Types of Arch wires

Summarized by Dr. Hani Alhebshi , from a course given by (Dr. Nabeel Talic from King Saud University). 

Classification of wires can be according to :

Material :

Stainless steel , Elgiloy , Titanium alloys , glass or polymers.

Coating :

Coated or non Coated : Ion implementation , Spray Coating , Sleeving.

Morphology :

Round , Square , Rectangular , Single or multi-strand.

Metal Wires :

  • Stainless steel
  • Cobalt Chromium ( Blue Elgiloy ).
  • B-Titanium Molybdenum ( TMA)
  • Titanium Niobium ( TiNb)
  • Nickle-Titanium ( NiTi).

Esthetic Wires

  • Plastic Coated wires
  • Composite wires.

_______________________________

Stainless steel

  • SS – 18% Chromium ( prevents corrosion ) , 8 % Nickle ( stabilize the material ),
  • Cobalt Chromium ( Elgiloy , Ramaloy , Bioloy , Forestaloy )
    • 40% Cobalt , 20 % Chromium , 15% Nickle
    • High strength with high formability
  • B-Titanium Molybdenum ( TMA – Ormco )
    • 78% Titanium , 12% Molybdenum
    • Its stiffness is 40% of SS or Elgiloy.
    • It is truely weldable
    • No Nickle – so more biocompatable.
    • High corrosion resistance.
    • Highest friction than other wires. ( roughest )
  • Titanium Niobium ( TiNb)
    • 60% stiffness of TMA

NiTi Wires

have 2 important properties

  • Shape Memory – thermoelasticity
  • Superelasticity – high reversable strains

Different Generations of NiTi wires :

1st : Stabilized M-Niti
  • no phase transition
  • no formability and  brittle
  • eg. Nitionol ( Unitek ) Titanol
2nd : Psudoactive A-Niti 
  • phase transition by mechanical loading
  • e1g, Chinese Niti ( Ormco )
  • eg2. Nitionol SE (SE = Superelastic).
3rd : Active M-Niti Thermoelastic.
  • Heat activated phase transformation by mouth temperature.
  • eg1,Neosentaloy
  • eg2,  Cu- NiTi available in 3 temperatures :
    • 27 c – good in mouth breathers.
    • 35 c – good in normal body temperature.
    • 40 c – activated on eating hot food , used in patients with compromised periodontal support.
  • As Cu is increased in the material it reacts with more temprature.
4th : Bioforce
  • it has gradient of force levels
  • applies little force on anterior teeth
  • and higher forces on posterior teeth.
5th : Esthetic Wires :
  • Composite wires

NOTE ( from Proffit’s Contemporary Orthodontics Textbook) :

**TMA has twice range of SS

M-Niti has twice range of TMA

M-Niti has 4 times range of SS.

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