
define the load/elongation curve
L/E curve takes into consideration the geometry of the specimen aka extrinsic stiffness

define S/S curve
normalizes out geometry aka intrinsic stiffness

true/false: elastic modulus can be obtained from a L/E curve
false. it cannot be obtained from the L/E curve


define proportion limit
point at which any permanent deformation is first observed

define yield point
deformation of 0.1%, wire will not return to its original state

define ultimate tensile strength
maximum load, greater than yield strength

define failure point
point at which the wire breaks

define stiffness
proportional to elastic modulus. steeper slope = stiffer wire.

define springness
1/stiffness or 1/elastic modulus. more horizontal the slope = springier wire.

define range
distance wire will bend elastically before permanent deformation

define strength
stiffness x range

define resiliance
area under S/S curve from 0 to proportional limit/yield stength

define formability
amount of permanent bending the wire will tolerate before it breaks or fails. area under S/S curve from YP to FP

what happens to strength, stiffness, springiness and range if the diameter is increased?
 increase: strength, stiffness
 decrease: springiness, range

what happens to strength, stiffness, springiness and range if the length is increased?
 increase: springiness, range
 decrease: strength, stiffness

round or rectangular wires elicit more force?
rectangular (more stiffness)

list 4 ways loops are used in arch wires
 1. align teeth
 2. increase force of the wires
 3. increase flexibility of wires
 4. hold soft tissues away from orthodontic brackets

