Intro to Biomaterials Flashcards
3 main classes of materials
metals, ceramics, and polymers
____ and ____ are considered polymer-ceramic
composite resin; glass-ionomer
____ are considered metal-ceramic
metal-ceramic crowns
material used to construct artificial organs, rehabilitation devices, or prostheses and replace natural body tissues, without causing any harm or negative reactions
biomaterials
synthetic biomaterials
composites
silicone impression materials
natural biomaterials
alginates
hydrocolloids
tissue-engineered biomaterials
stem cells replacement tissues (growing a tooth from a bud)
metals are considered ___, ____, and ____
hard, ductile (tough), strong
ceramics are considered ___, ____ and ____
hard, brittle, strong
polymers are considered ____, ____, and ____
soft, ductile (tough), weak
____ and ____ have high processing temperatures
metals; ceramics
____ tend to have lower processing temperatures
polymers
polymers tend to be used as ____ processing materials
direct
metallic elements have ____ in their outer shell
1,2,3 electrons
____ are key to metallic bonds and are ____ bound to nucleus
electrons; loosely
electrons have free ____; ___ and ____ conductivity and ductility-bend without breaking
mobility; thermal and electrical
mixture of 2 or more metals
metal alloys
metal alloys include ___ and ____
cast metals for crowns; amalgams
pure metal is ____; atoms can slide
ductile
solid solution alloy is ____ but less _____
stronger; ductile
____ must be made to resist deformation; modified to impede dislocations
strengthening noble metals
noble metals include
Au, Ag, Pd, Pt
___ and ___ bonds are associated with ceramics
ionic; covalent
ionic and covalent bonds are ____ than metallic bonds
stronger
covalent bonds are ____ than ionic bonds
stronger
ionic bonds have an ____ and ____
electron donor; electron acceptor
covalent bonds have ____ shared electrons
equally
ceramics are a mixture of ___ and ____ elements
metallic; non-metallic
3 metallic oxides most common ceramics in dentistry
SiO2, Al2O3, K2O
____ is the building block
SiO4 tetrahedron
most dental ceramics are ____ or _____
semicrystalline; polycrystalline
SiO4 tetrahedron is the building block of ____
dental porcelain
porcelain is primarily a ____ with some ____ residuals
glass; crystalline
porcelain is processed by ____ or ____ at high temperatures
sintering; melting
characteristic polymer bonds are ____ bonds with high _____; long molecules composed principally of ____ elements
covalent; molecular weight; nonmetallic elements (C, O, N, and H)
polymers are ____ long chains like cooked spaghetti that derive strength and properties from the ____
entangled; entanglement
polymerization process
- light activation of initiator molecule (I) to generate a free radical (R)
- initiation of a monomer to generate a free radical
- propagation of free radical with four monomers
- termination of free radical
polymerization can be initiated by ____, ____, and ____
light; heat; chemical mixing
a _____ utilizes light to generate a free-radical
visible light initiator
free radicals will initiate _____
methacrylate polymerization
_____ (yellow) absorbs visible light and interacts with ____ to generate free radicals
CQ ; DMAEMA
four stages of chain reaction polymerization
activation- free radical initiation
initiation- free radical combination with monomer unit, double bond opening
propagation- chain growth, volume decrease, shrinkage
termination
monomer functional groups
monomethacrylates- linear chains
dimethacrylates- branched and cross-linked
polymerization allows for ____ processing for ____ placement
in vivo; direct
metals are indirect placement with high processing temps, except ____
amalgam
ceramics are indirect placement with high processing temps except _____
cements
polymers are direct placement with low processing temps except _____
indirect composites
uses of polymers in dentistry
provisionals (temporary crowns)
adhesives
restoratives
registration materials (impression materials)
provisionals are ____
linear
adhesives are ____
cross-linked
restoratives are ____
cross-linked
physical mixtures of metals, ceramics, and/or polymers
composites
By knowing the phases present in the structure of any material and interfacial interactions, it is possible to predict the overall properties fairly well
rule of mixtures
dental composite dispersed phase
glass fillers
dental composite matrix phase
monomer resin
fillers are chemically bonded to ____ phase to improve properties
resin
what happens when you increase filler volume
increase strength, increase modulus, increase viscosity, decrease shrinkage
what happens when you increase filler size
increase surface roughness
filler types
silicate glass (larger) colloidal silica (smaller)
filler amount
75-80 wt%
mass property measured in weight/unit volume
density
relative density or density of material/density of water
specific gravity
most things ____ when heated and ____ when cooled (thermal expansion)
expand; contract
thermal expansion measured in ____
LCTE (linear coefficient of thermal expansion)
thermal expansion trend
ceramics < metals < polymers
tooth < amalgam < composite
teeth are ____ due to high mineral content
insulators
metals have high ____ so they need a ____ like base
thermal conductivity; thermal insulator
composites have ____ thermal conductivity so they do not need an insulator base
low
metal restorations conduct ____ while composites and ceramics are electrical ____
electricity; insulators
optical properties include:
color, translucency, gloss, and surface texture
3 dimensions of color
hue, value, and chroma
2 objects that appear the same color under one light source and different under another light source; have different spectral characteristics
metamerism
color is defined in a _____
3D coordinate system
