Test 1 Flashcards
why is it easier to heal bone than cartilage
bone has a higher metabolism than cartilage (it has a higher turnover rate)
ceramics bond type?
ionic bonds
why are ceramics used for osseointegration
they have calcium phosphate in them which allows it to integrate into the bone
metal bond type?
metallic bonds
metallic bond characteristics?
highly mobile electrons
hydrogel characteristics
swell many times when put in water but won’t dissolve
why don’t hydrogels dissolve when put in water
crosslinked
physical hydrogels vs chemical hydrogels
physical –> held together with entanglements
chemical –> held together with covalent bonds
FDA doesn’t approve __
it doesn’t approve materials, it approves devices
synthetic vs. natural debate
- natural polymers have similar chemical properties to the tissues they are replacing
- natural are more easily integrated
- natural has lower mech. properties
- difficult to remove pathogens from chemical
- sythetic do not interact in an active manner
- synthetic can be specifically tailored
distance of surface properties
1nm
surface properties dictate __
biological response; where proteins will attach
anisotropy meaning
different mechanical properties in different directions
chemical vs. physical surface properties
chemical –> hydrophobicity
physical –> roughness
bonding in metal is __
nondirectional
coordination number
number of nearest neighboring atoms
FCC
APF = .74
4 atoms in each unit
BCC
APF = 0.68
2 atoms in each cell
HPC
APF .70
in Titanium, which is the more ductile crystal structure
BCC is more ductile than HCP
describe process for miller indicies
- determine where it crosses the xyz axis
- tape reciprocal of intercepts
- multiple by integers to clear fractions
- write integers in parentheses, no commas (h k l)
dimension of point defects
zero dimensional
examples of point defects
vacancies and interstitial
both vacancies and interstitial cause __
lattice strain