EP0828860A1 - ARTICLES MEDICAUX, DENTAIRES ET ORTHODONTIQUES EN ALLIAGES Ni-Ti-Nb - Google Patents

ARTICLES MEDICAUX, DENTAIRES ET ORTHODONTIQUES EN ALLIAGES Ni-Ti-Nb

Info

Publication number
EP0828860A1
EP0828860A1 EP96916776A EP96916776A EP0828860A1 EP 0828860 A1 EP0828860 A1 EP 0828860A1 EP 96916776 A EP96916776 A EP 96916776A EP 96916776 A EP96916776 A EP 96916776A EP 0828860 A1 EP0828860 A1 EP 0828860A1
Authority
EP
European Patent Office
Prior art keywords
alloy
article according
mpa
alloys
orthodontic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP96916776A
Other languages
German (de)
English (en)
Other versions
EP0828860A4 (fr
Inventor
Farrokh Farzin-Nia
Rohit C. L. Sachdeva
Peter A. Besselink
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ormco Corp
Original Assignee
Ormco Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ormco Corp filed Critical Ormco Corp
Publication of EP0828860A1 publication Critical patent/EP0828860A1/fr
Publication of EP0828860A4 publication Critical patent/EP0828860A4/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/02—Inorganic materials
    • A61L27/04—Metals or alloys
    • A61L27/06—Titanium or titanium alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C14/00—Alloys based on titanium
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2310/00—Prostheses classified in A61F2/28 or A61F2/30 - A61F2/44 being constructed from or coated with a particular material
    • A61F2310/00005—The prosthesis being constructed from a particular material
    • A61F2310/00011—Metals or alloys
    • A61F2310/00023—Titanium or titanium-based alloys, e.g. Ti-Ni alloys
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L2400/00—Materials characterised by their function or physical properties
    • A61L2400/16—Materials with shape-memory or superelastic properties
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L2430/00—Materials or treatment for tissue regeneration
    • A61L2430/12—Materials or treatment for tissue regeneration for dental implants or prostheses

