WO2012152279A1

WO2012152279A1 - Orthodontic arch wires

Info

Publication number: WO2012152279A1
Application number: PCT/DK2012/050145
Authority: WO
Inventors: Jan HANQUIST HANSEN
Original assignee: Hanquist Hansen Jan
Priority date: 2011-05-09
Filing date: 2012-05-01
Publication date: 2012-11-15
Also published as: DK177318B1; DK201100357A

Abstract

An improved, removable and adjustable arch wire (1) is presented, in particular a transpalatal arch (TPA) wire (1), capable of accurately transmitting corectional forces to a pair of brackets mounted on opposing molars. The transpalatal arch wire (1) comprises a heavy orthodontic wire, which can be attached to molar tubes. The wire has a loop (4) immediately adjacent to means for fixing (2) the transpaltal arch wire (1) in the molar tubes. The presence of these loops (4) facilitates placement, removal and adjustment of the appliance. The loops also facilitates a distal movement of the molars. Furthermore these loops (4) reduce the force/deflection value of the appliance, which reduces the risk of root resorption. Additionally the arch wire (1) can be used as a lower lingual arch wire (LLA). On the TPA and LLA, mounting brackets (5) with rails fitting the loops (4) can be mounted. The mounting bracket (5) can be used for multiple puposes.

Description

ORTHODONTIC ARCH WIRES

FIELD OF THE INVENTION

The present invention relates to the field of orthodontic arch wires, and more particularly to an improved, removable and adjustable arch wire, especially an arch wire, capable of accurately transmitting correctional forces to a pair of brackets mounted on opposing teeths, such as molars.

BACKGROUND OF THE INVENTION

The practice of orthodontics is concerned not merely with the aesthetic alignment and appearance of teeth, but primarily addresses the proper positioning of teeth in relation to the bony structure of the face. For an individual facial structure, one can construct the optimum formation of the maxillary and mandibular arches, and the degree of an individual's orthodontic malformation can be related to the departure from those optima. In general, orthodontic practice seeks to realign teeth to form arches closely resembling the optimum shapes.

A palatal bar or arch is a known orthodontic appliance which is used during treatment to reposition misaligned molars by application of rotating, tipping or torquing, intrusional forces. An equally important application is in stabilizing and maintaining molar teeth in an orthodontically correct position while the molars are used as force-reaction anchors during application of corrective forces for repositioning of other teeth (incisors, cuspids and bicuspids) in the patient's mouth.

The palatal bar is used in the upper or maxillary dental arch, and is positioned within the arch to be mounted on and extend between the left and right upper molars. The specific teeth are typically the first permanent molars which erupt years before the second permanent molars, but the palatal bar can be used on any reasonably erupted pair of molars. The bar has an upwardly arched central or bridging portion which generally follows the curvature of the hard palate to avoid tongue interference. The central bridging portion is connected between palatal-bar terminal ends which are engaged in brackets (typically welded to tooth-encircling metal bands) mounted on the lingual or tongue-facing surface of the molars.

The application and general function of palatal bars is known, and is described in greater detail in e.g. U.S. Pat. Nos. 3,792,529 and 4,582,725.

An important and growing orthodontic method is so-called lingual treatment where orthodontic brackets and associated arch wires are mounted on the inner or lingual surfaces of the teeth. This technique is especially appealing to teenage or adult patients, as the brackets and wires are largely concealed by the teeth and are not plainly visible during smiling. The palatal bar is inherently a lingual device and is a useful component in carrying out a lingual treatment program. The bar, however, is also useful when applied in a treatment program using conventional brackets and arch wires on the outer or buccolabial tooth faces.

The prior arches are associated with some problems.

First, the molar brackets to which the palatal-bar ends are secured should also receive a lingual arch wire which spans the upper dental arch and applies corrective forces to teeth anterior of the molars. It is necessary to remove and adjust (or replace) the arch wire as treatment progresses, and priorart brackets typically require painstakingi??) and time- consuming removal and replacement of the palatal bar to gain access to the arch wire.

Second, it is a problem with prior art arches that the rotation point or fulcrum cannot be sufficiently distalized. This gives rise to unacceptable control of tooth movement, when distal rotation combined with expansion is required.

Third, as prior art TPA are relatively rigid appliances. There is a risk for large force being generated, which might lead to root resorption.

SUMMARY OF THE INVENTION

The present invention overcomes many of the problems associated with prior art arches. In particular, the present invention provides a TPA having a load-deflection curve that is less stiff than a conventional TPA of the same size. This reduces the force levels, which the TPA generates, and it increases its elastic range. Moreover, the TPA of the present invention allows for easier mounting and dismounting than a conventional TPA.

