WO2011087985A1

WO2011087985A1 - Mixed dentition bracket systems and related methods

Info

Publication number: WO2011087985A1
Application number: PCT/US2011/020674
Authority: WO
Inventors: Paul E. Lewis
Original assignee: Ultradent Products, Inc.
Priority date: 2010-01-13
Filing date: 2011-01-10
Publication date: 2011-07-21

Abstract

A bracket system (100) including an orthodontic bracket (102) including a channel (108) formed within the bracket body (106), and two or more interchangeable inserts (104a, 104b, 104c) configured to mate within the channel (108) of the bracket body (106). Each insert (104a, 104b, 104c) includes a slot (114a, 114b, 114c) configured to receive an arch wire therein. The configurations of the slots (114a, 114b, 114c) are different so that during use, one insert provides movement of the tooth in a first direction (e.g., so as to rotate the root of a lateral incisor away from an adjacent erupting adult canine) while another insert provides movement in another direction. The system advantageously provides for a first movement of the tooth, followed by a second movement of the tooth (which may be opposite in direction), without requiring removal of the bracket (102). The bracket system (100) and method may be used with mixed dentition patients where rotation of a tooth root away from an adjacent unerupted adult tooth is desirable.

Description

MIXED DENTITION BRACKET SYSTEMS AND RELATED METHODS

BACKGROUND OF THE INVENTION

1. The Field of the Invention

The present invention relates to orthodontic brackets and their use with one or more arch wires in correcting spacing and orientation of the teeth.

2. The Relevant Technology

Orthodontics is a specialized field of dentistry that involves the application of mechanical forces to urge poorly positioned or crooked teeth into correct alignment and orientation. Orthodontic procedures can be used for cosmetic enhancement of teeth, as well as medically necessary movement of teeth to correct overjets and/or overbites. For example, orthodontic treatment can improve the patient's occlusion, or enhanced spatial matching of corresponding teeth.

The most common form of orthodontic treatment involves the use of orthodontic brackets and wires, which together are commonly referred to as "braces." Orthodontic brackets are small slotted bodies configured for direct attachment to the patient's teeth or, alternatively, for attachment to bands which are, in turn, cemented or otherwise secured around the teeth. Once the brackets are affixed to the patient's teeth, such as by means of glue or cement, a curved arch wire is inserted into the bracket slots.

The brackets and the arch wire cooperate to guide corrective movement of the teeth into proper alignment. Typical corrective movements provided by orthodontic treatment can include torque, rotation, angulation, leveling, and other movements needed to correct the spacing and alignment of misaligned teeth. Torque refers to movement (i.e., tipping) of the tooth in a labial or lingual direction. Rotation refers to rotational movement of the tooth about the tooth's longitudinal axis. Angulation refers to angular movement of the tooth about an axis passing essentially perpendicularly through the labial tooth surface in order to bring the occlusal edge of the tooth in line with the occlusal plane of the dental arch. Angulation therefore refers to angular movement of the tooth in a mesial-distal direction or distal-mesial direction relative to the occlusal edge of the tooth. Leveling relates to moving the occlusal edges of the teeth up or down and into proper alignment. Arch wires typically have either a square, rectangular, or round cross-section.

Square and rectangular cross-sections allow the arch wire to be used to apply a torquing force when engaged in an arch wire slot of an orthodontic bracket. Although a relatively thinner wire having a round cross-section does not allow application of torquing forces when engaged within an arch wire slot, it does provide a greater degree of flexibility and generally applies less force in use, which is more comfortable for the patient. The characteristic low force of round arch wires is due to their thinner cross-section. As such, wires having a round cross-section are often useful during the beginning stages of orthodontic treatment when the teeth are most mal-aligned. Use of a round arch wire allows for movement of teeth to correct mainly angulation, rotation and spacing of a patient's teeth with relatively light (and therefore more comfortable) forces.

