The present invention relates to an orthodontic bracket, a bracket cover therefor, and a method of use of the bracket and cover. The bracket includes a liner for reducing friction with an archwire, and an archwire slot/channel in the bracket. The bracket cover is for covering the archwire slot in the bracket, wherein the bracket cover attaches and detaches from the bracket, and when attached can be rotated between a position for covering the archwire slot/channel, and a position for uncovering the archwire slot/channel.
In orthodontic treatment, tiny devices known as brackets are secured to the patient's teeth. An archwire is received in a slot of each bracket, and is typically held in place in the slots by ligating wires or by small elastic O-rings that extend around each bracket and the archwire. The teeth, to which the brackets are attached, are urged toward orthodontically correct positions by bends or twists placed in the archwire, and/or by elastomeric bands interconnecting the brackets. One or more archwires each serves as a track to guide sliding movement of the brackets so that the teeth to which they are attached may be shifted toward desired positions.
In the past, orthodontic brackets were often made of stainless steel, and archwires were made of stainless steel or alloys containing stainless steel, nickel and titanium. In general, frictional resistance to sliding movement of the metal brackets has not been a factor considered overly important by most orthodontists since the metal on metal sliding coefficient of friction is not high enough to typically be of concern. However, metal brackets are not aesthetic, and accordingly alternative materials have been used for such brackets such as plastics and ceramics of various types that are non-opaque or translucent.
Orthodontic brackets made of non-opaque plastic materials such as polycarbonate have been introduced by various manufacturers. Unfortunately, some plastic brackets exhibit undue deformation of the archwire slots as orthodontic forces are applied by the archwire to the brackets. Undue deformation of the archwire slots may prevent precise control of movement of the associated teeth, and in some instances may cause the brackets to fracture. Replacement of brackets during orthodontic treatment is time consuming and is often considered a nuisance by the orthodontist as well as by the patient.
It has been proposed in the past to provide metallic archwire slot liners for plastic brackets, in part as an attempt to avoid deformation of the plastic material. Examples of archwire slot liners are described in U.S. Pat. Nos. 3,964,165, 4,299,569, 4,302,532, 6,264,469 and 6,913,459, each of these references being incorporated fully herein by reference. Metallic archwire slot liners for plastic brackets provide sliding mechanics that may resemble the sliding mechanics experienced when an all-metal bracket is used.
Orthodontic brackets have also been made of translucent ceramic material such as polycrystalline aluminum oxide as is described in U.S. Pat. No. 4,954,080, also fully incorporated herein by reference. Ceramic is a relatively hard material in comparison to plastic and does not exhibit creep deformation in areas adjacent the archwire slot when subjected to forces of the archwire. However, application of an undue force by the archwire may fracture the bracket, possibly because of localized areas of relatively high stress concentrations.
As a further drawback to ceramic, the sliding mechanics of a metallic archwire in a slot of a ceramic bracket are not as satisfactory; i.e., the coefficient of friction is high and can cause binding of the archwire in the bracket. In particular, undue resistance of a ceramic bracket to sliding movement along an archwire may lengthen treatment time and thus provide an additional expense to both the orthodontist and the patient. This type of friction is referred to herein as “binding friction”. Some attempts have been made to address the problem of binding friction.
Additionally, difficulties exist in providing a bracket that serves both early and late stages of treatment, as well as treatment between these stages. These problems are due to the desired amount of tooth alignment force exerted by the archwire on the bracket slot at different periods of treatment, wherein such an alignment force may be generally traverse to the length of the archwire. Typically, a minimal amount of alignment force is desired for moving a bracket (and its tooth) in a desired direction relative to an archwire during the early phase of treatment. In contrast, typically a greater amount of alignment force is desired between a bracket and an archwire in the later phase(s) of treatment. Accordingly, it would be advantageous to provide an orthodontic bracket that provides an orthodontist the ability to vary the alignment force during the various phases of treatment. Moreover, there is still a need for a bracket and method of application that offers a range of alignment forces, while reducing the problems associated with binding friction.