Definitions

  • the invention relates to medical, dental and orthodontic articles, and more particularly to such articles made from Ni-Ti-Nb alloys having shape memory and super-elastic characteristics.
  • Ni-Ti based alloys are known to exhibit shape memory properties associated with transformations between martensite and austenite phases. These properties include thermally induced changes in configuration in which an article is first deformed from a heat-stable configuration to a heat-unstable configuration. Subsequent exposure to increased temperature results in a change in configuration from the heat-unstable configuration towards the original heat-stable configuration.
  • the loading plateau stress is defined by the inflection point on the stress/strain graph.
  • Subsequent increases in strain are accompanied by increases in stress.
  • On unloading there is a decline in stress with declining strain to the start of the "unloading plateau, " as evidenced by the existence of an inflection point (which is characteristic of the superelastic behavior with which the present invention is concerned) along which stress changes little with reducing strain.
  • the unloading plateau stress is also defined by an inflection point on the stress/strain graph. Any residual strain after unloading to zero stress is the permanent set of the sample.
  • Characteristics of the elastic deformation, the loading plateau, the unloading plateau, the elastic modulus, the plateau length and the permanent set are established, and are defined in, for example, "Engineering Aspects of Shape Memory Alloys", at page 376. Typical values for commercially available
  • Ni-Ti binary alloys are:
  • Ni-Ti-Nb based alloys The thermally-induced recovery, shape memory properties of Ni-Ti-Nb based alloys have been investigated. It has been found that the characteristic temperatures of the shape transformation of certain Ni-Ti-Nb based alloys can be modified by appropriate treatment, so that alloys which would normally exist in the austenite phase at ambient temperature can be stored in the martensite phase at room temperature in a deformed configuration from which they will recover when heated. Such alloys are disclosed in EP-A-185452.
  • the advantageous properties of the Ni-Ti-Nb based alloys disclosed in EP-A-185452 lie in their ability to respond to a treatment to change temporarily the characteristic temperatures of the thermally induced change in configuration. No consideration has been given to their superelastic properties.
  • transformation hysteresis can be expanded in the way referred to above (i.e., to make an alloy stable temporarily at ambient temperature in the martensite phase) suggests that such alloys would not be useful as superelastic alloys.
  • transformation hysteresis is as small as possible in a superelastic alloy. See, e.g., "Engineering Aspects of Shape Memory Alloys", T. W. Duerig et al., p. 382, Butterworth-Heinemann
  • the present invention is concerned with the previously unrecognized superelastic behavior of Ni-Ti-Nb alloys, having properties which are superior to those of other alloys which exhibit superelastic behavior, such as Ni-Ti binary alloys.
  • the invention provides a method of processing a Ni-Ti-Nb based alloy which comprises working an article formed from such an alloy at a temperature which is less than the recrystallization temperature of the alloy. Recrystallization of an alloy involves the formation of new, defect-free, low energy grains or crystals, which consume and replace highly worked, high energy grains. It involves the loss of a textured structure introduced by working.
  • the invention also provides articles, particularly medical, dental and orthodontic articles, formed from such alloys.
  • the invention provides a method of processing a Ni-Ti-Nb based alloy which contains from about 4 to about
  • the method of the invention gives rise to beneficial properties in the processed alloy.
  • the plateau stresses of both loading and unloading are increased significantly vis-a-vis conventional binary alloys.
  • the permanent set for a given deformation can in some circumstances be reduced compared with such conventional alloys.
  • the method of the invention provides this increased stiffness without an undesirable permanent set, which has accompanied previous attempts to increase stiffness in superelastic, shape memory alloy materials, as for example by varying the compositions of the alloys.
  • a further advantage of the alloys of the invention is that the tendency found in some Ni-Ti based alloys to revert to an R-phase (a transitional phase between the austenite and martensite phases) is reduced. This in turn reduces the tendency of the elastic modulus to be lowered, which is important for certain applications, for example when the alloy is used in a catheter guidewire or an orthodontic archwire where the modulus controls the geometric stability of the wire against lateral stresses.
  • Yet another advantage of the invention is that it provides articles with superelastic properties which are more resistant to corrosion than articles formed from alloys used previously for their superelastic properties.
  • Fig. 1 is a generic representation of the stress-strain relationship for a superelastic, shape-memory alloy
  • Fig. 2 is the stress-strain relationship for a superelastic, shape-memory Ni-Ti-Nb alloy according to the present invention
  • Fig. 3 is the stress-strain relationship for a superelastic, shape-memory NiTi binary alloy, as known in the prior art.
  • the present invention provides Ni-Ti-Nb based alloys whose superelastic properties are such that: (a) the loading plateau on loading at 25 °C is at least about 600 MPa, preferably at least about 700 MPa, more preferably at least about 800 MPa, and even more preferably at least about 900 MPa; and (b) the permanent set after tensile deformation of 6% at 25 °C is less than about 2.5%, preferably less than about 1.5%, and more preferably less than about 1.0%.
  • the alloys on which the med od is practiced comprise nickel, titanium and niobium. It is preferred that the alloy contains at least about 4 at. % niobium, more preferably at least about 6 at. % , and even more preferably at least about 9 at.%. Furthermore, it is preferred that the alloy contains not more than about 14 at. % niobium, more preferably not more than about 12 at. %, and even more preferably not more than about 10 at.%. Additionally, it is preferred that the ratio of atomic percent Ni to atomic percent Ti is in the range of about 0.8-1.2, and more preferably in the range of about 0.9-1.1.
  • the alloy may contain a quantity of an element other than nickel, titanium and niobium for the purpose of regulating the transformation temperamre (A f ) at which the alloy is transformed from the austenite phase to the martensite phase, and vice versa.