Once these corrections have been achieved, a relatively thicker square or rectangular wire typically replaces the round arch wire so as to allow torquing of selected teeth to complete the treatment. In addition to being square or rectangular in cross-section, these arch wires are also thicker so as to limit any "play" of the arch wire within the slot of the bracket. Limiting this play increases the forces (as a result of increased arch wire thickness) applied by the wire and also increases engagement between the arch wire and the bracket slot. Such engagement is important in achieving the desired movement of the teeth. Because of these characteristics, in a typical orthodontic treatment a patient may typically require 6-9 different arch wires that are used progressively, beginning with relatively thin light force round arch wires and progressing towards stiffer, thicker square or rectangular arch wires.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to bracket systems and related methods capable of providing movement to a given tooth in a first direction followed by movement of the tooth in a different direction with a single bracket. According to one embodiment, the bracket system includes an orthodontic bracket having a bracket body including a generally mesially-distally extending channel formed within the body, and two or more interchangeable inserts configured to mate within the channel of the bracket body. Each insert includes a slot formed into the insert that is configured to receive an arch wire during use. The configuration of the slot of one insert is different from the configuration of the slot of at least one other insert so that during use, a second insert provides movement of the tooth that is different than that provided by a first insert.

When a selected insert is matingly received within the channel of the bracket body and an arch wire in placed in the slot, a desired movement of the tooth will occur. When the insert is removed and replaced with a different insert, because the slot configurations of the inserts are different, a different movement of the tooth will result. Such a bracket system advantageously allows a single bracket to be used to move the tooth in a first direction using a first insert, and then by replacing the first insert with a second insert, to move the tooth in a different direction, all with the same bracket.

Patients having some deciduous (i.e., baby) teeth and some adult teeth are referred to as having mixed dentition. According to one contemplated use, the bracket system may be used with mixed dentition patients where a malpositioned tooth and its root interferes with the eruption of an adjacent incoming permanent adult tooth. In such a case, it would be desirable to be able to move the interfering root and/or tooth out of the way of the incoming permanent adult tooth, and then to move the malpositioned tooth and/or root to its final desired position.

These and other advantages and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

To further clarify the above and other advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is appreciated that these drawings depict only illustrated embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: Figure 1 is a perspective view of an exemplary bracket system including a bracket and three separate interchangeable inserts, each configured to mate within the channel of the bracket;

Figure 2A is a perspective view of the exemplary bracket shown in Figure 1 including the first insert mated within the channel of the bracket;

Figure 2B is a perspective view of the exemplary bracket shown in Figure 1 including the second insert mated within the channel of the bracket;

Figure 2C is a perspective view of the exemplary bracket shown in Figure 1 including the third insert mated within the channel of the bracket;

Figure 3 A is a schematic view of a mixed dentition patient's teeth and roots in which the root of one misaligned tooth interferes with an unerupted and incoming adjacent adult tooth;

Figure 3B is a schematic view of the teeth of Figure 3 A in which brackets have been attached to the teeth, including attachment of the bracket of Figure 1 to the misaligned interfering tooth;

Figure 3C is a schematic view of the teeth and brackets of Figure 3B and in which the interfering root and tooth has begun to rotate out of the way of the adjacent unerupted and incoming adult tooth;

Figure 3D is a schematic view of the teeth and brackets of Figure 3C and in which the interfering root and tooth has is rotated fully out of the way of the adjacent unerupted and incoming adult tooth; and

Figure 3E is a schematic view of the teeth and brackets of Figure 3D in which the insert within the bracket on the originally misaligned interfering tooth has been replaced with the third insert of the system of Figure 1 so as to rotate the originally misaligned tooth back towards a final desired position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

I. Introduction

The present invention is directed to bracket systems and related methods that may be used to move a given tooth in first direction, followed by movement of the tooth in a different direction using a single bracket. For example, it is often the case that adjacent teeth interfere with one another, particularly as the first set of deciduous (baby) teeth exfoliate and are replaced with incoming permanent adult teeth. Patients having some deciduous teeth and some permanent adult teeth are referred to as having mixed dentition. For example, it is common for the root of a lateral incisor to interfere with an incoming adjacent permanent canine as the root of the misaligned lateral incisor obstructs the pathway that the incoming permanent adult canine would follow as it descends (or ascends in the case of a lower canine) prior to eruption through the gingiva. The bracket system may be used to rotate the root of the misaligned lateral incisor out of the way so as to allow the adjacent adult canine to emerge unimpeded. Once the incoming canine has cleared the adjacent lateral incisor root, the same bracket may be used (without requiring its detachment from the tooth) to cause the lateral incisor and its root to move or rotate back towards the opposite direction and into a final desired position.

