Orthodontic archwire

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Demonstration of an archwire Week 4 of braces.jpg
Demonstration of an archwire

An archwire in orthodontics is a wire conforming to the alveolar or dental arch that can be used with dental braces as a source of force in correcting irregularities in the position of the teeth. An archwire can also be used to maintain existing dental positions; in this case it has a retentive purpose. [1]

Contents

Orthodontic archwires may be fabricated from several alloys, most commonly stainless steel, nickel-titanium alloy (NiTi), and beta-titanium alloy (composed primarily of titanium and molybdenum).

Types

Noble Metal alloy

Noble metals such as gold, platinum, iridium, silver and their alloys were used early on in the field of Orthodontics because of their good corrosion resistance. Some of the other qualities that these alloys had were high ductility, variable stiffness (with heat), high resilience and ease of soldering. Disadvantages of these alloys were: Less elasticity, less tensile strength and greater cost. Composition of both platinum and palladium raised the melting point of the alloy and made it corrosion resistant. Copper material, along with the cold-working of the material, gave the strength to the alloy. The alloy composition of the wires made of noble metals would be Gold (55%-65%), Platinum (5-10%), Palladium (5-10%), Copper (11-18%) and Nickel (1-2%). These composition were similar that of Type IV Gold casting alloys. Edward Angle first introduced the German Silver in orthodontics in 1887 when he tried replacing the noble metals in this practice. At that time, John Nutting Farrar condemned Angle for using a material which lead to discoloration in the mouth. He then in 1888, started altering the alloy composition around the German Silver. However, Angle's composition were extremely difficult to reproduce and therefore, the usage of Silver-based alloys did not get popular in orthodontics. Angle was also known to use materials such as rubber, vulcanite, piano wire and silk thread. [2]

Stainless steel archwire

In 1929, stainless steel was introduced for the use of making appliances. This was the first material that truly replaced the usage of noble alloys in Orthodontics. Steel wire alloys, in comparison to the noble metals, were relatively cheaper. They also had better formability and can be readily used to be soldered and welded for fabrication of complex orthodontic appliances. [3] The stainless steel alloys are of "18-8" austenitic type which contain Chromium (17-25%) and Nickel (8-25%) and Carbon (1-2%). [4] [5] Chromium in this stainless steel alloy forms a thin oxide layer which blocks the diffusion of oxygen into the alloy and allow for the corrosion resistance of this alloy. Angle used stainless steel in his last year practicing orthodontics. He used it as a ligature wire in his patient's mouth. At that time, Emil Herbst was the main opponent of the Stainless steel based alloys. According to him, he preferred using Noble alloys over stainless steel. By 1950, 300 series stainless steel alloy was used by the majority of orthodontists in United States, as European Orthodontists believed in using functional appliances such as Activator appliance with patient's malocclusions.[ citation needed ]

Stainless steel archwires have high stiffness, low springiness, corrosion resistant, low range and good formability. These wires are often cheaper than the other archwires and can readily be used as "working" archwires in an orthodontic treatment. Space closure after extractions is often done by placing these archwires in the mouth.

Multi-Strand Stainless Steel archwires

This type of stainless steel archwire is made up multiple 0.008 in SS wires coiled together. There are 3 types: Coaxial, Braided and or Twisted. The coaxial type of archwire includes 6 strands of 0.008 in strands which are coiled together. The braided archwire includes 8 strands and twisted archwire includes 3. These wires can provide either a round shape or rectangular shaped stainless steel wire. The properties of these wires are drastically different from the traditional stainless steel archwires. They have low stiffness and can be used for initial leveling and aligning stage in orthodontics. However, due to their lower elastic limit they can be readily deformed if acted upon by any other force such as food. [6]

Australian archwire

Arthur J. Wilcock, along with Raymond Begg, created the "Australian archwire" in the 1940s in Australia. He was a metallurgist from Victoria, Australia. This archwire was prominently used in what is known as Begg Technique. Begg was seeking a stainless steel wire that was light, flexible stayed active for long periods of time in the mouth. The wire had high resiliency and toughness and were heat treated. The initial wire produced had dimension of 0.018in. [7] These wires are often used in the treatment of deep bites because of their increased resistance to permanent deformation. [8] The wire is composed of Iron (64%), Chromium (17%), Nickel (12%) and others.

