WO2013139397A1

WO2013139397A1 - Archwire for orthodontics

Info

Publication number: WO2013139397A1
Application number: PCT/EP2012/055179
Authority: WO
Inventors: Christian DROST
Original assignee: Dr Christian Drost
Priority date: 2012-03-23
Filing date: 2012-03-23
Publication date: 2013-09-26

Abstract

The invention relates to an archwire (3) for orthodontics, wherein the archwire (3) is a single-piece archwire (3). This archwire (3) comprises a first set of sections (IS1, IS2, IS3,... ISn) arranged to be situated between brackets (1) attached to teeth (2) and a second set of sections (SS1, SS2, SS3,... SSn) arranged to be situated within said brackets (l). Said first and second set of sections (IS1; IS2; IS3,... ISn; SS1, SS2, SS3,... SSn) being arranged in alternating sequence. At least one section (IS1) of said first set of sections (IS1, IS2, IS3,... ISn) has a different cross-sectional area (30) with respect to other sections (IS2, IS3,... ISn) of said first set of sections (IS1, IS2, IS3,... ISn) or of said second set of sections (SS1, SS2, SS3,... SSn).

Description

Archwire for orthodontics

The present invention relates to an archwire for

orthodontics according claim 1, a method for manufacturing the same and an orthodontic brace.

Archwires are used in the field of orthodontics working like an "engine" giving the power to the brackets for straightening of teeth of the denture of an individual, i.e. straightening the individual archform. Known

straightening methods for applying archwires are e.g. edge- wise-technique or straight-wire-technique. Using the edge-wise-technique the information is in the segmented or multipart wire and the prescriptions in the brackets are all zero. Using the straight-wire-technique the information is in form of an individual prescription in the bracket and some more individual information can be given in addition into the segmented or multipart straight wire. The known segmented wire is put together by different segments, wherein the segments are connected to each other e.g. by soldering or by laser welding or by means of clips.

One object of the present invention is to provide an alternative archwire and an alternative method for

manufacturing the same. Another object of the invention is to provide an alternative orthodontic brace.

The features of the present invention are given in claim 1. Further embodiments according to the present invention are given in dependent claims. Furthermore, a method for manufacturing an archwire according to the present invention is given.

The archwire for orthodontics according to the present invention is a single-piece archwire comprising:

a first set of sections arranged to be situated between brackets attached to teeth and a second set of sections arranged to be situated within said brackets, wherein said first and said second set of sections are arranged in alternating sequence. Furthermore, at least one section of said first set of sections has a different cross-sectional area with respect to other sections of said first set of _· sections or said second set of sections. Thereby, an individualized archwire for an individual can be provided, which contains all the information necessary for correcting a misalignment of at least one tooth of the denture of the individual. Due to the fact, that the archwire is highly individualized (i.e. custom-made for an individual) unwanted teeth movement (so-called side-effects) can be prevented when the archwire is applied to the individual. Furthermore, no time-consuming additional manual adjustment of the archwire by bending is necessary anymore since the archwire is tailor-made and hence, correct fit is assured right from the start when applied. The archwire is filling the slots of the brackets already at the beginning of the process. Thus, "chair-time" of the individual at the orthodontist' s is reduced.

In one embodiment, at least one section of said first set of sections has a different shape with respect to other sections of said first set of sections. Thereby, an

individual tri-dimensional design of at least one or more sections of the first set of sections can be provided adapted to the needs of an individual having a specific misalignment of its teeth.

In a further embodiment, the cross-sectional area is substantially round, oval, square-like or rectangular.

Thereby, any individualized archwire can be provided exactly adapted to the needs for correcting a specific misalignment of the individual denture. Hence, the archwire e.g. can be in the same slot-dimension in the second set of sections (i.e. filling the slot) and can be smaller or in the same dimension in the interbracket section. Under the term interbracket section a specific section of the first set of sections is understood. Under the term slot section a specific section of the second set of sections is

understood. Furthermore, the archwire can easily be

replaced by an archwire with over corrections when the misaligned teeth of the individual have been straightened to some point but still a further correction is needed. In a further embodiment, the size of a cross section represents a cross-sectional area is up to about 0.0006 sq inches (0,4 mm²) . Dependent of the shape and the size of the dimension of the cross-sectional area needed, it is conceivable to select the diameter for a square-like shape of the cross section or, the diagonal for a round shape of the cross-sectional area, of at least one of: 0.008",

0.010", 0.012", 0.014", 0.016", 0.018", 0.020" (0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm),

indicated in inches as a commonly used size indication in the orthodontics field. For a rectangular shape of the cross-sectional area, it is conceivable to select the width and the length of the sides, or for an oval shape of the cross-sectional area, the longitudinal and the lateral diameter of at least one of: 0.014" x 0.025", 0.016" x 0.016", 0.017" x 0.022", 0.017" x 0.025", 0.019" x 0.022", 0.019" x 0.025", 0.021" x 0.025", 0.022" x 0.025"(0.35 mm x 0.6 mm, 0.4 mm x 0.4 mm, 0.4 mm x 0.55 mm, 0.4 mm x 0.6 mm, 0.5 mm x 0.55 mm, 0.5 mm x 0.6 mm, 0.5 mm x 0.6 mm, 0.55 mm x 0.6 mm) .

