AU5016399A - An archwire - Google Patents

Description

P/00/0oII Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT

S.

*too 00 Invention Title: AN ARCH WIRE Applicant: GOLDSCIIMIED PTY LTD the best method of performing it known to me: 1 C:\WINWORDWqARLO\D)AVID\53743.DQC AN ARCHWIRE The present application relates to an archwire suitable for use in orthodontic appliances. In particular, the application relates to an archwire which has a general cross section with both a square or rectangular section and a rounded section.

This invention is particularly applicable to the field of orthodontics that involves appliances and techniques to straighten or in some manner move the teeth within the mouth. As an integral part of such appliances, archwires are used. Forces applied upon the archwire during treatment generally apply some force, such as torque, rotation or angulation upon a tooth causing movement.

15 Generally, archwires that are used in orthodontic appliances have either a ribbon, round or rectangular cross section. The selection of a particular archwire is largely dependent upon the type of treatment required for the tooth.

Archwires are used in most known orthodontic appliances. For example, in the Edgewise technique, Edgewise brackets have a support into which either a 20 ribbon, round or rectangular archwire fits. The support is generally rectangular in shape, and the archwire is held in position by a ligature, such as an elastomeric latex or tie.

In the Begg technique, the Begg bracket incorporates a pin to hold the archwire in position rather than ligatures.

The orthodontic appliance described in Australian application 72071/96, the entire disclosure of which is incorporated herein by reference relates to an orthodontic appliance that includes a bracket having a securing member with a V-shaped terminal aspect, and a pin having an appendage that includes a recess, wherein a slot is formed between the V-shaped terminal aspect of the securing member and the recess. The pin is positioned within a channel in the MC C:\WINWORD\MARLO\ODELETE\DJT\SPECI\539743DOC 3 appliance and retains longitudinal movement. The longitudinal movement of the pin varies the size of the slot formed between the V-shaped terminal aspect and the recess in the appendage of the pin.

During treatment, an archwire is placed within the variable slot. The shape of the recess largely determines the force applied upon the archwire and the force applied upon the tooth. The V-shaped terminal aspect contacts the archwire at only one point which allows active movement of the bracket.

Generally, during the course of treatment using the various orthodontic appliances which are available, the archwire needs to be replaced during treatment to apply different forces upon the tooth.

0":0..The present application aims to provide an archwire that may be used in 15 a variety of orthodontic appliances, but particularly applicable to the appliance described in Australian application 72071/96, which reduces the number of 0 times an archwire may need replacing during treatment.

The present invention resides in an archwire for use in orthodontic S" 20 treatment, said archwire having a substantially uniform cross section transverse to its length, wherein the cross section includes a substantially square or rectangular section and a substantially rounded section.

Whereas the cross section of the archwire is substantially uniform transverse its length, preferably throughout the entire length of the archwire, it should be appreciated that the cross section may vary at particular points. For example, the ends of the archwire may be tapered to allow for correct fitting of the archwire into various orthodontic appliances.

The square or rectangular portion is designed to fit within the recess formed in the pin of the type described in Australian patent 72071/96. The recess in the pin forms part of the variable slot formed between the pin and the MC C:AWINWORD\MARLO\NODELETEfJT\SPECI\539743.DC securing member of that appliance. Accordingly, the shape of the square or rectangular portion may vary in accordance with the shape of the recess formed in the pin, but in most cases, this will be of a square or a rectangular configuration.

The square or rectangular configuration also allows the archwire to be used in other orthodontic appliances such as an Edgewise bracket, where the bracket includes a rectangular cross sectioned support or recess into which the archwire fits. The support in an edgewise bracket may be straight or angulated in order to provide torque to the tooth. The square or rectangular portion of the archwire may be manufactured to conform with the support in the edgewise Sa bracket to provide for a precise fit. The archwire of the present invention may also be used in other bracket types such as the Begg bracket or light wire S•bracket, which utilise a pin to secure the archwire rather than ligatures.

The rounded portion of the archwire is designed to provide a one point o*°a.

contact with the V-shaped terminal aspect of the securing member, or the pin or ligature as may be used in other appliances. The advantage of the rounded section is that it lessens the friction of the V-shaped terminal aspect, pin or 20 ligature on the archwire. The rounded cross section portion may vary in radius upon its desired use and to conform with particular appliances, but it is generally a semi circular section.