An exemplary bracket system includes an orthodontic bracket having a bracket body including a generally mesially-distally extending channel formed within the body, and two or more interchangeable inserts configured to be matingly received within the channel of the bracket body. Each insert includes a slot that is configured to receive an arch wire. The configuration of the slot of one insert is different from the configuration of the slot of at least another insert so that, during use, a first insert provides movement of the tooth in a first direction (e.g., so as to rotate the root of a lateral incisor away from the adjacent incoming unerupted adult canine) that is different than that provided by a subsequently used insert (e.g., which may rotate the root of a lateral incisor back towards the adjacent erupted adult canine). The system and method advantageously provides for a first movement of the tooth, followed by a second movement of the tooth (which may be opposite in direction relative to the first movement), all without requiring removal of the bracket.

II. Exemplary Mixed Dentition Bracket Systems and Methods

Figure 1 illustrates an exemplary system 100 including an orthodontic bracket 102, first insert 104a, second insert 104b, and third insert 104c. Bracket 102 includes a bracket body 106 within which is formed a channel 108. Bracket 102 may further include a bonding pad 1 10 and tie wings 1 12a, 1 12b. Channel 108 may extend generally mesially-distally through body 106, between opposing pairs of tie wings 1 12a and 1 12b, respectively. Depending on the configuration of body 106 between the tie wings, channel 108 may be continuous, or may comprise two separate portions. For example, a first portion of channel 108 may be disposed between tie wings 1 12a, while a second portion is disposed between tie wings 1 12b. The two portions may be separate from one another or continuous with each other, depending on the labial height of the bracket body 106 between tie wings 1 12a and 1 12b. In the illustrated example, the bracket body 106 between tie wings 1 12a and 1 12b is thin enough that the channel 108 actually comprises two separate sections. Alternatively, a thicker body 106 may be provided between tie wings 1 12a and 1 12b so that channel 108 is a single continuous channel (not shown).

As seen in Figure 1, the channel 108 may advantageously be outwardly flared at its mesial and distal ends so as to have a greater width adjacent each end than towards the center of the channel 108. Such a channel configuration prevents a mated insert from sliding mesially or distally out of the bracket channel 108.

Each insert is configured to be received within and mate with channel 108. In this way, the inserts are interchangeable with one another. First insert 104a seen in Figure 1 and mated within channel 108 of bracket 102 in Figure 2 A includes an arch wire slot 1 14a. Each arch wire slot 1 14 may be formed into the lingual surface of the respective insert 104 so that the slot 1 14 is open on the lingual side. This configuration is advantageous as the insert 104 aids in holding the arch wire within the slot and bracket, particularly if a ligature (not shown) is also engaged under the tie wings and over the insert. Disposition of the slot in the lingual surface is preferred for this reason. Alternative configurations are also possible. For example, the slot may be formed into the labial side of the insert, and the arch wire may be held in place by one or more ligatures. Although the inserts are interchangeable, the system includes at least two inserts with slots that are configured differently from one another so that the inserts effect different tooth movements.

Arch wire slot 1 14a is configured to effect movement of a tooth in a particular direction (e.g., counterclockwise angular rotation) during use. In the illustrated example, slot 1 14a extends through insert 104a so as to be offset and non-parallel relative to longitudinal axis A. Slot 1 14a extends from end 1 16a to end 1 18a such that end 1 16a is disposed gingivally relative to longitudinal axis A. End 1 18a is disposed occlusally relative to longitudinal axis A such that slot 1 14a crosses over axis A. During use, this exemplary configuration will apply a rotational force to bracket 102 and apply an angulation force to an attached tooth, causing the tooth to rotate counter-clockwise.

