened.
Once the archwire has separated from the bracket, control over
movement of the associated tooth is temporarily lost. In such
instances, the patient must return to the orthodontist's office so
that the wire can be re-inserted in the archwire slot in order to
resume treatment.
[0019] It is also often desired to restrain movement of the latch
in an opposite direction in some manner so that the latch does not
unintentionally detach from the body of the bracket when the latch
is opened. For example, the orthodontist may move the latch of each
bracket to a slot-open position during the course of treatment in
order to replace the archwire with an archwire having different
characteristics. If the latch becomes separated from the bracket
body during such procedures, the practitioner must interrupt the
procedure to retrieve the latch and replace it on the bracket
body.
[0020] Many practitioners prefer self-ligating orthodontic brackets
over brackets that are not self-ligating because the need to ligate
each bracket with an initially separate elastomeric O-ring or a
metal ligature wire can be avoided. However, conventional
self-ligating orthodontic brackets are not entirely satisfactory
because of the lack of optimal control over movement of the
underlying teeth. During the course of treatment, it may be
necessary to shift each tooth relative to adjacent teeth in order
to provide an aesthetically pleasing result at the conclusion of
treatment. Precise control over movement of the teeth is desirable
so that each tooth can be shifted as needed to its exact, intended
orientation and in proper orthodontic relation relative to other
teeth in the oral cavity.
[0021] In general, there are three types of tooth movement that are
important to orthodontic practitioners. Tipping movement is one
such type of movement, and may be defined as pivotal movement of
the long axis of a tooth in a mesial-distal direction. Another
movement is torque movement, and can be defined as pivotal movement
of the long axis of a tooth in a buccal-lingual direction. The
third type of tooth movement is rotational movement, and can be
defined as rotational movement of a tooth about its long axis.
[0022] An orthodontic bracket offering superior control over
movement of teeth during the course of orthodontic treatment is
described in U.S. Pat. No. 4,531,911. While the commercial
embodiments of the inventions described in U.S. Pat. No. 4,531,911
have been commercially successful and received widespread acclaim,
such brackets are not self-ligating and as a consequence do not
provide the advantages of the self-ligating brackets described
above. U.S. Pat. No. 5,857,850 describes a self-ligating bracket
that incorporates concepts of U.S. Pat. No. 4,531,911, but also is
not entirely satisfactory.
SUMMARY OF THE INVENTION
[0023] The present invention is directed to a self-ligating
orthodontic bracket having a latch that provides superior control
over movement of the underlying tooth. In brief, the bracket has a
movable latch that extends along archwire relief areas or pockets
when closed. Additionally, one or more flanges extend over a
portion of the latch in regions along the archwire relief areas and
are positioned to help ensure that the latch does not move
outwardly in a buccolabial direction when closed.
[0024] In more detail, the present invention is directed in one
aspect toward an orthodontic bracket that comprises a base, a body
extending from the base and an archwire slot extending along the
body. The archwire slot includes a mesial end section, a distal end
section and an intermediate section between the mesial end section
and the distal end section. The mesial end section and the distal
end section each include an archwire relief area having a greater
occlusal-gingival width than the occlusal-gingival width of the
intermediate section. The bracket also includes a latch that is
movable relative to the body. The latch is movable to a slot-open
position to enable insertion or removal of an archwire. The latch
is also movable to a slot-closed position in order to retain the
archwire in the archwire slot. At least one flange is connected to
the body and extends in a mesial-distal direction along at least a
portion of the mesial end section and the distal end section and
also extends over a portion of the latch in buccolabial relation to
the latch when the latch is in the slot-closed position.
[0025] Another aspect of the invention is also directed toward an
orthodontic bracket that comprises a base, a body extending from
the base and an archwire slot extending along the body. The
archwire slot includes a mesial end section, a distal end section
and an intermediate section between the mesial end section and the
distal end section. In this aspect, the mesial end section and the
distal end section each include an archwire relief area having a
greater labial-lingual depth than the labial-lingual depth of the
intermediate section. The bracket also includes a latch that is
movable relative to the body. The latch is movable to a slot-open
position to enable insertion or removal of an archwire. The latch
is also movable to a slot-closed position in order to retain the
archwire in the archwire slot. At least one flange is connected to
the body and extends in a mesial-distal direction along at least a
portion of the mesial end section and the distal end section, and
also extends over a portion of the latch in buccolabial relation to
the latch when the latch is in the slot-closed position.