Cobalt-Chromium Archwire

In the 1950s, cobalt-chromium alloy started being used in orthodontics. Rocky Mountain Orthodontics first started marketing the cobalt-chromium alloy as Elgiloy in the 1950s. It was the Elgin National Watch Company which introduced this alloy, composed of cobalt (40%), chromium (20%), iron (16%) and nickel (15%). Elgiloy offered increased resilience and strength, however, its stiffness was weak. These type of wires are still sold as alloys known as Remaloy, Forestaloy, Bioloy, Masel and Elgiloy. However, their use have decreased throughout the field of orthodontics due to the fact that no complex bends in wires are needed in today's treatment. [9]

Elgiloy is available in four levels of resilience. Blue Elgiloy (soft), Yellow Elgiloy (ductile), Green Elgiloy (semi-resilient) and Red Elgiloy (resilient).

Nickel-titanium (Niti) Archwire

NiTi alloy was developed in 1960 by William F. Buehler who worked at the Naval Ordnance Laboratory in Silver Springs, Maryland. The name Nitinol came from Nickel (Ni), Titanium (Ti), Naval Ordinance Laboratory (nol). The first Nickel titanium (NiTi) orthodontic alloy, introduced by Andraeson. This alloy was based on the research done by Buehler. Since their introduction, the wires made out of Niti alloys have become an important part of orthodontic treatment. The composition of the wire has 55% Nickel and 45% Titanium. The first nickel-titanium orthodontic wire alloy was marketed by the Unitek Corporation who are now known as 3M Unitek. These alloys have low stiffness, superelasticity, high springback, large elastic range and were brittle. The initial niti wires did not have shape-memory effect due to the cold-working of the wire. Thus these wires were passive and were considered as an Martensitic-Stabilized alloy.

Pseudoelastic Niti archwires were commercially launched in 1986 and were known as Japanese NiTi and Chinese NiTi. Japanese Niti archwire was first produced by Furukawa Electric Co in 1978. It was first reported for usage of orthodontics by Miura et al. [10] The Japanese alloy was marketed as Sentalloy. Heat-activated NiTi alloys became popular and commercially available in the 1990s. [11] Chinese Niti wires were also developed in 1978 by Dr. Hua Cheng Tien at a research institute in Beijing, China. This wire was first reported in orthodontic literature by Dr. Charles Burstone. These alloys are Austentic-Active alloy and the transition from the Austenitic phase to Martensitic phase happens due to the contact of wire with a force.

Copper nickel-titanium alloy

In 1994 Ormco Corporation introduced this alloy. This alloy was developed with the help of Rohit Sachdeva and Suchio Miyasaki. Initially, it was available in three temperature transition forms: Superelastic (CuNiTi 27 °C), heat-activated (CuNiTi 35 °C) and (CuNiTi 40 °C). This alloy is composed of nickel, titanium, copper (5%) and chromium (0.2% - 0.5%). [12] Addition of copper leads to better defined transition temperatures in this alloy. [13]

Shape memory

Niti wires are known to have a unique property of shape memory. Niti wires can exist in two forms known as Austenitic and Martensitic. A temperature phase known as Temperature Transition Range (TTR) serves to define these earlier phase of the Niti wire. Below the TTR temperature, the crystals of Niti wires exist in the Martensitic form and above the TTR, crystals exist as the Austenitic form. The austenitic form happens at high temperatures, low stresses and martensitic phase occurs at low temperatures and high stresses. Austenitic form has body centered cubic (BCC) structure and Martensitic has distorted monoclinic, triclinic or Hexagonal structure. The wire is manufactured and fabricated at temperatures which exist above the TTR. As the wire is warmed above this temperature, it remembers its original shape and conforms to it. Therefore, this property of the wire is known as Shape-memory alloy. [14]