Second insert 104b is similarly configured as described above with respect to first insert 104a. The principal difference is that the slot 114a of insert 104a is round in cross-section while the slot 114b of insert 114b is square or rectangular in cross- section. Second insert 104b will move the tooth in a similar direction relative to first insert 104a. The square or rectangular cross-sectioned arch wire slot 114b allows use of stiffer square or rectangular wires, so as to apply force in a similar direction as described relative to insert 104a, but with greater magnitude.

Third insert 104c is configured differently relative to first insert 104a, so as to apply a force in a different direction. Third insert 104c includes a slot 114c that is also non-parallel and offset relative to longitudinal axis A, but the offset is in an opposite direction relative to that provided by first slot 114a of first insert 104a. By way of example, end 116c is disposed occlusal to longitudinal axis A, while end 118c is gingival to longitudinal axis A. Because of the differences between the slot configurations, use of third insert 104c will apply a different force and result in a different movement of the tooth than first insert 104a. During use, the configuration of insert 104c will apply a rotational force to bracket 102, causing the tooth to also rotate, but in an opposite direction (i.e., clockwise) relative to first insert 104a.

For example, use of first and second inserts 104a and 104b will cause the tooth to which the bracket and insert is attached to rotate counter-clockwise. Replacement of the first or second insert with the third insert 104c will cause the tooth to then rotate clockwise, back the other way. While inserts providing angulation type movements are specifically illustrated, it will be understood that the slots of the inserts may alternatively be configured to provide leveling and/or rotational movements. Torquing movements may also be possible, depending on the thickness (i.e., the in-out dimension) of the inserts and/or brackets used.

The brackets and inserts may be formed of any suitable materials known in the art. For example, metals, polymeric materials, and/or ceramics may be used. Such materials may be manufactured into the desired brackets and/or inserts by any known method, for example by injection molding and/or by machining. Preferably, the brackets and inserts are formed of metal (e.g., stainless steel) and/or ceramic. In one embodiment, the insert used to provide a first movement may be formed by molding, as this is relatively inexpensive, while the insert used to provide the last movement may be formed by machining. Although machining may be more expensive, it provides for narrower dimensional tolerances and greater strength. Narrow dimensional tolerances are particularly advantageous for the last used insert as it is during this stage of treatment that the final positioning and orientation of the teeth is achieved. In systems including more than two inserts, the intermediate inserts may be molded or machined, as desired.

Figures 3A-3E illustrate an exemplary method of using the bracket system. Figure 3 A shows several teeth of an exemplary mixed dentition patient, including right central incisor 150, left central incisor 152, left lateral incisor 154, left canine 156, and left first bicuspid 158. Along with each tooth is shown a corresponding root, designated 150', 152', 154', and 156', respectively. No root is shown for tooth 158 for purposes of clarity of the drawing. Illustrated canine 156 is the patient's deciduous canine (i.e., a baby tooth), and will soon fall out as a result of incoming permanent adult canine 156a. As seen in Figure 3 A, the path of the incoming adult canine is impeded by the presence of the root 154' of misaligned adjacent lateral incisor 154. The inventive bracket system and method can be used to move root 154' out of the way of incoming adult canine 156a with the use of a set of brackets including a single specially configured bracket on tooth 154 and without requiring removal of the brackets during treatment.

Figure 3B shows brackets 202 installed on teeth 150, 152, and 158, with bracket 102 that comprises a part of the inventive bracket system installed on misaligned lateral incisor 154. Brackets 202 may comprise any known brackets used in the art. First insert 104a is shown mated within the channel of bracket 102. Arch wire 120 is engaged within slots of each bracket 202, as well as within slot 114a of first insert 104a. No ligatures are shown ligating the arch wire 120 within brackets 202 and 102 for purposes of clarity, although it will be understood that the arch wire may be ligated to each bracket with a suitable ligature or other ligating structure.