[0026] The archwire relief areas as described above provide
enhanced control over rotational, tipping and torquing movements of
the underlying teeth. Additionally, the flange or flanges help
secure the latch when the latch is in the closed position. In
instances where the teeth are severely malpositioned and the
archwire exerts substantial force on the bracket, the flange or
flanges help limit outward movement of the latch so that the latch
is not unduly deformed and/or unintentionally shifted to a
slot-open position.
[0027] An additional aspect of the invention is also directed
toward an orthodontic bracket that includes a base and a body
extending from the base. The bracket includes an archwire slot
extending along the body in a generally mesial-distal direction. A
pair of elongated cavities extend along at least a portion of the
archwire slot and are located buccolabially of the archwire slot.
One of the cavities extends along an occlusal side of the archwire
slot and the other cavity extends along a gingival side of the
archwire slot. The bracket also includes a latch that is received
in the cavities for retaining an archwire in the archwire slot.
[0028] These and other aspects of the invention are described in
more detail in the text that follows and are illustrated in the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 is a front elevational view of a self-ligating
orthodontic bracket constructed in accordance with one embodiment
of the present invention, wherein a sliding latch of the bracket is
shown in a slot-closed position;
[0030] FIG. 2 is a perspective view of the bracket shown in FIG. 1,
except that the latch has been removed from a bracket body for
purposes of illustration;
[0031] FIG. 3 is a side elevational view of the bracket illustrated
in FIG. 1;
[0032] FIG. 4 is a side cross-sectional view of the bracket shown
in FIG. 1 and taken along lines 4-4 of FIG. 1, except that the
latch has been moved to a slot-open position;
[0033] FIG. 5 is a perspective, exploded view somewhat similar to
FIG. 2 but showing an orthodontic bracket according to another
embodiment of the invention;
[0034] FIG. 6 is a perspective view of an orthodontic bracket
according to yet another embodiment of the invention;
[0035] FIG. 7 is an end elevational view of the bracket depicted in
FIG. 6;
[0036] FIG. 8 is a perspective view of a latch alone of the bracket
shown in FIGS. 6 and 7;
[0037] FIG. 9 is a view somewhat similar to FIG. 6 but in
accordance with still another embodiment of the invention; and
[0038] FIG. 10 is a view somewhat similar to FIG. 6 but showing an
orthodontic bracket according to a further embodiment of the
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] An orthodontic bracket 10 according to one embodiment of the
invention is shown in FIGS. 1-4. The bracket 10 includes a base 12
that is adapted for direct bonding to a surface of the tooth. The
base 12 is shown only in FIG. 2 and preferably has a compound
contour that matches the convex shape of the tooth. Optionally, the
base 12 is provided with grooves, undercuts, wire mesh,
particulates, adhesive-promoting coatings or any combination
thereof in order to enhance bonding of the bracket 10 to a
tooth.
[0040] The bracket 10 also includes a body 14 that extends
outwardly from the base 12. The body 14 can be integral with or
initially separate from the base 12. A pair of spaced apart
occlusal tiewings 16 and a pair of spaced apart gingival tiewings
18 are integrally connected to the body 14.
[0041] An archwire slot 20 extends generally in a mesial-distal
direction along the body 14. The archwire slot 20 includes a mesial
end section 22, a distal end section 24 and an intermediate section
26 located between the mesial end section 22 and the distal end
section 24. The intermediate section 26 has a rectangular
configuration in side view as can be observed, for example, by
reference to FIGS. 3 and 4 and preferably has dimensions that are
suitable for matingly receiving an archwire having a matching,
rectangular cross-sectional configuration.
[0042] Each of the archwire slot end sections 22, 24 presents a
curved cutout or pocket that provides an archwire relief area. More
specifically, each of the end sections 22, 24 has a width in an
occlusal-gingival direction that is greater than the
occlusal-gingival width of the intermediate archwire slot section
26. Additionally, each of the archwire slot end sections 22, 24
preferably has a labial-lingual depth that is greater than the
labial-lingual depth of the intermediate archwire slot section
26.
