Metallic Biomaterials Study guide Flashcards
Two important aspects of identifying a biomaterial to be used in the human body are fuctional performance and ___-
biocompatibility
____ are used widely as biomaterials for thier strength and toughness
metals
give 3 example of metals used throughout the human body
stainless steel
titanium
colbalt alloys
what is the most common type of medical grade stainless steel? Name 3 elements in this type of sS
Stainless steel 316L Fe 60-65 wt% Cr 17-19 wt% Ni 12-14 wt% C max .03%
state three physical properties of metals that make them attractive for their use as a metallic biomaterial?
strength, toughness, malleable-easy to mold, ductile- can draw out into wires for braces etc.
What element increases the formation of carbon carbide (Crv23Cv6)?
Carbon
name the overall classification of materials that could potential be used as biomaterials
metals, ceramics, composites, polymers
Give three examples of materials that can be used as dental metals
amalgam-fill cavities
gold&gold alloy-fill cavities
nitinol-braces (the wire)
Which of these metallic biomaterials have the best corrosion resistance? Cobalt alloys, stainless steel, or pure titanium
titanium
why is pure gold not useable in dental applications? What is added to make it a better dental biomaterial
it is too soft. platinum is added
whi is it advisable to reduce carbon content in medical grade stainless steel?
additional carbon will increase carbon carbide formation… an increase of carbon carbide can impare the formation of surface oxide thus speeding up corrosion rates
what is the main advantage of using a titanium alloy in bone as opposed to any other metal?
it has excellent bone bonding
what is the purpose of adding tungsten or nickel to cobalt based alloys?
to improve machinablity and frabrication
state three reasons why amalgam is preferred as a dental biomaterial
moldable, strong, hardens in time, inexpensive, stable
list four metallic implants materials and explain the composition properties and potential applications for one of them.
stainless steel L316 - stents Fe 60-65 wt% Cr 17-19 wt% Ni 12-14 wt% C max .03% easy to manufacture, cheap, high strength and toughness
Titanium Alloy- bone screws
gold- used in teeth
co-Cr Alloy-bone, joint replacement, dental implants
define biocompatiblity
the ability of a material to perform with a appropriate hose response in a devise inteded to interact with biological systems
what is nitinol?
shape memory alloy. this allows has the ability to return to a predetermined shape when heated. it can be used as wire in braces or even medical staples
name 3 medical devices
cardiovascular stent
bone screw
femoral hip stem
state two ways in which atoms of metals mix to form alloys
sustitution
interstitial
describe shape memory alloys
ability to return to predetermined shape when heated. nitinol is this. used in staples and in wire of braces
what is the outer layer that protects a metal from corrosion?
surface oxide
although several types of stainless steel are available for implant use in practice the most common is __ stainless steel. This alloy is composed predominantly ___ which makes up approximately 60-65% plus additon of ___, makes up 17-20% of the alloy. additionally approximately 12-14% of the alloy is composed of _____. in order to reduce possiblity of vivo corrosion, only trace amounts less than .03% of ___ are found in the alloy
Fe 60-65 wt%
Cr 17-19 wt%
Ni 12-14 wt%
C max .03%
define unit cell as it related to metallic crystal structure
smallest repetitive volume which contains complete lattice patter of a crystal
state and describe three types of imperfections/defects in metallic crystal structure
point defect:
vacancy atoms-atom missing
intersitital atom-extra atoms between atomic sites
substitutional atoms-atom replaces another
line defects= dislocations move causing a slip between crystal planes…