In a further embodiment, the shape of the archwire forms a labial archwire being substantially straight, tapered, squared or ovoid or wherein the shape of the archwire forms a lingual archwire being of a mushroom shape or straight.

Thereby, an archwire can be provided having a

tri-dimensional design according to the individual shape of the archform of an individual.

In a further embodiment, the archwire is out of metal and/or resilient material.

In a further embodiment, the metal is stainless steel and the resilient material is Nitinol Niti/NT; CuNiTi, TiMo alloy, head activated Nitinol. TiMo alloy is also referred to as TMA orthodontic metal.

Another aspect relates to a method for manufacturing an archwire according to the present invention, the method comprises a step a) of forming an archwire by treatment of a surface of a blank by at least one of the steps of:

- milling;

- applying a laser, ;

- applying Electrical Discharge Machining (EDM) ;

- form pressing; - metal injection molding (MIM) .

Thereby, a completely individualized archwire suitable to correct a misalignment of teeth of an individual can be provided.

In a variant, at least one of the steps is performed by a CAD-CAM-robot-apparatus , a laser apparatus, an electrical discharge machining apparatus, by a form pressing apparatus or a metal injection molding apparatus.

The blank can be of stainless steel (SS) , resilient

materials e.g. Nitinol Niti/NT, CuNiTi, Head activated

Nitinol (HANT) , or other resilient alloys like TiMo alloys. The design or form of the blank can be in every shape. But for the production it is useful to have already the shape like e.g. the average of tapered, squared, ovoid or

mushroom shapes and also upper and lower archwire-like form, but in a bigger dimension like a horse shoe. After all, the information about the position of the brackets is in a digital impression by having done an individual scanning process. The computer can calculate the slot- position by the given information about the prescriptions in the bracket. The computer can also calculate the virtual 3D model with or without brackets, like in the way of a virtual 3D set-up system via stereo-lithographie. The positions of the slots of the brackets are individualized and the archforms are individualized with a bending robot machine .

In a variant, the method comprises upstream step a) , the further steps of: al) scanning a current position of teeth of an individual by a 3D digital impression or via digital volume tomography or by cone beam computer tomography (CBCT) ;

a2) effecting a 3D set-up comprising a designated

position of the teeth of the individual.

A further embodiment provide an orthodontic brace with brackets and an archwire according to the above described embodiments, whereby the length of each section of the second set of sections is equal or greater than the length of the longitudinal slot of the respective bracket. The wire may thus slightly move along the slot and thereby letting the tooth adjusting its position during the

application of the brace.

A further embodiment provide an orthodontic brace where at least one bracket provides a central locking bar for fixing or ligating the respective section in the respective slot, by reducing its friction. The bracket concerned may thereby have a reduced size with respect to commonly used brackets. The present invention is further explained with the aid of exemplified embodiments, which are shown in figures. There is shown in:

fig. 1 schematically, a bracket with an archwire

inserted therein;

fig. 2 schematically, a front view of a part of a

denture; and

fig. 3 schematically, a top view of a denture. In figure 1, schematically, a bracket 1 designated to be mounted, e.g. bonded, on a tooth 2 (see figure 2) is depicted. An archwire 3 is inserted in a slot 4 of the bracket 1. By the term „slot" we understand a recess in a wing-like protrusion 5 of the bracket 1, wherein the size of the slot 4 is generally indicated in inch ("), e.g.

0.018" x 0.025" (0.45 mm x 0.6 mm), 0.022" x 0.028" (0.55 mm x 0.7 mm) called 18-system and 22-system. But also all other sizes are possible and the archwire 3 can be

manufactured individually. Generally, many types of

brackets are known: e.g. standard twin brackets 1 (shown in figure 1). The different systems differ to each other in e.g. having different prescriptions in their slots,

different slot shapes and different types of locking elements. The bracket 1, depicted in figure 1, is of the first type, i.e. standard twin bracket 1. The archwire 3 is conducted in known manner through the slots 4 of the bracket 1. The archwire 3 is defined by its diameter generally indicated in inch (") as a size indication to the orthodontist. The size of the archwire 3 can be e.g.