[0043] The bracket 10 also includes a latch 28 that is movable
relative to the body 14. In this embodiment, the latch 28 comprises
a generally U-shaped, resilient spring clip having a central,
occlusal recurve portion 30 as can be best appreciated by reference
to FIG. 4. The latch 28 also includes a labial section 32 and a
lingual section 34 which optionally has a length that is longer
than the length of the labial section 32.
[0044] The body 12 also includes a rectangular channel 36 that
extends in a generally occlusal-gingival direction. The channel 36
is located lingually of the archwire slot 20, and the lingual
section 34 of the latch 28 is received in the channel 36. Although
not shown in the drawings, in embodiments of the invention where
the base 12 is initially separate from the body 14, the channel 36
is optionally located on a lingual wall of the body 14 to
facilitate manufacture by a molding process, a milling process or
the like, and the lingual side of the channel 36 is subsequently
enclosed by the base 12 once the base 12 is connected to the body
14.
[0045] The latch 28 is movable relative to the body 14 in a
generally occlusal-gingival direction. In FIGS. 1 and 3, the latch
28 is shown in a slot-closed position wherein the labial section 32
of the latch 28 extends over the archwire slot 20 and defines a
buccolabial side of the latter.
[0046] FIG. 4 is an illustration of the latch 28 when moved to a
slot-open position as might be used to permit insertion or removal
of an archwire from the archwire slot 20. When the latch 28 is
moved to the slot-open position, the labial section 32 of the latch
28 flexes outwardly and comes to rest upon a labial-facing surface
of the occlusal tiewings 16.
[0047] The lingual section 34 of the latch 28 has a labially
extending protrusion 38 that is optionally provided by punching or
deforming a middle, gingival region of the lingual section 34. When
the latch 28 is moved to the slot-open position, the protrusion 38
engages a shoulder in the channel 36 as shown in FIG. 4. The
shoulder functions as a stop to limit further movement of the latch
28 in an occlusal direction. As such, the protrusion 38
substantially prevents the latch 28 from unintentionally separating
from the body 14.
[0048] An elongated flange 40 is integrally connected to the body
14 and extends in a generally mesial-distal direction along the
length of the archwire slot 20. Preferably, the flange 40 extends
from a mesial side to a distal side of the bracket body 14 in
continuous relation. However, the flange 40 could also be replaced
with two, three or more flanges or protrusions that are separate
and spaced apart from each other.
[0049] An elongated cavity 42 extends along a lingual side of the
flange 40. The cavity 42 receives an outer gingival edge portion of
the labial latch section 32 when the latch 28 is in the slot-closed
position. Consequently, the flange 40 extends over a portion of the
latch 28 in buccolabial relation to the latch 28 when the latter is
in its slot-closed position.
[0050] The cavity 42 and the flange 40 serve as a stop to limit
outward, buccolabial movement of the labial latch section 32 when
the latch 28 is closed. Advantageously, the flange 40 extends along
the mesial archwire slot end section 22 and the distal archwire
slot end section 24 in order to substantially preclude bending or
outward movement of the labial latch section 32 in areas next to
the mesial or distal side of the bracket body 14.
[0051] For example, if the bracket 10 is bonded to a maloccluded
tooth that is initially located a substantial distance in a lingual
direction from adjacent teeth, an archwire that is received in the
archwire slot 20 may, at least initially, place a substantial force
in a labial direction on the labial latch section 32. The force on
the labial latch section 32 in that instance might be greatest
adjacent the mesial and distal sides of the bracket body 14.
However, since the flange 40 extends across the gingival edge
portion of the labial latch section 32 from its distal side and to
its mesial side, the gingival edge portion of the latch 28 remains
captured in the cavity 42 and does not unduly deform or bend, even
in areas adjacent the mesial and distal sides of the bracket body
14. Such construction is an advantage in that the bracket 10 can be
subjected to somewhat greater forces by an archwire during initial
stages of treatment than would otherwise be possible.