To provide further background regarding the present disclosure, the following U.S. patents are also incorporated herein by reference in their entirety: U.S. Pat. Nos. 6,264,469 “Orthodontic Component, in Particular a Bracket with an Insert Element”; U.S. Pat. No. 5,441,408 “Orthodontic Device with a Ceramic Tooth Attachment”; U.S. Pat. No. D358,650 “Orthodontic Device Having a Ceramic Tooth Attachment”; U.S. Pat. No. D358,649 “Orthodontic Device Having a Ceramic Tooth Attachment”; U.S. Pat. No. 5,299,934 “Teeth Straightening Bracket”; U.S. Pat. No. 5,653,588 “Plastic Orthodontic Component Part and Method of Forming”; U.S. Pat. No. 5,254,002 “Orthodontic Plastic Bracket”; U.S. Pat. No. 5,362,232 “Orthodontic Appliance Mounting Base”; U.S. Pat. No. 5,470,228 “Edgewise Orthodontic Bracket”; U.S. Pat. No. 5,707,231 “Orthodontic Assembly with Reinforcement Structure”; U.S. Pat. No. 6,478,579 “Orthodontic Twin Bracket with Archwire Floor and Side Wall Relief”; and U.S. Pat. No. 6,846,178 “Orthodontic Bracket Base Apparatus and Method of Manufacture”.
An orthodontic bracket and method of use is disclosed herein that substantially reduces the archwire binding friction particularly prevalent in an initial stage(s) of orthodontic treatment wherein a patient's teeth may be exceptionally misaligned, and wherein substantial movement of the teeth is desired. The novel bracket disclosed herein preferably has a triple wing configuration (i.e., having mesial and distal tie wings extending gingivally and occlusally with a center tie wing between each pair mesial and distal tie wings) with a slot liner that reduces the binding friction between the bracket and archwire. The novel bracket the triple wing configuration provides for substantial variation in ligature orientations on the bracket for varying the tension that can be applied to hold an archwire in the bracket slot, wherein at least one such orientation provides appreciably less tension than is typically available with a twin wing or other bracket configurations. Accordingly, there is an appreciable reduction in binding friction. Moreover, since the novel bracket further includes a reduced friction liner in the bracket slot, wherein the liner (and possibly the slot as well) is flared at its mesial and distal ends (i.e., the archwire channel in the bracket expands at its ends) the, an even greater reduction in binding friction is obtained. In fact, the combination of the above recited features of the novel bracket provides for a reduction in binding friction reduction of at least approximately 5 times over brackets that do not have one or more of the above-recited bracket features. Accordingly, the novel bracket and method of use results in better tooth rotational control than heretofore has been available. Additionally, note that the expanded channel mesial and distal ends provide for enhanced ease of archwire insertion.
In one embodiment, the novel bracket may have a bracket body that is translucent or non-opaque with a low friction liner of gold liner.
In one embodiment, a midsection of the liner (of, e.g., at least ¼ to ⅘ of the liner length, and more preferably ½ to ⅘ of the liner length) provides straight effectively parallel sidewalls, thereby providing additional tooth rotational control.
In at least one embodiment the liner (and possibly the slot as well) may have a liner floor or base between the liner sidewalls that also expands the cross section of the channel as the cross section is taken closer to the mesial end of the channel, or closer to the distal end of the channel. In particular, the liner base or floor may flare out at its mesial and distal ends approximately 20 to 30% of the shortest height of the liner (i.e., channel) sidewalls. Moreover, such embodiments may additionally include a substantially planar or flat channel base or floor midsection for also enhancing tooth rotational control. In particular, a midsection of at least 25% of the channel's length may be planar or flat, and preferably between 50% and 80%.
Embodiments of the novel brackets disclosed herein may be central, lateral, cuspid, and bicuspid brackets as one of ordinary skill in the art will understand after reviewing the present disclosure.
Embodiments the novel bracket may include one or more of the following features in addition to the features recited hereinabove:
All tie wings extending gingival to occlusal from arch slot have equal length.
All tie wings having equal thickness mesially and distally.
There are no grooves between the tie wings on a same side (gingival or occlusal) for greater bracket strength.