Graded thermodynamic archwires possess different TTR at different segments of the archwires (frontal, premolar and molar), which corresponds respectively to frontal, premolar and molar areas of dental arch. The frontal segments possess the highest transition temperature, followed by the premolar segments. The lowest transition temperatures were reported for the molar segments. [15]

Superelasticity

Niti wires are known to have another unique property known as Superelasticity. It is the "rubber-like" behavior present in the Niti shape memory alloy. Superelastic Niti wires have excellent springback compared to other niti wires. They can also deliver constant forces over large wire-deflection. [16]

Beta-titanium (TMA) archwire

Pure titanium can exist in two phases: Alpha and Beta. Alpha phase represents low temperature (below 885 °C) and beta phase represents high temperature (above 885 °C). Charles J. Burstone and Dr. Goldberg developed the β-Titanium when they combined Molybdenum with pure titanium. [17] They devised this alloy to allow these wires to produce lower biomechanical forces compared to the stainless steel and cobalt-chromium-nickel wires. They have better formability and springback than the stainless steel wires. Thus this alloy came to be known as Beta-Titanium alloy. It consists of Titanium (79%), Molybdenum (11%), Zirconium (6%) and Tin (4%). This alloy is known commercially by the name TMA or Titanium-Molybdenum alloy. [18] This alloy does not involve nickel and can be used in patients who have allergy to nickel. TMA wires have rough surfaces and produce most friction out of all the wires used in orthodontics which was found in a study done by Kusy et al. in 1989. [19]

Connecticut new archwire (CNA)

This type of archwire is a brand of beta titanium.

Orthodontic Stages

Leveling and Aligning

Wires used in this initial phase in an orthodontic treatment requires them to have low stiffness, high strength and long working range. The ideal wires to use in this phase of treatment is a Nickel-Titanium archwires. Low stiffness will allow small forces to be produced when the wire is engaged in the bracket slots of teeth. High strength would prevent any permanent deformation when the wire is engaged in teeth which are severely crowded. [20]

There is evidence showing that multi-stranded superelastic NiTi wires can produce greater tooth movement than single-strand superelastic NiTi when used as the first archwire in a fixed (“train track”) brace. [21] [ needs update ] The use of multi-strand stainless steel vs superelastic NiTi does not have a noticeable difference in the pain experienced by the wearer. Currently more research is required to determine archwire material superiority in terms of alignment rate, time to alignment, pain and root resorption. [21]

Terms used in defining wires

Related Research Articles

<span class="mw-page-title-main">Stainless steel</span> Steel alloy resistant to corrosion

Stainless steel, also known as inox, corrosion-resistant steel (CRES) and rustless steel, is an alloy of iron that is resistant to rusting and corrosion. It contains at least 10.5% chromium and usually nickel, as well as 0.2 to 2.11% carbon. Stainless steel's resistance to corrosion results from the chromium, which forms a passive film that can protect the material and self-heal in the presence of oxygen.

Surgical stainless steel is a grade of stainless steel used in biomedical applications. The most common "surgical steels" are austenitic SAE 316 stainless and martensitic SAE 440, SAE 420, and 17-4 stainless steels. There is no formal definition on what constitutes a "surgical stainless steel", so product manufacturers and distributors often apply the term to refer to any grade of corrosion resistant steel.

<span class="mw-page-title-main">Orthodontics</span> Correctional branch of dentistry

Orthodontics is a dentistry specialty that addresses the diagnosis, prevention, management, and correction of mal-positioned teeth and jaws, as well as misaligned bite patterns. It may also address the modification of facial growth, known as dentofacial orthopedics.

<span class="mw-page-title-main">Martensitic stainless steel</span> One of the 5 crystalline structures of stainless steel

Martensitic stainless steel is a type of stainless steel alloy that has a martensite crystal structure. It can be hardened and tempered through aging and heat treatment. The other main types of stainless steel are austenitic, ferritic, duplex, and precipitation hardened.

