Lec 2.3: Types of Wires Flashcards
1
Q
- It was intensively used before 1940.
- Exhibit excellent formability, environmental stability and biocompatibility.
- The main drawbacks of these arch wires include high-cost, low-spring back and low-yield.
A
Gold
2
Q
- Exhibits adequate strength, high resilience, formability, high stiffness, biocompatibility and are economical
- The drawback of these arch wires includes high modulus of elasticity; more frequent activations are required to maintain the same force level.
A
Stainless steel
3
Q
Stainless steel wire was discovered by?
A
Wilkinson, 1929
4
Q
Basic components of S.S. Wire?
A
18% Cr
8% Ni
0.2% C
71% Fe
5
Q
Hardens steel
A
Cold working
6
Q
Softens steel
A
Annealing
7
Q
Makes steel dead soft
A
Fully annealed
8
Q
- Similar to SS
- Secret formula of Wilcock
- Key wire to Begg Technique
- Excellent working wire
- 20% stiffer than SS (more stiff – more brittle)
A
Australian wire
9
Q
Nickel titanium wires are also known as?
A
NITINOL
10
Q
Nickel titanium wires were invented by?
A
William R Buchler at Naval Ordinance Laboratory
11
Q
- The main advantage of this alloy over others is the high elasticity and shape-back memory.
- The drawback of these arch wires is that they cannot be welded or soldered and cannot receive bends or loops or helices.
A
Nickel titanium wires
12
Q
- Andreasen 1978: NITINOl (Nickel Titanium Naval Ordinance Lab)
- Poor formability – can’t be bent into loops / stops
A
First generation Ni-Ti
13
Q
- Shape memory (wire remembers its original shape)
- Super elasticity (force stays fairly constant during wire deformation)
A
Second generation Ni-Ti
14
Q
Low temperature
Less energy stable
Can change shape
A
Martensitic phase
15
Q
High temperature
More energy stable
Difficult to change shape
A
Austenitic phase