JPS58141147A - Tooth orthodontic apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an orthodontic appliance, a novel device for moving teeth for orthodontic purposes.

One orthodontic operation involves attaching brackets to individual teeth with bands that surround the teeth. A resilient wire is attached to the bracket in a manner that imparts bending and/or torsional stresses within the wire to generate a restoring force that tends to move the tooth toward the desired position. Such techniques broadly involve radgear to the neck of the tooth, the headgear involving a laterally offset U-shaped waiki attached only to the molars, but most often to the upper jaw by means of bifurcated brackets. or involves a parabolic arched wire that is attached to most of the teeth in the lower jaw.

Current orthodontic techniques for aligning teeth are generally /f-
Requires several arched wires made of fx ketens steel.

For several reasons, it is impractical to begin the procedure with a large size arched wire. Because the slots in the brackets are poorly aligned with each other, the wires must be twisted or deflected to accommodate large wires, such as approximately 0.3;01 mm (0.0.20 inf) (7). Diameter (D/I-1x denless steel undergoes permanent deformation even more easily than smaller wires, thus impairing its ability to apply moving forces to the teeth after being significantly twisted or deflected. As the wire moves during a visit to the orthodontist, the alignment forces are reduced. Spring-like loops are placed within the wire to avoid this problem; Such loops are a source of irritation and irritation and often result in ulceration of adjacent body tissue.

To avoid problems associated with large wires, approximately 0.33 mm (0.07 ≠
First use a small diameter arched wire (inches) and then approximately
Or about 0.11! The typical treatment sequence is to use a 7 mm (0.0/♂ inch) arched wire. In the final stage, arched wires of rectangular cross section may be used to fill the slots in the brackets, but in this stage of treatment the brackets are placed substantially close to each other so that the wires of rectangular cross section are not subject to significant deflection or twisting. Due to the wire having a rectangular transverse Wi shape, the wire is non-rotatable 6D with respect to each bracket and tooth, thereby applying a torque or uprighting force to the tooth.

The present invention is directed in seven aspects to reducing or eliminating archwire replacement and improving the properties of orthodontic appliances such as cervical headgear. Their purpose is to create mechanical memory by being able to deform with a martensitic shape when below a critical temperature and returning to its original shape when heated above the critical temperature.
This is achieved by using a wire made of a metal composition which has mechanical restorability (hereinafter referred to by this designation). The wire is optionally described as a single strand made of a metallic composition with a higher elastic limit and a lower packed modulus than a 1g- and stainless steel wire of the same cross-section.

Preferred compositions disclosed herein include Nitinol (NiLi
known in the art as a nickel and titanium alloy, which is a nearly stoichiometric (i.e., atomic ratio of 0/2) alloy of nickel and titanium, preferably with atoms replaced by nickel. and has a composition of approximately T1Ni-g35co-065.

Another concept of the invention relates to an orthodontic appliance that uses wires or ligatures that contract longitudinally during heating.

Existing orthodontic techniques sometimes require the use of spring loops or rubber bands within arched wires to apply force to the teeth to be moved. The elasticity of rubber bands deteriorates and loses its strength quickly, and must be replaced daily for effective treatment. However, such replacements are patient dependent, and experience has shown that many patients do not adhere to recommended replacement procedures. In order to eliminate the need for replacing rubber bands and to provide the orthodontic technician with control, the present invention utilizes a tooth and reference member (which has seven more teeth, 1llI1.+
It is contemplated to use a longitudinally retractable wire or ligature that is attached to a flexible arcuate wire or other convenient tie (1)-6. The wire or ligature is dimensionally fixed when placed in the mouth, but can contract in response to subsequent heating, either by body heat or an external heat source. The wire or other elongate member is heated, thereby causing the wire or elongate member to contract longitudinally such that it is placed in tension to apply a moving force to the tooth. Two examples of such concepts are disclosed herein. In one example, the wire is used as a ligature to pull a tooth-mounted bracket towards a rigid arch wire; in other examples, the arch wire itself is used to shorten the circumference of the arch. can be contracted,
This closes the space between adjacent teeth. For this purpose, the Nitinol alloy described above is suitable.