[0052] If desired, the latch 28 may be removed from the body 14
during the course of treatment without detaching the bracket 10
from the underlying tooth. To remove the latch 28 from the body 14,
the practitioner may insert a dental explorer or other fine-tipped
dental instrument in the channel 36 and press the lingual latch
section 34 in a lingual direction a distance sufficient to enable
the protrusion 38 to clear the shoulder of the channel 36. The
latch 28 can then be removed from the body 14 by moving the latch
28 in an occlusal direction. If desired, the bracket 10 can be used
without the latch 28 in a manner similar to a conventional twin
tiewing or single tiewing bracket, and conventional O-ring
elastomeric. ligatures or wire ligatures can be used in conjunction
with the occlusal and gingival tiewings 16, 18 in order to ligate
an archwire in the archwire slot 20.
[0053] During the course of treatment, the intermediate section 26
provides a precision active archwire slot constructed in accordance
with edgewise orthodontic therapy techniques. Preferably, the
archwire selected for edgewise therapy fits snugly in the archwire
slot 20 in mating relation. The intermediate archwire slot section
26 allows the practitioner to control tipping, torque and
rotational movements of the bracket 10 and consequently control
corresponding movements of the underlying tooth as may be
desired.
[0054] The archwire relief areas provided by the mesial and distal
archwire slot end sections 22, 24 present inactive archwire
reaction regions so long as the archwire does not flex sufficiently
to engage the labial latch section 32 or the wall portions defining
the end sections 22, 24. Consequently, the archwire relief areas
provided by the mesial and distal archwire slot end sections 22, 24
effectively increase the interbracket width by preventing archwire
interference in order to increase the available active length of
the archwire between adjacent brackets.
[0055] The bracket body 14 may be made of any suitable material,
such as metal, plastic or ceramic. Suitable metallic materials
include series 300 stainless steels. The latch 28 is preferably
made of a resilient metal or metallic alloy such as series 300
stainless steel. Optionally, the latch 28 may be made of a shape
memory, superelastic alloy such as nitinol or beta titanium.
[0056] An orthodontic bracket 10a according to another embodiment
of the invention is illustrated in FIG. 5. The bracket 10a is
identical to the bracket 10 described above, except that the single
flange 40 in FIGS. 1-4 has been replaced by two discrete, spaced
apart flanges 39a, 41a in FIG. 5. The flange 39a is adjacent a
mesial archwire slot end section 22a and the flange 41a is adjacent
a distal archwire slot end section 24a.
[0057] A cavity 42a is presented beneath each of the flanges 39a,
41a. Each cavity 42a receives part of the gingival edge portion of
a labial latch section 32a. The flanges 39a, 41a and the cavities
42a function in a manner similar to the function of the flange 40
and the cavity 42 described above. Remaining aspects of the bracket
10a are identical to the bracket 10 as set out above.
[0058] An orthodontic bracket 10b according to another embodiment
of the invention is illustrated in FIGS. 6-8. The bracket 10b
includes a body 14b and a base that is adapted to securely connect
the body 14b to a tooth. The base is not shown in the drawings but
is preferably identical or similar to the base 12 described
above.
[0059] The bracket 10b includes a pair of occlusal tiewings 16b and
a pair of gingival tiewings 18b. The bracket 10b also includes an
archwire slot 20b having a mesial end section 22b, a distal end
section 24b and an intermediate section 26b located between the
mesial and distal end sections 22b, 24b. The archwire slot 20b
(including the sections 22b, 24b, 26b) is preferably identical to
the archwire slot 20 as described above.
[0060] The bracket 10b also includes a latch 28b that, in this
embodiment, comprises a section of wire that has been formed or
bent to present a loop. The latch 28b includes an occlusal section
29b that extends along the occlusal tiewings 16b and a gingival
section 31b that extends along the gingival tiewings 18b. The
occlusal section 29b and the gingival section 31b preferably extend
in parallel relationship to each other.
[0061] The latch 28b also includes a mesial section 33b and a
distal section 35b, both of which are curved outwardly in a
buccolabially direction. The outwardly curved mesial and distal
sections 33b, 35b have a shape sufficient to pass over a
buccolabial side of an archwire 37b (shown in FIG. 7 only) when the
archwire 37b is received in the archwire slot 20b. As shown in FIG.