Hooks of various types may be provided on embodiments of the novel bracket. In fact, there may be one, two, or three hooks on each such bracket.
Gingival hooks may be placed on the central tie wing, mesial tie wing, or distal tie wing.
A tooth attachment surface of the bracket body for adhering to a patient's tooth may have a mesh pattern, a character pattern, a dovetail pattern, and/or a regular or an irregular pattern of undercuts thereon.
The tooth attachment surface may be electrolytically etched; roughened, such as sandblasted or a method by which particles are attached to the tooth attachment surface to create a rough pattern either by a mechanical or chemical technique.
The novel bracket may include identification markings for assisting in identifying placement of the bracket and/or identifying a particular embodiment of the novel bracket. Such identification may include an ink marking, an etching, or one or more mold marks. Such markings may include numbers, letters, or symbols.
In another aspect of the present disclosure, a novel bracket cap or cover is provided, wherein the bracket cap frictionally hinges and pivots in the recess 1228 between: (a) the gingival (occlusal) tie wings of a bracket, and (b) the base of the bracket. In particular, the bracket cap includes a rod (denoted a “hinge” hereinbelow) that is pivotally secured across a mesial distal extent of the bracket in each (or at least one) recess between a wing of (a) above, and the bracket base. The configuration of hinge and the recesses is such that once the hinge engages the recesses, the bracket cap is attached to the bracket, it is has a bias toward closing a slot cover of the bracket cap over at least a portion of the opening of the slot or channel in which the archwire resides in the bracket. The bracket cap may be repeatedly pivoted between: (i) covering the opening of the slot or channel, and (ii) allowing full access to the slot or channel via the opening.
Various embodiments of the present disclosure are set forth in the attached figures and in the detailed description of the disclosure as provided herein and as embodied by the claims. It should be understood, however, that this Summary does not contain all of the aspects and embodiments of the present disclosure, is not meant to be limiting or restrictive in any manner, and that the disclosure as disclosed herein is and will be understood by those of ordinary skill in the art to encompass obvious improvements and modifications thereto.
Additional advantages of the present disclosure will become readily apparent from the following discussion, particularly when taken together with the accompanying drawings.
Various embodiments of a bracket 10 are disclosed in
Referring now to
In at least the bracket 10 embodiments shown in most of the
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Referring now to
As noted herein, a bracket 10 preferably comprises a triple tie wing configuration. Such a triple wing configuration offers a variety of advantages when combined with the liner 18 of the archwire slot 14. More particularly, the bracket 10 allows for at least five different ligating options or modes, wherein each of these options provides distinct advantages. In
Referring now to
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When combined with a liner 18, the triple tie wing bracket offers advantages over a twin tie wing bracket because more alignment force control is provided to the orthodontist, while minimizing binding friction between the bracket and the archwire 16. The curved end portions of the liner 18 reduce binding friction, while the triple tie wing configuration offers early to late stage treatment versatility. Such advantages result in improved patient comfort and reduced treatment time. In addition, a gold liner 18 improves the appearance of the bracket, thereby improving patient satisfaction and cooperation. Note that embodiments of brackets 10 can be provided for various archwire 16 sizes, including sizes (diameters or widths) of 0.004 inches to 0.075 inches. In particular, the narrowest widths of the channels 15 can be varied to snuggly accommodate a corresponding archwire 16 size such that such widths are, e.g., approximately 1% to 5% wider than the corresponding archwire.
The following study provides evidence of the advantageous combination of a triple wing bracket 10 having a liner 18 flared at its ends.