A seventh aspect of the invention relates to the use of an elongate member, typically a wire formed from a Nitinol alloy, wherein the elongate member or wire has a predetermined shape before being attached to the teeth. , which is deformed by a deflection or twisting operation for attachment to the teeth, and has mechanical recoverability such that upon heating the elongated member or wire assumes the predetermined shape again. If such a wire is attached to misaligned (abnormally positioned) teeth and then heated, these teeth will try to prevent the wire from returning to its shape immediately; A force is applied to the teeth to align (or torque) the teeth.

Nitinol alloys are known to have special properties in that the alloy is extremely flexible when below a critical temperature (known in the literature as the transposition temperature range or TTR) due to its martensitic shape. Ori,
In this martensitic shape state, adjacent planes of atoms are displaced by a distance smaller than the total interatomic distance. The mass deformed in this way reaches its critical temperature (TTR
), the stubble undergoes mechanical rejuvenation/l:
4. '11〈l:' and returns to the original shape, that is, the shape before deformation. It is believed that a strong and effective directional electron gun pulls the moving atoms back to their previous positions. Such T iNi , 435
The TTR of a preferred unannealed wire of about 0.11 g 3 mm<0.0/9 ish) diameter of Co, 065 is about ≠≠°C (about tio*), It's lower than body temperature.

Hereinafter, some embodiments of the present invention will be described in detail with reference to the accompanying drawings. - As shown in Figure 1, the five teeth - are in an irregular position and are located at the first L75 premolar 2 and the first permanent large E-4. Each tooth is surrounded by a band /2) /4' placed on each tooth, except that the second permanent molar is placed at the end of the arched wire /g. It has a normal tube for holding.

Prior to placing the arched wire in the mouth, the clinician may cool the wire to a temperature below the TTR and bend it into a notch shape, or while the wire is still at a temperature above the TTR. The wire may be machined and bent with wire bending shears to obtain the desired initial arch shape and place a small bend in the wire known as an "offset". , can be eliminated if the arch wire is preformed and fixed into the desired arch shape at high temperatures by the manufacturer.

Both ends of the wire are annealed to allow the formation of loops for stops within the wire and to allow folding of the distal end of the wire. Alternatively, the stop may be soldered onto the wire.

The arched wire I♂ is subjected to bending stress by attaching it to each bracket/hole and tube/hole. Due to the resiliency of the arched wire which tends to return to its unstressed position indicated by the dashed line by reference numeral 20, the arched wire is subject to a relative force which tends to move the teeth into proper alignment. Add to the brackets and teeth. Namely.

The first premolar 2 and first permanent molar 4t are then pulled outward into alignment with the adjacent teeth.

If it is not possible to obtain a pre-formed one-arch shape,
The arched wire is coupled to the bracket using contouring jaws. The bonding operation is carried out in the conventional manner by using bonding wires bonded into each of the wide slots of the arched wire receiving 11 of the silakerato. A preferred system is that only seven wires are used, which wires are deflected or deflected from their unstressed rest position by at least 3 mm during the process of attaching them to the bracket, a distance that is greater than that of conventional wires. Possible for stainless steel arch wire
- This is a significantly larger distance than the distance that was. A typical two-pronged bracket is approximately 3. llj Tamiri (-'o, i3
s inch) and are spaced apart by an inter-bracket distance of approximately vogo millimeters (approximately 0.200 inch) when installed with average sized teeth.

After the orthodontic appliances are first fitted, the patient should have a brief test every 3 or 3 weeks, simply to visually check that the wires have not undergone excessive permanent deformation as a result of masticatory forces. undergo a medical examination. If the wire has not completely straightened the teeth after about three months from the time of initial installation, the wire can be removed and another wire of the same composition applied to the brackets. It will be seen that in a typical case, the arched wire has undergone permanent deformation resulting in a slight ridge of about 5-g5 as a result of wire cleavage and long-term mastication forces.

