Nanotechnology Flashcards
Nano = 10 ^ ____
-9
Human hair is ____ microns.
100
True or False: Nano is working on a scale less than 50nm
False, less than 500 nm
What are three applications of nanoscale in dental materials?
nanofillers
nanophase
nanoroughness
True or False: Microelectronics is a bottom-up approach.
False, Top-down (“Lab on a chip”)
Nanotechnology requires control of _______ through a biological approach.
specific interactions
Describe the steps of biological self-assembly.
- purified protein isolated from cells
- exposure of protein to a high concentration of urea
- protein becomes denatured
- remove urea
- reformation of the original conformation of the protein
Composition of enamel:
____% hydroxyapatite
matrix is _______
90% HA
amelogenin matrix
Composition of dentin:
____% hydroxyapatite
matrix is _____
67% HA
Collagen I matrix
True or False: Nanomaterials have different properties.
True (? seems obvi)
As the size scale decreases toward nano particles, there is a _____ proportion of particles on the surface.
higher
What are two examples of nanostructured carbon?
graphite
diamond
True or False: Nanostructured carbon has unusual properties.
True
Which properties are changed in nanostructured carbon?
electronic
physical
optical
biological
True or False: Nano composites have better wear properties.
True
True or False: Nano composites have better control of color and optics.
True
What is the most prominent example of nanotechnology in dentistry?
nanofillers
What are the different components of composite resins?
Resin: bis-GMA-TEGDMA
Photoinitiator
Filler: Silica
Coupling Agent
Which component of composite resin is the organic phase?
resin (bis-GMA)
Which component of composite resin is the inorganic phase?
filler (silica)
It is important to balance the handling characterists with ____, wear, and shrinkage.
strength
What are the advantages to nanofillers?
wear
color
polishability
What are the disadvantages of nanofillers?
resin viscosity increase
low levels of filler
True or False: Increased filler volume is the same as increased filler size.
False
Increased filler volume will increase ______ and ____.
strength and viscosity
Increased filler size will increase _____.
surface roughness
Increased filler size will decrease _____.
shrinkage
What are two types of fillers?
silicate glass
colloidal silica
Which filler is larger, silicate glass or colloidal silica?
silicate glass
collo-idal is lid-al
Filler amount for hybrid dental composite is _____ % weight.
75-80
Which type of filler leaves the roughest surface?
Macrofill
Which type of filler is conventionally used?
midifill
What are the two types of fatigue that are evaluated for composites?
surface contact
flexural
True or False: Increased particle size results in increased size of wear facets.
True
Rank the visual opacity of the nanocomposites: Microfill vs FST vs Hybrid.
Most Translucent: . . FST (Filtek Supreme Translucent) Microfill Hybrid . . Most Opaque
What is the problem with nanofillers in Glass Ionomer cements?
increased surface area leads to rapid setting and higher viscosity
What type of resin and glass is in Ketac Nano?
methacrylate resin
AlFSiO glass
(ketAC….methaAC….Nano…small like an Elf…AlF-SiO)
True or False: Ketac Nano has an independent acid-base setting reaction which makes it a GI cement.
False! does not have an acid base setting reatction and is not really a GI cement
What makes RMGI different from compomers/composites?
GI = acid-base reaction which is independent of light cure Composites = require visible light to cure
True or False: The fear of nanotoxicity from dental materials is justified.
False, no clinical data or studies
True or False: Nanoparticles are known to be hazardous to the cardiovascular system.
True
True or False: studies confirmed that there is no conclusive human risk from nanoparticles in dental composites.
True
What are functional nanofillers?
adding nanoparticles that will release ions such as calcium, phosphate, and fluoride to aid in remineralization or silver for antibacterial properties
What are whisker composites?
whiskers are SiN fibers that are created through fusion of silica particles and used in visible light cured systems
True or False: Whiskers have high strength compared to silica.
True
True or False: Whiskers have better crack stopping properties
True, aspect ratio makes it difficult for cracks to propagate
Functional whiskers contain added ____- nanoparticles that will dissolve quickly and leave voids.
Calcium Phosphate (CaPO4)
What is POSS?
Polyhedral Silsesquixanes
- Smallest silica particle
- unimolecular
- highly functional
- commercially available
POSS provided _____ at low loading levels.
reinforcement
POSS showed evidence of ____ at higher loading levels.
aggregation
What is a dendrimer?
unimolecular, low viscosity material that has been considered in replacing the monomer component