Any of various ligatures may be used (e.g., elastomeric o-ring ligatures or self- ligating brackets including a cover that holds the arch wire within the slot of the respective bracket). With respect to bracket 102, a ligature may be hooked under tie wings 1 12a and 1 12b, and then stretched cross-wise over the center of insert 104a so as to aid in holding insert 104a within channel 108 and arch wire 120 within slot 1 14a.

During the early stages of treatment, arch wire 120 may comprise a round, relatively thin cross-section arch wire. For example, it may have a diameter of about 0.016 inch. Such a thin, flexible, low force arch wire applies relatively light forces to the engaged brackets. The use of light forces early in treatment has been shown to actually result in overall reduced treatment times and increased comfort for the patient. Because of the configuration of slot 1 14a of first insert 104a, arch wire 120 will apply an angulation force through bracket 102 to attached lateral incisor 154, causing tooth 154 and root 154' to rotate in a counter-clockwise direction. Such movement will tend to move root 154' out of the path of adjacent incoming adult canine 156a.

Such movement is seen in Figure 3C, as tooth 154 and root 154' are rotated (or angulated) counter-clockwise. Depending on practitioner preference, first insert 104a may be replaced with second insert 104b once a portion of the desired rotational movement has been achieved. Slot 1 14b of insert 104b is configured similarly to slot 1 14a of insert 104a, but may be somewhat larger so as to accommodate a larger, stiffer archwire. As shown in Figure 2B, slot 1 14b may also include a square or rectangular cross-section. The practitioner may replace the thin arch wire 120 with a somewhat thicker arch wire (e.g., about 0.018 inch diameter round arch wire) to increase the forces being applied to tooth 154 and root 154'. A square or rectangular arch wire may also be used at this stage, or after use of a somewhat larger (e.g., 0.018 inch diameter) round arch wire. Preferably, any square or rectangular arch wire used at this state is still relatively thin (e.g., about 0.016 to about 0.020 inch thick).

Use of second insert 104b and arch wire 120 continues to effect a counterclockwise rotation of tooth 154 and root 154' as incoming adult canine 156a pushes down on the root 156' of the deciduous tooth 156, causing the root 156' to dissolve and be absorbed by the forming adult tooth 156a. As shown in Figure 3D, deciduous canine 156 will soon be lost by the patient, and adult canine 156a is clear of root 154'. Figure 3E shows adult canine 156a erupting through the gingiva 160 once deciduous canine 156 has been lost. In addition, second insert 104b has been replaced with third insert 104c, which includes an oppositely configured slot 114c, as described above. The configuration of slot 114c will apply a force to tooth 154 through bracket 102, causing the tooth 154 and root 154' to rotate clockwise to a final desired position.

Advantageously, there is no need to remove and reattach or replace bracket 102 during the treatment. This is advantageous as it provides a relatively simple procedure for moving one tooth of an adjacent pair of teeth in one direction, followed by movement of the tooth in a different, even opposite direction using the same bracket. All that is required is the removal and replacement of one insert with another.

The system and method advantageously provides for a first movement of a tooth, followed by a second movement of the tooth (which may be opposite in direction relative to the first movement), all without requiring removal of the bracket. Although described in conjunction with rotation of a misaligned lateral incisor so as to provide an unimpeded pathway for an adjacent incoming adult canine, it will be understood that the system and method may be used with other adjacent teeth where a first movement followed by a second different movement of one of the teeth is desired. Furthermore, while the rotational movement of the lateral incisor may be characterized as an angulation type movement, it will be understood that the slots of the insert may alternatively be configured to provide leveling and/or rotational movements. Furthermore, torquing movements may be possible, depending on the height (i.e., the in-out dimension) of the inserts and/or brackets used.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

What is claimed is:

Claims

1. An orthodontic bracket system comprising:

an orthodontic bracket having a bracket body including a generally mesially-distally extending channel formed therein;

a first insert configured to mate within the channel of the bracket body, the first insert including a first slot configured to receive an arch wire therein; and

a second insert that is interchangeable with the first insert so as to also selectively mate within the channel of the bracket base, the second insert including a second slot configured to receive an arch wire therein, the second slot being differently configured relative to the first slot so that use of the second insert causes movement of a tooth to which the bracket is attached that is different from a movement caused when the first insert is used within the bracket slot.