  • suitable additional elements include Fe, Co, Cr, V and Al. When such an additional element is included, it is appropriate to adjust the Ni/Ti ratio to maintain the characteristic transformation temperatures of the alloy (especially the A, temperature) at appropriate levels.
  • the method of the invention may comprise subjecting the article made from the alloy to work under warm work conditions; that is, at a temperamre less than the recrystallization temperature, but greater than the ⁇ temperamre at which recovery processes take place.
  • Preferred conditions for such working might be, for example, at a temperamre which is greater than about 300°C, more preferably greater than about 400°C, and even more preferably greater than about 450°C.
  • the warm working will preferably be conducted at a temperature not greater than about 700°C, more preferably not greater than about 625 °C, and even more preferably not greater than about 500 ⁇ C.
  • the method of the invention alternatively may comprise subjecting the article made from the alloy to work under cold work conditions; that is, at a temperamre less than that at which a significant level of recovery processes take place.
  • Preferred conditions for such working might be, for example, at a temperamre which is higher than about -100°C, more preferably higher than about -50°C, and even more preferably higher than about 10°C.
  • the cold working will preferably be conducted at a temperamre not greater than about 200°C, more preferably not greater than about 100°C, and even more preferably not greater than about 50°C. In the case of either warm working or cold working, the alloy can be annealed before it is worked.
  • the method of the invention may further include a step in which the alloy is heat treated after it has been worked.
  • the work that is to be measured in the context of the method of the invention is the work that is imparted after the final drawing and prior to the final heat treatment.
  • the method includes a subsequent heat treatment step when the alloy is cold worked.
  • the heat treatment is preferably carried out at a temperamre which is less than the recrystallization temperamre of the alloy.
  • the heat treatment may be carried out at a temperamre not more than about 700°C, preferably less than about 625 °C, and more preferably less than about 500°C.
  • the heat treatment is preferably carried out at a temperature which is greater than about 300°C, and more preferably greater than about 400°C.
  • the duration of the heat treatment step depends on the temperature that is chosen and is readily ascertainable by persons skilled in the art.
  • the amount of work imparted to the article should be at least 10%, more preferably at least 12%, even more preferably at least about 15%, and even more preferably at least 20%.
  • the work can be measured as a change in cross-sectional area of the article.
  • the cross-sectional area of the article after the working step of the method will not exceed about 5 mm 2 , more preferably it will not exceed about 3.5 mm 2 , and even more preferably it will not exceed about 2.5 mm 2 .
  • the method of the invention may include steps in addition to the working and optional heat treatment steps described above. Such additional steps include, for example, bending, swaging, pressing and so on. Any such additional steps should generally be carried out after the working and heat treatment steps.
  • the articles of the invention are comprised of an alloy of Ni, Ti and Nb processed according to the above-described methodology, so as to possess both shape-memory and superelastic properties, and may be configured for any one of a number of different applications.
  • the articles may be in the form of wires or mbes.
  • the articles might be used in eyeglass frames.
  • the articles are suitable for use in medical, dental and orthodontic applications, for example as an orthodontic wire, an orthodontic coil spring, an endosseous dental implant, endodontic reamers and files and other instruments used in dentistry, a catheter, a catheter guidewire, flexible cutting tools for arthroscopic procedures or tissue excision and other instruments used in surgery (such as reamers and files), vascular clips, vascular, biliary and urological ste s, bone anchor pins, and as components (such as a spring) of any of these articles.
  • the articles may also be used in a suture needle or a surgical needle. Particularly in the context of orthodontic treatment, and especially after the initial stage of tooth leveling and alignment, articles according to the present invention are highly advantageous.
  • the reasons for their significant advantages are the increased stiffness and forces provided by the shape-memory, superelastic Ni-Ti-Nb alloys of the invention vis-a-vis know Ni-Ti alloys used in the field of orthodontics.
  • the Ni-Ti- Nb alloys treated in accordance with the method of this invention exhibit greater stiffness, combined with greater resilience, as compared to known Ni- Ti alloys used in orthodontics.
  • the loading and unloading forces exhibited by articles of the present invention are approximately double or more than the loading and unloading forces of known alloys. While these characteristics make these high-stiffness, superelastic alloys particularly suitable for orthodontic archwires, including intermediate wires, and various springs, they are also well-suited for brackets and other fixed orthodontic appliances.
  • the invention provides an article which comprises at least one component formed from a Ni-Ti-Nb based alloy processed as described herein, wherein the component exhibits superelastic and shape memory properties.
  • the article can be used in, for example, any of the applications referenced above.
  • Figure 2 shows the properties of the resulting wire described in the above Example 1 compared to the analogous properties of a typical archwire such as is commercially available from Raychem under the trade name Alloy BB, which are shown in Figure 3.
  • the recovery stresses which are obtainable in articles of the present invention can be modified in one of several ways: (1) varying the amount of the Nb alloying element; (2) including a fourth element, such as Fe, Co, Cr, V and Al; (3) modifying the cold work ratio; and/or (4) modifying the temperamre at which the heat treatment is performed.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Public Health (AREA)
  • Medicinal Chemistry (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Transplantation (AREA)
  • Epidemiology (AREA)
  • Inorganic Chemistry (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Dermatology (AREA)
  • Veterinary Medicine (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Dental Tools And Instruments Or Auxiliary Dental Instruments (AREA)

