Lab 4 + 5

Question 1

An ______ is a metal wire which is attached to the

orthodontic brackets to move the teeth.

Answer 1

Arch Wire

Question 2

What are the 3 materials are used in arch wires?

Answer 2

•Stainless Steel. (SS)
•Beta –Titanium. (TMA)
•Nickel –Titanium. (Ni-Ti)
➢Decreasing rigidity.

Question 3

Orthodontists choose an Arch Wire based on the patient’s

____ and ______

Answer 3

specific treatment and the desired outcome.

Question 4

The point at which any permanent deformation is first observed.

Answer 4

Elastic limit

Question 5

The most conservative measure is the ________, the highest point
where stress and strain still have a linear relationship.
• This linear relationship is known as Hooke’s law.
- point at which deformation occurs above it

Answer 5

proportional limit

Question 6

The slope of the stress–strain curve (E) is __________ , to which
stiffness and springiness are proportional.

Answer 6

the modulus of elasticity

Question 7

The ____ is the distance along the X-axis to the point at which permanent
deformation occurs.
• Usually taken as the yield point, at which 0.1% permanent deformation has occurred.

Answer 7

Range

Question 8

Clinically _______ occurs if the wire is deflected beyond the Yield Point.
• As to the point indicated here as “Arbitrary clinical loading”, but it no longer returns to its
original shape.

Answer 8

Spring-back