A total of 180 brackets were tested as follows:
A special metal jig 804 (
All the archwires 16 used in the frictional testing on the jig 804 were straight thermal NiTi 0.014 inch wires (Thermaloy. RMO, Denver Colo.). This particular archwire 16 was used because it is the most common archwire used for commencing orthodontic realignment. The ligatures used to tie these archwires to the brackets in the jig were elastic Synergy low friction ligatures (RMO, Denver Colo.), ligated conventionally in all the brackets except for triple wing brackets 10 and 716 (
A friction testing machine was designed and made by the Istituto per i Processi Chimico Fisici (IPCF) of the Consiglio Nazionale delle Ricerche (CNR) in Messina (Italy), especially for the friction testing of the brackets. The testing machine included a static carriage, which supports the test jig 804, wherein the jig is able to slide along two vertical parallel rods with four smooth linear ball bearings. The static carriage which holds the test jig is fixed to a vertical rod which acts on a force sensor. The output from the force sensor was read through an interface and fed into a computer. The archwire 16 (as in
Once the frictional data was obtained for each type of bracket in
The results of the frictional forces exerted by the different bracket types are shown in
Accordingly, a bracket 10 having the combination of a triple wing configuration, a liner 18 (of appropriate Knoop hardness, e.g., in the range of 50-1000 kg/mm2, and more preferably in the range of 100-500 kg/mm2), and wherein the liner 18 (as well as possibly the slot 14) are flared at its mesial and distal ends in the range of approximately 10% to 100% wider (more preferably 70% to 80% wider) as described hereinabove show a substantial reduction in the coefficient of friction over other types of brackets, such as tripe wing brackets without a liner 18, and brackets that have liners but are not flared at their mesial and distal ends. Moreover, such brackets 10 are particularly useful in the initial stage of orthodontic treatments for teeth realignment since an orthodontist may need to induce substantial three dimensional curves into an archwire 16 in order to attach the archwire and brackets together appropriately for commencing initial movement of a patient's teeth. For example,
U.S. Pat. No. 3,504,438 (fully incorporated herein by reference) proposes an orthodontic bracket made of a stainless steel or chrome alloy and coated with a polymeric material such as polytetrafluoroethylene to provide a relatively low coefficient of friction for sliding movement of the bracket. U.S. Pat. No. 5,203,804 (which is assigned to the assignee of the present invention) describes the use of a hard carbon coating such as a diamond-like coating on a metallic orthodontic archwire or on a metallic or ceramic orthodontic bracket.
Brackets, such as embodiments of bracket 10, may be provided with a cover or cap for assisting in securing an archwire 16 in the bracket slot (e.g., the channel 15 hereinabove).
When the bracket cap 1204 is provided on a bracket (e.g., bracket 10), as shown in
The hinge 1208 may be cylindrical; alternatively (and more preferably) the hinge may have an oval cross section 1234 as indicated by the hinge end view shown in
When it is desired to remove the slot cap 1216 from the opening 1236, i.e., pivot the cross members 1212 according to the direction arrow 1256, the friction and/or biasing force from the sidewalls 1240 and 1244 pressing on the hinge 1208 must be overcome to perform the pivot. Due to the sidewall 1244 being concave adjacent the closed end 1260 of the recess 1228, the sidewall friction and/or biasing force on the hinge 1208 does not substantially increase when pivoting of the cross members 1212 in the direction of arrow 1256. Moreover, since the biasing tension does not substantially increase there is substantially reduced likelihood of the hinge 1208 or the sidewalls 1240 and/or 1244 permanently deforming, cracking or breaking during such pivoting.
Accordingly, from the above description it is evident that the resilient nature of the sidewalls 1240 and 1244 act as a spring mechanism for maintaining a tension on the hinge 1208 in a manner that keeps the slot cap 1216 securely covering the opening 1236 during even extended periods between visits to the orthodontist. However, the rotational leverage that can be applied by, e.g., an orthodontist via a cap holder 1220 or the placement/removal tab 1224 is effective for overcoming the friction and/or biasing force from the sidewalls 1240 and 1244 pressing on the hinge 1208.
As can seen in
Other shapes (e.g., cross sectional shapes) of the hinge are within the scope of the present disclosure. For example, the above advantages of the oval cross section may be provided by an egg shaped hinge cross section, or by providing a circular cross section wherein the diameter that would correspond to the
Instead of the one or more cap holders 1220 (or in addition to the cap holders), the placement/removal tab 1224 may used for positioning the bracket cap 1204 on its bracket, closing the slot cap 1216 over the opening 1236, and/or pivoting the slot cap away from the opening 1236. In particular, such a placement/removal tab 1224 may be grasped by orthodontic tweezers for performing such actions. Note that the placement/removal tab 1224 may provide an easier way to open and close the slot/channel opening 1236 since the tab 1224 can used to flip the bracket cap 1204 to the open position (where the slot cap does not cover the opening 1236), and/or flip the bracket cap 1204 to the closed position (where the slot cap covers the opening 1236). Moreover, such flipping may be performed without taking time to grasp the tab 1224 with orthodontic tweezers.