Conventional clinical techniques have shown that the wire or wires do not deflect more than λ millimeters from their unstressed rest position between adjacent brackets. The reason for this is that the diameter of approximately O, SO♂ mm < o, o, zo inches) is
It will be understood by reference to the dashed line 2.2 which shows the amount of permanent deformation that the stainless steel has undergone after 7 hours. Of course, permanent deformation of this magnitude would not occur if a smaller diameter stainless steel wire was used in accordance with normal procedures. It undergoes substantially less permanent deformation than in the case of the present invention and returns to position 20 when the profiling pliers are not used.

When the wire according to the invention was attached to the bracket by using profiling pliers, the deformation was somewhat greater, but the wire still returned at least a distance to its previous position. In this same experiment, an annealed wire of the same alloy was permanently deflected by a distance comparable to that of a standard stainless steel wire of approximately the same dimensions;
It was a conventional arched wire sold under the trade name ``wistflex''.

The circular arched wire shown in Figure 1 utilizes bending stress applied to the wire during installation to generate tooth movement forces, and wires of preferred compositions also undergo threading stress during installation. Good too. When non-rotatably mounted to a bracket, the torsionally stressed wire exerts a torsional stress on the bracket and the tooth to which it is attached.

As is well known in the orthodontic art, the tooth is prepared by using a torsionally stressed rectangular cross-section arched wire that completely fills the slot in the bracket so that it cannot rotate with respect to the bracket. Can be moved. This technology is known as "torque applied correction" in this industry.
, 6 upright orthodontics, or °°parallel orthodontics. The arched wire 2≠ of rectangular cross section is subjected to torsional stresses such that it simultaneously moves the teeth in the same manner as the arched wire of circular cross section shown in FIG. 1 and parallelizes the teeth in FIG. and bending stress.

In Figure 2, the arched wide for torsion distribution is 2j
It is shown in This arched wire is a bracket,
It has a rectangular cross section that corresponds to the shape of the slot in 2. The bracket is a conventional two-pronged bracket J attached to the tooth by a surrounding band λgK with spaced pairs of ears 30 for receiving arched wires between the ears. Each of these ears has four portions or slots facing toward the attached tooth for receiving a ligature 32. Ligation line 3 as shown in Figure 2
．． 2 an arched wire along the slot of each ear 30;
4' and then passed back over the arched wire, where it is twisted together, and the twisted portion is secured in a manner that does not irritate the patient's adjacent mucosal tissue. . The arched wire 2≠ of rectangular cross section is twisted about its longitudinal axis between adjacent brackets, thereby correcting the tooth into an upright position with torque.

Although most of the above description relates to the use of arched wires, the present invention is applicable to other spring-container configurations such as spring-contact configurations that are attached to molar canals in conventional cervical gear systems. Structures can also be used: - the embodiments of figures 3, q and 5 are essentially dimensionally fixed when placed in the mouth, and then dimensionally change in response to an increase in temperature due to body heat or an external heat source; The wire TFC or other wires that change shape are related to the use of elongated members. Nitenol alloys exhibit this characteristic known as mechanical resilience. Sometimes these are martensite':i
Due to IJ cutting, it is extremely flexible, and adjacent planes of atoms are displaced by a distance smaller than the total interatomic distance. When a mass thus deformed is heated to a temperature above its critical temperature or transposition temperature range (TTR), the mass returns to its original shape or configuration prior to deformation due to its mechanical restorability. A powerful and effective directional electron beam pulls the displaced atoms back to their previous positions. Such wires are bent or stretched while they are at a temperature below the TTR, and the forces generated by the resiliency then return the wires to a predetermined uncurved or unextended configuration to generate tooth alignment forces. It is heated as it is.