8, the latch 28b is an open loop in that the gingival latch section
31b is not closed or continuous and presents two legs that are
spaced apart from each other.
[0062] The bracket 10b has a gingival flange 40b that extends over
a buccolabial side of a gingival cavity 42b. The bracket 10b also
has an occlusal flange 44b that extends over a buccolabial side of
an occlusal cavity 46b. Preferably, the flanges 40b, 44b and the
cavities 42b, 46b extend along the entire mesial-distal extent of
the archwire slot 20b including the sections 22b, 24b, 26b,
although other constructions are also possible.
[0063] As illustrated in FIG. 6, the mesial latch section 33b
preferably extends past the mesial side of the bracket body 14b in
a mesial direction, and the distal latch section 35b preferably
extends past the distal side of the bracket body 14b in a distal
direction. Such construction is an advantage, in that enhanced
control over rotational movements of the associated tooth is
provided. As an alternative, however, the mesial section 33b and/or
the distal section 35b could be located inwardly of the mesial and
distal sides of the bracket body 14b.
[0064] Optionally, one of the flanges 40b, 44b is staked so that
the latch 28b is captured in the underlying cavity. For example,
the occlusal flange 44b may be pressed in a lingual direction in
order to capture the occlusal section 29b of the latch 28b in the
occlusal cavity 46b. In that embodiment, the occlusal flange 44b is
preferably crimped or staked along the intermediate archwire
section 26b at the locations designated 48b in FIG. 6. The staking
is controlled so that the occlusal latch section 29b is
non-releasably retained in the occlusal cavity 46b, but is not
fixed relative to the body 14b in the occlusal cavity 46b. As a
result, the latch 28b is free to pivot about the longitudinal axis
of the occlusal latch section 29b when desired.
[0065] FIGS. 6 and 7 illustrate the latch 28b in a slot-closed
position wherein the archwire 37b is retained in the archwire slot
20b. The latch 28b is also movable to a slot-open position when
desired by releasing the gingival latch section 31b from the cavity
42b. To release the gingival latch section 31b from the cavity 42b,
the latch 28b is moved along the cavities 42b, 46b in a mesial or
distal direction until one of the two disconnected legs of the
gingival section 31b is clear of the cavity 42b. Next, that leg is
lifted in a buccolabial direction until it is past the labial face
of the bracket body 14b in a labial direction and the latch 28b is
then moved in an opposite (i.e., in a mesial or distal) direction
while the lifted leg of the gingival section 31b slides across the
labial face of the bracket body 14b. The latch 28b continues to be
moved in that direction until the remaining leg of the gingival
section 31b clears the cavity 42b, whereupon that leg is also
lifted labially of the labial face of the bracket body 14b. At that
time, the gingival latch section 31b is free of the gingival cavity
42b and the latch 28b pivots in the cavity 46b about the
longitudinal axis of the occlusal latch section 29b to open the
slot. The latch 28b may be moved to a slot-closed position when
desired by reversing the sequence of those steps.
[0066] Preferably, the latch 28b is slidable along the cavities
42b, 46b in a mesial or distal direction to any one of a number of
self-retained positions in use as chosen by the practitioner. Such
sliding movement enables the latch 28b to be moved to an off-center
position and vary the moment arm presented by the latch 28b. As a
result, a choice of enhanced rotational control over movement of
the underlying tooth is provided.
[0067] The latch 28b is preferably made from a shaped section of
heat treated wire. Preferably, the wire may be made of a shape
memory alloy such as nitinol or beta titanium. An example of a
suitable wire diameter is 0.008 in. (0.4 mm).
[0068] The embodiment of the invention illustrated in FIGS. 6-8 is
an advantage in that contact of the latch 28b with the archwire is
minimal, resulting in a relatively low coefficient of friction
between the bracket 10b and the archwire 37b. It is theorized that
such a low coefficient of friction may facilitate sliding movement
of the bracket 10b along the archwire 37b and as a consequence
reduce the overall time needed to complete the orthodontic
treatment program.