Abstract

Articles dentaires et orthodontiques constitués d'alliages Ni-Ti-Nb possédant des propriétés à la fois superélastiques et de mémoire de forme. Les articles peuvent être des arcs en fil métallique, des tubes, des ressorts orthodontiques ou analogues, ou d'autres articles médicaux/dentaires. L'alliage présente de préférence une force de chargement minimale d'au moins 800 MPa et une force de déchargement minimale d'au moins 400 MPa, tout en présentant une déformation superélastique dans la plage de 8 % à 14 % avant de présenter une déformation plastique lorsqu'il est soumis à une charge.
EP96916776A 1995-05-30 1996-05-30 ARTICLES MEDICAUX, DENTAIRES ET ORTHODONTIQUES EN ALLIAGES Ni-Ti-Nb Withdrawn EP0828860A4 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US45401695A 1995-05-30 1995-05-30
PCT/US1996/008015 WO1996038594A1 (fr) 1995-05-30 1996-05-30 ARTICLES MEDICAUX, DENTAIRES ET ORTHODONTIQUES EN ALLIAGES Ni-Ti-Nb
US454016 1999-12-03

Publications (2)

Publication Number Publication Date
EP0828860A1 true EP0828860A1 (fr) 1998-03-18
EP0828860A4 EP0828860A4 (fr) 1998-09-30

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP96916776A Withdrawn EP0828860A4 (fr) 1995-05-30 1996-05-30 ARTICLES MEDICAUX, DENTAIRES ET ORTHODONTIQUES EN ALLIAGES Ni-Ti-Nb

Country Status (2)

Country Link
EP (1) EP0828860A4 (fr)
WO (1) WO1996038594A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6638064B1 (en) 2000-06-07 2003-10-28 Robert Scott Nance Flexible endodontic syringe
DK1608416T3 (da) * 2003-03-31 2009-03-16 Memry Corp Medicinske indretninger med lægemiddelelueringsegenskaber og fremgangsmåder til fremstilling deraf
US10716645B2 (en) * 2016-10-22 2020-07-21 Ormco Corporation Variable heat-treat endodontic file
WO2024033706A1 (fr) 2022-08-11 2024-02-15 Petrus Antonius Besselink Dispositif flexible et orientable à souplesse réglable

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58157934A (ja) * 1982-03-13 1983-09-20 Hitachi Metals Ltd 形状記憶合金
US4631094A (en) * 1984-11-06 1986-12-23 Raychem Corporation Method of processing a nickel/titanium-based shape memory alloy and article produced therefrom
JPS6396234A (ja) * 1986-10-09 1988-04-27 Tokin Corp 形状記憶合金材料
US4770725A (en) * 1984-11-06 1988-09-13 Raychem Corporation Nickel/titanium/niobium shape memory alloy & article

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100205160B1 (ko) * 1991-04-09 1999-07-01 마스나가멘로파크가부시끼가이샤 Ni-ti계 합금과 이종금속의 접합부 및 그 접합방법

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58157934A (ja) * 1982-03-13 1983-09-20 Hitachi Metals Ltd 形状記憶合金
US4631094A (en) * 1984-11-06 1986-12-23 Raychem Corporation Method of processing a nickel/titanium-based shape memory alloy and article produced therefrom
US4770725A (en) * 1984-11-06 1988-09-13 Raychem Corporation Nickel/titanium/niobium shape memory alloy & article
JPS6396234A (ja) * 1986-10-09 1988-04-27 Tokin Corp 形状記憶合金材料

Non-Patent Citations (5)

* Cited by examiner, † Cited by third party
Title
PAIO, MIN. MIYAZAKI, SHUICHI. OTSUKA, KAZUHIRO. NISHIDA, NORIMASA: "Effects of Niobium addition on the microstructure of titanium-nickel alloys" MATER. TRANS., JIM, vol. 33, no. 4, 1992, pages 337-345, XP002072269 JAPAN *
PATENT ABSTRACTS OF JAPAN vol. 007, no. 281 (C-200), 15 December 1983 & JP 58 157934 A (HITACHI KINZOKU KK), 20 September 1983 *
PATENT ABSTRACTS OF JAPAN vol. 012, no. 338 (C-527), 12 September 1988 & JP 63 096234 A (TOHOKU METAL IND LTD), 27 April 1988 *
SACHDEVA, R. ET AL.: "Shape memory NiTi alloys-applications in dentistry" MATERIALS SCIENCE FORUM, CONFERENCE: MARTENSITIC TRANSFORMATIONS. II. PROCEEDINGS OF THE 6TH. INTERNATIONAL CONFERENCE, 3 - 7 July 1989, pages 693-698, XP002072270 SIDNEY, AU *
See also references of WO9638594A1 *

Also Published As

Publication number Publication date
WO1996038594A1 (fr) 1996-12-05
EP0828860A4 (fr) 1998-09-30

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