The embodiment of the invention shown in FIG. 3 includes a longitudinally retractable arched wire that is attached to the tooth by a conventional band and bracket arrangement. In the lower jaw, tooth 31A-
'10 has a conventional bifurcated bracket of the type shown in Figure 2, and molars ≠ 2 have standard retractable molar tubes tIl.
have. The arched wire is preferably a near stoichiometric alloy of nickel and titanium, which, as mentioned above, will react when heated above a critical temperature known as the transposition temperature range (TTR). It is known to have mechanical quaternity. Preferably, the TTR is above normal room temperature of about 2.2.2°C (below about 7.2°C) and below normal body temperature. about,! 6.7-32.2℃
(approximately ♂O-ta θT) is ideal. Prior to placing the wire in the mouth, the wire is stretched to increase its length and decrease its cross-sectional area. A typical arched wire length is about 100 mm, and this length is stretched by about 70%, so that the wire is stretched by about 7 or g inches until it is heated again. The entire drawing operation is performed while the wire is at a temperature below its TTR. The wire remains dimensionally fixed while at this temperature, as it is fitted into the mouth, and its ends are soldered at ≠≠ to attach the wire to the canal ≠≠ for the entrance tooth. bent or bent. The wire is then heated, either by body heat or an external heat source -75. This results in a longitudinal contraction effect, which tends to shorten the length of the arch and close the space between teeth 3 and 3g.

Preferably, the wire ttg is made relatively rigid by substituting cobalt for nickel by atoms. This allows the wire to be used to align and upright teeth in the manner described with respect to Figures 1 and 2. Mechanical recovery properties are also useful in this example. For example, this arched wire≠f 11
It can be formed into the desired final shape by the manufacturer at temperatures above the TTR. For some Nitinol alloys approx. ;
It is appropriate to apply a temperature of 3g-O≠℃ (approximately 1000-/200?) over a period of 2 to 3 minutes. The desired final shape is generally a parabolic shape, which includes offsets, insets, secondary pends, pendants, loops, curves, and curves (all of which are well known in the orthodontic field). Such an arched wire is then attached to the dental bracket by means of a ligature while at a temperature below its TTR, and for this attachment as necessary. It is bent and twisted. The wire is then heated to a temperature above its TTR to bring about the mechanical resilience of the wire. tending to return to its shape) exerts a force on the tooth, which forces the tooth into a position where the arched wire is again in its desired final shape.These forces are bonding forces, and these bonding forces serves multiple purposes: aligning the teeth, closing, and murmuring upright.

If the treatment does not require closing the spaces between the teeth, there is no need to pre-stretch the arched wire ψg, and the mechanical restorability of the preformed arched wire merely serves to level the teeth connected thereto and/or Otherwise, it only serves to perform torque applied correction.

Moving under the influence of retractable arch wire -h
To further control the positioning of the teeth, a double arched wire device of the type shown for the upper jaw in FIG. 3 may be used. In this case, the upper arcuate wire jO is the same as the writable retractable arcuate wire +y both with regard to its metallurgical composition and its mounting method. Of course, the wire jO
also tends to close the space between the two teeth 3;-2 and j≠.

