composite and amalgam Flashcards
name 4 prop of composite
esthetically pleasing, strong, wear resistant, but have low to no fluoride release
what classes are composite recommended for
III to V
name the three phases of which composite is made of
resin matrix
dispersed inorganic filler particles
silane coupling agent
suggest a method to overcome or minimize the effect of polymerization shrinkage
insert and polymerize composite in layers
compressive and flexural strengths and elastic modulus or stiffness of microhybrid composites are dominated by what
the amount of filler and increases exponentially with the volume fraction of filler
name a downside to composite
loss of surface contour, which results from a combination of abrasive wear from chewing and toothbrushing and erosive wear from degredation of the composite in the oral environment
how to manipulate composite
with fourth abd 5th generation bonding agents:
1.enamel and dentin are etched with phosphoric acid
2.acid is flushed away with water
3.surface is dried gently with a steam of air
with 6th and 7th generation bonding agents:
etching and priming are accomplished at the same time and no rinsing is required
how are single paste composites activated
light activated thats why they come in an opaque plastic syringe to protect the material from exposure to light and thus provide adequate shelf life
name 4 direct esthetic restorative materials and name the date in which each one appeared
composite 1960
glass inomer 1972
Hybrid inomers 1990
compomer 1995
classify each material from the most releasing of fluoride to the least
- conventional glass inomer
- resin modified glass inomer
- compomer
- conposite
classify from most wear resistant to least
- composite
- compomer
- RMGi
- conventional glass inomer
what are Bis gma or UDMA (oligomers) characterized by
carbon double bonds
define an oligomer and give examples
it is a moderate molecular weight organic molecule made up of 2 or more molecules قليلة الحيدات
what is the principle system to achieve polymerization(setting) of composite
the visible light curing system
what is the exposure time to blue light
20 to 40 sec
what must be avoided when dealing with self-curing systems
the initiator and acceleratot must be kept separated and not mixed until just before the restoration is placed
describe the process of visible light curing systems
the composite is polymerized by exposure of it to intense blue light, the light absorbed by the diketone, which in tthe presence of an organic amine, starts the polmerization rxn.
what are the two types of composite
anatomical تشريحي
opaque كتيم
explain: the more the resin matrix, the higher the linear coeff of thermal expansion
because the polymers that are present i the resjn matrix have a hugher value than that of filler particles (molecules of filler particles are almost inert)
fill in the blank
most comosites are cosidered radiopaque when comapred with _____, and radiolucent when comapred with____
- dentin
2 .enamel
in class V caries do we use a composite with less or more filler particles
less, because we want it to be somewhat elastic
difference between coupling agents and bonding agents
coupling agents are used to bond resin matrix to inorganic filler particles while bonding agents are used to bond composite to prepared tooth
why is the sixth and seventh generation bonding agents very practical,require no rinsing and are called self-etching
because they are self etching, as in the acid the primer and the bonding agent all come in one bottle so etching and priming are essentially done simultaneously
not that the acid used for etching is not phosphoric acid but a weaker acid beacause no rinsage will be done
if a patient has sensitive teeth what bond generation is best to use and why
6th and 7th because the etchant is a weak acid which has a large molecular weight and thus a low likelihood of going into the dentinal tubules and to the pulp