0.008", 0.010", 0.012", 0.014", 0.016", 0.018", 0.020", 0.016" x 0.016", 0.014" x 0.025", 0.017" x 0.022", 0.017" x 0.025", 0.019" x 0.022", 0.019" x 0.025", 0.022" x 0.025" (0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.4 mm x 0.4 mm, 0.35 mm x 0.6 mm, 0.4 mm x 0.55 mm, 0.4 mm x 0.6 mm, 0.5 mm x 0.55 mm, 0.5 mm x 0.6 mm, 0.55 mm x 0.6 mm) . The cross-sectional area 30 of the archwire 3 shown in figure 1 is substantially rounded. It is also conceivable that the cross-sectional area 30 can be substantially rectangular or oval or square-like. Furthermore, the bracket 1 has a base plate 6 which is mounted onto the tooth (see figure 2), e.g. by bonding.

In figure 2, schematically, a front view of a part of a denture 7 is shown having different types of teeth 2 like e.g. incisors and canines. The brackets 1 are arranged on the teeth 2. The archwire 3 is inserted into the slot 4 of the corresponding bracket 1. The archwire 3 comprises a first set of sections IS1, IS2, IS3, ... , ISn being situated between the brackets 1. A first section IS1 of the first set of sections IS1, IS2, IS3, ... , ISn is arranged between the neighboring wing-like protrusions 5 of two neighboring brackets 1. A second set of sections SSI, SS2, SS3,

SS4, ... , Sn is situated within the brackets 1. A first section SSI of the second set of sections SSI, SS2, SS3, SS4, ... , Sn is arranged between the two wing-like

protrusions 5 of the corresponding bracket 1. This section SSI has a length that either corresponds to the length of the slot 4 or is slightly longer than the length of the slot 4. The first set of sections IS1, IS2, IS3, ... , ISn and the second set of sections SSI, SS2, SS3, SS4, ... , Sn are arranged in alternating sequence. At least one section IS1 of the first set of sections IS1, IS2, IS3, ... , ISn has a different cross-sectional area 30 with respect to the other sections IS2, IS3, ... , ISn of the first set of sections IS1, IS2, IS3, ... , ISn or the second set of sections SSI, SS2, SS3, SS4 ... , Sn. This allows to select and to control the necessary correction forces in ascending order to be applied onto a misaligned tooth in adapting the elasticity of the archwire 3. The elasticity depends on the geometry of a cross-sectional area 30 of the sections IS1, 152, IS3, ... , ISn of the first set of sections ISl, IS2,

153, ... , ISn or of the second set of sections SSI, SS2, SS3, SS4, ... , SSn. The elasticity is directly proportional to the length of a particular section and the elasticity is inversely proportional to the cross-sectional area of the particular section. The shape of the second section IS2 of the first set of sections ISl, IS2, IS3, ... , ISn is bended as depicted in figure 2 as a stop. This section may as well be shaped as a hook, stop, ring, loop or providing

attachment elements. The shape of the first section ISl and of the third IS3 of the first set of sections ISl, IS2, IS3, ... ; ISn is straight as depicted in figure 2. The shape of a specific sections of the first set of sections ISl, IS2, IS3, ... , ISn can be formed individually.

In figure 3, schematically, a top view of the denture 7 is depicted. The brackets 1 are arranged on the teeth 2. As an example, an ectopic tooth 12 is in a current misaligned position of the denture 7. The misaligned current position can be altered with the aid of an archwire 3 comprising the individualized interbracket and slot sections necessary for correcting the position of the ectopic tooth 12. Thereby, the ectopic tooth 12 can be moved into a designated

position (moving direction indicated by an arrow F) . The tri-dimensional shape of the archwire 3 has an individual straight shape. Treated with lingual orthodontics, the lingual shape of the archwire 3 can be done also

individually .

Before mounting the individualized archwire 3 onto the denture 7, scanning of a current position of teeth 2 of an individual by a 3D digital impression, via digital volume tomography (DVT) or via cone beam computer tomography

(CBCT) is carried out. Subsequently, a 3D set-up is

effectuated comprising a designated position of the teeth 2 of the individual. The individualized archwire sequence 3 is manufactured comprising a step a) of forming the

archwire 3 by treatment of a surface of a blank by applying at least one of the steps of: milling; applying a laser, applying Electrical Discharge Machining (EDM) , form

pressing or metal injection molding (MIM) . Step a) can be carried out by a CAD-CAM-robot-apparatus, by a laser apparatus, by an electrical discharge machining apparatus by a form pressing apparatus or a metal injection molding apparatus. When applying the archwire 3 to an individual, firstly, the brackets 1 are positioned onto the teeth 2 e.g. by bonding. After this, the archwire 3 is inserted into the foreseen slots 4 of the brackets 1 and so the teeth can be guided into a determined position. The