[0069] FIG. 9 is an illustration of an orthodontic bracket 10c
according to another embodiment of the invention Except as
described below, the bracket 10c is essentially the same as the
orthodontic bracket 10b discussed above and illustrated in FIGS.
6-8.
[0070] The bracket 10c includes a bracket body 14c having a notch
50c located between gingival tiewings 18c and adjacent a
buccolabial face of the bracket body 14c. The notch 50c enables the
practitioner to insert a fine-tipped hand instrument such as a
dental explorer or probe on a gingival side of a wire latch 28c.
The hand instrument is used to urge a gingival latch section 31c of
the latch 28c in an occlusal direction in order to clear a gingival
cavity 42c. Once the gingival latch section 31c is free of the
gingival cavity 42c, the latch 28c may be pivoted about the
longitudinal axis of an occlusal latch section 29c in order to move
the latch 28c to a slot-open position.
[0071] To move the latch 28c to a slot-closed position, the latch
28c is pivoted in an opposite direction and the hand instrument is
then used to deflect the gingival latch section 31c in an occlusal
direction in order to enable the latch 28c to pivot to a fully
closed position. Once the latch 28c is in a slot-closed position,
the gingival latch section 31c is released and the inherent bias of
the gingival latch section 31c causes the latter to spring back
into the gingival cavity 42c in order to thereafter retain the
latch 28c in the slot-closed position. Optionally, the
practitioner's fingers may be used instead of a hand instrument in
order to close the latch 28c and snap the gingival latch section
31c into the gingival cavity 42c.
[0072] In the embodiment shown in FIG. 9, the gingival latch
section 31c is optionally closed as shown in the drawing so that a
continuous loop is presented. Ends of the loop could be closed by
any one of a number of suitable techniques, such as by a brazing or
a welding operation. As an alternative, however, the gingival latch
section 31c could be discontinuous and present two spaced-apart
legs similar to the embodiment shown in FIG. 8.
[0073] A self-ligating orthodontic bracket 10d constructed in
accordance with another embodiment of the invention is illustrated
in FIG. 10. The bracket 10d is essentially the same as the bracket
10b described above, except for the aspects set out in the
following paragraphs.
[0074] The bracket 10d includes a latch 28d having an occlusal
section 29d and a gingival section 31d. The gingival section 31d
has two legs, each of which are bent in a curve to present a small
hook or eyelet. The eyelets present a convenient opening for
insertion of a fine-tipped hand instrument such as a dental
explorer or probe.
[0075] The latch 28d is movable to a slot-open position in a manner
similar to movement of the latch 28c described in connection with
the bracket 10c shown in FIG. 9. However, a notch (such as notch
50c) need not be provided. Instead, the hand instrument is placed
within the opening of the eyelets, which then function as a
convenient handle for lifting each leg of the gingival latch
section 31d from the gingival cavity 42d. Once each leg has been
released from the gingival cavity 42d, the latch 28d is pivoted
about the longitudinal axis of the occlusal latch section 29d in
order to move the latch 28d to a slot-open position.
[0076] The latch 28d may be closed when desired by pivoting the
latch 28d in an opposite direction and guiding the legs of the
gingival latch section 31d into the gingival cavity 42d.
Advantageously, the curved eyelets present a convenient, enlarged
location for contact with the practitioner's finger so that the
finger may be used to guide the legs of the gingival latch section
31d into the gingival cavity 42d. As an alternative, however, the
hand instrument as described earlier can also be used in order to
move the gingival latch section 13d into the gingival cavity
42d.
[0077] Many other variations of the invention are also possible.
For example, the latch of FIGS. 6-10 could comprise a bail having a
configuration other than the configuration shown in the drawings.
Moreover, the latch in any of the embodiments could be a sliding
plate or a pivotal cover having mesial and distal sections that
extends over mesial and distal archwire relief areas and are
adjacent one or more flanges to prevent undue or unintended outward
movement in a buccolabial direction. As a consequence, the
invention should not be deemed limited to the specific, presently
preferred embodiments that are set out above in detail, but instead
only by a fair scope of the claims that follow along with their
equivalents.
* * * * *