Be Chapter 5 Part 1

Front 1

What component of the body creates an environment that favors the corrosion of metallic implants?

Back 1

presence of aqueous media containing ions

Front 2

What local changes may occur around a device after implantation?

Back 2

Actions of inflammatory cells:
1) Excretion of strong oxidizing agents (peroxides)
2) Lowering of pH
all of which affect degradation time

Front 3

What material is subject to more degradation and why?

Back 3

metal because of the chemical composition of physiologic fluids

Front 4

what is degradation of metals referred to as?

Back 4

Corrosion

Front 5

How can corrosion of metals affect the body?

Back 5

Leaching of ions from the metallic surface occurs which may have deleterious short or long term biological consequences
they can also induce hypersensitivity or allergic reactions

Front 6

what is the voltage between the anode and the cathode dependent on?

Back 6

temperature and concentration of metals

Front 7

what does a more negative voltage difference indicate?

Back 7

more favorable disintegration from electrochemical standpoint

Front 8

The galvanic series was measured in what environment?

Back 8

sea water, to mimic the ions in the body

Front 9

What is galvanic corrosion?

Back 9

corrosion when two metals are present in a corrosive environment, the more active metal will dissolve at an accelerated pace

Front 10

What becomes the salt bridge for two metals in the body?

Back 10

physiological fluids

Front 11

What is one way to prevent corrosion

Back 11

Having oxidation and reduction rates equal, such as passivation

Front 12

What is a pourbaix diagram

Back 12

for given metals depicts regions of corrosion and noncorrosion as a function of pH and voltage which is formed by the nernst equation

Front 13

What occurs in between the dashed lines of the pourbaix diagram, and what happens outside of the pourbaix diagram?

Back 13

inside: aqueous corrosion/passivation
outside: water breaks down, not the metals