Embodiments of the bracket cap 1204 may used with the bracket 10 described hereinabove. However, embodiments of the bracket cap 1204 may also be used with brackets having twin tie wings on each of their gingival and occlusal sides. For such brackets, there may be a single cross member 1212 attached centrally along the length of the hinge 1208. Accordingly, when the bracket cap 1204 is in the closed position, the cross member 1212 extends across the gingival to occlusal recess extending between: the mesial pair of wings 20, and the distal pair of wings 20. However, the operation of the hinge 1208 when engaging the recesses 1228 between the bracket's base 1232 and each wing 20 of the gingival or occlusal pair is identical to the description provided hereinabove.
Even though the slot cap 1216 is typically intended to facilitate holding an archwire 16 in the archwire slot/channel 14 or 15, various embodiments of the slot cap 1216 may provided. For example, the mesial distal length of the slot cap 1216 may: (a) cover only a portion to the slot/channel (e.g., at least 10% of such length), (b) completely cover the slot/channel, or (c) extend past the mesial and/or distal edges of the bracket for an enhanced control of tooth movement. Depending on, e.g., (i) the extent to which the surface of the slot cap 1216 facing the slot/channel enters the opening 1236, and (ii) the texture and composition of this surface, various amounts of binding friction may be generated. In one preferred embodiment, this surface will not contact the archwire 16 in a manner that materially increases the binding friction.
In other embodiments, the cross section 1234 of the hinge 1208 may be polygonal shaped, and the concave shape of, e.g., the sidewall 1244 may have a mating polygonal shape so that the polygonal shaped portion of the cross section can mate at discrete positions between (and including): (a) the slot cap 1216 engaging and covering the opening 1236, and (b) the slot cap not occluding any portion of the opening 1236.
The bracket cap 1204 may be provided as a replacement for ligating bands in certain instances such as in an initial orthodontic treatment. In other instances, a ligating band 54 may be placed over a bracket cap 1204, thus further securing the cap to the bracket. That is, a bracket cap 1204 is first secured to a bracket, and then a ligating band 54 secured to the bracket/bracket cap combination. In this latter method of use, the bracket cap 1204 may be repeatedly attached and detached from a bracket (e.g., bracket 10). For example, in an initial orthodontic treatment, a ligating band may be placed on bracket 10 as shown in
The present disclosure, in various embodiments, includes components, methods, processes, systems and/or apparatus substantially as depicted and described herein, including various embodiments, subcombinations, and subsets thereof. Those of ordinary skill in the art will understand how to make and use the present disclosure after understanding the present disclosure. The present disclosure, in various embodiments, includes providing devices and processes in the absence of items not depicted and/or described herein or in various embodiments hereof, including in the absence of such items as may have been used in previous devices or processes, e.g., for improving performance, achieving ease and\or reducing cost of implementation.
It is to be noted that the term “a” or “an” entity refers to one or more of that entity. As such, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein. It is also to be noted that the terms “comprising”, “including”, and “having” can be used interchangeably.
The foregoing discussion of the disclosure has been presented for purposes of illustration and description. The foregoing is not intended to limit the invention to the form or forms disclosed herein. In the foregoing Detailed Description for example, various features of the invention are grouped together in one or more embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the invention.
Moreover, though the description of the invention has included description of one or more embodiments and certain variations and modifications, other variations and modifications are within the scope of the invention, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative embodiments to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.
The present application claims the benefit of U.S. Provisional Patent Application No. 60/788,267 filed on Mar. 31, 2006, and entitled “ORTHODONTIC BRACKET WITH LINED ARCHWIRE SLOT”, the entire content of which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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60788267 | Mar 2006 | US |