In metallurgy, a shape-memory alloy (SMA) is an alloy that can be deformed when cold but returns to its pre-deformed ("remembered") shape when heated. It is also known in other names such as memory metal, memory alloy, smart metal, smart alloy, and muscle wire. The "memorized geometry" can be modified by fixating the desired geometry and subjecting it to a thermal treatment, for example a wire can be taught to memorize the shape of a coil spring.

<span class="mw-page-title-main">Dental braces</span> Form of orthodontics

Dental braces are devices used in orthodontics that align and straighten teeth and help position them with regard to a person's bite, while also aiming to improve dental health. They are often used to correct underbites, as well as malocclusions, overbites, open bites, gaps, deep bites, cross bites, crooked teeth, and various other flaws of the teeth and jaw. Braces can be either cosmetic or structural. Dental braces are often used in conjunction with other orthodontic appliances to help widen the palate or jaws and to otherwise assist in shaping the teeth and jaws.

Titanium alloys are alloys that contain a mixture of titanium and other chemical elements. Such alloys have very high tensile strength and toughness. They are light in weight, have extraordinary corrosion resistance and the ability to withstand extreme temperatures. However, the high cost of both raw materials and processing limit their use to military applications, aircraft, spacecraft, bicycles, medical devices, jewelry, highly stressed components such as connecting rods on expensive sports cars and some premium sports equipment and consumer electronics.

<span class="mw-page-title-main">Superalloy</span> Alloy with higher durability than normal metals

A superalloy, or high-performance alloy, is an alloy with the ability to operate at a high fraction of its melting point. Key characteristics of a superalloy include mechanical strength, thermal creep deformation resistance, surface stability, and corrosion and oxidation resistance.

<span class="mw-page-title-main">Intergranular corrosion</span> When crystallite boundaries are more corrosive than their interiors

In materials science, intergranular corrosion (IGC), also known as intergranular attack (IGA), is a form of corrosion where the boundaries of crystallites of the material are more susceptible to corrosion than their insides.

<span class="mw-page-title-main">Austenitic stainless steel</span> One of the 5 crystalline structures of stainless steel

Austenitic stainless steel is one of the five classes of stainless steel by crystalline structure. Its primary crystalline structure is austenite and it prevents steels from being hardenable by heat treatment and makes them essentially non-magnetic. This structure is achieved by adding enough austenite-stabilizing elements such as nickel, manganese and nitrogen. The Incoloy family of alloys belong to the category of super austenitic stainless steels.

<span class="mw-page-title-main">SAE steel grades</span> Standard alloy numbering system for steel grades

The SAE steel grades system is a standard alloy numbering system for steel grades maintained by SAE International.

Alloy steel is steel that is alloyed with a variety of elements in total amounts between 1.0% and 50% by weight to improve its mechanical properties.

Pseudoelasticity, sometimes called superelasticity, is an elastic (reversible) response to an applied stress, caused by a phase transformation between the austenitic and martensitic phases of a crystal. It is exhibited in shape-memory alloys.

<span class="mw-page-title-main">Nickel titanium</span> Alloy known for shape-memory effect

Nickel titanium, also known as nitinol, is a metal alloy of nickel and titanium, where the two elements are present in roughly equal atomic percentages. Different alloys are named according to the weight percentage of nickel; e.g., nitinol 55 and nitinol 60.

The Damon system of orthodontics is one of many fixed, passive, self-ligating methods of correcting malocclusions. Passive self-ligating systems use brackets that do not require elastic o-rings to hold the wires in place. By not using the elastic o-rings, it is said that the wires freely slide through the slots without friction. However, this may not be correct as it allows more rotation or tipping of teeth before the bracket edges contact the wire, resulting in friction. It is believed that not using o-rings results in better oral hygiene but the research is equivocal, with findings both for and against the theory. To hold the wires in place, the Damon System uses small sliding doors. The addition of 'stops' on the wires helps prevent the wire from becoming displaced from its intended location.