2. An orthodontic bracket system as recited in claim 1, further comprising a third insert that is interchangeable with the first and second inserts, the third insert including a third slot configured to receive an arch wire therein.

3. An orthodontic bracket system as recited in claim 1, wherein the first slot of the first insert is substantially round in cross-section, and wherein the second slot of the second insert is rectangular or square in cross-section.

4. An orthodontic bracket system as recited in claim 1, wherein the first slot of the first insert is non-parallel to a longitudinal axis of the channel and extends through the first insert from a mesial end disposed gingival to the longitudinal axis of the channel to a distal end disposed occlusal to the longitudinal axis of the channel.

5. An orthodontic bracket system as recited in claim 4, wherein the second slot of the second insert is non-parallel to a longitudinal axis of the channel and extends through the first insert from a mesial end disposed occlusal to the longitudinal axis of the channel to a distal end disposed gingival to the longitudinal axis of the channel.

6. An orthodontic bracket system as recited in claim 5, wherein tooth movement caused by use of the first insert is in a direction that is substantially opposite to tooth movement caused by use of the second insert.

7. An orthodontic bracket system as recited in claim 1, wherein both ends of the channel within the bracket body are outwardly flared so as to have a greater width at the mesial and distal ends of the channel as compared to a width at a central portion of the channel.

8. An orthodontic bracket system as recited in claim 1, wherein the slot of each insert is disposed in a lingual surface of the respective insert and the slot is open along a lingual side.

9. An orthodontic bracket system as recited in claim 1, wherein the first and second inserts are configured to provide at least one of angulation movement, leveling movement, rotation movement, or torque movement.

10. An orthodontic bracket system comprising:

a second insert that is interchangeable with the first insert so as to also selectively mate within the channel of the bracket base, the second insert including a second slot configured to receive an arch wire therein;

wherein the first slot is non-parallel to a longitudinal axis of the channel and extends through the first insert from a mesial end disposed gingival to the longitudinal axis of the channel to a distal end disposed occlusal to the longitudinal axis of the channel.

11. An orthodontic bracket system as recited in claim 10, further comprising a third insert that is interchangeable with the first and second inserts, the third insert including a third slot configured to receive an arch wire therein.

12. An orthodontic bracket system as recited in claim 10, wherein the first slot of the first insert is substantially round in cross-section, and wherein the second slot of the second insert is rectangular or square in cross-section.

13. An orthodontic bracket system as recited in claim 10, wherein tooth movement caused by use of the first insert is in a direction that is substantially opposite to tooth movement caused by use of the second insert.

14. An orthodontic bracket system as recited in claim 10, wherein both ends of the channel within the bracket body are outwardly flared so as to have a greater width at the mesial and distal ends of the channel as compared to a width at a central portion of the channel.

15. An orthodontic bracket system as recited in claim 10, wherein the slot of each insert is disposed in a lingual surface of the respective insert and the slot is open along a lingual side.

16. An orthodontic bracket system as recited in claim 10, wherein the inserts are configured to provide at least one of angulation movement, leveling movement, rotation movement, or torque movement.

17. A method of orthodontic treatment comprising:

providing an orthodontic bracket system as recited in claim 1 ;

attaching the orthodontic bracket of the system to a tooth of a patient; selecting an insert from a plurality of differently configured inserts included within the system;

placing an arch wire within the slot of the selected insert and placing the selected insert into the channel of the orthodontic bracket body so as to effect movement of the tooth in a first direction;

removing the insert from the channel of the orthodontic bracket body and replacing the insert with a different insert selected from the plurality of differently configured inserts included within the system so as to effect movement of the tooth in a second direction that is different from the first direction.

18. A method as recited in claim 17, wherein the second direction is substantially opposite relative to the first direction.

19. A method as recited in claim 17, further comprising removing the first insert and replacing said insert with a third insert.