*I In the appliance described in Australian application 72071/96, the slot formed between the pin and the V-shaped terminal aspect is variable as the pin is able to move within a channel that is used to house the pin. The pin retains longitudinal movement and is able to move as a result of forces applied upon it by the positioning of the archwire. The particular shape of the archwire having a substantially square or rectangular section that is able to secure in the appendage of the pin and a rounded section that contacts the V-shaped terminal aspect of the securing member allows the archwire to remain active following movement of the pin.

MC C:\WINWORD\MARLO\NODELETEDJT\SPECJ 539743DOC The invention will now be described with reference to the accompanying drawings. The drawings are intended to be illustrative of the invention and the invention should not be considered to be limited thereto.

Figures la and 1b illustrate the cross-section of the archwire transverse to its length in accordance with the invention.

Figures 2a and 2b illustrate the archwire positioned within a pin suitable for use in accordance with the orthodontic appliance described in Australian application 72071/96.

Figure 3a illustrate the archwire in accordance with the invention as used in a Edgewise type bracket.

Figure 3b illustrates a rectangular archwire used in an Edgewise type bracket.

Figure 4 illustrates the archwire used in a Begg type bracket.

Figures la and lb illustrate an archwire having a cross section transverse to the length of the archwire that includes a square or rectangular section and a rounded section The total width of the archwire may vary, as illustrated by the difference between the configuration of the archwires illustrated in Figures la and 1b, but generally the square or rectangular section, and the rounded section are approximately the same thickness. The cross section is substantially uniform through the entire length of the archwire.

Figures 2a and 2b illustrate the use of the archwire in a pin that is suitable for use in the orthodontic appliance as described in Australian application 72071/96. The archwire is able to be secured in the recess of the pin (4a) and Pin (4a) and (4b) are illustrated as having different MC C\WINWORD\MARLO\NODELETE\DJT\SPECIl539743DOC 6 angled surfaces 5(a) and 5(b) respectively. The V-shaped terminal aspect of the bracket, is illustrated as an arrow and contacts the archwire at a single point The archwire is able to fit securely within the pin due to the square cross section component, yet friction is reduced between the V-shaped terminal aspect and the archwire due to the rounded cross section component. The Vshaped terminal aspect is able to retain contact with the archwire at differing angles of the archwire due to its rounded cross-section shape.

Figure 3a depicts the archwire as used in an Edgewise bracket The archwire fits within the support of the bracket and is held in position by an elastomeric latex (10) which is tied to wings Figure 3b illustrates a rectangular archwire (12) in accordance with the prior art.

o o As is apparent from Figure 3a, there is only one point of contact between 15 the archwire and the elastomeric latex. This has the advantage of lessening the friction between the latex and the archwire. The elastomeric latex contacts a rectangular archwire at many points as illustrated in Figure 3b, which also increase the rate at which the elastomeric latex and/or archwire may wear.

20 Figure 4 illustrates the archwire used in a Begg bracket The Begg bracket includes a pin (14) which again has only one point of contact upon the archwire This lessens the friction of the pin in the system.

The archwire of the present invention has the particular advantage that it is able to fit securely within a number of types of bracket such as the Begg or light wire bracket, and combination brackets, yet retain only one point of contact between the archwire and other aspects of the orthodontic appliance such as a pin, elastomeric latex or tie or the V-shaped terminal aspect of the orthodontic appliance described in Australian application 72071/96. There is also less need to replace the archwire during treatment as an operator is able to retain fine control of the movement of the tooth due to the single point contact with the MC C:\WINWORDWARLO\NODELETE\DJT\SPECI\539743.OC rounded portion, yet retain the movement associated with the rectangular portion of the archwire.

It should be understood that the above description is merely illustrative of the present invention and any modification without departing from the spirit or ambit of the invention is also to be included herein.

9 e 99 MC C:\WINWORDWARLO\NODELETEXDJT\SPECI\539743.DC

Claims (5)

1. An archwire for use in orthodontic treatment, said archwire having a substantially uniform cross section transverse to its length, wherein the cross section includes a substantially square or rectangular section and a substantially rounded section.

2. An archwire as claimed in claim 1, wherein the rounded section is a semi circular section.

3. An archwire, according to claim 1 or 2 wherein, the rounded section and I* the square or rectangular section are about of the same thickness.

4. An archwire according to any one of the preceding claims wherein the 15 square or rectangular section is shaped to fit in a correspondingly shaped recess within an orthodontic appliance. S S 4

5. An archwire in accordance with claim 1 substantially as hereinbefore described with reference to any one of the drawings. DATED: 28 September, 1998 PHILLIPS ORMONDE FITZPATRICK Attorneys for: GOLDSCHMIED PTY LTD MC C \WINWORD\MARLO\NODELETE\DJT\SPECI\39743.DOC