archwire 3 can be out of metal or a resilient material, e.g. (inclusive Teflon) coated metal or of stainless steel SS, resilient materials e.g. Nitinol Niti/NT, CuNiTi, TiMo alloy, Head activated Nitinol (HANT) , or any other suitable resilient alloys. When the archwire 3 is mounted onto the brackets 1 the second set of sections of the selected archwire 3 fills out the slots 4 in individualized desired manner to reduce side-effects. The wire can be ligated to the bracket by a central locking bar in the bracket, thereby allowing the use of a bracket of smaller overall dimensions with respect to commonly used brackets. And in order to achieve the necessary forces in the first set of sections to correct the misaligned tooth 12, the diameter is individually selected or calculated by a computer program. In case, the current positions of two adjacent teeth 2 of the denture 7 are already in the designated positions, the cross-sectional area 30 of its interbracket section IS1 is selected such that its

dimension is equal to the dimension of the corresponding slots 4 of the respective adjacent brackets 1. This

provides less elasticity but more stiffness to the wire and further reduces side effects.

Generally spoken, any combination is conceivable, if not contradictory to the present invention. Thus, the archwire 3 is manufactured such that it is custom made for an individual having a specific misalignment of the teeth 2.

Claims

1. Archwire (3) for orthodontics, wherein the archwire (3) is a single-piece archwire (3) comprising:

a first set of sections (IS1, IS2, IS3, ... ISn) arranged to be situated between brackets (1) attached to teeth (2); a second set of sections (SSI, SS2, SS3, ... SSn) arranged to be situated within said brackets (1);

said first and said second set of sections (IS1; IS2;

IS3, ... ISn ; SSI, SS2, SS3, ... SSn) being arranged in alternating sequence;

characterized in that at least one section (IS1) of said first set of sections (IS1, IS2, IS3, ... ISn) has a

different cross-sectional area (30) with respect to other sections (IS2, IS3, ... ISn; SSI, SS2, SS3, ... ; SSn) of said first set of sections (IS1, IS2, IS3, ... ISn) or of said second set of sections (SSI, SS2, SS3, ... SSn) .

2. Archwire (3) according to claim 1, characterized in that at least one section (IS1) of said first set of sections (IS1, IS2, IS3, ... ISn) has a different shape with respect to other sections (IS2, IS3, ... ISn) of said first set of sections (IS1, IS2, IS3, ... ISn) .

3. Archwire (3) according to claim 1 or claim 2,

characterized in that the cross-sectional area (30) is substantially round, oval, square-like or rectangular.

4. Archwire (3) according to one of the claims 1 to 3, characterized in that the size of said cross-sectional area (30) is up to about 0.0006 sq inches (0.4 mm²).

5. Archwire according to one of the claims 1 to 4, characterized in that the shape of the archwire (3) is designed individually and forms a labial archwire being substantially straight, tapered, squared or ovoid or forms an individually shaped lingual archwire being substantially of a mushroom shape or straight.

6. Archwire (3) according to one of the claims 1 to 5, characterized in that the archwire (3) is out of metal and/or resilient material.

7. Archwire (3) according to claim 6, characterized in that the metal is stainless steel and the resilient

material is Nitinol Niti/NT; CuNiTi; TiMo alloy, head activated Nitinol HANT .

8. Method for manufacturing an archwire (3) according to one of the claims 1 to 7, the method comprises a step a) of forming an archwire (3) by treatment of a surface of a blank by applying at least one of the steps of:

- milling;

- applying a laser, ;

- applying Electrical Discharge Machining (EDM) ;

- form pressing; - Metal Injection Molding (MIM) .

9. Method for manufacturing an archwire (3) according claim 8, wherein at least one of the steps is performed by a CAD-CAM-robot-apparatus , a laser apparatus, an electrical discharge machining apparatus, a form pressing apparatus or by a metal injection molding apparatus.

10. Method according to one of the claims 8 or 9, wherein the method comprises upstream step a) , the further steps of:

al) scanning a current position of teeth (2) of an

individual by a 3D digital impression, via digital volume tomography (DVT) or via cone beam computer tomography (CBCT) ;

a2) effecting a 3D set-up comprising a designated

position of the teeth (2) of the individual.

11. Orthodontic brace with brackets and an archwire according to one of the claims 1 to 7, characterized in that the length of each section of the second set of sections (SSI, SS2, SS3, SSn) is equal or greater than the length of the longitudinal slot (4) of the respective bracket ( 1 ) .

12. Orthodontic brace according to claim 11 where at least one bracket (1) provides a central locking bar for fixing or ligating the respective section (SSI, SS2, SS3, ..., SSn) in the respective slot (4).