TERMS

Question 1

mechanical properties of the material that allow it to perform the fxn which it is intended

Answer 1

mechanical compatibility

Question 2

a biomaterial must not produced an adverse effect on the tissue into which it is implanted

recipient tissue must not have a detrimental effect on the performance of the biomaterial

Answer 2

biologic compatibility

Question 3

force/cross sectional area equals?

Answer 3

stress

Question 4

elongated length-original length/original length equals?

Answer 4

strain

Question 5

material property related to the slope of the stress strain curve of a specific material

indicative of the stiffness of the material

allows for comparison of mechanical properties between materials

not used to describe the stiffness or strength of a device

Answer 5

modulus of elasticity

Question 6

measure of degree of plastic deformation sustained at fracture

measured as % elongation or % area reduction

brittle materials - ceramics

ductile materials - metals, polymers

Answer 6

ductility

Question 7

time-dependent permanent deformation that occurs under stress

Answer 7

viscoelasticity

Question 8

delayed failure resulting from fluctuating stresses
-fatigue limit

crack initiation and propagation

Answer 8

fatigue

Question 9

measure of a materials resistance to localized plastic deformation
-indicative of materials resistance to wear

Answer 9

hardness

Question 10

similar in composition to mineral component of bone

excellent biocompatibility

wide variation in mechanical properties due to difference in manufacturing

used as porous or solid implants

biocoating

Answer 10

hydroxyapatite

Question 11

bioglass, ceravital

consists of P, Na, Si and Ca components

direct bone bonding by Ca-P layer

strict adherence to composition

fillers for bone cement

Answer 11

glass ceramics

Question 12

immune reaction that involves both humoral and cell mediated response (B/T cells)

Answer 12

metal insensitivity

Question 13

redness, edema, eczema

skin response can be local or remote

Answer 13

contact dermatitis

Question 14

results from sustained inflammatory reaction at the site of the implant

Answer 14

osteolysis

Question 15

bone mass is decreased over an extended period of time as a result of the presence of a rigid device

Answer 15

stress shielding

Question 16

name this type of corrosion

occurs when two dissimilar metals are placed in contact within a common electrolytic solution

material with the lower corrosion resistance will begin to corrode

i.e stainless steel screws and cobalt chromium plate

Answer 16

galvanic corrosion

Question 17

name this type of corrosion

localized corrosion that occurs in confined spaces

occurs over the entire specimen, both on the free surface and within the crevice

accumulation of chloride ions and a low pH result in accelerated attack within the crevice

Answer 17

crevice corrosion

Question 18

name this type of corrosion

occurs as a result of repeated relative micro motion between two surfaces

motion causes mechanical disruption of the protective oxide layer

repeated cycle of breakdown and reformation of the oxide layer resulting in corrosion of the exposed metal

Answer 18

fretting corrosion

Question 19

occurs when two materials that are articulating against one another bond together and then dislodge as the materials continue to slide past each other

debris from one material is transferred to the surface of the other

Answer 19

adhesive wear

Question 20

occurs when a hard material tears through a softer material

source of the hard material

• articulating surface
• wear particle lodged between two articulating surfaces

Answer 20

abrasive wear