The plaquets used for the upper teeth of FIG. 3 have double slots with which the racket can be accommodated with the second or lower arched wire. The lower arch wire is non-shrinkable and may be made of unannealed Nitinol alloy or plain /♂-g stainless steel. The function of the lower archwire is to guide the teeth during the closing movement of the teeth caused under the influence of the retractable upper archwire jo. Lower arched wire! B is also subjected to a force which causes the wire to level and torque the teeth. This ``technique'' can, of course, better control the movement of the teeth during closure of the teeth in orthodontic treatment.
It can also be used to pull teeth (in abnormal positions) toward the ideal arch shape as shown in Figures ≠ and 5. In this case, wires or ligatures are used in place of the wire bands used in the prior art. In Figures ≠ and 5, the rigid arched wire j♂ is connected to the tooth 0-≠ with the band and bracket attached. Teeth 01, 2 and 6 are approximately in the desired position, and the brackets for them are connected directly to arched wire j♂ in a standard manner. On the other hand, tooth otsu/to6
3 is in an abnormal position and has teeth. , Otsu 2 and I) l/L
It is necessary to move it so that it is aligned with 7. One aspect of the present invention is to use a contractible elongated member, preferably a Nitinol alloy ligature.
The sts is stretched while at a temperature below its TTR, and the arched wire j is stretched while at a temperature below its TTR.
It is attached between the male and the brakerato of tooth-Z/and z3 and then heated to a temperature above its TTR by body heat or an external heat source. This causes a longitudinal contraction of the ligature, which places it under tension and pulls the arched wire 3. Pull it towards the side. The length of this retractable ligature is approximately 0.2 mm (approx., oi.

inch) diameter and is mounted between the bracket and the arch wire 3g in the manner best shown in FIG. The ligature of the wire first extends around the arc of the arched wire, then to the bracket, where it passes along the slot in the ear of the bracket as shown in FIG.

The ligature Oj is then passed back to the arched wire 31 and around it, and is connected and twisted into a pigtail 6gK at ζ, the pigtail being folded back towards the teeth so as not to irritate the surrounding oral tissues.

If the mechanical resiliency of the ligature interferes with the illustrated screw and pigtail type attachment scheme, other members may be used to attach the ligature to the bracket or the ligature itself. Due to the mechanical restorability of the ligature which produces a contraction action, the ligature gt is placed in tension and is directed towards the rigid arched wire jg and the ligature gt is placed in tension and the ligature gt is directed towards the rigid arched wire jg and the ligature gt is placed in tension.
,,! : Generates a force that pulls it towards the 1st row position.

This technique is the basic step leading to the use of arched wires in flexion and/or tension as described with respect to the embodiments of FIGS. 1 and 2.

The Nitinol alloy used in connection with the present invention is preferably a near stoichiometric alloy of nickel and titanium, which can be used in combination with T+Ni, g35Co if expected to be subjected to torsional or bending stresses. Cobalt can be substituted to provide a composition of -oss.

A wire of such composition, when unannealed and in single strand form, has a much higher elastic limit and a lower modulus of elasticity than a female/male stainless steel wire of the same cross-sectional area.

Even without cobalt, Nitinol alloys are capable of martensitic shave deformation when below a critical temperature (transition temperature range or TTR) and when heated above this critical temperature. It has mechanical restorability by returning to its original shape.

The TTR of the wire should be oral temperature F in all modes of use, preferably at or above room temperature when the mechanical restorability of the wire can be utilized. When using the mechanical restorability of the wire, approximately 2 O, 7-3.2. ．．
A TTR of 2°C (approximately ♂0-90 below) is optimal. This allows the wire to be shaped while in a flexible state without the need for cooling, yet returns to its predetermined state to provide the various tooth movement forces described above when the temperature rises to the mouth temperature. Tend.

When the wire is used to apply a leveling force or torque to the teeth, it should have a relatively high stiffness. Such stiffness is a property of alloys containing the transitional element cobalt, which is substituted atomically by nickel. Ta! Other suitable transition elements for Nitinol alloys are tantalum, niobium and copper; further experiments have shown that other atom-for-atom substitutions may be cum and platinum.

Seven alloys of the type used in the practice of this invention are disclosed in U.S. Patent No. 33. ! This is disclosed in the f/4t1,3 specification. Other references disclosing processing techniques and characteristics of suitable compositions include William J., published by Wire Journal, Inc./R.