The R-phase is a phase found in nitinol, a shape-memory alloy. It is a martensitic phase in nature, but is not the martensite that is responsible for the shape memory and superelastic effect.

NiTiNOL 60, or 60 NiTiNOL, is a Nickel Titanium alloy discovered in the late 1950s by the U. S. Naval Ordnance Laboratory. Depending upon the heat treat history, 60 NiTiNOL has the ability to exhibit either superelastic properties in the hardened state or shape memory characteristics in the softened state.

Charles J. Burstone was an American orthodontist who was notable for his contributions to biomechanics and force-systems in the field of orthodontics. He was well known for co-development of new orthodontic material such as beta titanium, nickel titanium, and long fiber-reinforced composite. He wrote more than 200 articles in scientific fields.

<span class="mw-page-title-main">Ferritic stainless steel</span> High chromium, low carbon stainless steel type

Ferritic stainless steel forms one of the five stainless steel families, the other four being austenitic, martensitic, duplex stainless steels, and precipitation hardened. For example, many of AISI 400-series of stainless steels are ferritic steels. By comparison with austenitic types, these are less hardenable by cold working, less weldable, and should not be used at cryogenic temperatures. Some types, like the 430, have excellent corrosion resistance and are very heat tolerant.

References

  1. ↑ "The Orthoevolution of Orthodontic Archwires - Orthodontic Products". Orthodontic Products. Retrieved 2016-10-30.
  2. ↑ Singh G (2015-02-20). Textbook of Orthodontics. JP Medical Ltd. ISBN   9789351524403.
  3. ↑ Tian KV, Passaretti F, Nespoli A, Placidi E, Condò R, Andreani C, et al. (August 2019). "Composition-Nanostructure Steered Performance Predictions in Steel Wires". Nanomaterials. 9 (8): 1119. doi: 10.3390/nano9081119 . PMC   6723625 . PMID   31382607.
  4. ↑ Tian KV, Festa G, Basoli F, Laganà G, Scherillo A, Andreani C, et al. (May 2017). "Orthodontic archwire composition and phase analyses by neutron spectroscopy". Dental Materials Journal. 36 (3): 282–288. doi: 10.4012/dmj.2016-206 . hdl: 2108/173807 . PMID   28228627.
  5. ↑ Tian KV, Festa G, Szentmiklósi L, Maróti B, Arcidiacono L, Lagana G, et al. (2017-06-23). "Compositional studies of functional orthodontic archwires using prompt-gamma activation analysis at a pulsed neutron source". Journal of Analytical Atomic Spectrometry. 32 (7): 1420–1427. doi:10.1039/C7JA00065K. ISSN   1364-5544.
  6. ↑ Nagalakshmi S, Sriram G, Balachandar K, Dhayanithi D (July 2014). "A comparative evaluation of mandibular incisor decrowding with coaxial and optiflex arch wires and their load-deflection rates". Journal of Pharmacy & Bioallied Sciences. 6 (Suppl 1): S118-21. doi: 10.4103/0975-7406.137412 . PMC   4157247 . PMID   25210351.
  7. ↑ Pelsue BM, Zinelis S, Bradley TG, Berzins DW, Eliades T, Eliades G (January 2009). "Structure, composition, and mechanical properties of Australian orthodontic wires". The Angle Orthodontist. 79 (1): 97–101. doi: 10.2319/022408-110.1 . PMID   19123699.
  8. ↑ Pelsue BM, Zinelis S, Bradley TG, Berzins DW, Eliades T, Eliades G (January 2009). "Structure, composition, and mechanical properties of Australian orthodontic wires". The Angle Orthodontist. 79 (1): 97–101. doi: 10.2319/022408-110.1 . PMID   19123699.