In accordance with the invention, an improved orthodontic arch bar type appliance is provided, in particular a TPA for application to the patient's dental upper arch is provided. The TPA comprises a length of heavy orthodontic wire adapted for application across the upper arch palate and between the first permanent molars of the upper arch. Compared to the conventional TPA the arch does not start straight upon exiting the molar tube, but it is first bent twice (backwards and upwards) with essentially 90-degree angles or similar to a "U". Accordingly, the improved arch wire defines a pair of U-like bends adjacent the end portion of the arch wire and has its loop leg portions coplanar related, with the wire body portions at their respective other ends being doubled over and disposed normally of the respective body portions in substantial coplanar.

Accordingly in a first aspect of the present invention there is provided a transpalatal arch (TPA) wire comprising

• a heavy orthodontic wire having at each terminal end means for fixing the arch wire in bracket openings of the teeths to which the arch wire is to be attached;

• said wire having a loop immediately adjacent to said means for fixing the arch wire in bracket openings.

Preferably, the loop has a U-shaped, V-shaped, or IJ-shaped, the latter obtained by bending the wire three times in 90 degrees angles, while the last leg of the loop is part of the means for fixing the arch wire in bracket openings. The means for fixing the arch wire in bracket openings is preferably configured by doubling over the ends of the wire.

In a normal embodiment of the present invention the width of the loop is between 2 and 10 mm, preferably between 3 and 8 mm.

Due to the presence of the loop at the immediate proximity to the means for fixing the arch wire in bracket openings it is possible to stably mount an L-shaped mounting bracket (MB) with a rail fitting the loop area of the transpalatal arch. Such an L-shaped MB is also part of the present invention. The MB slits may be provided in the rail to accommodate ligature wires for fixing the mounting bracket to the transpalatal arch wire. In a second aspect of the present invention there is provided a complete transpalatal arch and bracket system, comprising:

• a transpalatal arch of the present invention having an upwardly arched centre section; and

• an orthodontic bracket, the bracket defining an upwardly extending socket with a generally occlusogingival axis when the bracket is mounted on a maxillary tooth, the bracket further defining a slot extending from the socket to receive the transpalatal arch.

In a third aspect of the present invention there is provided lower lingual arch (LLA) wire comprising

As with the TPA, the loop of the LLA has a U-shaped, V-shaped, or IJ-shaped, the latter obtained by bending the wire three times in 90 degrees angles, while the last leg of the loop is part of the means for fixing the arch wire in bracket openings. The means for fixing the arch wire in bracket openings is preferably configured by doubling over the ends of the wire.

The LLA follows the lingual surface of the mandibular/ teeth.

Due to the presence of the loop at the immediate proximity to the means for fixing the arch wire in bracket openings it is possible to stably mount an L-shaped mounting bracket (MB) with a rail fitting the loop area of the LLA arch. Such an L-shaped MB is also part of the present invention. The MB slits may be provided in the rail to accommodate ligature wires for fixing the mounting bracket to the LLA arch wire.

In a second aspect of the present invention there is provided a complete LLA arch and bracket system, comprising: • a LLA arch of the present invention having an forwardly arched centre section; and

• an orthodontic bracket, the bracket defining an upwardly extending socket with a generally occlusogingival axis when the bracket is mounted on a mandibulary tooth, the bracket further defining a slot extending from the socket to receive the LLA arch.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows side, frontal and top views of the TPA of the present invention with anterior (a) and posterior (p) directions indicated.

Figure 2 is a schematic top view of the distalization of the fulcrum of the TPA of the present invention (top) compared to a conventional TPA (bottom).

Figures 3A-3D show how L-shaped mounting bracket may be placed on the backward and upward segments of the TPA of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the invention, the arch bar of the present invention comprises an arch wire, bent in the form of figures 1 and 2 which is of one piece construction, and is in the form of a length of a suitable filamentous, resiliently flexible material, such as or comparable to stainless steel wire, which in the preferred form is a 0.08" or 0.09" round stainless steel or beta-Ti wire; however, it is to be understood that other materials and diameter sizes could be utilized for the purposes of this invention, and the invention is by no means to be limited or confined in this respect.

The indicated stainless steel wire has an inherent spring -like resiliency. The arch wire is formed from wire lengths of varying dimensions to fit each particular patient's dental arch, as determined by the measurement in millimeters made by the orthodontist between the upper arch first molars across the palate represented by the upper jaw.

