Orthodontic archwire
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.
Composition of both platinum and palladium raised the melting point of the alloy and made it corrosion resistant.
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%).
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.
However, Angle's composition were extremely difficult to reproduce and therefore, the usage of Silver-based alloys did not get popular in orthodontics.
At that time, Emil Herbst was the main opponent of the Stainless steel based alloys.
This type of stainless steel archwire is made up multiple 0.008 in SS wires coiled together.
However, due to their lower elastic limit they can be readily deformed if acted upon by any other force such as food.
Begg was seeking a stainless steel wire that was light, flexible stayed active for long periods of time in the mouth.
It was the Elgin National Watch Company which introduced this alloy, composed of cobalt (40%), chromium (20%), iron (16%) and nickel (15%).
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.
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).
Since their introduction, the wires made out of Niti alloys have become an important part of orthodontic treatment.
These alloys have low stiffness, superelasticity, high springback, large elastic range and were brittle.
It was first reported for usage of orthodontics by Miura et al.[10] The Japanese alloy was marketed as Sentalloy.
[11] Chinese Niti wires were also developed in 1978 by Dr. Hua Cheng Tien at a research institute in Beijing, China.
Charles J. Burstone and Dr. Goldberg developed the β-Titanium when they combined Molybdenum with pure titanium.
Wires used in this initial phase in an orthodontic treatment requires them to have low stiffness, high strength and long working range.
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.