  9. ↑ Alobeid A, Hasan M, Al-Suleiman M, El-Bialy T (October 2014). "Mechanical properties of cobalt-chromium wires compared to stainless steel and β-titanium wires". Journal of Orthodontic Science. 3 (4): 137–41. doi: 10.4103/2278-0203.143237 . PMC   4238082 . PMID   25426458.
  10. ↑ Miura F, Mogi M, Ohura Y, Hamanaka H (July 1986). "The super-elastic property of the Japanese NiTi alloy wire for use in orthodontics". American Journal of Orthodontics and Dentofacial Orthopedics. 90 (1): 1–10. doi:10.1016/0889-5406(86)90021-1. PMID   3460342.
  11. ↑ Gravina MA, Brunharo IH, Canavarro C, Elias CN, Quintão CC (2013-08-01). "Mechanical properties of NiTi and CuNiTi shape-memory wires used in orthodontic treatment. Part 1: stress-strain tests". Dental Press Journal of Orthodontics. 18 (4): 35–42. doi: 10.1590/S2176-94512013000400007 . PMID   24262415.
  12. ↑ Sachdeva R (July 2002). "Sure-Smile: technology-driven solution for orthodontics". Texas Dental Journal. 119 (7): 608–15. PMID   12138533.
  13. ↑ Gravina MA, Brunharo IH, Canavarro C, Elias CN, Quintão CC (2013-08-01). "Mechanical properties of NiTi and CuNiTi shape-memory wires used in orthodontic treatment. Part 1: stress-strain tests". Dental Press Journal of Orthodontics. 18 (4): 35–42. doi: 10.1590/S2176-94512013000400007 . PMID   24262415.
  14. ↑ TechXpress.net. "Shape Memory Alloy - Nitinol Shape Memory". jmmedical.com. Retrieved 2017-02-25.
  15. ↑ Stoyanova-Ivanova, A.; Georgieva, M.; Petrov, V.; Martins,J.N.R.; Andreeva, L.; Petkov, A.;Petrova, N.; Georgiev, V. Thermal Behavior Changes of As-Received and Retrieved Bio-Active® (BA) and TriTanium® (TR) Multiforce Nickel–Titanium Orthodontic Archwires. Materials 2023, 16, 3776.https://doi.org/10.3390/ma16103776
  16. ↑ Ye J, Gao Y (January 2012). "Metallurgical characterization of M-Wire nickel-titanium shape memory alloy used for endodontic rotary instruments during low-cycle fatigue". Journal of Endodontics. 38 (1): 105–7. doi: 10.1016/j.joen.2011.09.028 . PMID   22152631.
  17. ↑ Burstone CJ, Goldberg AJ (February 1980). "Beta titanium: a new orthodontic alloy". American Journal of Orthodontics. 77 (2): 121–32. doi:10.1016/0002-9416(80)90001-9. PMID   6928342.
  18. ↑ Gurgel JA, Pinzan-Vercelino CR, Powers JM (May 2011). "Mechanical properties of beta-titanium wires". The Angle Orthodontist. 81 (3): 478–83. doi: 10.2319/070510-379.1 . PMC   8923551 . PMID   21299389.
  19. ↑ Kusy RP, Whitley JQ (July 1989). "Effects of sliding velocity on the coefficients of friction in a model orthodontic system". Dental Materials. 5 (4): 235–40. doi:10.1016/0109-5641(89)90067-5. PMID   2638266.
  20. ↑ Aghili H, Yasssaei S, Ahmadabadi MN, Joshan N (September 2015). "Load Deflection Characteristics of Nickel Titanium Initial Archwires". Journal of Dentistry. 12 (9): 695–704. PMC   4854749 . PMID   27148381.
  21. 1 2 Wang Y, Liu C, Jian F, McIntyre GT, Millett DT, Hickman J, Lai W (July 2018). "Initial arch wires used in orthodontic treatment with fixed appliances". The Cochrane Database of Systematic Reviews. 2018 (7): CD007859. doi:10.1002/14651858.cd007859.pub4. PMC   6513532 . PMID   30064155.
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