For most purposes, a number of different wire lengths will provide adequate variety to accommodate the majority of patients. However, the lengths of the wire employed to form the respective arch bars is not a critical feature of the present invention, and the invention is by no means to be limited in this respect.

The preferred arch wire comprises the wire length being formed to define defines a pair of U-like bends or loops adjacent the end portions of the arch wire.

The arch wire body portions at the ends define terminal end portions that project laterally of the arch bar. As indicated in Figure 1 , the arch wire body portions extend generally normally of the open loop leg portions and the respective terminal end portions.

The terminal end portions are similar in configuration, the end portion comprising a doubled over segment of the wire involving substantially abutting lengths that give the terminal end portion the rectilinear elongate configuration that is effectively quardilateral in cross section when the arch bar is shaped.

The arch bar and specifically its respective body portions has a first spur or fitting formed in the body portion and a second spur or fitting formed in the body portion. The spur or fitting comprises a doubled over segment of the wire comprising wire sections.

Compared to the conventional TPA the arch does not start straight upon exiting the molar tube, but it is first bent twice (backwards and upwards) with 90-degree angles. By doing this, the following advantages over a conventional TPA are claimed:

• Due to there being more wire in the appliance, the load-deflection curve is more flat than for a conventional TPA of the same size. This reduces the force levels, which the TPA generates, and it increases its elastic range.

• Easier mounting and dismounting than a conventional TPA due to the "stops" of the vertical segments for the pliers.

• The rotation point or fulcrum is distalized compared to a conventional TPA. This provides better control of tooth movement, when distal rotation combined with expansions is required (Fig. 2).

• Easier adjustment following treatment, due to bonds in the wire. The TPA (Fig. 3 A) may include an L-shaped mounting bracket (MB, Fig. 3 B), which can be placed on the transpalatal arch (Fig. 3C). Slits in the rail of the MB allow for ligature wires to be placed in order to tie the MBs to the TPA. Due to the L-shape of the MB, it cannot slide along the wire of the TPA. The MB is suitable for use as a base for a multipurpose auxiliary wire, which can easily be welded on the horizontal section (Fig. 3D). As such an auxiliary wire is fixed to the MB and not directly to the TPA itself, it is easy to connect it to the TPA in the mouth of the patient and can again easily be removed in case it needs adjusting. The auxiliary wire can be used as a lever arm for intrusion, a lever arm for expansion/rotation, anchorage for spring attachment, connection to skeletal anchorage unit, and anchorage of multiple tooth movements.

Claims

1. A transpalatal arch wire (1) comprising:

• a heavy orthodontic wire having at each terminal end means for fixing (2) the arch wire in bracket openings of the teeths to which the arch wire (1) is to be attached;

• said wire having a loop (4) immediately adjacent to said means for fixing (2) the arch wire in bracket openings, wherein the width of the loop (4) is between 2 and 10 mm.

2. The transpalatal arch wire (1) of claim 1 , wherein the loop (4) has a form selected from U-shaped, V-shaped, and IJ-shaped.

3. The transpalatal arch wire (1) of claim 1 or 2, wherein the means for fixing (2) the arch wire in bracket openings is configured by doubling over the ends of the wire (1).

4. The transpalatal arch wire (1) of claim 1 , wherein the width of the loop (4) is between 3 and 8 mm.

5. An L-shaped mounting bracket (5) with a rail fitting the loop area of the transpalatal arch wire (1) of any one of the claims 1 to 4, said L-shaped mounting bracket preferably equipped with an auxiliary wire (7).

6. The L-shaped mounting bracket (5) of claim 5, wherein slits (6) are provided in the rail to accommodate ligature wires for fixing the mounting bracket to the transpalatal arch wire.

7. A transpalatal arch and bracket system, comprising:

• a transpalatal arch wire (1) of any one of the claims 1 to 6; and

• an orthodontic bracket.

8. A lower lingual arch wire comprising:

· a wire of spring steel having at each terminal end means for fixing the arch wire in bracket openings of the teeths to which the arch wire is to be attached;

• said wire having a loop immediately adjacent to said means for fixing the arch wire in bracket openings, wherein the width of the loop (4) is between 2 and 10 mm.

9. The lower lingual arch wire of claim , wherein the loop has a form selected from U- shaped, V-shaped, and IJ-shaped.

10. The lower lingual arch wire of claim 9 or 10, wherein the means for fixing the arch wire in bracket openings is configured by doubling over the ends of the wire in substantial coplanar relation to project from the wire in substantially the same direction as the loop.

1 1. The lower lingual wire of claim 8, wherein the width of the loop is between 3 and 8 mm.