Metallic Implant Materials Flashcards
1
Q
Requirements
A
Excellent biocompatibility Corrosion resistance Adequate strength and ductility Adequate fatigue and wear resistance Appropriate modulus Formability
2
Q
Why use
A
High elastic moduli Reasonable yield points High ductility Plastic deformation Withstands cyclic loading Fabrication
3
Q
Physical and chemical properties
A
Luster Good conductors of heat and electricity High melting point Ductile Malleable Easily lose electrons Surface reactive Loss of mass Change in mechanical properties
4
Q
Cobalt-chromium (CoCr) alloys
A
30-60% cobalt 20-30% chromium Corrosion resistant Good biocompatibility Wear resistant Long service life Fracture and fatigue resistant
5
Q
Gold and platinum
A
Used in dental fillings
Electrodes for cochlear implants
6
Q
Silver tin copper alloys
A
Used in dental amalgams
7
Q
Stainless steel
A
Temporary implant devices
Corrosion resistant
Best:
302, 316, 316L, 316L VM
8
Q
Titanium alloys
A
Compared to cobalt chrome and stainless steel: Lower elastic mod Lower density Fatigue resistant Corrosion resistant Osseointegration tendencies Poor wear(low shear strength) Does not machine well
9
Q
Nickel titanium alloys
A
Shape memory effect(Ni-Ti)
Low elastic moduli
Resilient
10
Q
Tantalum
A
Very biocompatible
High density
80% porous
High coefficient of friction
11
Q
Trabecular metal
A
High strength to weight ratio
Compressive strength and elastic mod more similar to bone
Low stiffness facilitates physiologic load transfer
12
Q
Stress shielding
A
Lack of stress decreases bone mass
