Resin Composites 1 Flashcards
what make up the resin matrix?
methacrylate or dimethacrylate monomers
what are examples of monomers
BISGMA
Urethane dimethacrylate
What are examples of co monomers?
TEGMA
What does TEGMA do?
controls viscosity
What else are present in resin composites?
inhibators
What do products based on silorane produce?
expansion that offsets shrinkage
what do c=c bonds take part in?
free radical polymerisation
What do unreacted monomers in resin composites allow for?
scope for chairside repair
What does the viscosity of the matrix polymer do?
reduces mobility of untreated monomers
What are two types of siloranes?
siloxanes
oxiranes
what do siloxanes contribute to resin composties?
factor of hydrophobicity
What do oxiranes contribute to resin composites?
ring opening polymerisation
catatonic cure?
camphorquinone iodium salt electron doner ring opening polymerisation allows for less shrinkage
what are fillers?
quartz
silica
glasses
What are glasses in resin composites?
aluminasilicates
bora silicate
barium oxide
what are coupling agents?
methacryloxypropyltrimethoxysilane
silane interacts and bonds with glass
What does high filler content mean?
higher surface hardness
what does high filler content mean re. volume setting contraction?
higher filler the lower % of volume setting contraction
The higher filler means what to thermal expansion?
higher filler, the less co efficient of thermal expansion
what does camphorquinone do re. polymerisation
yields necessary free radical to start polymerisation
at what level does camphorquinone become excited?
40-60 nm- visable blue light
What is blue light most readily generated by?
quartz halogen lights
What is the downside to resin in composite?
susceptible to shrinkage upon polymerisation
what are resins?
modified methacrylate/acrylate
oxirane- ring opening
what is the function of the filler>
shock absorber
What is the function of the coupling agent?
transfers stress from loading from rigid riller to more flexible and ductile matrix
What are the types of resin composites?
conventional- used for posterior/ occlusal restoration
micro filled- anterior
hybrid
nano composites
What other properties are there to resin composite?
gradual set from outer surface
required incremental cure
with increased porosity?
less strength
less fatigue
with decreased coupling?
less strength
less fatigue
What is cfactor?
measure of bond strength
number of bonded surface/number of unbonded surfaces
