ch 6 dental materials
Card Set Information
ch 6 dental materials
ch 6 dental materials
what is the most common type of composite resin used in a private practice?
what are 2 advantages of of the dual cure (2-paste system) polymerization?
curing light initiates setting reaction
chemical setting rxn continues in areas where light cannot be reached
light cured composite resin is preferred because:
there is no mixing needed
cured when the operator is ready
is macrofilled composite used today? what um is it? is it easy or hard to polish? does it get rougher with age and function?
macrofilled is NOT used today
hard to polish
rougher with age and function
t/f microfilled composites make for large surface area (many small vs few large)
what is the filler volume of microfilled composites? are they weaker or stronger? more or less wear resistant
35-50% (others are 70-85)
less wear resistant
t/f large particle composites are replaced by hybrid composites for posterior restorations
hybrid composites consist of ____ and ____ fillers
micro and macro
hybrid composites are ____ and _____ well
strong and polish well
what is the filler content of hybrid composites?
75-85% by weight
what is the particle size of microhybrid? filler content?
what have a particle size of .005-.02 um, shrinkage reduced from 3% to 1%, strong, and high shine?
flowable composites have ___ viscosity
low (how low can ya flow)
particle size of flowable composite is ___-___um and has ___ adaptation to tooth walls
t/f flowable composites are not used in conservative dentistry
false! great in conservative dentistry
what is a preventative resin, used for sealants, class V non carious lesion, and as a liner?
what has higher shrinkage, more wear, and weaker than a hybrid?
t/f flowable composite is an excellent choice for areas of high occlusal function or high wear
false i say! not bloody likely!
can fillers be high to low in sealant material?
highly viscous resins contain high volume filler particles in _______ composites
what are stronger and more wear resistant than hybrids, and shrink less on polymerization (more filler/less resin)?
what is a smart composite?
good for poor oral hygiene patient
remineralizes the tooth
there is no clinical study to confirm effectiveness....just a nice idea
smart composites release: (3)
core-build up composites can be: (3) what type of cured?
light, self, or dual
what are the advantages of composite provisional restorations vs acrylic? (4)
less heat as cured
repaired easily with flowable composite
what are three disadvantages of a composite restoration vs an acrylic restoration?
break more easily in longer span bridges
chemicals released from new deep composite resins can enter dental tubules and into pulp.. what is this called?
which composite is able to be used for anterior and posterior restorations?
which is more wear resistant, a sealant or flowable composite? why?
it has more filler particle content
t/f the lower the elastic modulus, the more flexible the material. the higher the elastic modulus, the stiffer the material
which shrink more when polymerized? hybrid or flowable?
flowable about 5 to 7%
t/f chemicals released from new deep composite resins can enter dentinal tubules into the pulp and cause an inflammatory rxn
t/f when the tubules are sealed by a dentin bonding agent or protected with a base or liner, there is no chemical entering the dentinal tubules
can someone be allergic to a certain composite resin material?
yes, anything is possible, just put your mind to it and you can do it
larger filler particles = stronger, tension, compression. is this correct?
probably....the answer is yes and i am tired
are microfills weaker than macrofills?
does composite or amalgam wear faster?
what affects the wear rate of composite?
does more filler = better wear?
yes, more is better for shizzle
t/f microfills and flowables wear faster
with a chemical cure, where does it shrink?
toward the center of the bulk of the composite
does light cure shrink toward the center of the bulk of composite like chemical cure?
t/f light cured resin shrinks towards the light
false! towards the center of the bulk of the composite
t/f with smaller increments there is less polymerization shrinkage
post insertion sensitivity= ______ increments (leakage)
larger increments of composite placement results in what ?
tension on cusps
greater shrinkage (bigger is not always better)
thermal conductivity of composite should be close to _____ ______ _______
natural tooth structure
composite material should be _______ protective for the dental ______
the greater the filler content, the _____ the CTE or the greater the resin content, the _______ the CTE
(CTE=coefficient of thermal expansion)
what type of content is the greater filler content = lower cte?
what type of composite is the greater resin content= greater cte
_______ and _______ have higher CTE than hybrid or packable
flowable or microfilled
what is the young's modulus (elastic modulus) of composite? what is it determined by?
the stiffness which is determined by the amount of filler
the greater the volume of filler, the ______ the elastic modulus and more wear resistant the restoration
t/f the elastic modulus is an important consideration for selection of the type of composite
microfilled and flowable composites have fewer ________ and more ______
(better for non-stress bearing restorations)
for a CLV restoration, what type of material is needed. stiff or flexible?
FLEXIBLE for all the flexion (esp because abfraction occurs due to the forces of the tooth flexion)
t/f resin matrix absorbes water over time
if there is a greater resin content, then more OR less water will be absorbed?
t/f microfills and flowables absorbe more water