Biomaterials Exam 2 Flashcards
Which sterilization technique would be least appropriate for a titanium implant that is coated with hydroxyapatite?
Steam
Which statement is least accurate?
a. All of the choices given are correct
b. Mercury is an important component of Amalgam.
c. Sintering of ceramics involves binder burnout
d. Carbon fibers are stronger than carbon in the bulk
e. Hydroxyapatite is compatible with bone
A. All of the choices are correct
An important characteristic of super elastic alloys such as NiTi is hysteresis in its bending moment vs bending angle deformation profile?
True
Which of the following is correct regarding piezoelectricity?
a. Can occur in metals
b. Requires a high degree of symmetry in the basic unit of its microstructure
c. Can be observed in glass at low temperatures
d. Is exhibited in polymers such as Teflon
e. None of the choices presented is correct
e. None of the choices presented is correct
Stainless steel is widely used for implant materials. Which of the following is most accurate about stainless steel?
a. Ultimate strength increases as % elongation increases
b. Ni stabilizes the martensitic phase
c. The austentitic phase has a BCT unit cell
d. 316 L is non-ferromagnetic
e. Molydenum improves crevice corrosion resistance
f. None of the choices presented are correct
d. 316 L is non-ferromagnetic
Thermal analysis of a bioglass yields a curve, whose specific volume v is Given by function v(T) . The Tg may be determined in the following manner…
a. Determine the integral of v(T) over the domain of T
b. None of the choices presented are correct
c. Determine where v”(T)=0
d. Determine where v’(T) =0
e. Tg cannot be determined mathematically
c. Determine where v”(T)=0
Oxygen diffusivity in hydrogels decreases with water content due to excessive bonding and crosslinking?
False
_____________ is a degradation process in polymers that results in at least two distinctly different byproducts.
Disproportionation
Implants that are made of polypropylene generally do not degrade after implantation.
True
Higher molecular weight linear polymers are more susceptible to environmental attack in-vivo.
False
Titanium alloys are widely used for implant materials. Which if the following is least accurate concerning titanium alloys?
a. Prone to oxidation at high temperature
b. Must be welded in an inert environment
c. Must be machined at slow speeds using sharp tools
d. None of the choices presented are correct
e. Vanadium lowers the transformation temperature
f. Aluminum stabilizes the alpha phase
d. None of the choices presented are correct
Which statement is least accurate?
a. Amalgam is comprised of mercury, silver, and tin
b. Hydroxyapatite is compatible with bone
c. Grain boundaries are susceptible to corrosion
d. Cobalt Chromium alloys exhibit good fatigue life
e. None of the choices presented are correct
f. Carbon fibers are stronger than carbon in bulk
e. None of the choices presented are correct
The basis for piezoelectricity in polymers is derived from?
a. Chain ends
b. Free volume in the amorphous phase
c. The existence of kinks in the chains
d. None of the choices presented
e. Three-fold symmetry of the monomers
d. None of the choices presented
Accelerated degradation in ceramic implant materials may be a result of the following conditions, except?
a. Applied stress
b. Cyclic loading
c. Elevated temperatures
d. Presence of silica
e. None of the choices presented
f. Presence of crosslinking agents
f. Presence of crosslinking agents
A dynamic mechanical experiment was performed and it corroborated an earlier DSC test comparing two samples of polyethylene, one branched and the other unbranched. The branched sample would be expected to show a lower glass transition than the unbranched counterpart.
True
Which statement is least accurate?
a. Carbon fibers are stronger than carbon in the bulk
b. Hydroxyapatite is compatible with bone
c. Surface roughness influences biocompatibility
d. Noble metals do not elicit an immune response
e. Nickel tantalum alloys exhibit shape memory
f. None of the above
e. Nickel tantalum alloys exhibit shape memory
As it relates to blood compatibility a rough surface is inherently thrombogenic?
True
Implants that are made with fabrics or are covered with fabrics are particularly prone to encapsulation?
False
Implanted titanium tends to exhibit minimal tissue reaction and is not prone to corrosion because it undergoes ___________ in-vivo.
passivation
The following are routinely added to zirconium oxide in order to improve mechanical and tribological properties, except?
a. Magnesium oxide
b. Aluminum oxide
c. Calcium oxide
d. Yttrium oxide
e. All of the choices presented are correct
b. Aluminum oxide
Which of the following biomedical implant materials will display the highest degree of viscoelastic behavior?
a. Pyrolytic carbon
b. 302 stainless steel
c. Zr-MgO-YO2
d. Hydroxyapatite
e. None of the choice presented
f. CoCrNiMo
e. None of the choice presented
Histological analysis of tissue surrounding a hip prosthesis showed no evidence of inflammation nor capsule formation after being implanted for six months. Which of the following is the most likely clinical explanation?
a. The wound is infected
b. The implant is porous
c. The implant had metal on metal interface
d. All of the choices presented
e. The patient may be experiencing a delayed implant rejection
b. The implant is porous
Implants that are made of longer nylons i.e., N11 versus shorter nylons , such as N5 are more prone to degradation in the body.
True
Which statement is least true about glass?
Their melt temp if a function of heating rate
Physically induced response to an implant may occur due to biodegradation?
False
The Pourbaix is used to determine the rate of corrosion of metallic implants in the body?
False
NiTi alloys exhibits the shape memory effect. This is evidence in the__________ behavior in plots depicting bending movement versus bending angle.
Hysteresis
The equilibrium distance between atoms in a metal also known as the d-spacing can be determined using:
Bragg’s Law
In addition of being used as contact lens material, polymer gels are also used in maxillofacial repair. Which stamen is least accurate about gels?
a. They are formed from monmers with functionality >2
b. Explained by Carothers’s theory
c. At the gel point the viscosity is finite
d. Early stage of gelation yields small crystals
e. All choices are correct
d. Early stage of gelation yields small crystals
Poly Acrylamide is a hydrogel that is used in contact lens applications. Which statement is most accurate about gels?
The O2 diffusivity increases with water content