A paper by Dr. Buehler (the main developer of the Tinol alloy material) and William B. Cross" t
t = Tinol...Unique alloy wire (Ta3
N1tinol...Unique A11oy W
A description of this material and some of its properties can be found in the brochure ``Nitinol Characterization Study'' published on September 2013.
itinolCharacterizationSt
This document is identical to NASA CR-71133 and was published by the Clearing House for Scientific Research, Springfield, Virginia, USA. And Technical In 7 Ohme/Yo 7 (Cl
earring House For 5cientif
IC and Technical Information
available from ). The entire disclosures of these publications are incorporated herein by reference.・
□Previous research on the subject matter of the present invention has been published by the deceased and his collaborators in the Journal of the American Dental Association, published July 2007.
ericanDentalMusgociation =
JADA)” Volume g2 No. 7373@, hereafter /
The Angle 0rthodontist, published in 972 months.
Volume 41-2, pages 172-777 of
f Qrthodonties)”.

The disclosure content of these publications, together with the original content of the documents cited and cited therein, is incorporated herein by reference.

Those skilled in the art will understand that the above description shows only 2.3 possible embodiments of the invention and that the invention is not limited to the above description. Although some aspects of the present invention are directed to specific uses of Nitinol alloys, other compositions may exist or be developed that can accomplish the same results in some respects in the same manner, and are further described herein. It should be understood that there may be uses of Nitinol alloys to provide tooth movement forces other than those disclosed herein.

[Brief explanation of drawings]

FIG. 1 illustrates the use of a circular cross-section arched wire to align teeth by applying forces to the teeth generated by bending stresses in the arched wire. Figure 2 shows 7 with standard bifurcated bracket and ligature.
This is an enlarged view of a real tooth, and this tooth is connected with a rectangular cross-section or an arched wire, which is referred to in the art as tooth torque applied orthodontics, upright orthodontics, or parallel orthodontics. Screw stress is applied to move the tooth root in the manner shown. Figure 3 shows two ways in which mechanically resilient arched wires can be used for tooth movement: 1: in a two-pronged bracket with paired slots in the upper set of slots; a retractable arch wire in the lower set of slots and a second non-retractable arch wire in the lower set of slots, the latter aligning the teeth to the ideal arch shape and collapsible arch wires in the lower set of slots. In the lower jaw, mechanically restorable preformed arched wires align the teeth and torque them to correct them to an upright orientation. It is also used to close the spaces between teeth. Figures t and 5 illustrate the use of a retractable ligature to pull a displaced tooth towards a rigid arched wire, and Figures μ illustrate the relative position of the support member and tooth for the arched wire. Showing multiple teeth as shown, 5th
The figure shows details of the seven teeth with attached bands and brackets, and the connection connecting the retractable ligature to the rigid arch wire. 7.2...Obi, /Hiroshi...Bracket, /Otsu...Pipe, ig...Bracket, 2g...Obi, 3o...Ear,
3.2...ligature wire, ≠za...arch shaped wire,! 0
．． ! ;Otsu, jg...Arch shaped wire, Otsuj...ligature wire, Otsu2...bracket ear. Name of the agent: Kawahara 1) - Written amendment to the proceedings February 1920, 1939, and Date 1.5, Director-General of the Office, Kazuo Wakasugi, 11th r+ table, J: Patent Application No. 3 Zaichi 6730, Showa 2 Name of the invention Relationship with the person 111'l who performs the straightening device 3 draw 11 Patent applicant 4th agent Postal code 105 fl Address 8th floor, Mori Building 9, 1-2-2 Atago, Minato-ku, Tokyo (Telephone: 434-2951~ 3) Contents of amendment The scope of patent claims that can be submitted first is revised as follows.

Claims (1)

[Claims] An orthodontic appliance comprising means for coupling a wire and a plurality of spaced apart portions of the wire to the teeth for applying a force to the teeth to move the teeth, the wire having a predetermined shape and a critical temperature. and has mechanical restorability to cause a change from the deformed shape to the predetermined shape when heated above the critical temperature, and the critical temperature is below the oral temperature; The device wherein the wire is attached to the connecting means below the critical temperature and then heated above the critical temperature.